Axillary nerve and posterior circumflex humeral artery
Mnemonic
“Axillary nerve and posterior circumflex humeral artery”.
Boundaries: teres minor above, teres major below, the long head of triceps medially, and the surgical neck of the humerus laterally.
“The axillary nerve wraps the surgical neck”, which is why it is injured in surgical neck fractures and anterior shoulder dislocation, giving:
- Weak abduction from deltoid paralysis
- Numbness over the regimental badge area of the lateral upper arm
Sensation over the regimental badge must be tested and documented before and after reduction of every shoulder dislocation.
The two neighbouring spaces complete the set: the triangular space (circumflex scapular artery) and the triangular interval (radial nerve and profunda brachii), bounded by teres major above, the long head of triceps medially and the humerus laterally.
Expansion
Contents:
- Axillary nerve
- Posterior circumflex humeral artery
Borders:
- Superior - teres minor
- Inferior - teres major
- Medial - long head of triceps
- Lateral - surgical neck of the humerus