An unusual relationship between the axillary artery and brachial plexus in a cross-breed dog cadaver: a proposal for revising the terminology for nerve loops.

In the left axilla of a formalin-embalmed adult female cross-breed dog, an unusual course of the axillary artery in relation to the brachial plexus was noted. A part of the axillary artery after the origin of the subscapular artery coursed through the loop formed by the contributions of the caudal pectoral and lateral thoracic nerves and then between the median and ulnar nerves. Thus, the common trunk for the latter two nerves was missing. Instead, in the proximal brachium, they communicated with each other in both directions. A communicating branch between the cranial and caudal pectoral nerves forming a nerve loop, ansa pectoralis lacked the axillary artery and was instead traversed by the subscapular artery. This is a variation in the relationship between the axillary artery and brachial plexus in the domestic dog and has not been reported in the literature yet. The axillary artery entrapped by the contributions of the caudal and lateral thoracic nerves may be considered as a risk factor for the neuroarterial compressions with non-specific signs and should be taken into account both in surgery and imaging.

Entrapment of subscapular artery by the splitting of radial nerve- putative clinical implications.

The third part of the axillary artery has an intimate relationship with the cords of the brachial plexus. The subscapular artery, the largest branch of the axillary artery, arises from its third part. The radial nerve is a branch of the posterior cord of the brachial plexus and its supplies the extensors of the arm, forearm and dorsum of the hand. During routine undergraduate dissection of the axilla of a formalin-fixed cadaver of about 70 years, the subscapular artery was found sandwiched between two divisions of the radial nerve. These anterior and posterior divisions of the radial nerve arose immediately after the formation of the radial nerve and encircled the subscapular artery and fused to form a single nerve subsequently. This variant anatomy can lead to conditions like subscapular entrapment causing ischemia of the scapular region and radial nerve compression causing weakness of the extensors of the upper limb. Injury to the nerve and vessel can occur while performing diagnostic and therapeutic procedures in the area. Knowledge of these variations provides a precautious approach by surgeons and other interventionists while working on this area.

The thoracoacromial trunk: a detailed analysis.

PURPOSE: The thoracoacromial trunk (TAT) originates from the second part of the axillary artery and curls around the superomedial border of the pectoralis minor, subsequently piercing the costocoracoid membrane. Knowledge about the location, morphology, and variations of the TAT and its branches is of great surgical importance due to its frequent use in various reconstructive flaps. METHODS: A retrospective study was conducted to establish anatomical variations, their prevalence, and morphometric data on TAT and its branches. The results of 55 consecutive patients who underwent neck and thoracic computed tomography angiography were analyzed. A qualitative evaluation of each TAT was performed. RESULTS: A total of 15 morphologically different TAT variants were initially established. The median length of the TAT was set at 7.74 mm (LQ 3.50; HQ 13.65). The median maximum diameter of the TAT was established at 4.19 mm (LQ 3.86; HQ 4.90). The median TAT ostial area was set to 13.97 mm (LQ 11.70; HQ 18.86). To create a heat map of the most frequent location of the TAT, measurements of the relating structures were made. CONCLUSION: In this study, the morphology and variations of the branching pattern of the TAT were presented, proposing a new classification system based on the four most commonly prevalent types. The prevalence of each branch arising directly from the TAT was also analyzed. It is hoped that the results of the present anatomical analysis can help to minimize potential complications when performing plastic or reconstructive procedures associated with TAT.

Anatomic landmarks for arthroscopic suprapectoral biceps tenodesis: a cadaveric study.

