Deltoid middle action?

Deltoid middle action?

• A. Abducts arm after first 15º
• B. Flexes arm
• C. Extends arm
• D. Adducts arm

Answer: (A)

The middle portion of the deltoid is the primary mover for lifting the arm away from the body once the movement has passed the initial phase. The first 15 degrees of arm abduction are driven by the supraspinatus; after that, the middle deltoid fibers take over to abduct the arm through roughly 15 to 90 degrees. The anterior deltoid mainly flexes and medially rotates the arm, while the posterior deltoid extends and laterally rotates it. Adduction isn’t a main action of the deltoid. So, the statement describing the middle deltoid as abducting the arm after the initial 15 degrees best fits its established role.

The middle portion of the deltoid is the primary mover for lifting the arm away from the body once the movement has passed the initial phase. The first 15 degrees of arm abduction are driven by the supraspinatus; after that, the middle deltoid fibers take over to abduct the arm through roughly 15 to 90 degrees. The anterior deltoid mainly flexes and medially rotates the arm, while the posterior deltoid extends and laterally rotates it. Adduction isn’t a main action of the deltoid. So, the statement describing the middle deltoid as abducting the arm after the initial 15 degrees best fits its established role.