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Background: The lateral antebrachial cutaneous nerve (LACN) is the terminal sensory branch of the musculocutaneous nerve and is rarely entrapped or injured. This study describes the electrodiagnostic (EDX) findings and etiologies of LACN neuropathy. Methods: This is a review of 49 patients with pain and/or paresthesia of the forearm who underwent EDX studies. The diagnosis of LACN neuropathy was based on clinical and sensory conduction abnormalities. Results: The most common etiology of LACN neuropathy was iatrogenic injury in 30 (61.2%) patients, primarily due to biceps tendon repair at the elbow (11 [36.7%]) and phlebotomy (5 [16.7%]). Fifteen (30.6%) patients sustained a non-iatrogenic injury at the proximal forearm/elbow, consisting of six (60%) laceration injuries and five (33.3%) stretch injuries. Four (8.2%) patients comprised the "other" etiology category, including two mass lesions causing LACN compression. Pain, paresthesia, and/or numbness in the LACN distribution were reported in 33 (67.3%), 27 (55.1%), and 23 (46.9%) patients, respectively. Hypoesthesia was detected in 45 (91.8%) patients, and dysesthesia in 7 (14.3%). The sensory nerve action potentials (SNAPs) of the LACN on the symptomatic side were absent in 44 (89.8%) patients. Of the five patients whose SNAPs of the LACN were detected, all had a decreased amplitude, and two had increased sensory latency. Conclusions: The most common etiology for LACN neuropathy in this series was iatrogenic injury; repair of biceps tendon at the elbow was the most frequent provoking cause. Protection of the LACN during surgical procedures at the elbow and forearm is vital to prevent iatrogenic injury. [ABSTRACT FROM AUTHOR]

BACKGROUND: According to the literature, the brachial plexus presents a high rate of anatomical variations in the human neural system. The musculocutaneous nerve, a vital component of the brachial plexus, exhibits significant anatomical variations that hold clinical relevance across multiple medical disciplines. This case report, with a comprehensive review, explores the different variations in the course, branching patterns, and clinical implications of the musculocutaneous nerve. Understanding these variations is essential for surgeons, radiologists, and clinicians to enhance surgical precision, improve diagnostic accuracy, and reduce the risk of iatrogenic complications. CASE REPORT: During an anatomical dissection we observed a very rare anatomical variation of the musculocutaneous nerve. Based on this discovery, we performed research in the literature with the aim of finding if this variation has been previously described. Firstly, we identified various classifications of anatomical variations of communicating branches between the musculocutaneous and median nerves, and then we observed that these variations corresponded to various rates of frequency. Our finding is a rare undescribed anatomical variant within the variants classified as Type II according to Le Minor, which is observed in 6.8-10.7% of cases. CONCLUSIONS: The peculiar position of anatomical variations and anastomosis has clinical and functional relevance. Healthcare professionals must be aware of these variations to minimize surgical complications, accurately diagnose neurovascular pathologies, and optimize patient management. Further research into the genetic and embryological underpinnings of these variations may provide additional insights into this intriguing aspect of human anatomy. [ABSTRACT FROM AUTHOR]

During routine dissection of the anterior compartment of the arm region, we encountered several variations in the muscular and neural structures in the right upper extremity of a female cadaver. We observed one superiorly positioned extramuscular head with fibers originating from both the biceps brachii (BB) and coracobrachialis (CB) muscles and one inferiorly positioned extramuscular head with fibers solely from the BB muscle. The musculocutaneous nerve did not penetrate the CB muscle, but instead provided a muscular branch that communicated with the median nerve (MN). Both the MN and brachial artery (BA) flow beneath the extra head. This case suggests that the described variations may contribute to the entrapment of the MN and compression of the BA. Understanding these variations is crucial before surgical intervention. The failure to recognize such anatomical nuances could lead to inadvertent nerve injury or compromised vascular perfusion, emphasizing the need for preoperative planning and intraoperative vigilance. [ABSTRACT FROM AUTHOR]

Background: Musculocutaneous nerve (MCN) is a mixed nerve arising from the lateral cord of brachial plexus having root values C5, 6, and 7. It supplies the muscles of the flexor compartment of the arm namely; coracobrachialis, most part of brachialis and both heads of biceps brachii. It is cutaneous to the lower lateral part of forearm. Variations in the origin, course, branching pattern, termination, and connections of MCN are very common. Knowledge about these variations is important while evaluating unusual presentations of peripheral nerve injuries, during surgical procedures such as arthroscopy of shoulder joint, corrections of fracture humerus, brachial plexus block, and so on. Aims and Objectives: The study was conducted to find out any variations in the origin, course, branching pattern of the MCN. The secondary objective was to understand about the communication of the MCN with any other nerve. Materials and Methods: A descriptive study was conducted in 60 upper limb specimens dissected from 10% formalin embalmed 30 cadavers (adult) in the Department of Anatomy, Government Medical College, Kottayam. All limbs were carefully dissected and studied about the origin, course, termination, and variations of MCN. Results: Out of 60 specimens studied, in 46 specimens MCN Originate from lateral cord, eight from medial cord, and in six from the lateral root of the median nerve (MN). In 52 specimens, MCN supplies coracobrachialis but only in 34 it pierces this muscle. In four specimens, there is a communication between MCN and MN was seen. Conclusion: The MCN has significant variations and knowledge of these variations is clinically important in diagnosis and management of peripheral nerve injuries as well as surgical interventions in the arm. [ABSTRACT FROM AUTHOR]

Background: The lateral antebrachial cutaneous nerve (LACN) is the terminal sensory branch of the musculocutaneous nerve and is rarely entrapped or injured. This study describes the electrodiagnostic (EDX) findings and etiologies of LACN neuropathy. Methods: This is a review of 49 patients with pain and/or paresthesia of the forearm who underwent EDX studies. The diagnosis of LACN neuropathy was based on clinical and sensory conduction abnormalities. Results: The most common etiology of LACN neuropathy was iatrogenic injury in 30 (61.2%) patients, primarily due to biceps tendon repair at the elbow (11 [36.7%]) and phlebotomy (5 [16.7%]). Fifteen (30.6%) patients sustained a non-iatrogenic injury at the proximal forearm/elbow, consisting of six (60%) laceration injuries and five (33.3%) stretch injuries. Four (8.2%) patients comprised the “other” etiology category, including two mass lesions causing LACN compression. Pain, paresthesia, and/or numbness in the LACN distribution were reported in 33 (67.3%), 27 (55.1%), and 23 (46.9%) patients, respectively. Hypoesthesia was detected in 45 (91.8%) patients, and dysesthesia in 7 (14.3%). The sensory nerve action potentials (SNAPs) of the LACN on the symptomatic side were absent in 44 (89.8%) patients. Of the five patients whose SNAPs of the LACN were detected, all had a decreased amplitude, and two had increased sensory latency. Conclusions: The most common etiology for LACN neuropathy in this series was iatrogenic injury; repair of biceps tendon at the elbow was the most frequent provoking cause. Protection of the LACN during surgical procedures at the elbow and forearm is vital to prevent iatrogenic injury.

