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Background: Direct common carotid puncture (DCP) is conventionally used as a bailout technique in stroke patients. However, little is known about the relevant anatomy. Our objective was to examine the relationship of the common carotid artery (CCA) to surrounding structures based on different DCP trajectories passing through the artery's center., Methods: Fifty randomly selected head/neck CTAs were analyzed. The trajectory of DCP and relationship to the internal jugular vein (IJV) and thyroid were analyzed at 1 cm intervals above the clavicle on 7 axial sections. Using the trans-carotid sagittal plane as the 0° trajectory, we plotted 3 additional trajectories at 30° intervals and the relationship with the IJV and thyroid proximity was graded as following: 0=absent, 1=adjacent, and 2=crossing. The CCA tortuosity index was also analyzed for each vessel., Results: Analysis of 2800 trajectories across 100 CCAs showed that the IJV and thyroid were least encountered on the axial sections 2 cm above the clavicle, at 0° on the right (9 thyroids and 6 IJV), and at 90° on the left (0 Thyroids and 14 IJVs). The tortuosity index of the CCA was significantly lower above the clavicle than its entire length (P < 0.001)., Conclusions: DCP performed 2 cm above the clavicle at 0° on the right, and 90° on the left appears to minimize encounters with the IJV and thyroid gland, reducing potential complications. However, despite these findings, ultrasound guidance remains vital for DCP safety. Further focus on endovascular device safety in DCP is needed., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: The current supraomohyoid neck dissection (SOHND) is performed above the omohyoid muscle to dissect levels I, II, and III in the levels of cervical lymph nodes. However, the anatomical boundary between levels III and IV is the inferior border of the cricoid cartilage. We investigated the anatomical relationship between the omohyoid muscle and cricoid cartilage using contrast-enhanced CT (CE-CT) images to assess the validity of the current SOHND., Methods: CE-CT images of the head and neck regions in patients were reviewed. The patients were divided into two groups: "malignant tumors" and "others". The vertebral levels corresponding to the positions of anatomical structures such as the intersection of the omohyoid muscle and internal jugular vein (OM-IJ), and the inferior border of the cricoid cartilage (CC), were recorded., Results: The OM-IJ was located around the seventh cervical to the first thoracic vertebra. There was a significant difference between the malignant tumor and others groups in females (p = 0.036). The CC was located around the sixth to seventh cervical vertebrae. There was a significant sex difference in each group (malignant tumor: p < 0.0001; others: p = 0.008). Both sexes tended to have lower OM-IJ than CC, and females had significantly lower OM-IJ than males., Conclusion: This study provides clear anatomical evidence showing the difference between the SOHND dissection area and levels I, II, and III. It could be considered that in most cases SOHND invades level IV, not just levels I, II, and III, especially in female patients., (© 2024. The Author(s).)

Purpose: Central venous catheterization (CVC) carries inherent risks which can be mitigated through the use of appropriate ultrasound-guidance during needle insertion. This study aims to comprehensively understand patient anatomy as it is visualized during CVC by employing a semi-automated image analysis method to track the internal jugular vein and carotid artery throughout recorded ultrasound videos., Methods: The ultrasound visualization of 50 CVC procedures were recorded at Penn State Health Milton S. Hershey Medical Center. The developed algorithm was used to detect the vessel edges, calculating metrics such as area, position, and eccentricity., Results: Results show typical anatomical variations of the vein and artery, with the artery being more circular and posterior to the vein in most cases. Notably, two cases revealed atypical artery positions, emphasizing the algorithm's precision in detecting anomalies. Additionally, dynamic vessel properties were analyzed, with the vein compressing on average to 13.4% of its original size and the artery expanding by 13.2%., Conclusion: This study provides valuable insights which can be used to increase the accuracy of training simulations, thus enhancing medical education and procedural expertise. Furthermore, the novel approach of employing automated data analysis techniques to clinical recordings showcases the potential for continual assessment of patient anatomy, which could be useful in future advancements., (© 2024. Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB).)

Background and Objectives : The jugular bulb (JB) is the uppermost part of the internal jugular vein receiving the sigmoid sinus. The aim of the present research is to aid the comprehension of the JB, its abnormalities, and surrounding structures for improving both academic and surgical awareness. Materials and Methods : Various studies on this topic were critically reviewed. Cone-beam CT scans and CT and MR angiograms were used to demonstrate each type of the discussed variations. Results : Variations in the JB anatomy were thoroughly documented: high JB, dehiscent JB, hypoplasia and hyperplasia, and diverticula of the JB, as they have significant clinical implications, particularly in the context of otological and neuro-otological surgery, skull base pathology, and diagnostic imaging. Definitions and critical arguments were also specified to clarify existing literature. Additionally, we present a case report illustrating a high and dehiscent JB, an anatomical variation of clinical interest due to its potential for misdiagnosis as a glomus tumor. Another case describes a dehiscent JB with a hypotympanic air cell protruding into it, further highlighting the variability of this condition. Conclusions : It is necessary to proceed with caution when observing abnormal morphological characteristics of the JB. Preoperative assessment of each case is essential for optimal outcomes.

