Axillary arch in Bulgarian population: clinical significance of the arches

Axillary arch (of Langer): A large-scale dissection and simulation study based on unembalmed cadavers of body donors

Connective or muscular tissue crossing the axilla is named axillary arch (of Langer). It is known to complicate axillary surgery and to compress nerves and vessels transiting from the axilla to the arm. Our study aims at systematically researching the frequency, insertions, tissue composition and dimension of axillary arches in a large cohort of individuals with regard to gender and bilaterality. In addition, it aims at evaluating the ability of axillary arches to cause compression of the axillary neurovascular bundle. Four hundred axillae from 200 unembalmed and previously unharmed cadavers were investigated by careful anatomical dissection. Identified axillary arches were examined for tissue composition and insertion. Length, width and thickness were measured. The relation of the axillary arch and the neurovascular axillary bundle was recorded after passive arm movements. Twenty-seven axillae of 18 cadavers featured axillary arches. Macroscopically, 15 solely comprised muscular tissue, six connective tissue and six both. Their average length was 79.56 mm, width 7.44 mm and thickness 2.30 mm. One to three distinct insertions were observed. After passive abduction and external rotation of the arm, 17 arches (63%) touched the neurovascular axillary bundle. According to our results, 9% of the Central European population feature an axillary arch. Approximately 50% of it bilaterally. A total of 40.74% of the arches have a thickness of 3 mm or more and 63% bear the potential of touching or compressing the neuromuscular axillary bundle upon arm movement.

Ultrasound Detection of the Axillary Arch as a Cause of Thoracic Outlet Syndrome: A Prospective Dissection-Controlled Cadaver Study

Ultrasound as a diagnostic tool in thoracic outlet syndrome (TOS) is becoming increasingly important. The aim of this study was to investigate the diagnostic value of ultrasound in detecting the axillary arch, an ancillary muscle potentially causing TOS. Two hundred upper limbs of 100 fresh, non-frozen, non-embalmed body donors were screened for axillary arches. Sonographic findings were validated by anatomic dissection. Twelve axillary arches were found in 200 upper extremities, corresponding to a prevalence of 8.0% per individual and 6.0% per upper extremity investigated. Ultrasound had low diagnostic performance in identifying axillary arches, with a sensitivity of 66.7% and specificity of 95.7%. There was a tendency to identify more easily arches consisting of purely muscle tissue. Axillary arch thickness, its cross-sectional area and the predominant tissue type were associated with compression of the neurovascular bundle during shoulder elevation. Ultrasound seems to have limited potential to identify axillary arches. However, arches consisting predominantly of muscle tissue may be identified more easily and were associated with compression of neurovascular structures, thus potentially causing symptoms. Further clinical trials are needed to clarify the true value of ultrasound in patients with symptoms of TOS.

Anatomical Variations of the Axillary Arch and Implications in Breast Surgery

INTRODUCTION

Langer's axillary arch (AA), the most common anatomical variant in the axillary area of definite clinical significance. This is an updated review of the reported variations in the structure, highlighting its morphological diversity and its potential in complicating axillary lymph node biopsy, lymphadenectomy, or breast reconstruction.

METHODS

A review of the literature concerning the AA published between 1812 and 2020 was performed using the PubMed, Scopus, Embase, and Cochrane medical databases. The frequency, laterality, morphology, origin, lateral attachment points, vascularization, and neurosis of the AA were the parameters retrieved from the collected data.

RESULTS

The prevalence of AA ranged from 0.8% to 37.5%. It is more often unilateral, muscular in nature, and extending from the latissimus dorsi to the pectoralis major. It is vascularized by the lateral thoracic vessels or the subscapular artery and innervated by the thoracodorsal nerve.

CONCLUSIONS

Langer's AA, when present, may complicate surgical procedures in the area; therefore, every surgeon performing breast or axillary surgery should be aware of this entity and its variations to ensure maximal effectiveness and safety in the management of patients.

Variations of the musculofascial axillary arch with the adjacent lymph nodes

PURPOSE

This unique case gives the extent of knowledge in the axilla area with axillary arch (AA) and a discussion of its clinical importance.

MATERIALS AND METHOD

The anatomical anomaly was found during the dissection class for the brachial plexus. It was identified through the precise dissection of the structures bilaterally.

RESULTS

The cadaver had fascial and muscular AA bilaterally. The fascial AA was separated into the superficial and deep arch group. The superficial arch group connected to the clavipectoral fascia and the axillary fascia. The deep arch group attached to the subscapular fascia. The muscular AA had superficial and deep variations. The superficial muscular AA attached between accessory slip of latissimus dorsi muscle (LDa) and pectoralis quartus muscle (PQ). The deep muscular AA attached to the crest of lesser tubercle of the humerus from LDa. The adipose tissue with the level one central lymph node was located lateral to the pectoralis minor muscle expand from pectoral lymph node through between LDa and PQ.

