The humeral head is spheroidal in s

The humeral head is spheroidal in shape in most individuals with an average diameter of 45 mm. 6 The bony architecture inferior to the articular surface is made up of the lesser (anterior) and greater (lateral) tuberosities. The greater tuberosity on average is 8 mm below the humeral articular surface. 6 These protuberances of bone serve as the attachment sites for the rotator cuff. The subscapularis attaches to the lesser tuberosity and the supraspinatus, infraspinatus, and teres minor attach to the greater tuberosity. The humeral head has an average retroversion of 25°, but there exists an SD of about 10°. 7 The head-­shaft angle is roughly 135°. 6 The blood supply to the humeral head is made up of the ascending branch of the anterior humeral circumflex and arcuate arteries, but the posterior humeral circumflex is the main contribution.