Objectives: This report presents a rare anatomical variation, double fenestration of the External jugular vein on the right side., Materials and Methods: During the routine dissection of a male cadaver aged 60 years, we observed a unilateral large double fenestration of the External jugular vein on the right side., Results: After its formation from the posterior division of the retromandibular and posterior auricular veins, External jugular vein descended in the posterior triangle of neck. Here, it divided into medial, intermediate, and lateral veins that united again before draining into the subclavian vein. Lateral vein was the largest (7.2 cm) and intermediate and medial veins were measuring 6.4 cm each. Two large fenestrations, measuring 5.8 cm each, arranged like a "double bubble" were seen in the External jugular vein extending from fourth to sixth cervical (C4 to C6) vertebrae. The medial branch of supraclavicular nerve was seen passing superficial to the distal part of External jugular vein. On the left side, the course of External jugular vein showed a standard pattern., Conclusion: Surgeons must be acquainted with the varied anatomy of the superficial neck veins to prevent major bleeding during operative procedures, including carotid endarterectomy, flap operations, & central venous catheterisation., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Purpose: This study investigated the internal carotid artery (ICA) and jugular bulb (JB) structures in terms of lateral temporal bone resection using 3D computed tomography (CT)., Methods: We retrospectively investigated 80 ears of 40 patients using 3D reconstruction data from normal temporal bone CT. Ten critical points (P) in the temporal bone were marked in the 3D object with reference to the axial, coronal, and sagittal images of the CT scans. An imaginary plane of the facial nerve (PLf) course was also reconstructed in relation to the three points of the chorda-facial junction, P5 (second genu), and P3 (cochleariform) process., Results: The distances (mean ± SD; mm) from points P3 to P1 (the highest level of the JB) and P2 (the posterior wall of the ascending petrous IAC at the level of the Eustachian tube) were 12.03 ± 2.56 and 9.79 ± 1.78, respectively. The distances from point P4 (chorda-facial junction) to P1 and P2 were 10.98 ± 2.70 and 17.66 ± 2.26, respectively. The angles (mean ± SD; degree) between the PLf to the line from Pa (point of the anterior bony canal) to P3 and P4 were 17.80 ± 10.05º and 8.93 ± 5.37º, respectively. The angles between the PLf to the line from P3 to P1 and P2 were - 36.35 ± 13.28º and - 24.78 ± 13.91º, respectively. The angles between the PLf to the line from P4 to P1 and P2 respectively were - 40.35 ± 15.37º and - 13.34 ± 7.63º., Conclusions: Understanding the anatomical relationships of P1 and P2 at P3 and P4 can be helpful in preventing iatrogenic trauma of the ICA and JB., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Purpose: This study aims to assess the anatomical possibilities of the jugular bulb (JB)., Methods: Fifty archived CBCT scans were analyzed., Results: The average distance between the internal acoustic canal (IAC) and the JB was 7.97 mm on both sides (Right: SD = 2.56 mm, range 3.16-13.3 mm; Left: SD = 2.5 mm, range 2.9-13.6 mm). JB walls' pneumatization was classified into eight patterns. Deep petrosal cells (DPCs) prevailed in the lateral wall of the JB. The absence of pneumatization (NP) was commonly found on the left side. The presence of infralabyrinthine and hypotympanic cells varied. Less common types included accessory occipital cells (AOCs), posteromedial tracts (PMTs), and basi-occipital cells (BOCs), which determined a consistent variation of the lateral wall pneumatization patterns. Pneumatization of the medial wall was not observed in 50 right sides and 49 left sides. The inferior wall analysis revealed symmetry in AOC distribution and a predominant occurrence of NP. Cases with hypotympanum (HT) in the lateral wall showed a statistically significant IAC-JB distance increase by an average of 4.67 mm compared to NPs. Specific pneumatizations, particularly HT on the lateral side, have a significant effect on the IAC-JB distance, showing a clear pattern of increasing distance from DPC to NP and then to HT. A significant distance increase in HT pneumatization was noted. There were also recorded instances of JB hypoplasia and hyperplasia, JB diverticula, dehiscent JBs, and high JBs., Conclusion: This study establishes a novel classification of JB pneumatizations to aid in the understanding of the temporal bone anatomy., (© 2024. The Author(s).)

Background: Spinal Accessory Nerve (SAN), which innervates the sternocleidomastoid (SCM) and trapezius muscles, is closely related to the internal jugular vein (IJV) in the anterior triangle of the neck and passes superficially in the posterior triangle. Injury to SAN is a major complication of level II neck dissection, leading to shoulder syndrome. The present study aims to assess the course and its relation to the SCM muscle and IJV in the Tamil ethnolinguistic groups in South India., Methods and Materials: The anterior and posterior triangles of the neck were dissected in 28 formalin-fixed adult cadavers. The course of the SAN and the entry and exit points of SAN along the SCM muscle were assessed using the mastoid process as the reference. Recorded data was analyzed using SPSS software., Results: The SAN was anteriorly related to the IJV in 58.73%, posteriorly in 37.5%, and pierced through the IJV in 3.57% of the specimens. The entry and exit points of SAN from the mastoid process were 37.86±7.26mm and 48.55±8.22mm, respectively. In 86.67% of the cases, the SAN traversed through the SCM muscle, and in 13.33%, it was deep to the SCM., Conclusion: The present study reports that the SAN is variable in its course, and relation to SCM and IJV. Knowledge about the variant anatomy of the SAN in the triangles of the neck is important and it aids surgeons to prevent iatrogenic injuries to SAN or IJV and enhance surgical safety in neck procedures., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Purpose: The superficial venous system (SVS) of the neck receives blood from the face and oral cavity. The SVS comprises the anterior jugular vein (AJV), external jugular vein (EJV), and facial vein (FV). Comprehensive knowledge of the normal anatomy and potential variations in the venous system is valuable in surgical and radiological procedures. This study aimed to update the anatomic knowledge of the SVS using a radiographic approach, which is a beneficial data source in clinical practice., Methods: Contrast-enhanced computed tomography images of the neck of patients with head and neck cancer treated between 2017 and 2020 were retrospectively evaluated. Each side of the neck was counted separately. A total of 302 necks of 151 patients were enrolled in this study., Results: The medial AJV was absent in 49.7% (75/151) of the patients on the left side, which was significantly greater than the 19.2% (29/151) on the right (p < 0.001). The left AJV drained into the right venous system in 6.6% (10/151) of the necks. In 48.3% (146/302) of the necks, the FV did not flow into the internal jugular vein but rather into the EJV or AJV; these findings were significantly more frequent than those reported in previous studies. The diameters of the veins were significantly larger when they received blood from the FV than when they were not connected to the FV., Conclusion: These findings indicate that the AJV has a rightward preference during its course. The course of the FV is diverse and affects the diameter of connected veins., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Background: Cannulation of a central vein is crucial in patients for hemodynamic management and when insertion of a peripheral line is not possible. The internal jugular vein is the preferred access site; however, in the case of not being accessible, the second cannulation site of choice is still unclear. The study aimed to access the feasibility of external jugular vein cannulation versus internal jugular vein cannulation in terms of success, cannulation time, number of attempts and complications., Materials and Methods: In this prospective, randomised double-blinded study, 100 patients received 7Fr size triple-lumen central vein catheter either in the internal jugular vein (n = 50) or external jugular vein (n = 50) through the landmark technique as a part of anaesthetic care in the operation theatre. The number of attempts, cannulation time and incidence of complications in both the techniques were observed and recorded., Results: The success rate in internal jugular vein cannulation was 88%, while in the external jugular vein, it was 78% (p = 0.17). The external jugular vein cannulation was comparatively quicker in our study (p = 0.01). Similarly, elevated body mass index did not affect the success rate in the number of cannulations attempts in either group (p = 0.08). In terms of complications, the internal jugular vein group had a total of 20% and the external jugular vein group had 28% complications; however, the complications were more severe in the internal jugular vein group., Conclusion: Anaesthetists should rethink alternate routes for the insertion of central vein cannulation. The external jugular cannulation route is one of them., 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.

