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Purpose: The brachioradialis muscle (BRM) belongs to the lateral group of forearm muscles and contributes to the elbow flexion. Accessory brachioradialis muscle (ABRM) or "brachioradialis accessorius" represents an uncommon BRM variant, not been enough studied. The present study investigates the prevalence of the ABRM, along with its origin, insertion, and innervation., Materials: Eighty-three upper limbs were meticulously dissected at the arm, forearm, and cubital fossa to investigate the ABRM presence. When the variant muscle was identified, morphometric measurements were obtained., Results: The ABRM was identified in two upper limbs (2/83, 2.4%), in a male cadaver, bilaterally. Its origin was located along with the typical BRM, and its insertion was identified into the anterior surface of the radius (proximal third). The ABRM was innervated by the radial nerve, coursing posteriorly (deeply)., Conclusions: In the current study, the variant muscle was observed in 2.4%. Radial nerve compression, at the forearm, is not an uncommon entrapment neuropathy. The relationship between the radial nerve and the ABRM could precipitate radial neuropathy., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Purpose: The current systematic review with meta-analysis aimed to investigate the pooled prevalence of the superior thyroid artery (STA) pattern of origin (distinct or fused-common origin with adjacent arteries in the form of a common trunk). The standard and uncommon variants were also studied, considering the STA's exact surface of origin and the relationship with the upper border of the thyroid cartilage (TC, reference point), considering the laterality effect. Thus, the STA topographical anatomy was considered., Methods: An evidence-based systematic review with meta-analysis was performed according to the PRISMA 2020 guidelines. A literature search was conducted in four online databases using specific keywords, the pooled prevalence was calculated using statistical analysis in the R programming language, and multiple subgroup analyses were performed., Results: The most common distinct origin of the STA was from the external carotid artery (ECA) (56.94% pooled prevalence, 95%CI: 50.89-62.89), and the rarest one was from the internal carotid artery (ICA) (< 0.01%, 95%CI: 0.00-0.00). Common trunks were also investigated, with the thyrolingual trunk emanating from the ECA estimated at 0.61% (95%CI: 0.21-1.14), representing the most common. Subgroup analysis based on the nationality, type of study, and sample size, as well as a comparison between left and right sides and males and females, were investigated., Conclusions: The most common STA origin was estimated as the ECA, the medial surface of origin, and above the TC upper border. Adequate knowledge of STA origin is paramount for surgeons, especially during thyroidectomy, not to cause iatrogenic injury to the external branch of the superior laryngeal nerve., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

The thyrohyoid muscle belongs to the infrahyoid group located in the carotid triangle. It normally originates from thyroid cartilage and inserts into hyoid bone. Quite often, it is continuous with the sternohyoid muscle. Furthermore, there are variants that have their origin in the cricoid cartilage only, however, this occurs very rarely. During anatomical dissection, a two-headed variant of this muscle was found. One head had its origin in the cricoid cartilage and the other in the thyroid cartilage. This variant of thyrohyoid had not been previously described in the available literature. Therefore, we believe that it may be referred to as the cricothyrohyoid muscle. As the thyrohyoideus is often used as a landmark during surgical procedures in the prelaryngeal area and as a muscle graft, a thorough knowledge of its anatomy and variation is extremely important. We speculate that the two-headed version of this muscle may be problematic during surgical procedures in this region, however, it may also provide more options as a muscular graft., (© 2024. The Author(s).)

Background: The lateral ankle joint comprises the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL). The purpose of this study was to propose a classification of CFL morphology., Methods: The material comprised 120 paired lower limbs from human cadavers (30 male, 30 female), mean age 62.3 years. The morphology was carefully assessed, and morphometric measurements were performed., Results: A 4-part method for anatomic classification can be suggested based on our study. Type 1 (48.3%), the most common type, was characterized by a bandlike morphology. Type 2 (9.2%) was characterized by a Y-shaped band, and type 3 (21.7%) by a V-shaped band. Type 4 (20.8%) was characterized by the presence of 2 or 3 bands. Type 2 and 4 were divided into further subtypes based on origin footprint., Conclusion: The aim of our study was to describe variations of calcaneofibular ligament. Our proposed 4-part classification may be of value in clinical practice in future recognition of CFL injuries and in its repair or reconstruction., Clinical Relevance: The anatomy of the CFL plays an important role in stability of the ankle. Greater recognition of anatomical variation may help improve reconstructive options for patients with chronic lateral ankle instability., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosure forms for all authors are available online.