Background: Musculocutaneous nerve (MCN) is a mixed nerve arising from the lateral cord of brachial plexus having root values C5, 6, and 7. It supplies the muscles of the flexor compartment of the arm namely; coracobrachialis, most part of brachialis and both heads of biceps brachii. It is cutaneous to the lower lateral part of forearm. Variations in the origin, course, branching pattern, termination, and connections of MCN are very common. Knowledge about these variations is important while evaluating unusual presentations of peripheral nerve injuries, during surgical procedures such as arthroscopy of shoulder joint, corrections of fracture humerus, brachial plexus block, and so on. Aims and Objectives: The study was conducted to find out any variations in the origin, course, branching pattern of the MCN. The secondary objective was to understand about the communication of the MCN with any other nerve. Materials and Methods: A descriptive study was conducted in 60 upper limb specimens dissected from 10% formalin embalmed 30 cadavers (adult) in the Department of Anatomy, Government Medical College, Kottayam. All limbs were carefully dissected and studied about the origin, course, termination, and variations of MCN. Results: Out of 60 specimens studied, in 46 specimens MCN Originate from lateral cord, eight from medial cord, and in six from the lateral root of the median nerve (MN). In 52 specimens, MCN supplies coracobrachialis but only in 34 it pierces this muscle. In four specimens, there is a communication between MCN and MN was seen. Conclusion: The MCN has significant variations and knowledge of these variations is clinically important in diagnosis and management of peripheral nerve injuries as well as surgical interventions in the arm.

Background: Anatomical variations in the musculocutaneous and median nerve present unique challenges for surgeons performing distal nerve transfers in cases of brachial plexus injuries, with reported rates as high as 11%. Understanding these variations is crucial, particularly when selecting the donor nerve for biceps reconstruction, a decision made even more complex in cases of upper brachial plexus injuries. We aimed to investigate the optimal donor nerve for biceps nerve transfer in patients with upper brachial plexus injuries (C5, C6, and C7) who have anatomical variations between the median and musculocutaneous nerves. Methods: A retrospective analysis was performed on 15 patients with anatomical variations between the median and musculocutaneous nerves who underwent biceps nerve transfer at a single hand surgery center. The median nerve, the junction between the median and musculocutaneous nerves, or the ulnar nerve was used as the donor nerve. Patient demographics, anatomical variations, nerve transfers, and functional outcomes were evaluated. Results: The mean patient age was 26 years (range, 19–35 years). The most frequent anatomical variation was a communication between the median and musculocutaneous nerves. The donor nerves were the median nerve (n = 10), the junction between the median and musculocutaneous nerves (n = 4), and the ulnar nerve (n = 1). All patients achieved good elbow flexion (M4/5), and no donor nerve deficits were observed. Conclusions: This study suggests that the median nerve or the junction between the median and musculocutaneous nerves are viable donor options for biceps nerve transfer in patients with upper brachial plexus injuries and anatomical variations between the median and musculocutaneous nerves. These findings can help in surgical decision-making in such anatomical variations. Level of Evidence: Level IV, Therapeutic. [ABSTRACT FROM AUTHOR]

Objective: Evaluate safety and effectiveness of thermal radiofrequency in the musculocutaneous nerve in patients with focal elbow flexor spasticity. Design: Ambispective observational follow-up study. Patients with focal spasticity secondary to central nervous system injury with elbow flexor pattern who received thermal radiofrequency treatment in the musculocutaneous nerve between 2021 and 2023 were included. Subjects: 12 patients. Methods: Ultrasound-guided thermal radiofrequency was applied to the musculocutaneous nerve at 80°C for 90 s. Effectiveness was assessed prior to thermal radiofrequency and at 6 months using scales to measure pain (VAS), spasticity (MAS), disability (DAS), quality of life (SQol-6D), patient-perceived and physician-perceived satisfaction (PIG-C, PGA), and goal attainment (GAS). Elbow joint range of motion was evaluated via goniometry. Safety was evaluated by assessing side effects. Results: Patients had statistically significant improvements in spasticity (p = 0.003), severe elbow flexion (p = 0.02), pain (p = 0.046), functioning (p < 0.05), and spasticity-related quality of life (p < 0.05 in three sections). Furthermore, treatment goals were attained. Patient- and physician-perceived clinical improvement was achieved. Regarding side effects, two patients had dysesthesia that was self-limiting, with maximum duration of 1 month. Conclusion: Thermal radiofrequency in the musculocutaneous nerve can be a safe, effective treatment for patients with severe spasticity with an elbow flexor pattern. [ABSTRACT FROM AUTHOR]

The anatomical variations of coracobrachialis muscle (CBM) are of great clinical importance. This study aimed to elucidate the morphological variations, innervation patterns and musculocutaneous nerve (MCN) relation to CBM. Upper limbs of fifty cadavers (30 males and 20 females) were examined for proximal and distal attachments, innervation pattern of CBM and its relation to MCN. Four morphological types of CBM were identified according to number of its heads. The commonest type was the two-headed (63.0%) followed by the single belly (22.0%), three-headed (12.0%) and lastly fourheaded (3.0%) type. Moreover, an abnormal insertion of CBM was observed in four left limbs (4.0%); one inserting into the medial humeral epicondyle, the second into the upper third of humeral shaft, the third one in the common tendon of biceps, and the fourth one showing a bifurcated insertion. Also, four different innervation patterns of CBM were identified including MCN (80.0%), lateral cord (14.0%), lateral root of median nerve (4.0%), and median nerve itself (2.0%). The course of MCN was superficial to the single belly CBM (19.0%) and in-between the heads in the other types (71.0%). Measurements of the length and original distance of CBM muscular branches originating from MCN revealed no sex or side significant difference. Awareness of the anatomic variations, innervation patterns, and MCN relation of CBM is imperative in recent diagnostic and surgical procedures to obtain definite diagnosis, effective management and good outcome. [ABSTRACT FROM AUTHOR]

This pooled analysis evaluates the association between the number of nerves transferred and postoperative outcomes after intercostal nerve (ICN) nerve transfer for elbow flexion. A systematic and pooled analysis of studies reporting individual patient demographics and outcomes after ICN-musculocutaneous nerve (MCN) transfer for traumatic brachial plexus injury was conducted. The primary outcome was the ability to attain an elbow flexion Medical Research Council (MRC) score of ≥4 at the final postoperative follow-up visit. Ten studies were included for a total of 128 patients. There were 43 patients who underwent two ICNT, 77 patients who underwent three ICNT, and 8 patients who underwent four ICNT. The three groups did not differ in ability to achieve MRC ≥ 4 (2ICNT 48.8%, 3ICNT 42.9%, 4ICNT 50.0%, p = 0.789). The number of ICNs transferred was not associated with MRC scores ≥4 on the multivariable analysis (OR: 0.55, p = 0.126). These results indicate that two ICN transfers may be as effective as three ICN and four ICN transfers and highlight the potential for nonsurgical factors to influence postoperative outcomes. Taken together, this pooled analysis leads us to question the utility of transferring >2 ICNs for MCN neurotization. [ABSTRACT FROM AUTHOR]

