Human Body Muscles: Origins And Insertions

The deltoids are a group of muscles located in the shoulder region. They have three origins, one of which is the lateral third of the clavicle, which is the collarbone. The other origins are the acromion, which is a bony process on the shoulder blade, and the spine of the scapula, which is a ridge on the back of the shoulder blade. Therefore, the correct answer is clavicle.

The correct answer is "lateral" because the teres minor muscle originates from the lateral border of the scapula. This means that it attaches to the outer edge of the scapula, specifically the part that is furthest away from the spine.

The pectoralis major muscle originates from the anterior surface of the clavicle, sternum, and the costal cartilage of the upper 6 ribs. This means that it attaches to these structures and originates from them. Therefore, the statement is true.

The rotator cuff muscles are a group of four muscles that help stabilize and move the shoulder joint. These muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis. They work together to provide strength and stability to the shoulder, allowing for a wide range of motion.

The pectoralis minor muscle inserts on the medial border of the coracoid process of the scapula. This means that the muscle attaches to the inner edge of the coracoid process, which is a bony projection on the scapula. Therefore, the statement is true.

The action of the supraspinatus muscle is to abduct the arm. Abduction refers to the movement of the arm away from the midline of the body. The supraspinatus muscle is one of the four muscles that make up the rotator cuff in the shoulder. It is located on the top of the shoulder blade and attaches to the upper arm bone. When the supraspinatus muscle contracts, it helps to initiate and assist in the movement of lifting the arm out to the side, away from the body.

The main action of the serratus anterior muscle is protraction of the scapula. This means that it is responsible for pulling the scapula forward and away from the spine. This action is important for movements such as reaching forward or pushing objects away from the body. The serratus anterior also assists in stabilizing the scapula against the rib cage during arm movements, but its primary function is protraction of the scapula.

The pectoralis minor is indeed a muscle that contributes to scapula stabilization. It originates from the third, fourth, and fifth ribs and inserts into the coracoid process of the scapula. When contracted, it pulls the scapula forward and downward, aiding in stabilizing the shoulder blade. Therefore, the statement "Pectoralis minor is a muscle of scapula stabilization" is true.

The origin of the rhomboids major muscle is from the T2-T5 vertebrae.

The action of the pectoralis minor muscle is to depress the shoulder and scapula. This means that it pulls the shoulder and scapula downward, towards the feet. This action is important for movements such as lowering the arm or retracting the scapula.

The origin of the deltoids is not the deltoid tuberosity on the lateral surface of the shaft of the humerus. The deltoids actually originate from the lateral third of the clavicle, the acromion process of the scapula, and the spine of the scapula. The deltoid tuberosity, on the other hand, is the insertion point for the deltoid muscle, where it attaches to the humerus. Therefore, the correct answer is False.

The pectoralis major muscle inserts into the lateral border of the bicipital groove of the humerus. This means that the muscle attaches to the upper arm bone (humerus) at a specific location along its outer edge.

The correct answer is T1-T5 because the origin of the middle fibers of the trapezius muscle is from the spinous processes of the first to the fifth thoracic vertebrae. These fibers then insert into the acromion process and the spine of the scapula.

The correct answer is "lateral third of the scapula and acromion." The trapezius muscle is a large muscle that extends from the base of the skull down to the middle of the back and laterally to the shoulder. It has multiple insertion points, but the upper fibers of the trapezius insert into the lateral third of the scapula and the acromion. These insertion points allow the trapezius muscle to play a role in the movement and stabilization of the shoulder blade and shoulder joint.

The subscapularis muscle is responsible for the medial rotation of the arm, not the lateral rotation. Therefore, the statement that the action of the subscapularis is lateral rotation of the arm is incorrect.