Figure 1. Muscles of Facial Expression<\/strong><\/p>\n\n\n\n Many of the muscles of facial expression are inserted into the skin surrounding the eyelids, nose, and mouth, producing facial expressions by moving the skin rather than bones.<\/p>\n\n\n\n The\u00a0orbicularis oris\u00a0is a circular muscle that moves the lips, and the\u00a0orbicularis oculiis a circular muscle that closes the eye. The\u00a0occipitofrontalis\u00a0muscle 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. Instead, the two bellies are connected by a broad tendon called the\u00a0epicranial aponeurosis, or galea aponeurosis (galea = \u201capple\u201d). The physicians originally studying human anatomy thought the skull looked like an apple.<\/p>\n\n\n\n The majority of the face is composed of the\u00a0buccinator\u00a0muscle, 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\u00a0corrugator 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\u00a0Figure 2.<\/p>\n\n\n Figure 2. Muscles in Facial Expression<\/strong><\/p>\n\n\n\n The movement of the eyeball is under the control of the\u00a0extrinsic 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 3\u00a0and\u00a0Table 3). 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.<\/p>\n\n\n In anatomical terminology, chewing is called\u00a0mastication. Muscles involved in chewing must be able to exert enough pressure to bite through and then chew food before it is swallowed (Figure 4\u00a0and\u00a0Table 4). The\u00a0masseter\u00a0muscle is the main muscle used for chewing because it elevates the mandible (lower jaw) to close the mouth, and it is assisted by the\u00a0temporalis\u00a0muscle, which retracts the mandible. You can feel the temporalis move by putting your fingers to your temple as you chew.<\/p>\n\n\n Figure 4. Muscles That Move the Lower Jaw<\/strong><\/p>\n\n\n\n The muscles that move the lower jaw are typically located within the cheek and originate from processes in the skull. This provides the jaw muscles with the large amount of leverage needed for chewing.<\/p>\n\n\n\n Although the tongue is important for tasting food, it is also necessary for mastication,\u00a0deglutition\u00a0(swallowing), and speech (Figure 5\u00a0and\u00a0Figure 6). Because it is so moveable, the tongue facilitates complex speech patterns and sounds.<\/p>\n\n\n Figure 5. Muscles that Move the Tongue<\/strong><\/p>\n\n\n Figure 6. Muscles for Tongue Movement, Swallowing, and Speech<\/strong><\/p>\n\n\n\n Tongue muscles can be extrinsic or intrinsic. Extrinsic tongue muscles insert into the tongue from outside origins, and the intrinsic tongue muscles insert into the tongue from origins within it. The extrinsic muscles move the whole tongue in different directions, whereas the intrinsic muscles allow the tongue to change its shape (such as curling the tongue in a loop or flattening it).<\/p>\n\n\n\n The extrinsic muscles all include the word root glossus (glossus = \u201ctongue\u201d), and the muscle names are derived from where the muscle originates. The\u00a0genioglossus\u00a0(genio = \u201cchin\u201d) originates on the mandible and allows the tongue to move downward and forward. The\u00a0styloglossus\u00a0originates on the styloid bone and allows upward and backward motion. The\u00a0palatoglossus\u00a0originates on the soft palate to elevate the back of the tongue, and the\u00a0hyoglossus\u00a0originates on the hyoid bone to move the tongue downward and flatten it.<\/p>\n\n\n\n Everyday Connections<\/p>\n\n\n\n Anesthesia and the Tongue Muscles<\/strong><\/p>\n\n\n\n Before surgery, a patient must be made ready for general anesthesia. The normal homeostatic controls of the body are put \u201con hold\u201d so that the patient can be prepped for surgery. Control of respiration must be switched from the patient\u2019s homeostatic control to the control of the anesthesiologist. The drugs used for anesthesia relax a majority of the body\u2019s muscles.