Purpose: Anterior compartment muscles of the arm present high morphological variability, with possible clinical significance. The current cadaveric report aims to describe a bilateral four-headed brachialis muscle (BM) with aberrant innervation. Emphasis on the embryological background and possible clinical significance are also provided. Methods: Classical upper limb dissection was performed on an 84-year-old donated male cadaver. The cadaver was donated to the Anatomy Department of the National and Kapodistrian University of Athens. Results: On the left upper limb, the four-headed BM was supplied by the musculocutaneous and the median nerves after their interconnection. On the right upper limb, the four-headed BM received its innervation from the median nerve due to the musculocutaneous nerve absence. A bilateral muscular tunnel for the radial nerve passage was identified, between the BM accessory heads and the brachioradialis muscle. Conclusion: BM has clinical significance, due to its proximity to important neurovascular structures and frequent surgeries at the humerus. Hence, knowledge of these variants should keep orthopedic surgeons alert when intervening in this area. Further dissection studies with a standardized protocol are needed to elucidate the prevalence of BM aberrations and concomitant variants. [ABSTRACT FROM AUTHOR]

ObjectiveEvaluate safety and effectiveness of thermal radiofrequency in the musculocutaneous nerve in patients with focal elbow flexor spasticity.DesignAmbispective observational follow-up study. Patients with focal spasticity secondary to central nervous system injury with elbow flexor pattern who received thermal radiofrequency treatment in the musculocutaneous nerve between 2021 and 2023 were included.Subjects12 patients.MethodsUltrasound-guided thermal radiofrequency was applied to the musculocutaneous nerve at 80°C for 90 s. Effectiveness was assessed prior to thermal radiofrequency and at 6 months using scales to measure pain (VAS), spasticity (MAS), disability (DAS), quality of life (SQol-6D), patient-perceived and physician-perceived satisfaction (PIG-C, PGA), and goal attainment (GAS). Elbow joint range of motion was evaluated via goniometry. Safety was evaluated by assessing side effects.ResultsPatients had statistically significant improvements in spasticity (p = 0.003), severe elbow flexion (p = 0.02), pain (p = 0.046), functioning (p

Purpose : This study aims to determine the utility of selective partial neurectomy of the musculocutaneous nerve (MCN) in pediatric patients with bilateral spastic elbow. Methods: A prospective, cross-sectional, case series study was performed in nine pediatric patients (four females and five males) with bilateral spastic elbow, all with a 11.4-year-old average age, where 18 selective partial neurectomies of the MCN were carried out. They were evaluated with goniometry of both spastic elbows at resting position and active amplitude, and staging spasticity employing the Modified Ashworth Scale (MAS) in the preoperative and postoperative period. The results are reported 1 year after surgery. Results: The etiology of the spasticity was secondary to cerebral palsy in eight patients (88.8%) and in one patient (11.11%) secondary to traumatic brain injury. A clinical improvement was observed in goniometry comparing the preoperative and postoperative resting position, a mean preoperative of 44.38 degrees (SD ± 7.61) versus 98.05 degrees (SD ± 24.44), respectively, and preoperative active amplitude a mean of 86.55 degrees (SD ± 15.97) versus the mean postoperative of 47.33 (SD ± 17.86). A relevant decrease on the MAS after surgical intervention was observed, resulting from an average preoperative state according to MAS of 3.78 (SD ± 0.42) to a postoperative state according to MAS of 1.44 (SD ± 0.51), these changes being statistically significant (p ≤ 0.001). No postoperative complications were observed. Conclusions: Selective partial neurectomy of the MCN has shown good results in patients with bilateral spastic elbow in whom antispastic drugs and physical therapy have failed, and has prove permanent effects. [ABSTRACT FROM AUTHOR]

The musculocutaneous nerve is important in the upper extremity because it provides motor innervation to the musculature of the anterior arm region and sensory innervation to the skin on the lateral side of the forearm region. During the dissection of approximately 74 aged male cadaver for the 2021-2022 academic year at the Department of Anatomy, Faculty of Medicine, International University of Africa, Sudan. Considerable variation was present; the musculocutaneous nerve was observed to be absent in both upper extremities. The median nerve replaces the musculocutaneous nerve innervation’s role on both sides except for the coracobrachialis muscle on the right side. A direct branch from the lateral cord innervated it. Reporting these variations has a critical impact on many surgical and clinical procedures.

Knowing the motor branches and variations of the musculocutaneous nerve to the muscles along its course will facilitate the treatment of flexor spasticity and supracondylar fractures of the humerus in order to minimize nerve lesion. In fetal cadavers, the purpose of our study was to determine the number and course of the formation variations and motor branches of the musculocutaneous nerve. The significance of studying fetal nerve variations is due to injury to the brachial plexus roots during birth. Our study was conducted using the anatomical dissection technique on 102 upper limbs from 51 fetuses ages ranged from 17 to 40 weeks. Throughout its course, the variations and motor branches of the musculocutaneous nerve were analyzed. In 13.7% of cases, the musculocutaneous nerve did not pierce the coracobrachialis. The musculocutaneous nerve gave the muscles 1–3 motor branches. Additionally, motor branches terminated with 1–7 fringes. The biceps brachii motor branches of the musculocutaneous nerve were typed. Accordingly, 15.6% were type 1A, 3.9% were type 1B, 35.4% were type 1C, and 19.6% were type 1D. It was determined that 23.5% of the extremities were type 2 and that 1.9% were type 3. The distance between the musculocutaneous nerve's motor branches and the acromion was proportional to the arm's length. There were no statistically significant differences between the sides and genders for any measurement. Our study's findings will aid in the diagnosis and treatment of pediatrics, orthopedics, surgical sciences, and radiology conditions. It reduces the risk of iatrogenic injury and postoperative complications. We also believe that our research will serve as a resource for anatomists and other scientists. [ABSTRACT FROM AUTHOR]

Background: To restore elbow flexor muscle function in case of traumatic brachial plexus avulsion, the phrenic nerve transfer to the musculocutaneous nerve has become part of clinical practice. The nerve transfer can be done by means of video-assisted thoracic surgery without nerve graft or via supraclavicular approach in combination with an autograft. This study focuses on a detailed microscopic and macroscopic examination of the phrenic nerve. It will allow a better interpretation of existing clinical results and, thus, serve as a basis for future clinical studies. Material and Methods: An anatomical study was conducted on 28 body donors of Caucasian origin (female n = 14, male n = 14). A sliding caliper and measuring tape were used to measure the diameter and length of the nerves. Sudan black staining was performed on 15 µm thick cryostat sections mounted on glass slides and the number of axons was determined by the ImageJ counting tool. In 23 individuals, the phrenic nerve could be examined on both sides. In 5 individuals, however, only one side was examined. Thus, a total of 51 nerves were examined. Results: The mean length of the left phrenic nerves (33 cm (29–38 cm)) was significantly longer compared to the mean length of the right phrenic nerves (30 cm (24–33 cm)) (p < 0.001). Accessory phrenic nerves were present in 9 of 51 (18%) phrenic nerves. The mean number of phrenic nerves axons at the level of the first intercostal space in body donors with a right accessory phrenic nerve was significantly greater compared to the mean number of phrenic nerves axons at the same level in body donors without a right accessory phrenic nerve (3145 (range, 2688–3877) vs. 2278 (range, 1558–3276)), p = 0.034. A negative correlation was registered between age and the nerve number of axons in left (0.742, p < 0.001) and right (−0.273, p = 0.197) phrenic nerves. The mean distance from the upper edge of the ventral ramus of the fourth cervical spinal nerve to the point of entrance of the musculocutaneous nerve between the two parts of the coracobrachialis muscle was 19 cm (range, 15–24 cm) for the right and 20 cm (range, 15–25 cm) for the left arm. Conclusions: If an accessory phrenic nerve is available, it presumably should be spared. Thus, in that case, a supraclavicular approach in combination with a nerve graft would probably be of advantage. [ABSTRACT FROM AUTHOR]