CONCLUSION

This case showed the fascial and muscular AA together. The muscular AA had both complete and incomplete attachment types. It could give functional and neurological problems in the axilla, such as thoracic outlet syndrome. Additionally, the structures presented with the axillary lymph node. It helps to understand the patient's condition with the AA in the axilla and could provide.

The Role of the Axillary Arch Variant in Neurovascular Syndrome of Brachial Plexus Compression

Axillary arch muscles are often found. In their course through this area, they might interfere with regional neurovascular structures. This case report will examine the presence of the axillary arch muscle and its implication in brachial plexus compression. During routine dissection of the left axilla and upper limb, a variant muscle (axillary arch muscle) was identified arising from the distal tendon of the latissimus dorsi and extending laterally to insert onto the deep surface of the tendon of insertion of the deltoid muscle. In adduction of the upper limb, the muscle was lax without compression of any underlying neurovascular structures. However, in abduction, the aberrant band of muscles compressed the proximal branches of the brachial plexus. Clinicians should be aware of this anatomical variant and its clinical significance in neurovascular compression including brachial plexus compression, thoracic outlet syndrome, and hyperabduction syndrome. This literature will review the anatomy of the axillary arch and its clinical correlate regarding signs, symptoms, diagnosis, and treatment in brachial plexus compression.

Prevalence and anatomy of the axillary arch and its implications in surgical practice: A meta-analysis

PURPOSE

The following research aimed to investigate the prevalence and anatomical features of the axillary arch (AA) - a muscular, tendinous or musculotendinous slip arising from the latissimus dorsi and that terminates in various structures around the shoulder girdle. The AA may complicate axillary lymph node biopsy or breast reconstruction surgery and may cause thoracic outlet syndrome.

METHODS

Major electronic databases were thoroughly searched for studies on the AA and its variations. Data regarding the prevalence, morphology, laterality, origin, insertion and innervation of the AA was extracted and included in this meta-analysis. The AQUA tool was used in order to assess potential risk of bias within the included studies.

RESULTS

The AA was reported in 29 studies (10,222 axillas), and its pooled prevalence estimate in this meta-analysis was found to be 5.3% of the axillas: unilaterally (61.6%) and bilaterally (38.4%). It was predominantly muscular (55.1% of the patients with the AA), originated from the latissimus dorsi muscle or tendon (87.3% of the patients with the AA), inserted into the pectoralis major muscle or fascia (35.2% of the patients with the AA), and was most commonly innervated by the thoracodorsal nerve (39.9% of the patients with the AA).

CONCLUSION

The AA is a relatively common variant, hence it should not be neglected. Oncologists and surgeons should consider this variant while diagnosing an unknown palpable mass in the axilla, as the arch might mimic a neoplasm or enlarged lymph nodes.

Clinical significance of the axillary arch in sentinel lymph node biopsy

Purpose

The axillary arch is an anomalous muscle that is not infrequently encountered during axillary sentinel lymph node biopsy (SLNB) of breast cancer patients. In this study, we aimed to investigate how often the axillary arch is found during SLNB and whether it affects the intraoperative sentinel lymph node (SLN) identification rate.

Methods

We retrospectively analyzed the correlation between the presence of the axillary arch and the SLN sampling failure rate during SLNB in 1,069 patients who underwent axillary SLNB for invasive breast cancer.

Results

Of 1,069 patients who underwent SLNB, 79 patients (7.4%) had the axillary arch present. The SLNB failure rate was high when the patient's body mass index was ≥25 (p=0.026), when a single SLN mapping technique was used (p=0.012), and when the axillary arch was present (p<0.001). These three factors were also found to be statistically significant by multivariate analysis, and of these three factors, presence of the axillary arch most significantly increased the SLNB failure rate (hazard ratio, 10.96; 95% confidence interval, 4.42-27.21; p<0.001). Additionally, if the axillary arch was present, the mean operative time of SLNB was 20.8 minutes, compared to 12.5 minutes when the axillary arch was not present (p<0.001). If the axillary arch was present, the SLN was often located in a high axillary region (67%) rather than in a general low axillary location.

Conclusion

The axillary arch was found to be a significant factor affecting intraoperative SLN failure rate. It is necessary to keep in mind that carefully checking the high axillar region during SLNB in breast cancer patients with the axillary arch is important for reducing SLN sampling failure.

In vivo study of the surgical anatomy of the axilla

Background

Classical anatomical descriptions fail to describe variants often observed in the axilla as they are based on studies that looked at individual structures in isolation or textbooks of cadaveric dissections. The presence of variant anatomy heightens the risk of iatrogenic injury. The aim of this study was to document the nature and frequency of these anatomical variations based on in vivo peroperative surgical observations.

Methods

Detailed anatomical relationships were documented prospectively during consecutive axillary dissections. Relationships between the thoracodorsal pedicle, course of the lateral thoracic vein, presence of latissimus dorsi muscle slips, variations in axillary and angular vein anatomy, and origins and branching of the intercostobrachial nerve were recorded.