<\/p>\n\n\n\n Among the muscles affected during general anesthesia are those that are necessary for breathing and moving the tongue. Under anesthesia, the tongue can relax and partially or fully block the airway, and the muscles of respiration may not move the diaphragm or chest wall. To avoid possible complications, the safest procedure to use on a patient is called endotracheal intubation. Placing a tube into the trachea allows the doctors to maintain a patient\u2019s (open) airway to the lungs and seal the airway off from the oropharynx. Post-surgery, the anesthesiologist gradually changes the mixture of the gases that keep the patient unconscious, and when the muscles of respiration begin to function, the tube is removed. It still takes about 30 minutes for a patient to wake up, and for breathing muscles to regain control of respiration. After surgery, most people have a sore or scratchy throat for a few days.<\/p>\n\n\n\n The muscles of the anterior neck assist in deglutition (swallowing) and speech by controlling the positions of the larynx (voice box), and the hyoid bone, a horseshoe-shaped bone that functions as a solid foundation on which the tongue can move. The muscles of the neck are categorized according to their position relative to the hyoid bone (Figure 7).\u00a0Suprahyoid muscles\u00a0are superior to it, and the\u00a0infrahyoid muscles are located inferiorly.<\/p>\n\n\n Figure 7. Muscles of the Anterior Neck<\/strong><\/p>\n\n\n\n The anterior muscles of the neck facilitate swallowing and speech. The suprahyoid muscles originate from above the hyoid bone in the chin region. The infrahyoid muscles originate below the hyoid bone in the lower neck.<\/p>\n\n\n\n The suprahyoid muscles raise the hyoid bone, the floor of the mouth, and the larynx during deglutition. These include the\u00a0digastric\u00a0muscle, which has anterior and posterior bellies that work to elevate the hyoid bone and larynx when one swallows; it also depresses the mandible. The\u00a0stylohyoid\u00a0muscle moves the hyoid bone posteriorly, elevating the larynx, and the\u00a0mylohyoid\u00a0muscle lifts it and helps press the tongue to the top of the mouth. The\u00a0geniohyoid\u00a0depresses the mandible in addition to raising and pulling the hyoid bone anteriorly.<\/p>\n\n\n\n The strap-like infrahyoid muscles generally depress the hyoid bone and control the position of the larynx. The\u00a0omohyoid\u00a0muscle, which has superior and inferior bellies, depresses the hyoid bone in conjunction with the\u00a0sternohyoid\u00a0and\u00a0thyrohyoid muscles. The thyrohyoid muscle also elevates the larynx\u2019s thyroid cartilage, whereas the\u00a0sternothyroid\u00a0depresses it to create different tones of voice.<\/p>\n\n\n\n The head, attached to the top of the vertebral column, is balanced, moved, and rotated by the neck muscles (Table 5). When these muscles act unilaterally, the head rotates. When they contract bilaterally, the head flexes or extends. The major muscle that laterally flexes and rotates the head is the\u00a0sternocleidomastoid. In addition, both muscles working together are the flexors of the head. Place your fingers on both sides of the neck and turn your head to the left and the right. You will feel the movement originate there. This muscle divides the neck into anterior and posterior triangles when viewed from the side (Figure 8).<\/p>\n\n\n Figure 8. Posterior and Lateral Views of the Neck<\/strong><\/p>\n\n\n\n The superficial and deep muscles of the neck are responsible for moving the head, cervical vertebrae, and scapulas.<\/p>\n\n\n\n The posterior muscles of the neck are primarily concerned with head movements, like extension. The back muscles stabilize and move the vertebral column, and are grouped according to the lengths and direction of the fascicles.<\/p>\n\n\n\n The\u00a0splenius\u00a0muscles originate at the midline and run laterally and superiorly to their insertions. From the sides and the back of the neck, the\u00a0splenius capitis\u00a0inserts onto the head region, and the\u00a0splenius cervicis\u00a0extends onto the cervical region. These muscles can extend the head, laterally flex it, and rotate it (Figure 9).<\/p>\n\n\n Figure 9. Muscles of the Neck and Back<\/strong><\/p>\n\n\n\n The large, complex muscles of the neck and back move the head, shoulders, and vertebral column.