BACKGROUND: Biceps tenodesis reduces the incidence of Popeye deformity occurring with tenotomy, but pain may occur with tenodesis superior to or within the bicipital groove. Arthroscopic suprapectoral tenodesis is an attractive alternative. The purpose of this study was to establish landmarks for arthroscopic suprapectoral tenodesis and determine the appropriate fixation point to optimize muscle tension. METHODS: Twelve fresh cadaveric shoulders were dissected. Urethane polymer was injected into the axillary artery. The position of the anterior branch of the axillary nerve was marked. The transverse humeral ligament was split, exposing the biceps (long head of the biceps [LHB]) from its origin to the pectoralis major tendon (PMT). The intra-articular portion was released. Measurements were taken from the proximal tendon to described landmarks. RESULTS: The mean length of the intra-articular LHB was 2.53 cm (range, 1.72-3.55 cm). The mean distance from the LHB origin to the inferior lesser tuberosity (LT) was 5.58 cm (range, 4.02-6.87 cm), and that to the superior border of the PMT was 8.46 cm (range, 6.46-10.78 cm). The suprapectoral tenodesis zone (inferior LT to superior PMT) was 2.96 cm (range, 1.54-4.40 cm). In all specimens, a branch of the anterior humeral circumflex arose medial to the LHB and distal to the LT and crossed the suprapectoral zone from medial to lateral at 1.49 ± 0.42 cm proximal to the PMT, approximately at the level of the axillary nerve. The musculocutaneous nerve was on average 3.06 cm (range, 1.86-3.76 cm) from the tenodesis zone. CONCLUSION: A branch of the anterior humeral circumflex is a reliable landmark for identifying the mid-suprapectoral zone. The distance from the proximal LHB tendon to this crossing vessel averaged 6.32 cm in female specimens and 8.28 cm in male specimens. These findings allow appropriate tensioning of the LHB during arthroscopic suprapectoral tenodesis.

Evaluation of the relationship between the topographical anatomy in the axillary region of the brachial plexus and the body mass index.

To investigate the topographic anatomy of the median, musculocutaneous, radial and ulnar nerves with respect to the axillary artery and to seek whether these configurations are associated with baseline descriptive data including age, gender, and body-mass index. This cross-sectional trial was carried out on 199 patients (85 women, 114 men; average age: 46.78 ± 15.45 years) in the department of anaesthesiology and reanimation of a tertiary care center. Topographic anatomy of the median, musculocutaneous, radial and ulnar nerves was assessed with ultrasonography. Localization of these nerves with respect to the axillary artery was marked on the map demonstrating 16 zones around the axillary artery. Frequencies of localizations of every nerve in these zones were recorded, and the correlation of these locations with descriptive data including age, gender and BMI was investigated. There was no difference between women and men for the distribution of the median (p = 0.74), ulnar (p = 0.35) and radial (p = 0.64) nerves. However, the musculocutaneous nerve was more commonly located in Zone A13 in men compared to women (p = 0.02). The localization of the median (p = 0.85), ulnar (p = 0.27) and radial (p = 0.88) nerves did not differ remarkably between patients with BMI < 25 kg/m2 and patients with BMI ≥ 25 kg/m2. Notably, the musculocutaneous nerve was more often determined in Zone A10 in cases with BMI ≥ 25 kg/m2 (p = 0.001). Our results imply that the alignment of the musculocutaneous nerve may vary in men and overweight people. This fact must be considered by the anaesthetist before planning the axillary block of brachial plexus. All these informations may enlighten the planning stages of the brachial plexus blockade.

Proper Choice of Vessels for Supermicrosurgery Training: An Experimental Animal study.