Background and Purpose: There has been limited literature regarding the bridging veins (BVs) of the medulla oblongata around the foramen magnum (FM). The present study aims to analyze the normal angioarchitecture of the BVs around the FM using slab MIP images of three-dimensional (3D) angiography., Methods: We collected 3D angiography data of posterior fossa veins and analyzed the BVs around the FM using slab MIP images. We analyzed the course, outlet, and number of BVs around the FM. We also examined the detection rate and mean diameter of each BV., Results: Of 57 patients, 55 patients (96%) had any BV. The median number of BVs was two (range: 0-5). The BVs originate from the perimedullary veins and run anterolaterally to join the anterior condylar vein (ACV), inferior petrosal sinus, sigmoid sinus, or jugular bulb, inferolaterally to join the suboccipital cavernous sinus (SCS), laterally or posterolaterally to join the marginal sinus (MS), and posteriorly to join the MS or occipital sinus. We classified BVs into five subtypes according to the draining location: ACV, jugular foramen (JF), MS, SCS, and cerebellomedullary cistern (CMC). ACV, JF, MS, SCS, and CMC BVs were detected in 11 (19%), 18 (32%), 32 (56%), 20 (35%), and 16 (28%) patients, respectively. The mean diameter of the BVs other than CMC was 0.6 mm, and that of CMC BV was 0.8 mm., Conclusion: Using venous data from 3D angiography, we detected FM BVs in most cases, and the BVs were connected in various directions., (© 2023. The Author(s).)

As the facial transplantation procedures are becoming more popular and frequent in recent years, for repairing facial trauma, variations in the veins of head and neck needs to be reported time and again. This study was undertaken to examine the course and drainage pattern of the facial vein and external jugular vein on this context and emphasize its surgical implications. The authors studied the head and neck region of 50 embalmed cadavers of both sexes to document normal and variant anatomy of facial, retromandibular, and external jugular veins. In 30% of the head and neck regions, different draining pattern of the above-mentioned veins were observed. One of the rare variation discovered was the splitting of the retromandibular vein to embrace the external carotid artery within the parotid gland. The data about variations in the termination of facial vein, retromandibular vein, and external jugular vein, as observed in the present study might be useful in avoiding accidental injury to these vessels during any surgical intervention in the face as well as neck. Level of Evidence: IV., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

Central venous access remains an integral part of perioperative and intensive care, and several methods have been described to locate the internal jugular vein (IJV) prior to cannulation. The apex of Sedillot's triangle between the manubrial and clavicular heads of the sternocleidomastoid (SCM) muscle is a commonly used anatomical landmark for a central percutaneous approach to the IJV, but the literature highlights failures and complications when adopting this method. This cadaveric study was designed to investigate the usefulness of Sedillot's triangle to locate the IJV. Sixty-one cadavers were used for investigation at the University of Cambridge Human Anatomy Centre. Sedillot's triangle was dissected and a pin was inserted in a sagittal plane at the apex of the triangle. The location of the pin in relation to the IJV was recorded. The distance between the sternal and clavicular heads of SCM was also measured. In total, the pin inserted at the apex of Sedillot's triangle pierced the IJV in 72/117 (61.5%) of dissections, with 71.4% on the right and 52.5% on the left. There was important variation in SCM anatomy, and there was no gap between its two heads in 12% of the neck dissections. We demonstrate an overall poor success rate of the central percutaneous approach using Sedillot's triangle, although our findings are limited being a simulated cadaveric study. We support education and use of ultrasound in addition to landmark techniques to aid the safe insertion of central venous catheters., (© 2023 American Association of Clinical Anatomists and British Association of Clinical Anatomists.)

Central venous access is an important procedure to understand and perform not only in the emergency unit but also for prolonged reliable venous access. All clinicians must be familiar and confident with this procedure. This paper will focus on applied anatomy in respect of common anatomical sites for venous access, the indications, the contraindications, the technique and complications that may arise following the procedure. This article is part of a series on vascular access. We have previously written on the intra osseous procedure and an article on umbilical vein catheterisation will follow.

Background: At present, there is a lack of normal magnetic resonance imaging (MRI) morphometric reference values for fetal internal jugular veins during middle and late pregnancy., Objective: We used MRI to assess the morphology and cross-sectional area of the internal jugular veins of fetuses during middle and late pregnancy and to explore the clinical value of these parameters., Materials and Methods: The MRI images of 126 fetuses in middle and late pregnancy were retrospectively analysed to determine the optimal sequence for imaging the internal jugular veins. Morphological observation of the fetal internal jugular veins in each gestational week was carried out, lumen cross-sectional area was measured and the relationship between these data and gestational age was analysed., Results: The balanced steady-state free precession sequence was superior to other MRI sequences used for fetal imaging. The cross section of fetal internal jugular veins was predominantly circular in both the middle and late stages of pregnancy, however the prevalence of an oval cross section was significantly higher in the late gestational age group. The cross-sectional area of the lumen of the fetal internal jugular veins increased with increasing gestational age. Fetal jugular vein asymmetry was common, with the right jugular vein being dominant in the high gestational age group., Conclusion: We provide normal reference values for fetal internal jugular veins measured by MRI. These values may form the basis for clinical assessment of abnormal dilation or stenosis., (© 2023. The Author(s).)

(1) Background : The external jugular vein (EJV) descends on the sternocleidomastoid muscle to drain deep into the subclavian vein. Anatomical variations of the EJV are relevant for identification of the greater auricular nerve, flap design and preparation, or EJV cannulation. (2) Methods : Different publications were comprehensively reviewed. Dissections and three-dimensional volume renderings of peculiar cases were used to sample the review. (3) Results : Different anatomical possibilities of the EJV were critically reviewed and documented: fenestrations and double fenestrations, true or false duplications, triplication, absence, aberrant origin or course, or bifurcation. Tributaries of the EJV, such as the facial and posterior external jugular veins, are discussed. The internal jugular vein termination of the EJV is also presented. (4) Conclusions : Care should be taken when different morphological features of the EJV are encountered or reported.

Purpose: High-riding jugular bulbs (JBs) among other anatomical variations can limit surgical access during lateral skull base surgery or middle ear surgery and must be carefully assessed preoperatively. We reconstruct 3D surface models to evaluate recent JB classification systems and assess the variability in the JB and surrounding structures., Methods: 3D surface models were reconstructed from 46 temporal bones from computed tomography scans. Two independent raters visually assessed the height of the JB in the 3D models. Distances between the round window and the JB dome were measured to evaluate the spacing of this area. Additional distances between landmarks on surrounding structures were measured and statistically analyzed to describe the anatomical variability between and within subjects., Results: The visual classification revealed that 30% of the specimens had no JB, 63% a low JB, and 7% a high-riding JB. The measured mean distance from the round window to the jugular bulb ranges between 3.22 ± 0.97 mm and 10.34 ± 1.41 mm. The distance measurement (error rate 5%) was more accurate than the visual classification (error rate 15%). The variability of the JB was higher than for the surrounding structures. No systematic laterality was found for any structure., Conclusion: Qualitative analysis in 3D models can contribute to a better spatial orientation in the lateral skull base and, thereby, have important implications during planning of middle ear and lateral skull base surgery., (© 2023. The Author(s).)