<\/p>\n\n\n\n The\u00a0erector spinae group\u00a0forms the majority of the muscle mass of the back and it is the primary extensor of the vertebral column. It controls flexion, lateral flexion, and rotation of the vertebral column, and maintains the lumbar curve. The erector spinae comprises the iliocostalis (laterally placed) group, the longissimus (intermediately placed) group, and the spinalis (medially placed) group.<\/p>\n\n\n\n The\u00a0iliocostalis group\u00a0includes the\u00a0iliocostalis cervicis, associated with the cervical region; the\u00a0iliocostalis thoracis, associated with the thoracic region; and the\u00a0iliocostalis lumborum, associated with the lumbar region. The three muscles of the\u00a0longissimus group\u00a0are the\u00a0longissimus capitis, associated with the head region; the\u00a0longissimus cervicis, associated with the cervical region; and the\u00a0longissimus thoracis, associated with the thoracic region. The third group, the\u00a0spinalis group, comprises the\u00a0spinalis capitis\u00a0(head region), the\u00a0spinalis cervicis\u00a0(cervical region), and the\u00a0spinalis thoracis\u00a0(thoracic region).<\/p>\n\n\n\n The\u00a0transversospinales\u00a0muscles run from the transverse processes to the spinous processes of the vertebrae. Similar to the erector spinae muscles, the semispinalis muscles in this group are named for the areas of the body with which they are associated. The semispinalis muscles include the\u00a0semispinalis capitis, the\u00a0semispinalis cervicis, and the\u00a0semispinalis thoracis. The\u00a0multifidus\u00a0muscle of the lumbar region helps extend and laterally flex the vertebral column.<\/p>\n\n\n\n Important in the stabilization of the vertebral column is the\u00a0segmental muscle group, which includes the interspinales and intertransversarii muscles. These muscles bring together the spinous and transverse processes of each consecutive vertebra. Finally, the\u00a0scalene muscles\u00a0work together to flex, laterally flex, and rotate the head. They also contribute to deep inhalation. The scalene muscles include the\u00a0anterior scalene muscle (anterior to the middle scalene), the\u00a0middle scalene\u00a0muscle (the longest, intermediate between the anterior and posterior scalenes), and the\u00a0posterior scalene muscle (the smallest, posterior to the middle scalene).<\/p>\n\n\n\n Muscles are either axial muscles or appendicular. The axial muscles are grouped based on location, function, or both. Some axial muscles cross over to the appendicular skeleton. The muscles of the head and neck are all axial. The muscles in the face create facial expressions by inserting into the skin rather than onto the bone. Muscles that move the eyeballs are extrinsic, meaning they originate outside of the eye and are inserted into it. Tongue muscles are both extrinsic and intrinsic. The genioglossus depresses the tongue and moves it anteriorly; the styloglossus lifts the tongue and retracts it; the palatoglossus elevates the back of the tongue; and the hyoglossus depresses and flattens it. The muscles of the anterior neck facilitate swallowing and speech, stabilize the hyoid bone, and position the larynx. The muscles of the neck stabilize and move the head. The sternocleidomastoid divides the neck into anterior and posterior triangles.<\/p>\n\n\n\n The muscles of the back and neck that move the vertebral column are complex, and overlapping, and can be divided into five groups. The splenius group includes the splenius capitis and the splenius cervicis. The erector spinae has three subgroups. The iliocostalis group includes the iliocostalis cervicis, the iliocostalis thoracis, and the iliocostalis lumborum. The longissimus group includes the longissimus capitis, the longissimus cervicis, and the longissimus thoracis. The spinalis group includes the spinalis capitis, the spinalis cervicis, and the spinalis thoracis. The transverospinales include the semispinalis capitis, semispinalis cervicis, semispinalis thoracis, multifidus, and rotatores. The segmental muscles include the interspinales and intertransversarii. Finally, the scalenes include the anterior scalene, middle scalene, and posterior scalene.