The insertions of these muscles have fibers intertwined with connective tissue and the dermis of the skin. Because the muscles insert in the skin rather than on bone, when they contract, the skin moves to create facial expression Figure 1. Figure 1. Muscles of Facial Expression. Many of the muscles of facial expression insert into the skin surrounding the eyelids, nose and mouth, producing facial expressions by moving the skin rather than bones. The orbicularis oris is a circular muscle that moves the lips, and the orbicularis oculi is a circular muscle that closes the eye.
The occipitofrontalis muscle moves up the scalp and eyebrows. The muscle has a frontal belly and an occipital near the occipital bone on the posterior part of the skull belly. In other words, there is a muscle on the forehead frontalis and one on the back of the head occipitalis , but there is no muscle across the top of the head. The physicians originally studying human anatomy thought the skull looked like an apple. The majority of the face is composed of the buccinator muscle, which compresses the cheek.
This muscle allows you to whistle, blow, and suck; and it contributes to the action of chewing. There are several small facial muscles, one of which is the corrugator supercilii , which is the prime mover of the eyebrows. Place your finger on your eyebrows at the point of the bridge of the nose.
Raise your eyebrows as if you were surprised and lower your eyebrows as if you were frowning. With these movements, you can feel the action of the corrugator supercilli. Additional muscles of facial expression are presented in Table 1. The movement of the eyeball is under the control of the extrinsic eye muscles , which originate outside the eye and insert onto the outer surface of the white of the eye.
These muscles are located inside the eye socket and cannot be seen on any part of the visible eyeball Figure 2 and Table 2. If you have ever been to a doctor who held up a finger and asked you to follow it up, down, and to both sides, he or she is checking to make sure your eye muscles are acting in a coordinated pattern. Figure 2. Muscles of the Eyes.
In anatomical terminology, chewing is called mastication. Muscles involved in chewing must be able to exert enough pressure to bite through and then chew food before it is swallowed Figure 3 and Table 3.
The masseter muscle is the main muscle used for chewing because it elevates the mandible lower jaw to close the mouth, and it is assisted by the temporalis muscle, which retracts the mandible.
You can feel the temporalis move by putting your fingers to your temple as you chew. Figure 3. Muscles That Move the Lower Jaw. There are also many arteries that branch off the various levels of the vertebral arteries to send blood to the spinal cord, bones, joints, and other areas. Neck Strain Treatments and Prevention. You are here Conditions Spine Anatomy. Peer Reviewed. Cervical Muscle Anatomy Animation Save.
Next Page: Cervical Discs. Editor's Top Picks. The muscle begins at the flexor retinaculum in…. The movement of the upper arm and shoulder is controlled by a group of four muscles that make up the rotator cuff.
The largest and strongest muscle in…. The extensor pollicis longus muscle begins at the ulna and the interosseous membrane, a tough fibrous tissue that connects the ulna and the radius in…. The biceps brachii, sometimes known simply as the biceps, is a skeletal muscle that is involved in the movement of the elbow and shoulder. It is a…. The skeletal system is the foundation of your body, giving it structure and allowing for movement.
The jejunum is one of three sections that make up the small intestine. Learn about its function and anatomy, as well as the conditions that can affect….
The muscles of the middle ear contract to dampen the amplitude of vibrations from the eardrum to the inner ear. The neck muscles, including the sternocleidomastoid and the trapezius, are responsible for the gross motor movement in the muscular system of the head and neck.
They move the head in every direction, pulling the skull and jaw towards the shoulders, spine, and scapula. Working in pairs on the left and right sides of the body, these muscles control the flexion and extension of the head and neck. Working individually, these muscles rotate the head or flex the neck laterally to the left or right.
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