Deltoid origin NOT an origin?

Deltoid origin NOT an origin?

• A. Lateral 1/3 of clavicle
• B. Acromion
• C. Spine of scapula
• D. Greater tubercle of humerus

Answer: (D)

The deltoid has three distinct origins: the lateral third of the clavicle, the acromion, and the spine of the scapula. These attachment points allow the different fibers to contribute to flexion/medial rotation, abduction, and extension/lateral rotation of the shoulder. The greater tubercle of the humerus is not an origin for the deltoid; it is an insertion site on the humerus (the deltoid inserts at the deltoid tuberosity there). The greater tubercle is where the rotator cuff muscles—especially the supraspinatus, infraspinatus, and teres minor—attach, helping you remember that this spot is an insertion, not an origin for the deltoid.

The deltoid has three distinct origins: the lateral third of the clavicle, the acromion, and the spine of the scapula. These attachment points allow the different fibers to contribute to flexion/medial rotation, abduction, and extension/lateral rotation of the shoulder. The greater tubercle of the humerus is not an origin for the deltoid; it is an insertion site on the humerus (the deltoid inserts at the deltoid tuberosity there). The greater tubercle is where the rotator cuff muscles—especially the supraspinatus, infraspinatus, and teres minor—attach, helping you remember that this spot is an insertion, not an origin for the deltoid.