Purpose: During retrosigmoid craniotomy, the mastoid emissary vein (MEV) can be a source of considerable bleeding during the operation, especially when the larger diameter MEV or sigmoid sinus is torn. In this study, we evaluated the relevant structure of the MEV for their anatomy and applied the data in surgery to summarize their clinical significance., Methods: The posterior craniocervical regions of 15 silicon-injected Chinese human cadaver specimens were dissected to expose the MEV and adjacent structures. Fifty-one patients who were scheduled to undergo retrosigmoid craniotomy were selected. All patients underwent preoperative routine CT of the head. The relevant data were collected on cadaveric anatomy and CT. Eventually, all patients underwent retrosigmoid craniotomy and the MEV was observed during the operation., Results: In cadaver specimens, the prevalence of the MEV was 90.0%. It originated from the middle and lower parts of the posterior wall of the sigmoid sinus and extended in the posterior direction in the mastoid process, usually having 1-2 external openings (86.7%) and only 1 internal opening. The intraosseous courses of the MEV were classified as straight and curved. The straight type accounted for 57.9%, and the curved type for 42.1%. The mean diameter of the MEV was 1.84 ± 0.85 mm, and the straight length of the MEV inside the mastoid process was 11.93 ± 3.58 mm. In 16.7% and 6.7% of all cadaver specimens, the MEV diameter was greater than 2.5 and 4 mm, respectively. In 51 patients (bilateral), routine head CT scan showed the MEV in 49.0% of the patients, and the MEV diameter was greater than 2.5 and 4 mm, respectively, in 17.6% (18/102) and 3.9% (4/102) of the cases. During surgery (unilateral) in the 51 patients, 48 had the MEV and 3 had no MEV. None of the patients had sigmoid sinus tears or massive bleeding., Conclusion: In the process of retrosigmoid craniotomy, detailed anatomical knowledge of the MEV, well-planned CT scan, and meticulous microsurgical techniques are key for successful operation, which can reduce the occurrence of complications., (© 2022. The Author(s).)

Introduction: The anterior jugular vein (AJV) is part of the superficial venous drainage system of the head and neck. Recently, interest in AJV is increasing as various surgical procedures have been developed. The authors conducted a cadaveric study to determine characteristics of AJV in Koreans., Methods: A total of 44 cadavers were dissected. Anatomical characteristics were analyzed for 34 cadavers in which AJV was well observed., Results: In this study, 21 were males and 13 were females. There were 8 cadavers with only 1 AJV from both sides. There was no significant difference in anatomical characteristics according to gender or AJV variation except for a difference in the length of the neck according to gender. However, it was possible to find a safety zone at the main landmark of the neck that could avoid AJV damage., Conclusions: By using this safety zone, it is possible to prevent damage to the AJV and reduce complications during various surgical procedures on the head and neck., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)

Background: The vagus ("wandering") nerve is the longest cranial nerve with the largest territory of innervation in the human body. Injury during various operative procedures involving the anterior or lateral neck may lead to serious complications. Per "textbook" descriptions, the cervical vagus nerve (CVN) commonly locates within the carotid sheath, in between the common carotid artery (CCA) and internal jugular vein (IJV). However, anatomic variations in its positioning may occur more often than expected and intraoperative identification may anticipate potential surgical pitfalls., Methods: A literature review was conducted per PRISMA guidelines for all studies describing positional variations of the CVN within the carotid sheath. A rare and potentially dangerous variation, occurring in only 0.7% of all reported cases, is illustrated with a cadaveric case., Results: Overall, 10 anatomic CVN variations have been described across 971 specimens. The non-textbook variations (26.5%) consist of: lateral (4.7%), anterolateral (8.7%), posteromedial (0.2%), posterior (5.8%), anterior (3.1%), medial (0.7%), and anteromedial (0.4%) to the CCA, as well as posterolateral (0.3%) and posterior (2.6%) to IJV. The "textbook" anatomic location is posterolateral to CCA (73.5%). Moreover, an increase in variability is reported on the left side (17.1%) compared with the right (11.3%). Our cadaveric dissection revealed a right-sided CVN directly medial to the CCA., Conclusions: Positional variations of the CVN occur in over 26% of patients and may add difficulty to an array of surgical procedures. Knowledge of these variations and their prevalence may aid the surgeon in conducting a more precise dissection possibly preventing significant potential adverse sequelae., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Many anatomical variations of the superficial veins of the head and neck have been reported throughout the literature. Accordingly, anatomists and surgeons must have a comprehensive understanding of these variations to avoid confusion. Duplication of the external jugular vein (EJV) is occasionally observed during routine cadaveric dissections; however, this variation seems to be reported less often than actual experience suggests. Therefore, to gain a better understanding of its anatomical and clinical implications, an analysis of the available data should be available. Thus, in this article, we reviewed the current available literature for studies reporting duplication of the EJV., Methods: We conducted a search using PubMed and Google Scholar with the following keywords: "duplication of the external jugular vein," "division of the external jugular vein," and "fenestration of the external jugular vein," "double external jugular vein," and "doubled external jugular vein." As a case illustration, we also describe a case of a duplicated EJV found during a right neck dissection of a female cadaver., Results: Twenty sides across sixteen different studies were analyzed including the present case. All studies were published between 2009 and 2020. EJV division patterns were classified as either duplication, fenestration, fenestration followed by duplication, or double fenestrations., Conclusions: We have reviewed the literature regarding cases documenting duplication/fenestration of the EJV. As it is often difficult to find recent studies that report on classic anatomical variations, therefore, revisiting older articles and textbooks is necessary for achieving a "comprehensive" review, especially across different languages., (© 2021. The Author(s), under exclusive licence to Springer-Verlag France SAS part of Springer Nature.)

Objective: We compared sonoanatomy of the internal jugular vein (IJV) the high (HA), conventional (CA) and the medial oblique approach (MA) to identify the best approach and head position for IJV cannulation., Materials & Methods: Total of 45 volunteers aged 18-65 years were included in this study. The degree of overlap in percentage, depth of IJV from skin, antero-posterior (AP) and transverse diameters (TD) of IJV were measured in real time with ultrasound (US). Measurements were taken in the HA, CA and MA in neutral and 30° head rotation on both the right and left side of the neck., Results: The HA had lower percentage of overlap when compared to CA and MA in neutral and 30° head rotation (p= 0.002 to ≤0.001). The IJV was more shallow in the CA and MA. The AP and TD of the IJV were larger in the MA when compared to HA (p=<0.001) and CA (p =0.026 to < 0.001) and the right IJV has a larger AP and TD in all approaches., Discussion: The HA had the least percentage of overlap compared to CA and MA, therefore the risk of accidental ICA puncture can be reduced. The apparent overlap seen in MA may not reflect the actual scenario because of the way the US beam cuts the vessel. The AP and TD of IJV were significantly increased in the MA, which would ease CVC., Conclusion: We conclude and recommend the medial oblique probe position with 30° head rotation provides optimal real time sonographic parameters for US guided IJV cannulation.