<\/p>\n\n\n\n anterior scalene<\/strong><\/p>\n\n\n\n a muscle anterior to the middle scalene<\/p>\n\n\n\n appendicular<\/strong><\/p>\n\n\n\n of the arms and legs<\/p>\n\n\n\n axial<\/strong><\/p>\n\n\n\n of the trunk and head<\/p>\n\n\n\n buccinator<\/strong><\/p>\n\n\n\n the muscle that compresses the cheek<\/p>\n\n\n\n corrugator supercilii<\/strong><\/p>\n\n\n\n prime mover of the eyebrows<\/p>\n\n\n\n deglutition<\/strong><\/p>\n\n\n\n swallowing<\/p>\n\n\n\n digastric<\/strong><\/p>\n\n\n\n muscle that has anterior and posterior bellies and elevates the hyoid bone and larynx when one swallows; it also depresses the mandible<\/p>\n\n\n\n epicranial aponeurosis<\/strong><\/p>\n\n\n\n (also, galea aponeurosis) the flat broad tendon that connects the frontalis and occipitalis<\/p>\n\n\n\n erector spinae group<\/strong><\/p>\n\n\n\n large muscle mass of the back; primary extensor of the vertebral column<\/p>\n\n\n\n extrinsic eye muscles<\/strong><\/p>\n\n\n\n originate outside the eye and inserted onto the outer surface of the white of the eye, and create eyeball movement<\/p>\n\n\n\n frontalis<\/strong><\/p>\n\n\n\n the front part of the occipitofrontalis muscle<\/p>\n\n\n\n genioglossus<\/strong><\/p>\n\n\n\n muscle that originates on the mandible and allows the tongue to move downward and forward<\/p>\n\n\n\n geniohyoid<\/strong><\/p>\n\n\n\n muscle that depresses the mandible, and raises and pulls the hyoid bone anteriorly<\/p>\n\n\n\n hyoglossus<\/strong><\/p>\n\n\n\n muscle that originates on the hyoid bone to move the tongue downward and flatten it<\/p>\n\n\n\n iliocostalis cervicis<\/strong><\/p>\n\n\n\n muscle of the iliocostalis group associated with the cervical region<\/p>\n\n\n\n iliocostalis group<\/strong><\/p>\n\n\n\n laterally placed muscles of the erector spinae<\/p>\n\n\n\n iliocostalis lumborum<\/strong><\/p>\n\n\n\n muscle of the iliocostalis group associated with the lumbar region<\/p>\n\n\n\n iliocostalis thoracis<\/strong><\/p>\n\n\n\n muscle of the iliocostalis group associated with the thoracic region<\/p>\n\n\n\n infrahyoid muscles<\/strong><\/p>\n\n\n\n anterior neck muscles that are attached to, and inferior to the hyoid bone<\/p>\n\n\n\n lateral pterygoid<\/strong><\/p>\n\n\n\n muscle that moves the mandible from side to side<\/p>\n\n\n\n longissimus capitis<\/strong><\/p>\n\n\n\n muscle of the longissimus group associated with the head region<\/p>\n\n\n\n longissimus cervicis<\/strong><\/p>\n\n\n\n muscle of the longissimus group associated with the cervical region<\/p>\n\n\n\n longissimus group<\/strong><\/p>\n\n\n\n intermediately placed muscles of the erector spinae<\/p>\n\n\n\n longissimus thoracis<\/strong><\/p>\n\n\n\n muscle of the longissimus group associated with the thoracic region<\/p>\n\n\n\n masseter<\/strong><\/p>\n\n\n\n main muscle for chewing that elevates the mandible to close the mouth<\/p>\n\n\n\n mastication<\/strong><\/p>\n\n\n\n chewing<\/p>\n\n\n\n medial pterygoid<\/strong><\/p>\n\n\n\n muscle that moves the mandible from side to side<\/p>\n\n\n\n middle scalene<\/strong><\/p>\n\n\n\n longest scalene muscle, located between the anterior and posterior scalenes<\/p>\n\n\n\n multifidus<\/strong><\/p>\n\n\n\n muscle of the lumbar region that helps extend and laterally flex the vertebral column<\/p>\n\n\n\n mylohyoid<\/strong><\/p>\n\n\n\n muscle that lifts the hyoid bone and helps press the tongue to the top of the mouth<\/p>\n\n\n\n occipitalis<\/strong><\/p>\n\n\n\n posterior part of the occipitofrontalis muscle<\/p>\n\n\n\n occipitofrontalis<\/strong><\/p>\n\n\n\n muscle that makes up the scalp with a frontal belly and an occipital belly<\/p>\n\n\n\n omohyoid<\/strong><\/p>\n\n\n\n the muscle that has superior and inferior bellies and depresses the hyoid bone<\/p>\n\n\n\n orbicularis oculi<\/strong><\/p>\n\n\n\n the circular muscle that closes the eye<\/p>\n\n\n\n orbicularis oris<\/strong><\/p>\n\n\n\n the circular muscle that moves the lips<\/p>\n\n\n\n palatoglossus<\/strong><\/p>\n\n\n\n muscle that originates on the soft palate to elevate the back of the tongue<\/p>\n\n\n\n posterior scalene<\/strong><\/p>\n\n\n\n smallest scalene muscle, located posterior to the middle scalene<\/p>\n\n\n\n scalene muscles<\/strong><\/p>\n\n\n\n flex, laterally flex, and rotate