BACKGROUND: Reconstruction using supermicrosurgery, a technique of microneurovascular anastomosis for smaller vessels (< 0.8 mm), has become popular. Experimental animal studies for supermicrosurgery training have been reported; however, there have been few studies performed according to vessel diameter and pedicle length. In this study, the external diameters of four vessels (femoral, superficial epigastric, axillary, and common thoracic) and pedicle length of two flaps (superficial epigastric and common thoracic-long thoracic) were measured. METHODS: The inguinal and pectoral regions of Sprague-Dawley rats (n = 19) were dissected anatomically, and the external diameters of the four vessels were measured (right and left, artery and vein measured separately). After elevating the superficial epigastric and common thoracic-long thoracic flaps, the pedicle length of the flaps was also measured. RESULTS: Among the 16 vessels examined, the external diameters of 11 and 5 vessels were above and below 0.8 mm, respectively. The external diameters of the superficial epigastric vessel and common thoracic vessel (both arteries and veins) were below 0.8 mm. The external diameters of the femoral and axillary vessels (veins) were above 0.8 mm. The length of the common thoracic-long thoracic pedicle was approximately10 mm longer than that of the superficial epigastric pedicle. CONCLUSIONS: The external diameters of the superficial epigastric vessel and common thoracic vessel are small enough for supermicrosurgery training. The pedicle lengths of both the superficial epigastric and common thoracic-long thoracic flaps are sufficient to perform free flap experiments. Supermicrosurgical free flaps using these two vessels and a study of the physiology and pharmacology of the flaps will likely be possible in the future.

The zonal pattern of arterial supply to the brachial plexus and its clinical significance.

PURPOSE: To provide the anatomical basis of blood supply of brachial plexus for the clinical microsurgical treatment of brachial plexus injury. METHODS: Thirteen adult anticorrosive cadaveric specimens (8 males, 5 females) were dissected in this study. 3 fresh cases (2 males, 1 female) were used to observe the zonal pattern of arteries supplying brachial plexus, and 10 cases (6 males, 4 females) were used to observe the source and distribution of the brachial plexus arteries under microscope. RESULTS: The brachial plexus is supplied by branches of the subclavian-axillary axis (SAA), and these branches anastomose each other. According to distribution feature, blood supply of the brachial plexus could be divided into three zones. The first zone was from the nerve roots of intervertebral foramina to its proximal trunks, which was supplied by the vertebral artery and the deep cervical artery. The second zone was from the distal nerve trunks of the brachial plexus, encompassing the divisions to its proximal cords, which was supplied by direct branches of the subclavian artery or by branches originating from the dorsal scapular artery. The third zone was from the distal portion of the cords to terminal branches of the brachial plexus, which was supplied by direct branches of the axillary artery. CONCLUSIONS: The zonal pattern of arterial supply to the brachial plexus is a systematic and comprehensive modality to improve anatomical basis for the clinical microsurgical treatment for brachial plexus injury.

Anatomical variations of median nerve formation, distribution and possible communication with other nerves in preserved human cadavers.

Formation, distribution and possible communication of the median nerve are essential to know in treatment and surgeries of various conditions of injuries e.g. repair or reconstruction of the median nerve post traumatic accident. In the present study, 44 upper limbs were dissected. Root forming the median nerve, the median nerve in relation with the axillary artery and communication of the median nerve with other nerves were noted.

Accessory subscapularis muscle - A forgotten variation?

The quadrangular space is a space in the axilla bounded by the inferior margin of the teres minor muscle, the superior margin of the teres major muscle, the lateral margin of the long head of the triceps brachii muscle and the surgical neck of the humerus, medially. The axillary nerve (C5-C6) and the posterior circumflex humeral artery and veins pass through this space in order to supply their territories. The subscapularis muscle is situated into the scapular fossa and inserts itself into the lesser tubercle of the humerus, thus helping stabilize the shoulder joint. A supernumerary muscle known as accessory subscapularis muscle originates from the anterior surface of the muscle and usually inserts itself into the shoulder joint. It is a rare variation with few reports of its existence and incidence. We present a case of the accessory subscapularis muscle in a male cadaver fixated with a 10% formalin solution. The muscle passed anteriorly to the axillary nerve, thus, predisposing an individual to quadrangular space compression syndrome. We perform a review of the literature and address its clinical, anthropological and anatomical significance.

Defining the minimum anatomical coverage required to protect the axilla and arm against penetrating ballistic projectiles.