Introduction: We determine the location of the common facial vein (CFV) in a sample of neonates and assess the safety of this vein as an alternative access route for a central venous catheter (CVC)., Materials and Methods: We dissected both the left and right sides of the neck region in 24 neonatal, formalin-fixed cadavers, exposing the underlying soft tissues and neurovascular structures. We identified the CFV, which we then pinned together with the internal jugular vein, cervical branch of facial nerve, marginal mandibular branch of the facial nerve, the cricoid cartilage, brachiocephalic vein, and the mastoid and sternal attachments of the sternocleidomastoid muscle. We measured the CFV and the related pinned structures., Results: In neonates, the CFV intersected the anterior border of sternocleidomastoid on average 19.53 mm (left) and 21.73 mm (right) from its sternal attachment., Conclusion: We found the CFV inferior to the upper one third and just superior to half of the length of the sternocleidomastoid muscle, indicating a possible "safe-zone" where a skin incision could be made over the anteromedial border of sternocleidomastoid. The CFV is easily identified from surrounding landmarks. It could be used as a safe, alternative route for inserting a CVC if its average length (8.72 mm) and diameter (1.50 mm) are taken into account., (© 2020 American Association of Clinical Anatomists.)

Knowledge of variations of the internal carotid artery is significant to surgeons and radiologists. The internal carotid artery normally runs a straight course in the neck. Its anomalies can lead to its iatrogenic injuries. We report a case of a large loop of the internal carotid artery in a male cadaver aged about 75 years. The common carotid artery terminated by dividing it into the external carotid artery and internal carotid arteries at the level of the upper border of the thyroid cartilage. From the level of origin, the internal carotid artery coursed upwards, backwards and laterally, and formed a large loop behind the internal jugular vein. The variation was found on the left side of the neck and was unilateral. The uncommon looping of the internal carotid artery might result in altered blood flow to the brain and may lead to misperceptions in surgical, imaging, and invasive procedures.

Rationale: The left internal jugular vein has a higher possibility of anatomical variation than the right side. Therefore, the complication risk during cannulation is expected to be higher., Patient Concerns: A 74-year-old woman was scheduled for elective surgery for left upper lobe wedge resection. We observed an anatomical abnormality at the location of the common carotid artery (CCA) and left internal jugular vein (IJV)., Diagnosis: During the ultrasound, the left IJV was detected at the medial side of the CCA, and this anatomical variation was confirmed by color Doppler ultrasonography. Enhanced chest computed tomography showed that the left CCA ran across the left IJV from medial to lateral at the level of the clavicle., Intervention: A triple-lumen central venous catheter was inserted at the right IJV to avoid complications caused by the anatomical variation., Outcomes: There were no intraoperative or postoperative complications., Lessons: Anesthesiologists should consider anatomical variation during central venous cannulation, especially with the left IJV approach. Because of anatomical variation, ultrasound-guided intervention is highly recommended to prevent procedure-related complications.

Otitic hydrocephalus (OH) comprises a form of benign intracranial hypertension, which is secondary to otogenic lateral sinus thrombosis (LST). Only a small percentage of the patients with otogenic LST go into developing OH, and this may be associated with the multiplicity of anatomic variations of the cerebral venous drainage pathways. We present two pediatric cases of OH, along with a comprehensive review of the relevant literature. Both cases discussed in this article had concomitantly a rather rare anatomical variation; a high-riding, dehiscent jugular bulb, which might have played a role in the development of their clinical syndrome. The pediatric population with this particular imaging finding should receive special attention. Clinical implications of this concurrence are fitly discussed., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: At present, no consensus has been reached on the compartmental subdivision of the jugular foramen (JF), which can complicate surgical planning in this area and hinder understanding of foraminal tumor growth patterns. The extradural neural axis compartment (EDNAC) might aid in producing a standardized model in the future. In the present review, we have summarized the models of JF compartmentalization and analyzed how sound they are anatomically., Methods: The present narrative review identified the key studies and supporting reports that had discussed, referenced, or first presented models of JF compartmentalization., Results: Three intraforaminal components serve as the basis for JF compartmentalization: the fibro-osseous bridge, neurovascular contents, and EDNAC. A total of 4 models have been proposed to date. These include the 2-part (bipartite) models by Hovelacque (1934) and Shapiro (1972) and the 3-part (tripartite) subdivisions by Katsuta (1997) and Bernard (2018)., Conclusions: The bipartite model has been criticized as being oversimplified and lacking surgical validity. However, support for this compartmentation has persisted despite the increasing popularity of the tripartite model. The 3-part subdivision of Bernard can be considered the most anatomically faithful model to date owing to the consideration of the dura and EDNAC. It is important that future studies consider the entire anatomy of the JF, which may generate an anatomically accurate and surgically applicable compartmental model., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The external anatomical landmark and the radiological landmark have been introduced to provide estimation of the depth of right internal jugular venous catheter during insertion., Aims: This study aimed to compare the accuracy, agreement, and reliability of the external anatomical landmark and the radiological landmark, confirmation being by transesophageal echocardiography., Methods: This prospective observational study was conducted in children ages 1-15 years. The catheter was placed at the superior vena cava and the right atrium junction guided by transesophageal echocardiography. The catheter depth derived from the transesophageal echocardiography, the external anatomical landmark, and the radiological landmark was recorded. The optimal zone of the catheter tip was 5 mm below and 10 mm above the superior vena cava and the right atrium junction. Accuracy was assessed by the difference between the transesophageal echocardiography and the external anatomical landmark or the radiological landmark. Agreement with Bland-Altman plots and correlation were tested., Results: Eighty participants, median age of 3 years, were enrolled. The median (IQR) differences between the depth of the transesophageal echocardiography and the external anatomical landmark or the radiological landmark were 0.30 (0, 0.70) and 0.10 (-0.20, 0.90) cm, respectively. Bland-Altman plots demonstrated good agreement between the depths. The catheter tips were located in the optimal zone more frequently with the external anatomical landmark than the radiological landmark (94.7% vs 64.5%). The external anatomical landmark showed a stronger correlation to transesophageal echocardiography than the radiological landmark (r = .95 vs .83)., Conclusion: Both the external anatomical landmark and the radiological landmark enabled accurate estimation of the central venous catheter depth close to the superior vena cava and the right atrium junction. The external anatomical landmark is of more potential use than the radiological landmark in clinical practice., (© 2020 John Wiley & Sons Ltd.)

