Which of the following is a large, deep muscle that protracts the scapula during punching?
a. Serratus anterior
b. Rhomboids
c. Levator scapulae
d. Subscapularis

Verified step by step guidance

1. Step 1: Understand the function of the muscles listed in the options. The question asks for a large, deep muscle that protracts the scapula, which means it moves the scapula forward, such as during a punching motion.
2. Step 2: Review the role of the Serratus anterior. This muscle is located on the side of the thorax and is known for pulling the scapula forward and around the rib cage, which is essential for protraction.
3. Step 3: Consider the Rhomboids. These muscles are located between the scapula and the vertebral column and primarily act to retract (pull back) the scapula, opposite of protraction.
4. Step 4: Examine the Levator scapulae. This muscle elevates the scapula and helps with downward rotation but does not protract the scapula.
5. Step 5: Look at the Subscapularis. This is a rotator cuff muscle located on the anterior surface of the scapula and mainly functions to medially rotate the humerus, not to protract the scapula.

Key Concepts

Muscle Anatomy of the Scapula

Understanding the muscles attached to the scapula is essential, including their location, size, and depth. This knowledge helps identify which muscles are responsible for specific movements like protraction or retraction of the scapula.

Scapular Movements and Functions

Scapular movements include protraction, retraction, elevation, and depression. Protraction involves moving the scapula forward around the rib cage, which is crucial during actions like punching.

Role of the Serratus Anterior Muscle

The serratus anterior is a large, deep muscle that originates on the ribs and inserts on the scapula. It is primarily responsible for protracting the scapula, stabilizing it against the thoracic wall during pushing or punching motions.