Washington Esthetician State Board Practice Exam

Which muscle group is primarily responsible for covering the shoulder joints?

1. Latissimus dorsi

2. Deltoid muscle

3. Rotator cuff muscles

4. Trapezius

The correct answer is: Deltoid muscle

The deltoid muscle group is primarily responsible for covering the shoulder joints due to its anatomical location and structure. This muscle group forms the rounded contour of the shoulder and is critical for the abduction of the arm, allowing it to move away from the body. The deltoid has three distinct parts: the anterior, lateral, and posterior fibers, each contributing to different movements of the shoulder, including flexion, extension, and rotation. While the other choices also pertain to muscles associated with the shoulder complex, they serve different primary functions. The latissimus dorsi, for example, is involved more in the extension, adduction, and rotation of the shoulder rather than just covering the joint. The rotator cuff muscles are essential for stabilizing the shoulder joint and facilitating its movements but do not cover the shoulder in the way that the deltoid does. The trapezius muscle, located in the upper back and neck, primarily supports the movements of the scapula rather than directly covering the shoulder joint. Understanding these distinctions highlights the deltoid muscle's unique role in the shoulder's anatomy and function, making it the primary muscle group that covers the shoulder joints.