Background and objectives: There is a paucity of research on the shape of internal jugular vein (IJV) and their association with an individual's morphology and various chronic diseases. Therefore, this study aimed to analyze the anatomy of the IJV across various patients and to relate the differences in anatomy to basic patient characteristics. Materials and Methods: This retrospective study included a total of 313 patients who underwent contrast-enhanced neck computed tomography between January 2017 and December 2018. The circumferences of the right and left IJVs were measured at three locations (hyoid bone, cricoid cartilage, and first thoracic vertebra) and parameters affecting the size of the IJV were analyzed. Results: The right IJV was significantly larger than the left IJV at each position ( p < 0.001), and the area of the lumen was the largest at the cricoid cartilage level ( p < 0.001). After dividing the right IJV data into two groups (above and below the median area), multivariate logistic regression analysis showed that age (odds ratio (OR) 1.040; 95% confidence interval (CI) 1.022-1.058, p < 0.001) and body mass index (BMI, OR 1.080; 95% CI 1.011-1.154, p = 0.0.23) affected size. Conclusions: The right IJV is larger than the left and has a rhomboid morphology. Age and BMI are significant factors affecting the IJV size., Competing Interests: None

Background: Many formulas based on the patient's height, weight and/or age exist to determine central venous catheter (CVC) depth in children. However, this information is unavailable in some emergency conditions. Therefore, direct methods should be developed to guide catheter position in children., Methods: Eighty patients aged 1-10 y were enrolled from July 2015 to August 2016 and seventy-five were completed; fifty were male, and twenty-five were female. The exclusion criteria were inability to identify the sternal angle or failure to use the right internal jugular vein approach. The catheter was inserted using the right internal jugular vein approach, the distance from the skin puncture point to the midpoint of the sternal angle plane was measured, and the catheter tip was positioned to this distance minus 1 cm. Chest radiography were performed for those children after catheter insertion. The relative position between the catheter tip and carina was confirmed and the longitudinal distance from the catheter tip to the carina was calculated on radiographic images, and related complications were recorded., Results: All catheter tips were above the carina, and the average distance from the catheter tip to the carina was 9.8 mm. No patients experienced serious complications., Conclusion: The sternal angle is a useful and reliable anatomic landmark for guiding CVC position in children. Using this landmark, the catheter can be quickly and conveniently placed at a safety position in right internal jugular vein, especially in some emergency conditions., (© 2019 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Surgical management of extensive skull base tumors, such as chordoma and chondrosarcoma, remains very challenging. The need for gross total removal to improve survival must be weighed against the risk of injury to neurovascular structures and the loss of stability at the craniovertebral junction. In cases of tumors that are already compromising craniovertebral junction stability, the occipital condyle can be exploited as a deep keyhole to reach the clivus, petrous apex, and sphenoid sinus., Methods: We performed an anatomic study on 7 cadaveric specimens to describe the main landmarks and boundaries of the corridor. We also provide a clinical case to demonstrate the feasibility of the approach., Results: In all specimens, using the space provided by the condyle, it was possible to drill the petrous bone up to the posterior wall of the sphenoid sinus following the direction of the inferior petrosal sinus. To successfully complete the approach, after the hypoglossal canal was exposed, endoscopic assistance was needed to overcome the narrowing of the visual field provided by the microscope., Conclusions: In cases of invasive skull base tumor involving the craniovertebral junction and affecting its stability, the occipital condyle can be exploited as a deep keyhole to the homolateral and contralateral petrous apex, clivus, and sphenoid sinus., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: The anatomical complexity of the jugular foramen makes surgical procedures in this region delicate and difficult. Due to the advances in surgical techniques, approaches to the jugular foramen became more frequent, requiring improvement of the knowledge of this region anatomy., Objective: To study the anatomy of the jugular foramen, internal jugular vein and glossopharyngeal, vagus and accessory nerves, and to identify the anatomical relationships among these structures in the jugular foramen region and lateral-pharyngeal space., Methods: A total of 60 sides of 30 non-embalmed cadavers were examined few hours after death. The diameters of the jugular foramen and its anatomical relationships were analyzed., Results: The diameters of the jugular foramen and internal jugular vein were greater on the right side in most studied specimens. The inferior petrosal sinus ended in the internal jugular vein up to 40mm below the jugular foramen; in 5% of cases. The glossopharyngeal nerve exhibited an intimate anatomical relationship with the styloglossus muscle after exiting the skull, and the vagal nerve had a similar relationship with the hypoglossal nerve. The accessory nerve passed around the internal jugular vein via its anterior wall in 71.7% of cadavers., Conclusion: Anatomical variations were found in the dimensions of the jugular foramen and the internal jugular vein, which were larger in size on the right side of most studied bodies; variations also occurred in the trajectory and anatomical relationships of the nerves. The petrosal sinus can join the internal jugular vein below the foramen., (Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.)

The objective of this study was to identify and analyze the anatomical variations in the termination of the thoracic duct (TD) in cadavers or patients by anatomical dissections and surgical or radiological procedures for better knowledge of the interindividual variations through a systematic review. The search strategy included PubMed and reference tracking. Studies were identified by searching the electronic Medline databases. The search terms included "TD," "Jugular Vein," "Subclavian Vein," or "Cervical," and the protocol used is reported herein. These search results yielded 20 qualitative review articles out of the 275 articles consulted. We collected all the important data from these 20 articles with 1,352 TD analyzed by varying sources in our search. Regarding the characteristics of the studies and the anatomy of the TD, the results were heterogeneous. The TD most commonly terminates in the internal jugular vein in 54.05% of cases (95% confidence interval [CI]: 54.03; 54.07), in the jugular-venous angle in 25.79% (95% CI: 25.77; 25.81), and in the subclavian vein in 8.16% of cases (95% CI: 8.14;8.18). Other terminations were found in 12% of cases. This systematic review provided an overview of the variations in the distal portion of the TD. This study can be helpful for surgeons in selecting the most appropriate methods to achieve successful surgical results and avoid complications, such as chylothorax; it also offers detailed information on the cervical termination of the TD in new diagnostic and therapeutic methods involving the TD. Clin. Anat. 32:99-107, 2019. © 2019 Wiley Periodicals, Inc., (© 2019 Wiley Periodicals, Inc.)