Purpose: The current cadaveric case series evaluates the coracobrachialis muscle morphology, the related musculocutaneous nerve origin, course, and branching pattern, as well as associated adjacent neuromuscular variants. Materials and methods: Twenty-seven (24 paired and 3 unpaired) cadaveric arms were dissected to identify the coracobrachialis possible variants with emphasis on the musculocutaneous nerve course and coexisted neural variants. Results: Four morphological types of the coracobrachialis were identified: a two-headed muscle in 62.96% (17/27 arms), a three-headed in 22.2% (6/27), a one-headed in 11.1% (3/27), and a four-headed in 3.7% (1 arm). A coracobrachialis variant morphology was identified in 37.04% (10/27). A three-headed biceps brachii muscle coexisted in 23.53% (4/17). Two different courses of the musculocutaneous nerve were recorded: 1. a course between coracobrachialis superficial and deep heads (in cases of two or more heads) (100%, 24/24), and 2. a medial course in case of one-headed coracobrachialis (100%, 3/3). Three neural interconnections were found: 1. the lateral cord of the brachial plexus with the medial root of the median nerve in 18.52%, 2. the musculocutaneous with the median nerve in 7.41% and 3. the radial with the ulnar nerve in 3.71%. Duplication of the lateral root of the median nerve was identified in 11.1%. Conclusions: The knowledge of the morphology of the muscles of the anterior arm compartment, especially the coracobrachialis variant morphology and the related musculocutaneous nerve variable course, is of paramount importance for surgeons. Careful dissection and knowledge of relatively common variants play a significant role in reducing iatrogenic injury. [ABSTRACT FROM AUTHOR]

Background: Variations in connections between the musculocutaneous and median nerves in the arm are not as uncommon as was once thought. Lesions of the communicating nerve may give rise to patterns of weakness that may impose difficulty in diagnosis. Objective: The aim of this study is to determine the variation of the musculocutaneous nerve (MCN) and analyze the incidence of nerve communication between the musculocutaneous and median nerves. Methods: Anatomical dissection was performed in the present work by using 62 arms from 31 adult cadavers, age ranging from eighteen to eighty years, which was donated to Medical Universities in Myanmar. Among the 62 studied arms, 26 arms (41.9%) were male, and 36 arms (58.1%) were female. Results: Nerve variation patterns were seen in four out of 62 studied arms (6.4%) and one arm (1.6%) showed no musculocutaneous nerve. One out of 62 studied arms (1.6%) revealed the musculocutaneous nerve did not pierce the coracobrachialis muscles but communicated with the median nerve in the upper third of arm. One out 62 studied arms (1.6%) revealed a musculocutaneous nerve piercing the coracobrachialis muscle and communicated with the median nerve in the upper third of arm. Communicating branch was found in two upper limbs (3.22%). Conclusion: The knowledge of these variations will allow physicians to correctly interpret anomalous innervation patterns of the upper limb. [ABSTRACT FROM AUTHOR]

Variations appearing in biceps brachii muscle are common with accessory head, different origins, variant insertion, and different pattern of nerve innervation. However, variations appearing in both origin and insertion, and with other anomalous morphology at the same time are seldom. Here we report a complex variational case on the right arm of a 91-year-old Japanese female cadaver. The complex variations included (1) the biceps brachii muscle bifurcated at its distal ending; (2) the long head had its own tendon, which divided into two parts, i.e., a lateral part fused into the fascia between the brachioradialis and extensor carpi brevis, and a medial part attached to the radius about one centimeter ahead of the radial tuberosity; (3) the short head had an accessory origin from the shoulder capsule; (4) the bicipital aponeurosis was of two parts with an anterior superior layer formed by the long head and a posterior deep one formed by the short head; (5) the musculocutaneous nerve was especially underdeveloped that only innervated the coracobrachialis; (6) the existence of communicating branch between the musculocutaneous and median nerves, and the median nerve issued muscular branches to the biceps brachii and brachialis muscles, and (7) the brachioradial muscle had two accessory muscular bundles that originated from the fascia of the brachial muscle (proximal one) and from the bicipital aponeurosis (distal one). [ABSTRACT FROM AUTHOR]

The traditional axillary perineural (PN) approach for brachial plexus block is frequently used, but separate musculocutaneous nerve (MCN) block is required and increases procedure time and patient discomfort. We hypothesized that a block using the proximal perivascular (PPV) method at the MCN branching from the lateral cord would obviate the need for an MCN block while ensuring a quality similar to that of the PN method. For the PN group (n = 25), a needle was placed on each nerve, and 8 mL local anesthetic was infiltrated around the radial, ulnar, and median nerves (total: 24 mL). We then injected 6 mL local anesthetic around the MCN. In the PPV group (n = 25), we moved the probe proximally until the branching junction of the the MCN in the lateral cord. The needle tips were placed in the 12-o'clock and 6-o'clock positions of the axillary artery, and 15 mL local anesthetic was injected (total: 30 mL). The procedure time, number of needle passes, procedure-related complications, sensory/motor block level, and onset time were recorded. The PPV group had a significantly shorter procedure time than the PN group (3.9 ± 1.0 vs. 7.5 ± 3.3 min, p < 0.001). Furthermore, the PPV group required fewer needle passes. The PN group showed a significantly faster onset time than the PPV group (6.4 ± 2.7 vs. 10.4 ± 2.9 min, p < 0.001). The induction time did not show significant intergroup difference. Sensory blockade in the PN group occurred significantly faster than that in the PPV group at 5 and 10 min. There were no significant differences in motor nerve paralysis. PPV axillary block under ultrasound guidance was as effective as the PN axillary block. Therefore, the PPV axillary block is a simple, safe and effective regional technique for upper limb surgery. [ABSTRACT FROM AUTHOR]

Background: This study was conducted to compare the response between the results of experimental data and the results achieved by the NARX neural network model to predict the electromyogram (EMG) signal on the biceps muscle in nonlinear stimulation conditions as a new stimulation model. Methods: This model is applied to design the controllers based on functional electrical stimulation (FES). To this end, the study was conducted in five stages, including skin preparation, placement of recording and stimulation electrodes, along with the position of the person to apply the stimulation signal and recording EMG, stimulation and recording of single-channel EMG signal, signal preprocessing, and training and validation of the NARX neural network. The electrical stimulation applied in this study is based on a chaotic equation derived from the Rossler equation and on the musculocutaneous nerve, and the response to this stimulation, i.e., the EMG signal, is from the biceps muscle as a single channel. The NARX neural network was trained, along with the stimulation signal and the response of each stimulation for 100 recorded signals from 10 individuals, and then validated and retested for trained data and new data after processing and synchronizing both signals. Results: The results indicate that the Rossler equation can create nonlinear and unpredictable conditions for the muscle, and we also can predict the EMG signal with the NARX neural network as a predictive model. Conclusion: The proposed model appears to be a good method to predict control models based on FES and to diagnose some diseases.