INTRODUCTION: Defining the minimum anatomical structural coverage required to protect from ballistic threats is necessary to enable objective comparisons between body armour designs. Current protection for the axilla and arm is in the form of brassards, but no evidence exists to justify the coverage that should be provided by them. METHOD: A systematic review was undertaken to ascertain which anatomical components within the arm or axilla would be highly likely to lead to either death within 60 min or would cause significant long-term morbidity. RESULTS: Haemorrhage from vascular damage to the axillary or brachial vessels was demonstrated to be the principal cause of mortality from arm trauma on combat operations. Peripheral nerve injuries are the primary cause of long-term morbidity and functional disability following upper extremity arterial trauma. DISCUSSION: Haemorrhage is managed through direct pressure and the application of a tourniquet. It is therefore recommended that the minimum coverage should be the most proximal extent to which a tourniquet can be applied. Superimposition of OSPREY brassards over these identified anatomical structures demonstrates that current coverage provided by the brassards could potentially be reduced.

The lateral thoracic artery revisited.

BACKGROUND: Although the variations in the origin of the branches of the axillary and subclavian arteries have been well documented, little information regarding the highly variable lateral thoracic artery (LTA) is available. Descriptions of the LTA variations may prove useful during procedures of the lateral aspects of the thorax such as reconstructive plastic surgery and modified radical mastectomy. PURPOSE: The aim of this study was to examine the anatomy of the LTA and offer an accurate account of its variability. METHODS: The entire course and distribution of the LTA was examined in 420 formalin-fixed adult human cadavers. RESULTS: The LTA was found in 96.7 % of the specimens, showing great morphological variability and classified into six types according to its origin. The most common type was where the LTA arose from the thoracoacromial artery (Type I 67.62 %). In decreasing order of incidence were origins from: the axillary artery (Type II 17.02 %), the thoracodorsal artery (Type III 5 %), and the subscapular artery (Type IV 3.93 %). Additionally, multiple LTAs were present (Type V 3.09 %) and complete absence of LTA (Type VI 3.33 %) was observed. CONCLUSION: Despite variations in origin of the vessels, our dissections demonstrated that the ultimate tissue distribution of the LTA remained typical in the vast majority of the specimens and descended on the lateral border of the pectoralis minor. Our results illustrate the need for re-evaluation of the branches of the thoracoacromial artery with possible consideration that the LTA arises from it, instead of directly from the axillary artery. We hope that the information supplied by this study will provide useful information to anatomists and surgeons alike.

Fenestration of axillary vein by a variant axillary artery.

Variations of venous pattern in the arm are common. In this case report, we present a variation of axillary artery and vein. During routine educational dissections of axillary region, it was observed that a fenestrated axillary vein was perforated by a variant axillary artery in right arm of an old male cadaver. The axillary artery which was fenestrated through axillary vein had only two branches arising from its second part and no branches from its remaining distal parts. The branches are thoraco-acromial (usual) and another large collateral (unusual) branch. This collateral branch is the origin of several important arteries as the subscapular, circumflex scapular, posterior circumflex humeral and lateral thoracic arteries. We propose to name this artery as collateral axillary arterial trunk. The course of this collateral axillary arterial trunk and its branches and also clinical significance of this variation are discussed in the paper.

Percutaneous left axillary artery approach for Impella 2.5 liter circulatory support for patients with severe aortoiliac arterial disease undergoing high-risk percutaneous coronary intervention.

The use of the Impella 2.5 liter (L) device for hemodynamic support has been well described. The typical access site for the Impella 2.5 L device is the femoral artery. The use of the axillary and subclavian artery has been described via surgical cut down for the Impella 5 L device when femoral artery access is not possible. In patients with severe aortoiliac disease and difficult anatomy the femoral artery access for the Impella 2.5 L device is not feasible. We describe the successful percutaneous use of the Impella 2.5 L device for hemodynamic support via the left axillary artery in 2 patients undergoing high-risk PCI with concomitant severe aortoiliac disease.