Shoulder pathology is a very common medical presentation and can be due to anatomical variations. Therefore, knowledge of variants is important for the clinician treating patients with such complaints so that misdiagnosis is minimized and iatrogenic injury prevented. A review of the literature was performed of the variant anatomy of the pectoralis minor muscle. The aim of this review is to better inform clinicians who might treat patients with shoulder pathology so that if identified, variants of the pectoralis minor muscle are better appreciated.

Introduction: The coracobrachialis muscle (CRM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. It inserts to the medial part of the humerus between the attachment of the medial head of the triceps brachii and the brachial muscle. Both the proximal and distal attachments of the CRM, as well as its relationship with the musculocutaneus nerve, demonstrate morphological variability., Material and Methods: One hundred and one upper limbs (52 left, and 49 right) fixed in 10% formalin solution were examined., Results: Three main types, with subtypes, were identified. The most common was Type I (49.5), characterized by a single muscle belly with a classical origin from the coracoid process, medially and posteriorly to the tendon of the biceps brachii. Type II (42.6%), characterized by two heads, was divided into two subtypes (A-B) depending on its origin: Type IIA, where one head originated from the coracoid process posteriorly to the tendon of the biceps brachii and the second head from the short head of the biceps brachii, and Type IIB, in which both heads originated from the coracoid process; however, the superficial head fused with the insertion of a short head of the biceps brachii, while the deep head was directly originating. Finally, Type III (7.9%) was characterized by three heads: two originated from the coracoid process (superficial and deep), and the third from a short head of the biceps brachii. Two types of insertion and two types of musculocutaneous nerve (MCN) relative to CRM could be distinguished., Conclusion: An adapted classification is needed for all clinicians working in this area, as well as for anatomists. The CRM demonstrates morphological variability in both its proximal and distal attachments, as well as the variable course of the MCN relative to the CRM. WHAT IS KNOWN ABOUT THIS SUBJECT "AND" WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE: Not much is known about the variability of coracobrachialis muscle. The present paper introduces a completely new classification, both clinical and anatomical.

The coexistence of different muscular-neurovascular variations is of significant clinical importance. A male cadaver, 76 years old at death, was subjected to routine anatomical dissection; the procedure was performed for research and teaching purposes at the Department of Anatomical Dissection and Donation, Medical University of Lodz. The right forearm and hand were dissected using standard techniques according to a strictly specified protocol. The presence accessory head of the flexor pollicis longus may potentially compress the anterior interosseous nerve. The present case report describes a rare variant of the ulnar head of the pronator teres, characterized by two independent bands (i.e., two proximal attachments). The main band originates from the coronoid process and the second originates from the tendon of the biceps brachii. This type of attachment could potentially affect the compression of the ulnar artery running between the two bands. Additionally, the accessory head of the flexor pollicis longus was observed, which started on the medial epicondyle; its coexistence with a high division median nerve creates a potential pressure site on the anterior interesosseous nerve.

The flexor pollicis longus (FPL) is located in the anterior compartment of the forearm. It is morphologically variable in both point of origin and insertion. An additional head of the FPL can lead to anterior interosseous syndrome. This report presents a morphological variation of the FPL (additional head in proximal attachment and bifurcated tendinous insertion in distal attachment) and an unrecognized structure that has not so far been described in the literature. This structure originates in six heads (attached to the FPL or interosseous membrane) that merge together, and inserts on to the FPL. All the variations noted have clinical significance, ranging from potential nerve compression to prevention of tendon rupture.

The coracobrachialis muscle (CBM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. Both the proximal and distal attachment of the CBM, as well as its relationship with the musculocutaneus nerve demonstrate morphological variability, some of which can lead to many diseases. The present case study presents a new description of a complex origin type (four-headed CBM), as well as the fusion of both the short biceps brachii head, brachialis muscle and medial head of the triceps brachii. In addition, the first and second heads formed a tunnel for the musculocutaneus and median nerves. This case report has clear clinical value due to the split mature of the coracoid process, and is a significant indicator of the development of interest in this overlooked muscle.

