AN10.1-13 | Axilla, Shoulder and Scapular region — Glossary

The pyramid-shaped space between the chest wall and the upper arm, serving as a passageway for vessels, nerves, and lymphatics to the upper limb

The apex of the axilla formed by the gap between the clavicle, scapula, and first rib, through which structures enter from the neck

The main artery supplying the upper limb, divided into three parts by pectoralis minor, giving off 1, 2, and 3 branches respectively

A small triangular muscle deep to pectoralis major that serves as a surgical landmark dividing the axillary artery into three parts

Twenty to thirty lymph nodes in the axilla arranged in five groups that filter lymph from the upper limb, breast, and chest wall

A network of nerves formed by the ventral rami of C5-T1 that supplies motor and sensory innervation to the entire upper limb

The junction of the C5 and C6 roots forming the upper trunk of the brachial plexus, site of injury in Erb's palsy

Upper brachial plexus injury (C5, C6) resulting in the characteristic waiter's tip position with arm adducted and medially rotated

Lower brachial plexus injury (C8, T1) resulting in claw hand deformity due to loss of intrinsic hand muscles

Four muscles (SITS: supraspinatus, infraspinatus, teres minor, subscapularis) whose tendons blend with the shoulder joint capsule to stabilise the humeral head

A large diamond-shaped superficial back muscle innervated by the spinal accessory nerve (CN XI) that elevates, retracts, and depresses the scapula

A broad muscle of the back innervated by the thoracodorsal nerve that extends, adducts, and medially rotates the arm

The 'boxer's muscle' innervated by the long thoracic nerve that protracts and rotates the scapula upward; paralysis causes winged scapula

A condition where the medial border of the scapula protrudes posteriorly due to paralysis of serratus anterior from long thoracic nerve injury

The ball-and-socket synovial joint of the shoulder, prioritising mobility over stability with a shallow glenoid cavity

A fibrocartilaginous ring attached to the margin of the glenoid cavity that deepens the socket to increase shoulder joint stability

An arterial anastomosis around the scapula connecting branches of the subclavian and axillary arteries, providing collateral circulation

A space bounded by teres minor, teres major, long head of triceps, and humeral neck through which the axillary nerve and posterior circumflex humeral artery pass

A branch of the posterior cord (C5, C6) that winds around the surgical neck of the humerus to supply deltoid and teres minor; vulnerable in fractures and dislocations

The area of skin over the deltoid supplied by the axillary nerve; sensory loss here indicates axillary nerve injury

A branch of the second part of the axillary artery that supplies the pectoral region, deltoid, and acromioclavicular joint

The largest branch of the third part of the axillary artery that gives off the circumflex scapular artery participating in scapular anastomosis

The nerve (C5, C6, C7) supplying serratus anterior; its injury causes winged scapula and inability to raise the arm above the head

Cranial nerve XI that provides motor supply to trapezius and sternocleidomastoid; vulnerable during posterior triangle surgery