Unilateral high origin of radial artery from axillary artery.

Variations in the vascular system of upper limbs are relatively common, with considerable significance towards the clinical and surgical point of view. The major arterial variations reported are of high origins of radial and ulnar arteries. During routine dissection of an upper extremity in the Department of Anatomy, Medical University of the Americas, Nevis, West Indies, a variation in the origin of the radial artery from the axillary artery was observed in the right upper limb of a 55-year-old female cadaver. The normal and variant origin of the radial artery has pragmatic importance for surgeons and radiologists. Also, the superficial position of an artery makes it vulnerable to injury during cannulation, which may lead to pseudoaneurysm.

A case of an extremely rare unilateral subscapular trunk and axillary artery variation in a male Caucasian: comparison to the prevalence within other populations.

A male Caucasian cadaver was found to have a large common trunk that branched off of the first part of the axillary artery of the left arm. This trunk gave rise to all but two arterial branches of the axillary region. The large common trunk first gave off a thoracoacromial artery followed by the main branch, the subscapular artery. The subscapular was the origin of the posterior circumflex humeral and lateral thoracic arteries immediately proximal to bifurcating into its two terminal branches, the circumflex scapular and thoracodorsal arteries. Only the superior thoracic and anterior circumflex humeral arteries arose directly from the axillary artery. Also found was a high origin of the radial artery, noteworthy by its serpentine route. In comparison, in the right arm, no variants appeared in the axillary, subscapular, or brachial arteries. A comparison with branching patterns of axillary arteries from demographically similar and dissimilar populations revealed the extreme rarity of this set of anomalies.

Morphology and clinical significance of the distribution of the median nerve within the arm of human cadavers.

OBJECTIVE: To describe the patterns of formation, level of beginning, variations of course, and relation of the median nerve within the arm of human cadavers. METHODS: Sixty upper limbs of 20 male and 10 female adult human cadavers were used in this study. The cadavers were obtained from the Anatomy Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia, and the study was conducted between February and December 2011. The axillary regions, arm, and forearm, of each limb were dissected to clarify the different patterns of median nerve formation and distribution within the arm. RESULTS: The formation of the median nerve from 2 roots was found in 88.3% of upper limbs, while in 11.7% of upper limbs, it had 3 roots. Moreover, the median nerve began at the level of the third part of the axillary artery in 93.3% of upper limbs, and at the coracobrachialis muscle insertion in 6.7% of upper limbs. However, in correlation to the brachial artery, the median nerve had 6 patterns of relationship. The median nerve passed deep to the coracobrachialis and brachialis muscles in 8.3% of upper limbs. Meanwhile, the median nerve supplied the front arm muscles in 3.3% of upper limbs where the musculocutaneous nerve was absent. In 13.3% of upper limbs, the musculocutaneous nerve gave a communicating branch to the median nerve. CONCLUSION: Knowledge of such variants of the median nerve helps clinicians and surgeons in the diagnosis of unexplained clinical cases.

The Unusual High Origin Radial Artery in a Black Kenyan Population: A Cadaveric Study.

Background: The anatomy of the radial artery draws great interests among anatomists for its frequent involvement in variations. Equally, these variations have gained significant attention from clinicians because of the preference to use the radial artery for catheterization. The commonest of radial artery variations involve its site of origin. In published literature, data on this variations exist, but the prevalence of such variations in a Kenyan population has hitherto been unknown. Methods: Sixty-two upper limbs from 50 formalin-fixed cadavers were studied during dissection in the Department of Human Anatomy, University of Nairobi. Results: Fifty-four (87.1%) radial arteries arose within the cubital fossa, while eight (12.9%) had a high origin. Out of the eight high arteries, two (3.2%) branched off from the axillary artery, another two (3.2%) were branches of the proximal third of the brachial artery and four (6.5%) arose from the middle third of the brachial artery. The high origin radial arteries were more common on the right upper limbs (5 out of the 8 cases). Both axillary and brachial origins were seen bilaterally. Conclusion: The present study details important variations in the anatomy of the radial artery in a Kenyan population. With the radial artery being utilized during clinical, surgical and radiological interventions so frequently, an increased understanding and anticipation of such topographic variances is paramount.