Purpose: We present a case of a seven-headed quadriceps femoris (QF) muscle and a systematic review of the literature concerning this anatomical variation., Methods: During a routine dissection of the lower limbs of a 72-year old cadaver, a QF with supernumerary heads was identified. Each head of the muscle was photographed and subjected to further measurement., Results: In addition to the four traditional heads of the QF muscle, we found a tensor of the vastus intermedius (TVI) muscle and two additional muscle bellies composed of tendons. Attachments of the TVI tendon and additional tendons were localized on the superior medial border of the patella., Conclusion: It is important to be aware of morphological variability of the quadriceps femoris muscle. The described case assists clinicist with avoiding misdiagnoses around the knee.

Purpose: Seemingly a well-known, weak, and vestigial plantaris muscle should not be a revelation. However, recent studies have shown that this structure is incredibly underestimated and perceived only as an infirm flexor of the talocrural joint, the knee joint or a great source of graft tissue. Usually, the origin of this inconspicuous muscle begins at the lateral supracondylar line of the femur and the knee joint capsule. It continues distally, forming a long and slender tendon. In most cases, it inserts onto the calcaneal tuberosity on the medial side of the Achilles tendon. However, many morphological variations have been discovered during anatomical dissections and surgical procedures. Nevertheless, according to the present literature, no other studies presented such a complex insertion variant, with indisputable clinical value and significant proof of development of this forgotten muscle., Methods: The dissection of the right thigh, knee, crural and talocrural region was performed using standard techniques according to a strictly specified protocol., Results: Four different insertion points were observed. The first band (A) inserted near to the tarsal canal flexor retinaculum. The second band (B) bifurcates into two branches-B1 and B2. B1 is located on the medial side and B2 is located on the lateral side of the calcaneal tuberosity. The third band (C) is inserted into the superior nonarticular calcaneal surface of the calcaneus anteriorly to the Achilles tendon., Conclusion: A differently shaped plantaris tendon could be considered a cause of harvesting procedure failure. In the light of new case reports perhaps what we are now witnessing is remodeling and transformation of the Plantaris muscle. If so, the awareness of the influence on the onset of Achilles midportion tendinopathy or a potential role in tibialis posterior conflict can be crucial for every clinician.

The plantaris is a small muscle that typically originates at the lateral supracondylar line of the femur and the knee joint capsule, from where it continues distally, forming a long and slender tendon. However, considerable controversy surrounds the status of this seemingly inconspicuous muscle: is it a residual muscle, or one that it is just developing? In addition, both the proximal and distal attachments are highly morphologically variable. These variations can lead to many diseases. Interestingly, the course of the PM tendon is also variable. The present case study presents a new description of a complex origin type and a rare course of the PM tendon. Understanding of the PM and its tendon has clear clinical value and is a significant indicator of the development of interest in this overlooked muscle.

The body is home to a number of unique and intriguing anatomical structures, plenty of which concern the muscles and their tendons. Of these, the plantaris muscle is reported to present a particularly high range of morphological variations. The muscle, passing distally throughout the length of the lower leg, consists of a small muscle belly and a long, thin tendon. It originates, traditionally, on the popliteal surface of the femur and the knee joint capsule, and then inserts to the calcaneal tuberosity. It has been suggested that mid-portion Achilles tendinopathy may be caused by certain plantaris tendon morphologies. This case report describes a new anomalous plantaris tendon insertion, closely related to the Achilles tendon. It comprise four distinct insertions and one direct merge with the calcaneal tendon. The current classification should be extended to accommodate such 'rare cases' to facilitate more successful Achilles tendinopathy treatment.

Introduction: Identifying the branching pattern of the popliteal artery (PA) is a vital step in planning radiological and surgical procedures involving the anterior and posterior tibial and fibular arteries. The aim of this study was to characterize the course and morphology of the terminal branches of the PA., Materials and Methods: The anatomical variations in the branching patterns of the anterior and posterior tibial and fibular arteries were examined in 100 lower limbs fixed in a 10% formalin solution. A dissection of the popliteal region of the leg was carried out according to a pre-established protocol, using traditional techniques. Morphometric measurements were then obtained twice by two researchers., Results: In most cases (72%) the PA divides to form the anterior tibial artery (ATA) and a common junction for the posterior tibial and fibular arteries (type I), which further splits into the fibular artery and the posterior tibial artery (PTA). This type was subdivided into two subgroups according to whether the ATA (subgroup a) or the common junction of the posterior tibial and fibular arteries (subgroup b) had the larger diameter. Other identified variations included division of the PA into the ATA and PTA-8% (type II), trifurcation-12% (type III), the division of the PTA into the ATA and FA-8% (type IV), and aplasia of the PTA-8% (type IV)., Conclusion: Although the typical PA branching type was observed, it can be classified further into two additional sub-types based on the diameter of the ATA and the common junction of the posterior tibial and fibular arteries.

