Posterior circumflex humeral a.

The posterior humeral circumflex artery (posterior circumflex artery, posterior circumflex humeral artery) arises from the axillary artery at the lower border of the subscapularis, and runs posteriorally with the axillary nerve through the quadrangular space.

It winds around the neck of the humerus and is distributed to the deltoid muscle (aka deltoideus) and shoulder-joint, anastomosing with the anterior humeral circumflex and profunda brachii.

It feeds the teres minor and deltoid muscles.