Y-shaped axillary arch muscle: A case report

Abstract

The axillary arch is a rudimentary part of the latissimus dorsi. Generally it has a single insertion either into tendon of the pectoralis major, coracobrachialis or fascia over the biceps. Clinically, this anomalous muscular slip is known to cause neurovascular compression of nearby structures. The present case reports an unusual bifurcated fibrous insertion of an axillary arch with Y-shaped limbs. The stem of this muscle was a fleshy belly measuring 7.8 cm. The upper limb of this muscle, measuring 5.6 cm, was attached to the fascia covering the short head of biceps brachii and the coracoid process while its lower limb, measuring 5.1 cm, ended by merging with the brachial fascia over the biceps brachii below the deltoid muscle. The persistence of such a Y-shaped anomalous axillary arch might restrict the hyperabduction of the arm and compress the neurovascular structures passing below it.

‘Digastricus’ axillary arch: A potential source of hyperabduction syndrome- Case report

“…The most common morphological description of the axillary arch is that they are bidirectional band with a solitary origin and insertion. Nevertheless, multiple studies have reported variations in their morphology, with Loukas et al, reporting the presence of numerous bands at the insertion sites 5 , while Shanthakumar et al reports the presence of an extraordinary 'Y' formed axillary arch with a bifid distal attachment, one to the short head of the biceps brachii, and the other to coracoid process 6 .…”