Background: Although the classic open Latarjet has a low recurrence rate in unstable shoulders, this advantage may be offset by the higher number of complications. We aimed to report the safety-driven nuanced steps and the resulting short-term complications of the Latarjet-Walch technique. Methods: Between 2016 and 2022, 150 patients who underwent the Latarjet procedure following the key safety-driven technical steps were retrospectively evaluated for intraoperative and short-term (3 months) complications. The complications were divided into 3 types: Any adverse event that did not need a change in the treatment protocol was a type 1 complication. An event that resulted in a prolongation of rehabilitation protocol or an additional medical line of treatment was classified as type 2, and an event that resulted in readmission, a resurgery, or one that affected the outcome was classified as a type 3 complication. Results: There were 12 (8%) short-term complications in 9 patients. Neurological complications were noted in 3 (2%) patients (1 axillary nerve injury, 1 suprascapular nerve injury, and 1 musculocutaneous nerve injury). Type 1 complications were noted in 2 patients: 2 patients had hematoma that was detected as superficial swelling, but no surgical drainage was needed, and both resolved at their 1-month follow-up. Type 2 complications were noted in 4 patients. One patient had surgical site infection and a second patient had superficial wound dehiscence in the lower part of the wound. The third patient had suprascapular nerve paresis and the fourth had musculocutaneous nerve paresis and shoulder stiffness. Both nerve injuries recovered completely after 6 months of rehabilitation. Type 3 complications were noted in 3 patients. One patient had axillary nerve paresis and shoulder stiffness. The axillary nerve palsy had recovered partially by 8 months. One patient had an intraoperative graft fracture and postoperative shoulder stiffness, and the third patient had shoulder stiffness. Conclusion: Following the safety-driven nuanced steps in the Latarjet-Walch procedure, the short-term complication rate was 8%, and the neurological complication was 2% (n = 3). The musculocutaneous and suprascapular nerves completely recovered, and the axillary nerve had partially recovered.

Objective. This literature review highlights the prevalence of the typical course of the musculocutaneous nerve (MCN) through the coracobrachialis muscle (CB), and evaluates the distance from the entrance point of the MCN to the CB, taking the coracoid process (CP) as a landmark. Methods. PubMed (MEDLINE), Scopus, and CINAHL online databases were searched in December 2022 for studies reporting the prevalence of the MCN's typical course and the distance between the CP and the MCN entrance point to the CB. Results. Twenty-eight studies were included (including 2846 subjects) investigating the MCN's typical course, and eliciting a prevalence of 93.4%. The mean distance of the CP to the entrance point of the MCN's main trunk into the CB was 5.6±2cm (median 6.1cm, in 550 subjects). In 76.12% of cases the MCN's accessory branches entered the CB proximally to the MCN's main trunk. The mean distance from the CP to the entrance point of the MCN's proximal branches to the CB was 3.8±1.2cm (median 3.7cm, in 140 subjects). Conclusion. In the vast majority of cases, the MCN had a typical course through the CB. In cases of altered anatomy, the MCN was either absent or passed medially to the CB (without piercing it). The average entrance point of the MCN into the CB from the CP is 5.6 cm. Proximal motor branches of the MCN to the CB are common and usually arise at a mean distance of 3.8cm from the inferior border of the tip of the CP. Surgeons should be aware of both the MCN's typical and its atypical course and these distances to avoid possible complications when operating in the area. [ABSTRACT FROM AUTHOR]

Perching is one of the essential natural behaviors for avian species. Providing an optimal perching design (e.g., shape, dimension, and materials) for commercial poultry production is critical for maintaining bird health, welfare, and production efficiency. This review paper summarized poultry perching studies and discussed the relationship between perch design, bird welfare, and production efficiency. Providing perches at an early stage may ensure optimum use during adulthood, reduce perching accidents, and lower the risk of floor eggs in cage-free (CF) hen houses. Therefore, a perch space of 15 cm per bird is recommended for the CF hen house. Similarly, rectangular perches are preferred to circular perches as the rectangular perch provides hens with an excellent tendon-locking mechanism to prevent slipping. In addition, perches with softer materials such as polyurethane and rubber coverings are recommended to increase the contact surface on the chicken's toes. Perching behavior (PB) promotes a musculocutaneous system and reduces the incidences of footpad dermatitis and lesions. Generally, providing perching may reduce aggression and stress in birds and improve welfare and production efficiency. In the case of broilers, it is found that the broiler perches less during the latter stage of their lives because they are comparatively heavier and exhibit a more inactive lifestyle. Studies have investigated the effect of the surface temperature of the perch on broilers' welfare. Perches with lower temperatures help improve performance and welfare by relieving heat stress and leg issues. Overall, PB is required to improve bird health and welfare. [ABSTRACT FROM AUTHOR]

Introduction: The clinical anatomical knowledge of the brachial plexus of the upper limb and its variants is essential for many upper extremity surgical procedures following hand injuries. Case Report: An unreported anatomical variation was observed during training surgery of the right upper limb of a male cadaver. The musculocutaneous nerve originates in the lateral cord and extends outwards, passing beneath the coracobrachialis muscle before proceeding to its initial branch, leading to the biceps brachialis muscle. The abnormal origination of the musculocutaneous nerve in the cadaver was in the midpoint of the arm from the median nerve. A thin nerve branch also innervated the coracobrachialis muscle, originated in the lateral cord, and continued laterally. Conclusion: Since no accurate similarity was reported, we consider this variation unusual and useful, especially for surgical purposes.

Introduction. Performing surgical manipulations and interventions on neurovascular bundles located in the anterior brachial region of human fetuses and newborns requires comprehensive knowledge of their topographical and anatomical features. The objective of the study was to establish the fetal topography peculiarities of both nerves and vessels in the anterior brachial muscle region. Materials and methods. The study was carried out on 32 human fetuses of 4-8 months with 81.0-310.0 mm crown-rump length (CRL) using macro microscopic dissection, vascular injections and morphometry. Results. We describe the main and additional sources of muscle blood supply and innervation of the anterior brachial region in human fetuses. Two to 4 branches of the musculocutaneous nerve take part in the innervation of both coracobrachialis and brachialis muscles, as well as the biceps brachii muscle. Some fetuses possess additional sources of innervation: for the coracobrachialis muscle there is a branch of the lateral bundle of the brachial plexus, the biceps brachii muscle has median nerve and for the brachialis muscle there is radial nerve. The largest number of arterial and nerve branches goes to the proximal and middle parts of the coracobrachialis and brachialis muscles, as well as the biceps brachii muscle. Conclusions. The established neurovascular correlations and features of the fetal anatomy of the anterior brachial muscle region determine the presence of relatively favourable conditions for cutting muscle flaps that are well innervated and supplied with blood.

