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

Cureus. 2018 Jun 25;10(6):e2875. doi: 10.7759/cureus.2875.

Rai R, Iwanaga J, Loukas M, Oskouian RJ, Tubbs RS.

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Abstract

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.

KEYWORDS:

axillary arch; brachial plexus compression; langer’s arch; median nerve; neurovascular

Figure 1

Case reported herein illustrating the left axilla and proximal upper limb.

Note the lax axillary arch muscle being lifted with the dissector. The attachments of this aberrant muscle are seen at the latissimus dorsi and deltoid muscles.

Figure 2

Abduction of the upper limb and note the compression of underlying nerves by the axillary arch muscle.