Background: Commonly used ultrasound-guided internal jugular vein (IJV) cannulation techniques, short axis out of plane and long axis in-plane, have significantly reduced complications but failed to eliminate them because of technical difficulties., Objective: This article describes a new anteroposterior short axis in-plane technique that combines advantage of in-plane technique to track the needle tip and short axis view of visualizing nearby anatomical structures by placing the probe on the side of the neck, oriented anteroposteriorly, perpendicular to the long axis of neck. This view visualizes IJV and its relationship to the carotid artery in short axis. The puncture needle is passed in-plane anteroposteriorly from the anterior aspect of the neck. Visualizing the needle, carotid artery, and IJV in single frame minimizes complications., Methods: A prospective evaluative clinical trial was conducted in patients who require IJV cannulation for various reasons by performers experienced in ultrasound-guided IJV cannulations. The efficacy of the technique is indicated by 3 primary outcome measures: access time, number of attempts and success rate, and safety by secondary outcome measure, which is the incidence of mechanical complications., Results: Seventy-five patients were enrolled. The average number of attempts was 1.17 (standard deviation 0.44), the access time was 27.12 s (standard deviation 21.47), and the success rate was 100%. This technique had 12% incidence of posterior venous wall punctures and 2.66% misplacements and no other complications., Conclusion: Anteroposterior short axis in-plane technique is relatively novel and could be alternatively used safely and effectively in place of existing techniques for IJV cannulation., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Ultrasonography (US) is the recommended imaging technique to evaluate jugular veins. This prospective randomized clinical study was designed to collect a series of B-mode US measurements of manually distended jugular veins in healthy Italian Standardbreds and to find possible correlations between ultrasound measurements and animal morphometric characteristics. Forty-two horses, eight males and 34 females (range 3-22 years; bodyweight 494.4 ± 41.7 kg), were included in the study. The diameters and wall thicknesses of both jugular veins were measured at three different sites of the neck. The differences in ultrasound measurements based on scans, age, gender, side, and site of the neck were evaluated by ANOVA or by the Kruskal-Wallis test. The effects of the morphometric measures on each ultrasound parameter were evaluated by MANOVA (P < 0.05)., Results: The ultrasound measurements did not differ significantly between the three different sites or between genders; hence, they were pooled together in the results. On the transverse scan, the mean dorsoventral and lateromedial diameters were 1.58 ± 0.23 and 2.20 ± 0.25 cm, respectively; the mean superficial and deep wall thicknesses (SWT and DWT) were 0.07 ± 0.01 and 0.08 ± 0.01 cm, respectively. On the longitudinal scan, the mean dorsoventral diameter was 1.59 ± 0.26 cm, and the SWT and DWT were both 0.08 ± 0.01 cm. Neck length, from the caudal edge of the mandible to the thoracic inlet, was related to the dorsoventral diameter in both longitudinal and transverse scan and to the SWT and DWT in transverse scan, whereas height at the withers (measured with tape) and estimated weight were related to the wall thickness. Dividing the subjects into groups by age in years ("young" 3-7, "mature" 8-14, "old" > 14), differences were found for the lateromedial diameter in the transverse scan and the SWT on the longitudinal scan. The main limitation of this study was that only one operator performed the measurements., Conclusion: The US measurements of the jugular veins and their relationship with morphometric measures reported in this manuscript might be considered as guidelines both for early diagnosis and monitoring jugular vein abnormalities in healthy Italian Standardbred horses.

Objective: Human internal jugular veins (IJVs) can collapse during posture change from supine to erect, which might influence intracranial hemodynamics. This study aims to quantitatively describe the gradual collapse behavior of human IJVs during head-up tilt tests from supine to erect., Approach: Ten male and ten female subjects were enrolled in head-up tilt tests. Ultrasound screening was performed on the right IJV at five equidistant points between its junction with the subclavian vein and the location of the bifurcation of the arteria carotis communis, with the body at 0°, +10°, +20°, +30°, 40°, +50°, +60°, +70°, +80°, and  +90°. Geometrical models were reconstructed and lumen areas were statistically analyzed based on extracted outlines of venous lumen., Main Results: The right IJV lumen area reduced significantly when tilt angle was increased from 0° to 20°, as the normalized lumen areas reduced to about 0.5 at the lowest point and about 0.2 at the others. The mean normalized lumen areas of the middle point were much smaller, which dropped below 0.1 when the tilt angle was larger than 40°., Significance: Collapse behavior of human right IJVs was quantitatively described by obtaining variations of lumen outlines and areas at different locations and tilt angles. Reconstructed geometrical models could be used to gain nonlinear pressure-volume relations and inner blood flow characteristics, which can benefit research on human cerebral venous outflow.

Background and Purpose: We evaluated the inferior petrosal sinus (IPS) and adjacent cerebellopontine angle (CPA) cistern as a potential implantation site for a novel venous endovascular transdural CSF shunt concept to treat communicating hydrocephalus. We analyzed the dimensions of the IPS, CPA cistern, and distances to adjacent neurovascular structures., Materials and Methods: Gadolinium enhanced T1 weighted brain MRI datasets of 36 randomly selected patients, aged 20-80 years, were analyzed with three-dimensional multiplanar reconstruction to measure IPS diameter and length, CPA cistern depth, and IPS proximity to the vertebrobasilar arteries and brainstem. Statistical analysis was used to assess gender, sidedness, and age dependence., Results: Mean IPS diameter ranged from 2.27 mm to 3.31 mm at three axial levels, with >90% larger than 1.46 mm. CPA cistern adjacent to the IPS exhibited a mean depth of 3.86 mm to 7.39 mm between the dura and brainstem at corresponding axial levels. There was no side dependence except for a longer distance from the IPS to the basilar artery on the left compared with the right (9.72 vs 7.28, P<0.019). Linear regression analysis showed that the distance from the IPS to the brainstem was statistically significantly increased with age (P<0.0002) and was greater in men, with little side variation (P=0.524)., Conclusion: Our results demonstrate sufficient CSF CPA cisternal space adjacent to the IPS and support the feasibility of an endovascular catheter delivered transdural implantable shunt. Such a device could serve to mimic the function of the arachnoid granulation by establishing a regulated path for CSF flow from the intracranial subarachnoid space to the venous system and provide a treatment for communicating hydrocephalus., Competing Interests: Competing interests: AMM and CBH are co-founders and investors of CereVasc, LLC. AMM, CBH, and BMB are shareholders of CereVasc, LLC., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

