The axillary arch: anatomy and suggested clinical manifestations

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.

[Focus on axillary anatomy: The Carl Langer muscle, a great forgotten muscle in the training of medical residents in gynecology and obstetrics]

OBJECTIVE

The Carl Langer muscle is the main anatomical variation of the walls of the axillary area, its incidence being about 7%. The presence of this muscle crossing the anterior edge of the axillary vessels can induce difficulties of exposure, location and dissection during axillary surgery. In addition, it may be responsible for primary lymphedema of the upper limb, venous thrombosis of the axillary vein or thoracic outlet syndrome due to vascular or nervous compression. The objective of this work was to evaluate the state of knowledge on Carl Langer muscle of the gynecology-obstetrics medical residents of the French Eastern Region.

MATERIAL AND METHODS

All the medical residents enrolled in the specialized diploma in gynecology-obstetrics in the 5 regions (Alsace, Bourgogne, Lorraine, Champagne-Ardenne and Franche-Comté) were questioned by means of a questionnaire sent by e-mail.

RESULTS

From February to March 2021, 94 of the 160 medical residents interviewed answered to the questionnaire. Ninety-one of them (97%) did not know Carl Langer's muscle. Three medical residents thought they knew this muscle (3%) but their knowledge was imperfect.

CONCLUSION

Our work has highlighted the general lack of knowledge of this anatomical variation, which is relatively frequent, among French gynecology-obstetrics medical residents who are required to examine or perform surgery on this area. This updated review of the literature should optimize the knowledge of the anatomy of the axillary area and consequently its surgery.

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.

Duplicated axillary arch muscles arising from the latissimus dorsi

Many origins and insertions of an axillary muscular slip (also known as Langer's or axillary arch muscles) have been documented previously. In this report, we found duplicated axillary arch muscles (two variant muscular slips) originating from the inferolateral border of the right side latissimus dorsi muscle. Obviously, these axillary arch muscles can be distinguished as short and long muscular strips. While the origin was the same, the short muscular slip inserts into the fascia covering on the pectoralis minor, whereas the longer one inserts on/into the aponeurosis of pectoralis major. For the surgery in the axillary region, this rare variation should be considered a cause of surgical interventions.

The innervation of the axillary arch determined by surface stimulodetection electromyography

The axillary arch (AA) is a muscular anatomical variation in the fossa axillaris that has been extensively studied in cadaveric specimens. Within these dissections, different innervations of the AA have been proposed, but this has never been explored in vivo. Knowledge of the innervation of the AA is required in order to better understand its function (e.g. predisposition for certain sports and/or activities, understanding shoulder injuries in overhead sports). Here, we report on the use of surface stimulodetection electromyography (SSEMG) to resolve the innervation of the AA in 20 subjects (12 women, eight men - mean age of 21.3 ± 2.7 years) with a uni- or bilateral AA. SSEMG of each muscle [M. latissimus dorsi (MLD) and M. pectoralis major] was performed with a four-channel electrostimulation measuring system in order to determine the innervation of the AA. The results showed co-contraction of the MLD in 85% of the subjects after AA stimulation. In the remaining subjects, no specific localized response was observed due to non-specific nerve stimulation, inherent to the proximity of the brachial plexus in these individuals. Our findings demonstrate that SSEMG exploration offers a practical and reliable tool for investigating anatomical aspects of muscle innervation in vivo. Using this approach, we conclude that the AA receives the same innervation as the MLD (the N. thoracodorsalis), and may be considered a muscular extension of the latter.

The Muscular Axillary Arch: An Anatomic Study and Clinical Considerations

Objective:

The muscular axillary arch is a musculotendinous structure that arises from the latissimus dorsi muscle and crosses the axilla before inserting to the humerus, brachial fascia, or coracoid process. Case reports have described the neurovascular compression symptoms caused by this anatomic variant and have reported that the symptoms can be relieved by division of the muscle. However, there has been little information published regarding this topic in the neurosurgical literature.

Methods:

We evaluated 70 axillary dissections in 35 cadavers to assess for the presence of this anomaly.

Results:

The muscular axillary arch was identified unilaterally in 3 (8.6%) of the 35 cadavers. All 3 arches arose from the anterior border of the latissimus dorsi muscle and inserted at a point along a line extending from the coracoid process to the intertubercular groove deep to the insertion of the pectoralis major muscle. All 3 arches crossed over the neurovascular bundle in the axilla.

Conclusion:

Compression by the muscular axillary arch should be considered in the differential diagnosis of patients with thoracic outlet and hyperabduction syndromes.

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.