the head; contribute to deep inhalation<\/p>\n\n\n\n segmental muscle group<\/strong><\/p>\n\n\n\n interspinales and intertransversarii muscles that bring together the spinous and transverse processes of each consecutive vertebra<\/p>\n\n\n\n semispinalis capitis<\/strong><\/p>\n\n\n\n transversospinales muscle associated with the head region<\/p>\n\n\n\n semispinalis cervicis<\/strong><\/p>\n\n\n\n transversospinales muscle associated with the cervical region<\/p>\n\n\n\n semispinalis thoracis<\/strong><\/p>\n\n\n\n transversospinales muscle associated with the thoracic region<\/p>\n\n\n\n spinalis capitis<\/strong><\/p>\n\n\n\n muscle of the spinalis group associated with the head region<\/p>\n\n\n\n spinalis cervicis<\/strong><\/p>\n\n\n\n muscle of the spinalis group associated with the cervical region<\/p>\n\n\n\n spinalis group<\/strong><\/p>\n\n\n\n medially placed muscles of the erector spinae<\/p>\n\n\n\n spinalis thoracis<\/strong><\/p>\n\n\n\n muscle of the spinalis group associated with the thoracic region<\/p>\n\n\n\n splenius<\/strong><\/p>\n\n\n\n posterior neck muscles; including the splenius capitis and splenius cervicis<\/p>\n\n\n\n splenius capitis<\/strong><\/p>\n\n\n\n neck muscle that inserts into the head region<\/p>\n\n\n\n splenius cervicis<\/strong><\/p>\n\n\n\n neck muscle that inserts into the cervical region<\/p>\n\n\n\n sternocleidomastoid<\/strong><\/p>\n\n\n\n major muscle that laterally flexes and rotates the head<\/p>\n\n\n\n sternohyoid<\/strong><\/p>\n\n\n\n muscle that depresses the hyoid bone<\/p>\n\n\n\n sternothyroid<\/strong><\/p>\n\n\n\n muscle that depresses the larynx\u2019s thyroid cartilage<\/p>\n\n\n\n styloglossus<\/strong><\/p>\n\n\n\n muscle that originates on the styloid bone, and allows upward and backward motion of the tongue<\/p>\n\n\n\n stylohyoid<\/strong><\/p>\n\n\n\n muscle that elevates the hyoid bone posteriorly<\/p>\n\n\n\n suprahyoid muscles<\/strong><\/p>\n\n\n\n neck muscles that are superior to the hyoid bone<\/p>\n\n\n\n temporalis<\/strong><\/p>\n\n\n\n muscle that retracts the mandible<\/p>\n\n\n\n thyrohyoid<\/strong><\/p>\n\n\n\n muscle that depresses the hyoid bone and elevates the larynx\u2019s thyroid cartilage<\/p>\n\n\n\n transversospinales<\/strong><\/p>\n\n\n\n muscles that originate at the transverse processes and insert at the spinous processes of the vertebrae<\/p>\n","protected":false},"featured_media":0,"template":"","mpcs-curriculum-tags":[],"mpcs-curriculum-categories":[],"class_list":["post-23788","mpcs-lesson","type-mpcs-lesson","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/bodyflyfitness.com\/website_31847406\/wp-json\/wp\/v2\/mpcs-lesson\/23788","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bodyflyfitness.com\/website_31847406\/wp-json\/wp\/v2\/mpcs-lesson"}],"about":[{"href":"https:\/\/bodyflyfitness.com\/website_31847406\/wp-json\/wp\/v2\/types\/mpcs-lesson"}],"wp:attachment":[{"href":"https:\/\/bodyflyfitness.com\/website_31847406\/wp-json\/wp\/v2\/media?parent=23788"}],"wp:term":[{"taxonomy":"mpcs-curriculum-tags","embeddable":true,"href":"https:\/\/bodyflyfitness.com\/website_31847406\/wp-json\/wp\/v2\/mpcs-curriculum-tags?post=23788"},{"taxonomy":"mpcs-curriculum-categories","embeddable":true,"href":"https:\/\/bodyflyfitness.com\/website_31847406\/wp-json\/wp\/v2\/mpcs-curriculum-categories?post=23788"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/figure>\n<\/div>\n\n\n
Muscles that Move the Eyes<\/h2>\n\n\n\n
<\/figure>\n<\/div>\n\n\n
Muscles that Move the Lower Jaw<\/h2>\n\n\n\n
![\"\"\/](\"https:\/\/bodyflyfitness.com\/website_31847406\/wp-content\/uploads\/2024\/09\/muscleofeyes.png\")
Muscles that Move the Tongue<\/h2>\n\n\n\n
Muscles of the Anterior Neck<\/h2>\n\n\n\n
Muscles that Move the Head<\/h2>\n\n\n\n
Muscles of the Posterior Neck and the Back<\/h2>\n\n\n\n
REVIEW<\/h2>\n\n\n\n
GLOSSARY<\/h2>\n\n\n\n
![Muscles of Lower Jaw<\/a>](\"https:\/\/bodyflyfitness.com\/website_31847406\/wp-content\/uploads\/2024\/09\/musclesoflowerjaw-1.png\"){kind=link}
![Muscles That Move the Head<\/a>](\"https:\/\/bodyflyfitness.com\/website_31847406\/wp-content\/uploads\/2024\/09\/musclesthatmovethehead.png\"){kind=link}