Purpose: The study report describes a rare bilateral variant of a six- and five-headed coracobrachialis muscle (CB). The musculocutaneous nerve (MCN) (bilaterally) and the median nerve (MN) lateral root (unilaterally) pierced CB heads, separating superficial from deep heads. Methods: The variant bilateral CB was identified in a 78-year-old formalin-embalmed male cadaver, derived from a body donation program after a signed informed consent. Results: At the right side: The 6-headed CB was pierced by the MCN, while the MN lateral root pierced the one superficial and deep head. CB was supplied by the lateral cord and the MCN. At the left side: A 5-headed CB was identified with three superficial distinct origins that fused into a common superficial head coursing anterior to MCN. The variant CB bilaterally (with 11 heads in total) coexisted with a MN variant formation, an atypical course of the MN lateral root through CB (right side), a connection of the MN lateral root with the MCN (left side) and a variant axillary artery branching pattern (bilaterally). Conclusions: Course and direction of the accessory CB heads may occasionally entrap the MCN and/or adjacent structures (brachial artery and MN). The MCN compression results in problems in the glenohumeral joint flexion and adduction, and tingling or numbness of the elbow joint, the forearm lateral parts and the hand. [ABSTRACT FROM AUTHOR]

Introduction: The biceps brachii muscle takes its name from its two proximally attached ‘heads’. On rare occasions, an anomalous third head arises from the superomedial part of the brachialis and is attached to the bicipital aponeurosis and the medial side of the tendon of insertion. The slip frequently descends in front of and behind the brachial artery and often causes compression of the median nerve or brachial artery. Aim: To calculate incidence of the supernumerary third head of the biceps brachii along with its incidence, anatomical and morphological variations to establish its clinical significance. Materials and Methods: The observational study was conducted in Department of Anatomy, Dr. Kiran C Patel Medical College and Research Institute, Bharuch, Gujarat, India, from October 2021 to September 2022. It included 32 cadaveric upper limbs- 16 right-sided and 16 left-sided. The morphometric measurements were done with the use of digital vernier caliper. The findings were photographed and recorded and the mean and standard deviation were hereby presented and analysed by Statistical Package for Social Sciences (SPSS) version 19.0. Results: The biceps brachii was constituted of supernumery third head in three (9.375%) limbs, one on the right and two on the left-side. In all cases, third head arose from the anteromedial aspect of the mid-humeral shaft; medial to the brachialis and inserted together with the other two heads of the biceps into bicipital aponeurosis and radial tuberosity. The mean length and mean width of the supernumerary head was measured as 141.16±43.63 mm, 25.22±4.99 mm, respectively. A significant difference was not found when compared for symmetrical sides. Conclusion: Three specimen of upper limb were observed with distinct occurrence for the third head with the incidence of 9.37% and predominance on the left-side. In case of various arm surgical procedures knowledge can be used to avoid injuries.

The article presents a case study of isolated musculocutaneous neuropathy in a 33-year-old male chef who experienced left arm weakness and atrophy following an injury. It mentions the patient's clinical history, the initial physical examination, the differential diagnosis, and the diagnostic results, including nerve conduction studies and electromyography, which indicated denervation of the long head of the biceps brachii.

Objective: The purpose of the current study was to investigate the coracobrachialis muscle (CB) anatomy along with the musculocutaneous nerve (MCN) course, and to identify possible differences after the comparison of adult and foetal cadavers. Methods: One hundred and sixty (from 100 human foetuses and 60 adults cadaveric) upper limbs (83 left-sided and 77 right-sided) were dissected and investigated for CB morphology, MCN course, and possible coexisted variants. Results: The commonest CB type was the two-headed muscle (having one superficial and deep head), with the MCN passing between two heads, in 93 upper limbs (56 in foetuses and 37 in adults, 58.1%). The second most common type was the singleheaded muscle, with the MCN coursing medially to the CB, in 30 upper limbs (18 in foetuses and 12 in adults, 18.8%). Other rarer types, such as the three-headed CB (two superficial, and one deep) with the MCN between the heads in 19 arms (12 in foetuses and 7 in adults, 11.9%), and a four-headed CB (two superficial, two deep heads) in 17 upper limbs (13 in foetuses and 4 in adults, 10.6%) were observed. The most common coexisted variants were the biceps brachii third head, the median nerve (MN) absence, and MCN-MN interconnections. Conclusion: CB's typical anatomy is the two-headed muscle, with one head superficial and the other deep to the MCN. In the current study, there was no difference between foetal and adult cadavers for the CB different morphological types. Adequate knowledge of CB typical and variant anatomy is of paramount importance for orthopaedic surgeons to avoid pitfalls and iatrogenic lesions. [ABSTRACT FROM AUTHOR]

Objective: Pressure ulcers (PUs) are highly prevalent and challenging wounds. In this study, patients with either tetraplegia or paraplegia, all of whom had multiple grade 4 PUs and who underwent single-session surgical treatment were included. In order to increase the mobility of the musculocutaneous flap, the gluteus maximus muscle, which cannot be used by immobile patients, was detached and inserted into the flap. Method: This was a retrospective case series and all PUs were reconstructed within the same surgical session. Results: A total of nine patients participated in the study, all of whom were male. Mean age was 33 years (range: 20–42 years). Mean follow-up period was 14.3 months (range: 9–24 months). All patients had a successful single-session repair of all PUs. Total or partial flap losses were not observed. Mean and total number of reconstructed PUs were 2.55 and 23, respectively. The mean area of reconstructed open wounds per patient was 174.6cm2 and the mean operation duration was 253 minutes. The level of blood loss was acceptable as the decrease in haemoglobin levels was not more than 2g/dl for each patient. Conclusion: Multiple PUs can be repaired in one session using gluteus maximus musculocutaneous flaps in immobile patients. Based on the fact that the gluteus maximus is an essential muscle for ambulation, our approach can only be used in the treatment of patients with irreversible paraplegia or tetraplegia. When all prerequsities are met, the amount of blood loss and operation duration are acceptable, and returning the patient to a wound-free state can be achieved more quickly compared to multi-session repairs. Air-fluidised beds are vital tools for accomplishing single session repairs of multiple PUs. The data shows that the approach is safe and can be used in patients with multiple PUs. [ABSTRACT FROM AUTHOR]

Objectives: Helical plates are preferably used for proximal humeral shaft fracture fixation and potentially avoid radial nerve irritation. Aims: Safety of applying four different long plate designs (straight, 45°-, 90°-helical and ALPS) with MIPO technique as well as assessment and comparison of their distances to adjacent anatomical structures. Methods: MIPO was performed in 16 human cadaveric humeri using either a straight (group 1), a 45°-helical (group 2), a 90°-helical (group 3) plate, or an ALPS (group 4). Applying CT angiography, distances between brachial arteries and plates were evaluated. All specimens were dissected and distances to the axillary, radial and musculocutaneous nerve were evaluated. Results: No specimens demonstrated injuries of the anatomical structures at risk after MIPO with all investigated plate designs. Closest overall distance (mean (range); mm) between each plate and the radial nerve was 1 (1–3) in group 1, 7 (2–11) in group 2, 14 (7–25) in group 3 and 6 (3–8) in group 4. It was significantly bigger in group 3 and significantly smaller in group 1 compared to all other groups, p < 0.001. Closest overall distance between each plate and the musculocutaneous nerve was 16 (8–28) in group 1, 11 (7–18) in group 2, 3 (2–4) in group 3 and 6 (3–8) in group 4. It was significantly bigger in group 1 and significantly smaller in group 3 compared to all other groups, p < 0.001. Conclusions: MIPO with 45°- and 90°-helical plates as well as with ALPS is safely feasible and demonstrates significantly bigger distances to the radial nerve compared to straight plates. However, the distances remain small and attention must be paid to the musculocutaneous nerve and the brachial artery when MIPO is applied using ALPS, 45°- and 90°-helical implants. [ABSTRACT FROM AUTHOR]