Topography and Anatomical Variations of the Axillary Artery.

Knowledge of anatomical variations of the limb's main arteries is significant for the clinicians. Thus, this study is aimed at examining the branching pattern and anatomical variations of the axillary artery. We conducted research on 59 upper limbs of adult human donated cadavers. All axillary artery branches' origins were assessed, and the correlations between points of origins and variations of specific branches were evaluated. The average length of the axillary artery was found to be 11.22 cm, and this length was defined as reference line. Based on this reference line, the first, second, and third parts were 37.56%, 39%, and 30.05%, respectively. The STA was originated from 25.11%. The TAA and LTA were 42.67% and 54.82%, respectively. The SSA, ACHA, and PCHA were 64.72%, 83.89%, and 84.53%, respectively. The origin of LTA was correlated with that of SSA (R = 0.473, P < 0.05) and AHCA (R = 0.307, P < 0.05), respectively. And there was a positive correlation between AHCA and PHCA (R = 0.705, P < 0.05). The number of branches ranged from 3~6, and 9 types were shown. The most frequent branching pattern was common origin of the LTA and SSA (22/59). And AHCA and PHCA were originated together in 19 cases, and both patterns were combined in 12 cases. TTA and LTA branched together in 9 cases, and common trunk for the SSA, PHCA, and AHCA was found in 2 cases. According to this pattern, the origin of LTA and PCHA was significantly different. This information is particularly useful for surgeons and clinicians.

A macroscopic comparison study on main branches of arteria brachialis and arteria subscapularis in Southern Karaman and Hasak sheep breeds.

BACKGROUND: The Southern Karaman sheep, which is very fertile in terms of meat and milk production and is often preferred in livestock raising, is known as a domestic sheep breed. The Hasak sheep is a breed formed by the triple crossbreeding of the German Black-headed, Hampshire and Akkaraman breeds. Arterial feeding of the forelimb is provided by arteria axillaris, a continuation of arteria subclavia. In this study, it was aimed to examine the forelimb arteries in Southern Karaman and Hasak sheep breeds. MATERIALS AND METHODS: Totally, 8 Southern Karaman and 8 Hasak sheep were obtained from Konya Bahri Dagdas International Agricultural Institute. The sheep were anesthetised with xylazine and ketamine and extravasated by cutting the arteria carotis communis in the neck area of the sheep. The forelimbs of the sheep separated from the body were fixed in 10% formaldehyde solution and then dissections were made and the course and branching of the arteries were examined. RESULTS: It was determined that the arteria brachialis was divided into two main branches as distal arteria brachialis and proximal arteria subscapularis at the articulatio humeri level of the arteria axillary. Arteria mediana, which is a continuation of arteria brachialis, was also examined in different parts of antebrachium and ended by splitting into branches. CONCLUSIONS: According to the findings of the Southern Karaman and Hasak sheep breeds, it was determined that the forelimb arteries had some anatomical differences but were similar in structure to many sheep breeds.

Neurovascular axillary variations: superficial brachial artery and single-corded brachial plexus.

Variants of the axillary artery and brachial plexus were found bilaterally in the axilla of an 86-year-old Asian female. On the left, the cadaver donor had a high bifurcation of the second part of the axillary artery, creating a superficial brachial artery. Meanwhile, the right axilla presented with root, trunk, and cord variations in the formation of the brachial plexus, the most interesting feature being a single, unified cord. Presented in this case report are the structural relationships of the variants with considerations regarding anatomy, embryology, prevalence, and clinical importance.