**Question:** Abduction of shoulder is done by all, EXCEPT

A. Infraspinatus
B. Subscapularis
C. Pectoralis Major
D. Levator Scapulae

**Correct Answer:** D. Levator Scapulae

**Core Concept:** The primary muscles responsible for shoulder abduction are the supraspinatus, infraspinatus, and teres minor muscles, all part of the rotator cuff. The subscapularis is primarily involved in internal rotation and medial rotation of the shoulder. The levator scapulae, on the other hand, is a minor muscle located on the posterior aspect of the neck, primarily involved in upward and lateral rotation of the scapula on the vertebral column.

**Why the Correct Answer is Right:** Levator scapulae is not a primary abductor of the shoulder joint, but rather a secondary muscle involved in scapular stabilization. It plays a role in upward and lateral rotation of the scapula, which is distinct from the primary action of shoulder abduction. In contrast, the other options are part of the rotator cuff, which primarily functions in shoulder abduction.

**Why Each Wrong Option is Incorrect:**

A. Infraspinatus: This muscle is part of the rotator cuff and contributes to abduction.
B. Subscapularis: Although subscapularis is involved in internal rotation and medial rotation, it is not primarily responsible for shoulder abduction.
C. Pectoralis Major: This muscle is part of the pectoral region and not involved in shoulder movement.

**Clinical Pearl:** Proper understanding of muscle anatomy and function is essential for accurate diagnosis and treatment planning in musculoskeletal disorders, particularly in cases involving the shoulder joint. A thorough understanding of muscle origins, insertions, and actions is crucial for medical professionals to make accurate clinical judgments.