Function Of The Muscles Of The Shoulder Girdle

The correct answer is "arm abduction beyond initial 15 degrees." The m. deltolideus, also known as the deltoid muscle, is responsible for the abduction of the arm. Abduction refers to the movement of the arm away from the midline of the body. The deltoid muscle is activated when the arm is lifted away from the body, and it allows the arm to be raised beyond the initial 15 degrees of abduction.

The correct answer is lateral rotation of arm. The infraspinatus muscle is one of the four muscles that make up the rotator cuff in the shoulder. It is responsible for the external or lateral rotation of the arm, which means it helps to rotate the arm away from the body. This muscle works in conjunction with the other muscles of the rotator cuff to stabilize and move the shoulder joint.

The m. teres minor is responsible for the lateral rotation of the arm. This means that it helps to rotate the arm away from the midline of the body, allowing for movements such as reaching out to the side or throwing a ball.

The m. teres major is responsible for the medial rotation of the arm. This muscle is located on the back of the upper arm and connects the scapula to the humerus bone. When it contracts, it pulls the arm inward, causing it to rotate towards the body's midline. This movement is important for various daily activities, such as reaching across the body or performing tasks that require internal rotation of the arm, like throwing a ball.

The m. subscapularis is responsible for the medial rotation of the arm. This muscle is located on the anterior side of the scapula and attaches to the humerus. When it contracts, it pulls the arm towards the midline of the body, causing it to rotate inward. This movement is important for various activities such as throwing a ball or reaching for objects on the opposite side of the body.

The m. supraspinatus is responsible for arm abduction to 15 degrees. This muscle is located in the supraspinous fossa of the scapula and works in conjunction with other muscles of the rotator cuff to facilitate the initial phase of arm abduction. It helps to lift the arm away from the body and raise it to a 15-degree angle. Beyond this point, other muscles take over to continue the abduction of the arm.