Quadrangular space

The quadrangular space is an axillary space in the arm. This is a clinically important anatomic space in the arm. In the quadrangular space, the axillary nerve and posterior circumflex humeral artery can be compressed or damaged due to space-occupying lesions or disruption in the anatomy due to trauma. Symptoms include axillary nerve related weakness of the deltoid muscle in the case of any significant mass lesions in the quadrangular space.

Boundaries

• Above/superior: the subscapularis and teres minor. Some sources exclude the teres minor.

• Below/inferior: the teres major

• Medially: the long head of the triceps brachii

• Laterally: the surgical neck of the humerus