The retrosigmoid approach for vestibular schwannoma surgery has remained the standard approach by most neurosurgeons. Drilling the posterior wall of the internal auditory meatus (IAM) is an essential step in removing the intrameatal tumor. During IAM drilling, three anatomical structures can be encountered, including the posterior semicircular canal, vestibular aqueduct, and jugular bulb. Any of these can be injured during drilling, especially if the jugular bulb lies above the inferior edge of the IAM. Although IAM drilling is performed in most vestibular schwannoma surgeries, information on how to manage complications such as jugular bulb injury is lacking. Here we use an intraoperative video to demonstrate how to manage the inadvertent injury to the jugular bulb in order to avoid massive blood loss. We present a case of a 39-year-old woman with hearing loss, diagnosed with a cerebellopontine angle mass extending into the IAM. Surgery was required due to tumor progression. We used the retrosigmoid approach to access the tumor. During IAM drilling, the jugular bulb was injured. A thin layer of bone wax was applied under continuous suction. The margins of the wax were then gently compressed with a dissector; great care was taken to avoid pushing the wax into the jugular bulb. Excess bone wax was removed (video 1). A small diamond drill (2 mm) was used for further drilling. Our instructional video shows the surgical approach, microsurgical anatomy, and technical aspects of managing massive bleeding from jugular bulb injury. It should therefore be helpful for young neurosurgeons., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Normally, the inferior root of Ansa cervicalis passes around the internal jugular vein and runs in an anterior direction to meet the superior root ventral to the common carotid artery. However, anatomical variants of the Ansa cervicalis are as yet not well investigated and understood. To close this gap the present study was undertaken. The Ansa cervicalis was examined in 54 human formalin-fixed cadavers and preparations of the head and neck by conventional dissection. In 66% of the specimens the Ansa cervicalis displayed the typical course that was classified as "internal type" (located medial to the internal jugular vein inside the carotid sheath). The remaining 34% pertained to the "external type" of the Ansa cervicalis (lateral to the internal jugular vein). The distance of the Ansa cervicalis relative to the superior margin of the thyroid cartilage was measured in every specimen. The external type Ansa cervicalis was located significantly lower than the internal type relative to the superior margin of thyroid cartilage. Regarding its location relative to the internal jugular vein four variants of combinations of the external and internal types of Ansa cervicalis on the right and left sides were distinguished. Based on their distance from the superior margin of the thyroid cartilage three types of Ansa cervicalis were defined., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Background: Increasing the size of the central veins is required to increase the success rate of central line placement and decrease complication risk. Right-sided approach for the central veins, Valsalva maneuver, and Trendelenburg position have been recommended, but these may not be available for some cases. This study aimed to determine a more convenient patient position that can result in the largest central vein diameter., Methods: Recruited subjects were placed in 60° and 30° upper body elevation, supine position, and 30° and 60° lower body elevation, and lumbar elevation (LE) was consecutively performed, with one position maintained for 10 min. Diameters of the subclavian vein (SCV) and internal jugular vein (IJV) were measured using high-resolution two-dimensional ultrasonography at each position., Results: The most suitable position on the ordinary bed for increasing central vein diameter was LE. The maximum and minimum SCV and IJV diameters in LE were significantly larger than those in the supine position (SCV: coefficients -0.633 and -0.863, p = 0.08 and 0.011, respectively; IJV: coefficients -1.09 and -1.15, p < 0.001 and = 0.001, respectively). Leg elevation for 10 min failed to dilate the central vein diameter., Conclusion: The LE without leg elevation produced a greater and more significant increase in central vein diameter than the supine position and may be useful for central line placement., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Minimally invasive aesthetic procedures of the neck are becoming more popular. However, anatomical studies on the venous structures of the neck in relation to these procedures are lacking., Objective: The aims of this study were to identify the locations and communication patterns of the anterior jugular vein and external jugular vein (AJV and EJV) and the communicating vein (CV) based on superficial anatomical landmarks and to determine dangerous areas for dermal filler injections into the neck., Materials and Methods: Thirty sides of the neck from Korean adult cadavers were dissected for this study., Results: Four anatomical variants were identified. In Type Ia, the CV ran along the anterior border of the sternocleidomastoid muscle (SCM) (33.4%); in Type Ib, a single vein was observed connecting the CV and the EJV at the level of laryngeal prominence (23.3%); in Type Ic, the CV proceeded separately from the medial side of the anterior border of the SCM (13.3%); and in Type II, the CV was absent while the EJV and AJV were observed (30%)., Conclusion: Given the 4 anatomical variants identified in this study, the authors recommend exerting caution when performing dermal filler injections approximately 10, 30, and 60 mm lateral to the midsagittal line to avoid iatrogenic side effects.

Given the common and increasing exploitation of superficial head and neck veins in a widening spectrum of clinical and surgical procedures, it is important to equally broaden understanding of the heterogeneity of the vascular anatomy of the region. We report an unusual course of the right common facial vein parallel to the course of external jugular vein, emptying into the ipsilateral subclavian vein in the lateral neck triangle behind the posterior border of the sternocleidomastoid muscle in a 78-year-old male cadaver. Such course may be hazardous for surgical procedures in the region given the high risk of profuse haemorrhage from any injury of the vessel. The variant anatomy may also cause problems in invasive techniques involving the vein, especially in emergency and intensive care settings. This index report, therefore, provides a new insight into the superficial head and neck vein anatomical variations in order to guide relevant clinical procedures in the region.

We report an unusual origin and course of the thyroidea ima artery in a male cadaver. The ima artery originated from the right subclavian artery very close to origin of the right vertebral artery. The artery coursed anteriorly between the common carotid artery medially and internal jugular vein laterally. It then coursed obliquely, from below upwards, from lateral to medial superficial to common carotid artery, to reach the inferior pole of the right lobe of thyroid and branched repeatedly to supply the anteroinferior and posteroinferior aspects of both the thyroid lobes and isthmus. The superior thyroid arteries were normal. Both the inferior thyroid arteries were absent. The unusual feature of this thyroidea ima artery is its origin from the subclavian artery close to vertebral artery origin, the location being remarkably far-off from the usual near midline position, and the oblique and relatively superficial course. This report is a caveat to neck surgeons to consider such a superficially running vessel to be a thyroidea ima artery.

Background: The internal jugular vein is one of the major vessels of the neck. The anatomy of this vessel is considered to be relatively stable. It is an important landmark for head and neck surgeons as well as the anaesthetists for both diagnostic and therapeutic purposes., Methods: We present two case reports of the posterior tributary of the internal jugular vein and review the surgical literature regarding anatomical variations of the vein., Findings: A total of 1197 patients from 27 published papers were included in this review. Of these patients, 99.6% had neck surgery and the rest were cadaveric dissections. Anatomical variations of the internal jugular vein were found in 2% of the patient cohort (n = 40). The majority of these patients had either bifurcation or fenestration of the vein. The posterior tributary of the internal jugular vein is unusual and is scarcely reported in the literature (three cases). Knowledge of variations in the anatomy of the internal jugular vein assists surgeons in avoiding complications during neck surgery and preventing morbidity. Two rare cases of posterior branching of the internal jugular vein and experience of other surgeons are demonstrated in this extensive review.