Results

Among a total of 73 axillary dissections, 43 (59 per cent) revealed at least one anatomical variant. Most notable variants included aberrant courses of the thoracodorsal nerve in ten patients (14 per cent)—three variants; lateral thoracic vein in 12 patients (16 per cent)—four variants; bifid axillary veins in ten patients (14 per cent); latissimus dorsi muscle slips in four patients (5 per cent); and variants in intercostobrachial nerve origins and branching in 26 patients (36 per cent). The angular vein, a subscapular vein tributary, was found to be a constant axillary structure.

Conclusion

Variations in axillary anatomical structures are common. Poor understanding of these variants can affect the adequacy of oncological clearance, lead to vascular injury, compromise planned microvascular procedures and result in chronic pain or numbness from nerve injury. Surgeons should be aware of the common anatomical variants to facilitate efficient and safe axillary surgery.

A rare case of multiple neuromuscular variations in the axilla and arm

During the dissection of a 73-year-old embalmed male cadaver, we noted unusual variations in the flexor compartment of the upper limb-bilateral axillary arch muscles, a three-headed biceps brachii muscle with two supernumerary bellies-and variations in the origin of the musculocutaneous and median nerves from the brachial plexus. The morphological and clinical significance of this unique coexistence of multiple neuromuscular variations are discussed.

Variety of transversus thoracis muscle in relation to the internal thoracic artery: an autopsy study of 120 subjects

Background

The transversus thoracis muscle is a thin muscular layer on the inner surface of the anterior thoracic wall that is always in concern during harvesting of the internal thoracic artery. Because the muscle is poorly described in the surgical literature, the aim of the present study is to examine in details its variations.

Methods

The data was obtained at standard autopsies of 120 Caucasian subjects (Bulgarians) of both sexes (97 males and 23 females), ranging in age from 18 to 91 years (mean age 52.8 ± 17.8 years). The transversus thoracis morphology was thoroughly examined on the inner surface of the chest plates collected after routine incisions.

Results

An overall examination revealed that in majority of cases the transversus thoracis slips formed a complete muscular layer (left - 75.8%, right - 83.3%) or some of the slips (left - 22.5%, right - 15%) or all of them (left - 1.7%, right - 1.7%) were quite separated. Rarely (left - 3.3%, right - 5.8%), some fibrous slips of the transversus thoracis were noted. In 55.8% of the cases there was left/right muscle symmetry; 44.2% of the muscles were asymmetrical. Most commonly, the highest muscle attachment was to the second (left - 53.3%, right - 37.5%) or third rib (left - 29.2%, right - 46.7%). The sixth rib was the most common lowest attachment (left - 94.2%, right - 89.2%). Most frequently, the muscle was composed of four (left - 31.7%, right - 44.2%) or fifth slips (left - 53.3%, right - 40.8%).

Conclusions

This study provides detailed basic information on the variety of the transversus thoracic muscle. It also defines the range of the clearly visible, uncovered by the muscle part of the internal thoracic artery and the completeness of the muscular layer over it. The knowledge of these peculiar muscle-arterial relations would definitely be beneficial to cardiac surgeon in performing fast and safe arterial harvesting.

The axillary arch - morphological and histological study with clinical importance

The latissimus dorsi is a muscle of the back which forms the posterior fold of the axilla and its tendon twists to insert into the floor of the intertubercular sulcus of the humerus. Occasionally, the muscle has a muscular slip which crosses the axilla to insert into the pectoralis major. This muscular slip is often termed as "axillary arch." In the present study, we report bilateral axillary arch detected in a 45-year-old male cadaver. The average vertical length of the axillary arch measured 7 cm. The average maximum width of the uppermost, middle and lower part of the arch measured 2, 3.5 and 3.2 cm, respectively. The presence of the axillary arch is an uncommon finding in humans, considering the fact that it is solely found in the animals who prefer to hang on the trees. A histological study of the axillary arch was also performed and it showed skeletal muscle fibres which was uniformly arranged. The presence of the axillary arch may assist in the adduction of the shoulder. It may also compress the axillary vessels and nerves thereby causing resultant symptoms. Prior anatomical knowledge of the presence of axillary arch may be helpful for surgeons performing radical dissection of the axillary lymph nodes and ligation of axillary vessels, clinicians diagnosing abduction syndromes and interventional radiologists interpreting axillary mass in day to day clinical practice.

Axillary arch in human: common morphology and variety. Definition of "clinical" axillary arch and its classification

In this work the authors summarize the extensive information available concerning the best-known variant muscular structure in the region of the human axilla--the axillary arch. Emphasis has been placed on the common morphology and variety of the axillary arches. From the anatomical descriptions, the authors extract the characteristics of a group of "typical" axillary arches and also noted the descriptions of a group of "unusual" axillary arches found in the recent literature. The axillary arch terminology, incidence in human population, innervation and origin are discussed. The clinical significance of the axillary arch is presented briefly and the need of a new concept for the axillary arch is stated. In conclusion, for the purpose of clinical practice, a new term--"clinical" axillary arch is defined, and its proper clinically oriented classification is presented.