A distal attachment site of a muscle innervated by the axillary nerve is which of the following?

A distal attachment site of a muscle innervated by the axillary nerve is which of the following?

• A. Inferior facet of the greater tuberosity of the humerus
• B. Middle third lateral border of the scapula
• C. Medial part of the bicipital groove
• D. Lateral third of clavicle, acromion, and spine of scapula

Answer: (A)

The axillary nerve supplies the deltoid and teres minor. The question asks for a distal attachment (insertion) of a muscle innervated by this nerve. Teres minor inserts on the inferior facet of the greater tubercle of the humerus, which is a distal attachment. (Deltoid inserts at the deltoid tuberosity, which is not listed.) The other options describe either muscle origins or insertions of muscles not innervated by the axillary nerve: the lateral border of the scapula is the origin for teres minor; the medial lip of the intertubercular groove is the insertion for teres major (innervated by the lower subscapular nerve); and the lateral third of clavicle, acromion, and spine of the scapula are origins for the deltoid.

The axillary nerve supplies the deltoid and teres minor. The question asks for a distal attachment (insertion) of a muscle innervated by this nerve. Teres minor inserts on the inferior facet of the greater tubercle of the humerus, which is a distal attachment. (Deltoid inserts at the deltoid tuberosity, which is not listed.)

The other options describe either muscle origins or insertions of muscles not innervated by the axillary nerve: the lateral border of the scapula is the origin for teres minor; the medial lip of the intertubercular groove is the insertion for teres major (innervated by the lower subscapular nerve); and the lateral third of clavicle, acromion, and spine of the scapula are origins for the deltoid.