Although there is much morphological variation in the anterior compartment of the leg, there is little information about the morphological variability of the fibularis tertius muscle (FTM). The main aim of the present study was to characterize the morphology (origin and insertion) and frequency of occurrence of the FTM and to use these findings as the basis for a new classification of the fibularis tertius tendon. Classical anatomical dissection was performed on 106 lower limbs fixed in 10% formalin. The presence of the FTM and the morphology of both its origin and its insertion were described. The FTM was present in 91 limbs (85.8%). Three types of origin were observed: Type 1, the most common type, with its origin on the distal half fibula (67%); Type 2, with the origin on the distal third fibula (22%); and Type 3, with an origin from the tendon of the extensor digitorum longus (11%). In addition, six types of insertion were distinguished. The most common was Type I (45%), a single distal attachment where the tendon inserts into the shaft of the fifth metatarsal bone. The rarest was Type VI, characterized by fusion with an additional band of the fibularis brevis tendon, which gives rise to the fourth interosseus dorsalis muscle. Two morphological variants of insertion could be distinguished, fan-shaped and band-shaped. Both the origin and insertion of the FTM are very morphologically variable, with three types of origin (Types 1-3) and six types of insertion point (Types I-VI) observed. Knowledge of such variations is essential for both clinicians and anatomists. Clin. Anat. 32:1082-1093, 2019. © 2019 Wiley Periodicals, Inc., (© 2019 Wiley Periodicals, Inc.)

Background: Morphological variations of the EHL concern mainly the accessory tendons and the site of their insertion. The aim of our study is to present a new classification of the EHL., Methods: Classical anatomical dissection was performed on 104 lower limbs (51 right, 53 left, fixed in 10% formalin solution)., Results: In the cadavers, three types of morphology (insertion and addidtional band) were observed. Type I, the most common type, was characterized by a single tendon that ends as an extensor hood on the dorsal aspect of the base of the distal phalanx of the big toe (57.7%). Type II was characterized by two distal tendons and was subdivided into three subtypes according to (A-29.9%, B-4.8% and C-5.7%). Type III was characterised by three distal tendons (two cases - 1.9%)., Conclusion: The EHL presents high morphological variability. Knowledge of particular types of insertion is essential for both clinicians and anatomists.

The pronator teres (PT) muscle is a forearm flexor with radial and ulnar heads. It is innervated by the median nerve (MN), which passes between these heads. Nerve entrapment, known as "PT syndrome", may occur in this passage. Anatomical variations in this region may be potential risk factors of this pathology. Therefore, the aim of the study was to determine the relationship between morphologic variations of the PT and the MN. In 50 isolated, formalin-fixed upper limbs, the cubital region and the forearm were dissected. The following measurements were taken: origin of the PT muscle heads, the length of these heads, the length of the forearm, diameter of the MN and the number of its muscular branches to the pronator teres muscle. The forearms with the humeral head originating from the medial humeral epicondyle and medial intermuscular septum (72%) were significantly shorter (p = 0.0088) than those where the humeral head originated only from the medial humeral epicondyle. Moreover, in these specimens, the MN was significantly thinner (p = 0.003). The ulnar head was present in 43 limbs (86%). The MN passed between the heads of the PT muscle (74%) or under the muscle (26%). In the majority of cases, it provided two motor branches (66%). There is an association between the morphologic variation of the PT muscle heads and the course and branching pattern of the MN. Both are related to differences in forearm length. This may have an impact on the risk of PT syndrome and the performance of MN electrostimulation.

The plantaris muscle usually begins with a short and small muscle belly on the popliteal surface of the femur and on the knee joint capsule. It continues distally to form a long and thin tendon typically fixed to the calcaneal tuberosity. However, the course and the insertion of the plantaris muscle is variable, which may influence the development of Achilles tendinopathy. The plantaris tendon may also be used for reconstruction of tendons and ligaments, such as talofibular and calcaneofibular ligament. In literature review no data concerning the co-occurrence of anatomic variations of the plantaris muscle tendon in different individuals has been found. This report presents a rare variant of the plantaris muscle insertion into the deep crural fascia on the left leg and absence of the plantaris muscle on the right leg of the same individual.