Purpose: To project the distance between the tip of the greater tubercle (GT), respectively, the proximal border of the tip of the coracoid process (CP) and the entry point of the coracobrachialis by the musculocutaneous nerve (MCN) proportionally onto the humeral length. Methods: Sixty-six upper extremities were included in the study. The distance between the tip of the GT and the distal tip of the lateral humeral epicondyle (LE) was evaluated as the humeral length (HL). The interval between the tip of the GT and the entry point of the coracobrachialis muscle by the MCN was measured. The distance between the proximal border of the tip of the CP and the distal portion of the medial humeral epicondyle (ME) and the entry point of the MCN into the coracobrachialis were evaluated. Proportions were used to project the entry point of the coracobrachialis by the MCN along the HL, respectively, the interval between the proximal border of the tip of the CP and the distal tip of the ME. Results: The entry point of the MCN into the coracobrachialis muscle can be expected at an interval between 14.9 and 33.9% of the HL (between the tip of the GT and the LE), starting from the tip of the GT. Regarding the reference line between the proximal border of the CP and the ME, the nerve's entry point was located between 14.2 and 34.4%, starting from the CP. Conclusion: Results represent easily applicable intervals for intraoperative localisation of the MCN. [ABSTRACT FROM AUTHOR]

Variations of the brachialis muscle are uncommon in the literature. During regular cadaveric dissection, we observed the unilateral presence of an accessory muscle in the front of the right arm of a female cadaver, taking its origin from the medial aspect of the brachialis and the adjacent intermuscular septum. The muscle belly descended downwards, crossed the neurovascular bundle in the cubital fossa and merged with the fibres of the pronator teres. There is no doubt regarding its significance in the etiogenesis of numerous compression syndromes due to its close topographical relationship with the neurovascular bundle. In our report, we consider the potential developmental process and therapeutic implications of this variation, which can aid surgeons in their strategy and management. [ABSTRACT FROM AUTHOR]

Background: This study was conducted to compare the response between the results of experimental data and the results achieved by the NARX neural network model to predict the electromyogram (EMG) signal on the biceps muscle in nonlinear stimulation conditions as a new stimulation model. Methods: This model is applied to design the controllers based on functional electrical stimulation (FES). To this end, the study was conducted in five stages, including skin preparation, placement of recording and stimulation electrodes, along with the position of the person to apply the stimulation signal and recording EMG, stimulation and recording of single-channel EMG signal, signal preprocessing, and training and validation of the NARX neural network. The electrical stimulation applied in this study is based on a chaotic equation derived from the Rossler equation and on the musculocutaneous nerve, and the response to this stimulation, i.e., the EMG signal, is from the biceps muscle as a single channel. The NARX neural network was trained, along with the stimulation signal and the response of each stimulation for 100 recorded signals from 10 individuals, and then validated and retested for trained data and new data after processing and synchronizing both signals. Results: The results indicate that the Rossler equation can create nonlinear and unpredictable conditions for the muscle, and we also can predict the EMG signal with the NARX neural network as a predictive model. Conclusion: The proposed model appears to be a good method to predict control models based on FES and to diagnose some diseases. [ABSTRACT FROM AUTHOR]

Report on a new transfer for the reinnervation of biceps and brachialis muscles after multilevel avulsive injuries of brachial plexus provided at least T1 is viable: the Medial Cord to Musculocutaneous (MCMc) and its variant, the Medial Cord to anterior Upper Trunk (MC-aUT). The MC-aUT is indicated in agenesia of musculocutaneous nerve and when a residual function in the biceps is present. The MCMc transfer would be unfeasible in the former and contraindicated in the latter. Three hundred and five consecutive patients, classified according to the quality of hand function, are available for a long-term follow-up after reconstructive surgery. They had multiple cervical root avulsive injuries at two (C5-C6), three (C5-C6-C7) and four (C5-C6-C7-C8) levels. The reinnervation was obtained via an end-to-end transfer from two donor fascicles located in the medial cord (MC) and aimed at the flexor carpi ulnaris or the flexor digitorum profundus. These transfers have no failures and no complications when the hand shows a normal function. In the case of suboptimal conditions of the hand, the technique is more challenging, but still has many satisfactory results. In the four-root avulsive injuries, on the contrary, strong limitations suggest that different strategies should be preferred. EMG shows a reinnervation in both biceps and brachialis muscles and this accounts for the quality of results. Tendon transfers for wrist and finger dorsiflexion, when required, remain unencumbered. The procedures are safe, effective and easily feasible. The ideal candidate has a C5-C6 injury and a normal hand function. [ABSTRACT FROM AUTHOR]

Background: The aim of the present work was to provide evidence about the anatomical variations as regard the origin, distribution, and branching pattern of the musculocutaneous nerve (MCN). Materials and methods: Brachial plexus was dissected in 40 upper limbs of 20 male adult cadavers. The pattern of the MCN was photographed by a digital camera. Results: The location and length of the nerve branches between left and right arms were recorded and statistically analysed. In 90% of specimens the MCN originates from the lateral cord of the brachial plexus, in 5% it arose from the median nerve (MN), while in the remaining 5% specimen, it was absent. The MCN pierced the coracobrachialis muscle in 90% of specimens, and in the remaining 10% did not pierce it. The motor branches to biceps brachii muscle were categorised into: type 1 (90%): one branch that divides to supply the two heads of biceps; type 2 (5%): double branches, innervating each head of biceps separately. The motor branches to brachialis muscle were categorised into: type 1 (82.9%): one branch; type 2 (14.2%): double branches and type 3 (2.9%): three branches that innervating brachialis muscle. Communications between the MCN and the MN were observed in 35% of specimens. Conclusions: The knowledge of the common and uncommon MCN variations is important especially to the surgeons for carrying out surgical procedures in axilla and arm. [ABSTRACT FROM AUTHOR]

