Final answer:
The frontalis raises eyebrows; the masseter aids in chewing; the sternocleidomastoid rotates/flexes the head; the pectoralis muscles help with shoulder joint movements; the biceps and triceps are involved in elbow flexion and extension; the trapezius moves the scapulae and supports the arm; and the deltoid lifts and moves the arm away from the body.
Step-by-step explanation:
Function of Specific Muscles
The frontalis muscle is part of the occipitofrontalis and is responsible for raising the eyebrows and wrinkling the forehead. The masseter is one of the strongest muscles in the human body; it plays a key role in chewing by elevating the mandible (lower jaw) to close the mouth.
The sternocleidomastoid muscle serves to rotate and flex the head. The pectoralis muscles, including pectoralis major and minor, are located in the chest and are responsible for movements of the shoulder joint, such as moving the arm across the body. The biceps brachii, commonly known as the biceps, is prominent in the front of the upper arm and functions to flex the elbow and rotate the forearm.
, the triceps brachii, or triceps, extends the elbow and is located in the back of the upper arm. The trapezius or trapeze is a large muscle in the upper back and neck that moves the scapulae and supports the arm. Lastly, the deltoid muscle forms the rounded contour of the shoulder and functions in lifting the arm and moving it away from the body.