Final answer:
The key backside muscles that move the upper limb include the pectoralis major, latissimus dorsi, trapezius, infraspinatus, and teres minor. They enable the arm to perform movements like rotation, abduction, and adduction. Understanding their anatomy and function explains the upper limb's movement.
Step-by-step explanation:
The muscles responsible for moving the upper limb can be categorized into different groups based on their location and function. For the backside muscles that move the upper limb, important ones include the pectoralis major and the latissimus dorsi. The pectoralis major is a large muscle located on the anterior thorax that helps move the humerus anteriorly. Meanwhile, the latissimus dorsi is a broad, triangular muscle situated on the inferior portion of the back, and it assists in moving the humerus inferiorly. Additionally, the trapezius muscle stabilizes and positions the pectoral girdle and contributes to the movement of the scapula.
Other vital muscles that move the humerus posteriorly are the infraspinatus and the teres minor, both of which help in lateral rotation and abduction of the arm. The teres major muscle helps to extend, adduct, and medially rotate the arm. Collectively, these muscles provide the upper limb with a comprehensive range of motion, including rotation, abduction, adduction, and flexion.
When learning about the muscular system, being familiar with the location, insertion points, and functions of muscles such as the pectoralis major, latissimus dorsi, trapezius, infraspinatus, and teres muscles is essential for understanding how we move our limbs.