Background: To restore elbow flexor muscle function in case of traumatic brachial plexus avulsion, the phrenic nerve transfer to the musculocutaneous nerve has become part of clinical practice. The nerve transfer can be done by means of video-assisted thoracic surgery without nerve graft or via supraclavicular approach in combination with an autograft. This study focuses on a detailed microscopic and macroscopic examination of the phrenic nerve. It will allow a better interpretation of existing clinical results and, thus, serve as a basis for future clinical studies. Material and Methods: An anatomical study was conducted on 28 body donors of Caucasian origin (female n = 14, male n = 14). A sliding caliper and measuring tape were used to measure the diameter and length of the nerves. Sudan black staining was performed on 15 µm thick cryostat sections mounted on glass slides and the number of axons was determined by the ImageJ counting tool. In 23 individuals, the phrenic nerve could be examined on both sides. In 5 individuals, however, only one side was examined. Thus, a total of 51 nerves were examined. Results: The mean length of the left phrenic nerves (33 cm (29–38 cm)) was significantly longer compared to the mean length of the right phrenic nerves (30 cm (24–33 cm)) (p < 0.001). Accessory phrenic nerves were present in 9 of 51 (18%) phrenic nerves. The mean number of phrenic nerves axons at the level of the first intercostal space in body donors with a right accessory phrenic nerve was significantly greater compared to the mean number of phrenic nerves axons at the same level in body donors without a right accessory phrenic nerve (3145 (range, 2688–3877) vs. 2278 (range, 1558–3276)), p = 0.034. A negative correlation was registered between age and the nerve number of axons in left (0.742, p < 0.001) and right (−0.273, p = 0.197) phrenic nerves. The mean distance from the upper edge of the ventral ramus of the fourth cervical spinal nerve to the point of entrance of the musculocutaneous nerve between the two parts of the coracobrachialis muscle was 19 cm (range, 15–24 cm) for the right and 20 cm (range, 15–25 cm) for the left arm. Conclusions: If an accessory phrenic nerve is available, it presumably should be spared. Thus, in that case, a supraclavicular approach in combination with a nerve graft would probably be of advantage.

Embryologically, the musculocutaneous nerve (MCN) comes from the lateral root of the median nerve, and thus numerous anatomical variations concerning the formation and branching pattern of these two nerves of the brachial plexus have been described. In this case study, we describe a relatively uncommon case of fusion of the median and MCNs that was identified during routine teaching dissection of a male human cadaver. The identification of this anatomical variation requires awareness of the embryological background, as it may be confused with biceps innervation from the median nerve or the existence of a communicating branch between the two nerves. In addition, awareness of such anatomical variations is of undisputable significance for the safety of surgical operations in the brachial plexus and the arm in general.

Introduction: Variations within musculocutaneus nerve (MCN) are very frequent. Such cases should be discussed extensively to reduce the risk of iatrogenic damage during surgery. Aim: In this paper, we wanted to present the unusual variability within the brachial plexus, which is the double MCN. Case study: We present a case of accesory MCN found during the cadaveric dissection. Results and discussion: In this paper we encountered two musculocutaneous nerves, of which MCN proper runs as standard innervating the biceps brachii and the coracobrachialis muscle, while MCN accessory extending distally from MCN proper and innervates the brachialis. Conclusions: The case analysed by us is rare in the literature. Brachial plexus variations are very common and clinically important. [ABSTRACT FROM AUTHOR]

The restoration of elbow flexion is of primary importance in the management of patients with brachial plexus injuries. Superior functional outcomes via fascicle transfer from the ulnar and median nerves have resulted in this transfer being considered the mainstay of recovery of elbow flexion in patients with intact C8 and T1 function. An understanding of the anatomy of the musculocutaneous nerve (MCN) and its branching pattern is key while performing these transfers. A prospective cohort study was conducted in patients who underwent nerve transfer for the restoration of elbow flexion following a traumatic brachial plexus injury. The anatomic course and branching pattern of the MCN were recorded in eligible cases, both as a line diagram and using intraoperative photographs. One hundred fifty patients underwent nerve transfer for the restoration of elbow flexion following an injury to the brachial plexus. The MCN in 138 patients (92%) was found to pierce the coracobrachialis muscle before emerging lateral to it. One hundred thirty-four patients (89.3%) demonstrated the "classical" anatomy. One hundred fifteen patients (76.6%) had a single primary branch to the biceps, whereas 25 patients (16.6%) demonstrated a discrete motor branch to each head. One hundred thirty-three dissections (88.6%) revealed a single muscular branch to the brachialis arising posteromedially from the MCN, distal to the origin of the branch to the biceps brachii. Notable unreported variations, such as the MCN penetrating the biceps as it descended, multiple brachialis branches, and trifurcation of divisions of the MCN, were documented. Variations in MCN anatomy are quite common, and even unreported variations can be encountered. Exploration of the MCN and its branches for nerve transfers requires knowledge of these anatomic variations and vigilance to prevent inadvertent injuries while dissecting them for nerve transfer surgery. [ABSTRACT FROM AUTHOR]

Background:  Nerve transfers from one common donor nerve to recipient nerves with multiple target branches can yield slower and unpredictable recovery in the target nerves. Our hypothesis is that steal phenomenon exists when multiple nerve neurotization comes from one donor nerve., Methods:  In 30 Sprague-Dawley rats, the left ulnar nerve (UN) was selected as the donor nerve, and the musculocutaneous nerve (MCN) and median nerve (MN) as the recipient target nerves. The rats were separated into three groups (10 rats in each): group A, UN-to-MCN (one-target); group B, UN-to-MN (one-target); and group C, UN-to-MCN and MN (two-target). The right upper limbs were nonoperative as the control group. Outcome obtained at 20 weeks after surgery included grooming test, muscle weight, compound muscle action potential, tetanic muscle contraction force, axon counts, and retrograde labeling of the involved donor and target nerves., Results:  At 20 weeks after surgery, muscles innervated by neurotization resulted in significant worse outcomes than the control side. This was especially true in two-target neurotization in the parameter of muscle weight and forearm flexor muscle contraction force outcome when compared to one-target neurotization. Steal phenomenon does exist because flexor muscle contraction force was significantly worse during two-target neurotization., Conclusion:  This study proves the existence of steal phenomenon in multiple target neurotization but does not significantly affect the functional results. Postoperative rehabilitative measures (including electrical stimulation, induction exercise) and patient compliance (ambition and persistence) are other crucial factors that hold equivalent importance to long-term successful recovery., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: The nerve supply of the upper limb, which is provided by the brachial plexus, is extremely important from a medical and surgical perspective. Muscles of the flexor compartment of the arm are destined to have their nerve supply from the musculocutaneous nerve, a branch from the lateral cord of the brachial plexus. Variations in the formation and branching of the brachial plexus are not uncommon. These variations have clinical significance during surgical procedures, in the brachial plexus block, and in diagnostic clinical neurophysiology. Material & methods: The study was carried out in the department of anatomy consisting of 56 limbs during routine undergraduate dissection classes. Dissection of the infraclavicular part of the brachial plexus was done. The variations in the origin, number, and distribution of the branches derived from the cords to the flexor compartment of the arm and their correlations to the coracobrachialis were noted. Observation & results: 47 limbs (83.92%) showed a normal morphological pattern of formation and distribution of brachial plexus to the flexor compartment of the arm. 9 limbs (16.07%) showed variations in one form or the other. Two limbs (3.57%) showed an absence of musculocutaneous nerve (MCN). In 3 limbs (5.35%) coracobrachialis was not being supplied by MCN, and 4 limbs (7.14%) exhibited a communication between MCN and Median Nerve (MN). Conclusion: Variations in the nerves supplying the flexor compartment of the arm have clinical implications in post-traumatic evaluations and exploratory innervations of the arm for peripheral nerve restoration. It is important for surgeons, clinicians, and anatomists to be aware of these possible anatomical variations to avoid unexpected complications.