Final Answer:
B. Posterior deltoid, latissimus dorsi, long head of the triceps, and pectoralis major are the primary muscles that extend the shoulder.
Step-by-step explanation:
The primary muscles B. responsible for extending the shoulder joint are the posterior deltoid, latissimus dorsi, long head of the triceps, and pectoralis major, as mentioned in option B. These muscles work together to execute the movement of extending the shoulder, which involves moving the arm backward.
The posterior deltoid, located at the back of the shoulder, plays a key role in shoulder extension. The latissimus dorsi, a large muscle in the back, contributes significantly to shoulder extension and adduction. The long head of the triceps, situated at the back of the upper arm, aids in extending the elbow joint, which is essential for shoulder extension. Additionally, the pectoralis major, despite its primary role in shoulder flexion, also assists in shoulder extension.
Understanding the involvement of these muscles in shoulder extension is essential in the context of exercise, rehabilitation, and overall shoulder function.
Strengthening these muscles can contribute to improved shoulder stability and function, preventing imbalances and reducing the risk of injuries. In summary, the collaboration of the posterior deltoid, latissimus dorsi, long head of the triceps, and pectoralis major is crucial for effective shoulder extension.