Muscle Overview

Overview

This lecture reviews the main muscles of the head, face, neck, and upper body, focusing on muscle names, locations, and specific actions.

Muscles of the Face and Scalp

• The muscle that raises eyebrows is the frontalis.
• The muscle that draws the scalp back is the occipitalis.
• The muscle in front of the ear is the auricularis anterior.
• The muscle above the ear is the auricularis superior.
• The muscle behind the ear is the auricularis posterior.
• The muscle between the eyebrows (controls drawing in and downward) is the corrugator.
• The muscle that raises eyelids is the levator palpebrae superioris.
• The orbicularis oculi is the muscle around the eye that closes the eyelids.
• The procerus covers the bridge of the nose and moves the eyebrows down.
• The nasalis is the muscle that flares the nostrils.
• The orbicularis oris is the muscle around the mouth, closes and puckers lips.
• The levator labii superioris raises the nostrils and upper lip (distaste expression).
• The depressor labii inferioris pulls lower lip down or to the side (sarcasm expression).
• The mentalis pushes lower lip up and wrinkles chin (doubt expression).
• The zygomaticus major draws mouth up and out (grinning).
• The levator anguli oris raises the angle of the mouth (snarling).
• The depressor anguli oris draws mouth corners down (sadness).
• The risorius draws mouth down and back (laughing).
• The buccinator compresses the cheek to release air.

Muscles of the Jaw and Neck

• The masseter and temporalis are used for opening and closing the jaw.
• The platysma draws down the lower lip and mouth angles, tenses neck skin, and helps depress the mandible.
• The sternocleidomastoid flexes the neck and rotates the head (nodding yes or no).
• The trapezius draws the head back and elevates the shoulder blades.

Muscles of the Arms and Shoulders

• The deltoid is triangular, covers the shoulder, and lifts or rotates the arm.
• The pectoralis major is under the arm, helps lift the arm, and aids in breathing.
• The biceps brachii is the primary muscle in the front of the upper arm; raises forearm, bends elbow, and turns palm down.
• The triceps brachii extends from the upper arm to the forearm, controlling forward forearm movement.
• Latissimus dorsi assists in swinging the arms.

Key Terms & Definitions

• Frontalis — Muscle that raises eyebrows.
• Occipitalis — Muscle that draws scalp back.
• Orbicularis Oculi — Encircles the eye; closes eyelids.
• Orbicularis Oris — Encircles mouth; closes and puckers lips.
• Zygomaticus Major — Draws mouth up and out.
• Masseter — A jaw muscle; closes the jaw.
• Sternocleidomastoid — Flexes neck and rotates head.
• Deltoid — Lifts and rotates arm.
• Biceps brachii — Raises forearm and bends elbow.
• Triceps brachii — Controls forward movement of the forearm.

Action Items / Next Steps

• Review and memorize the names, locations, and actions of major facial, neck, and upper body muscles.
• Practice labeling diagrams of head and arm muscles.
• Prepare for quiz on muscle identification and actions.