Axial Muscles- Muscles of the Head and Neck Flashcards
What are axial muscles?
- Have both their attachments on parts of the axial skeleton
- Support and move the head and spinal column
- Function in nonverbal communication by affecting facial features, move the mandible when chewing, assist in food processing/swallowing, aid in breathing and support/protect the abdominal and pelvic organs
- These muscles are not responsible for stabilizing or moving the pectoral or pelvic girdles or their attached limbs (appendicular muscles)
- Organized into 5 groups based on location
What are muscles of facial expression?
- Arise from the subcutaneous layer (deep to the skin) or on the skull bones
- These muscles insert on the subcutaneous layer so that when they contract, they contort the skin
- All but one muscle are innervated by the facial nerve (7th cranial nerve)
What is the epicranius? (facial muscle)
- Composed of the occipitofrontalis muscle and a broad epicranial aponeurosis
- The scalp muscles
What is the frontal belly? (facial muscle)
- Part of the occipitofrontalis muscle
- Is superficial to the frontal bone of the forehead
- When this muscle contracts it raises the eyebrows and wrinkles the forehead skin
What is the occipital belly? (facial muscle)
- Part of the occipitofrontalis muscle
- Covers the posterior side of the head
- When this muscle contracts it retracts the scalp slightly
What are the corrugator supercilii? (facial muscle)
- This muscle draws the eyebrows together and creates vertical wrinkle lines above the nose
What are orbicularis oculi? (facial muscle)
- Consists of circular muscle fibers that surround the orbit
- When this muscle contracts the eyelid closes
What is the levator palpebrae superioris? (facial muscle)
- Elevates the upper eyelid when you open your eyes
What are the nasalis? (facial muscle)
- Elevates the corners of your nostrils
- When you flare your nostrils you are using these muscles
What is the procerus? (facial muscle)
- Contracts when you wrinkle your nose in distaste after smelling something sour
- This muscle is continuous with the frontalis muscle
- Runs over the bridge of the nose, where it produces transverse wrinkles when contracted
What is the orbicularis? (facial muscle)
- Consists of muscle fibers that encircle the opening of the mouth
- When this muscle contracts you are closing your mouth or puckering your lips
What is the depressor labii inferioris? (facial muscle)
- Does what it’s name suggests
- When contracted it pulls the lower lip inferiorly
What is the depressor anguli oris? (facial muscle)
- Considered the “frown” muscle
- It pulls the corners of the mouth inferiorly
- Takes more than just this muscle to frown
What is the levator labii superioris? (facial muscle)
- Pulls the upper lip superiorly
- As if you are sneering or snarling
What is the levator anguli oris? (facial muscle)
- Does the opposite of the depressor anguli oris
- Pulls the corners of the mouth superiorly and laterally
- One of the muscles used to smile
What is the zygomaticus major? (facial muscle)
- Work with the levator anguli oris muscles to make you smile
What is the risorius? (facial muscle)
- Pulls the corners of the lips laterally
- Use these when you have a closed mouth smile
What is the mentalis? (facial muscle)
- Attaches to the lower lip
- When it contracts it protrudes the lower lip (poutes)
What is the platysma? (facial muscle)
- Tenses the skin of the neck and pulls the lower lip inferiorly
What is the buccinator? (facial muscle)
- Compresses the cheek against the teeth when we chew
- Reason why we dont look like chipmunks when we eat
What are extrinsic eye muscles?
- Also called extraocular muscles
- Move the eyeball
- Arise within the orbit and attach onto the outer sclera of the eye
- There are 6
What are rectus eye muscles?
- Medial, lateral, inferior and superior muscles
- Origin from a common tendinous ring in the orbit
- Attach on the anterior part of the eye
What are oblique eye muscles?
- Inferior and superior muscles
- Originate from within the orbit and attach to the posterolateral part of the eye
- Contracting these muscles pull the posterior part of the eye inferiorly
What is the medial rectus? (eye muscle)
- Attaches to the anteromedial surface of the eye
- Pulls the eye medially (adducts the eye)
- Innervated by the CN 11 (oculomotor nerve)
What is the lateral rectus? (eye muscle)
- Attaches to the anterolateral surface of the eye
- Pulls the eye laterally (abducts the eye)
- Innervated by CN V1 (abducens nerve)
What is the inferior rectus? (eye muscle)
- Attaches to the anteroinferior part of the eye
- Pulls the eye inferiorly (look down)
- Pulls the eye medially (look at your nose)
- Innervated by CN 111
What is the superior rectus? (eye muscle)
- Located superiorly
- Attaches to the anterosuperior part of the eye
- Pulls the eye superiorly (look up)
- Pulls the eye medially (look at your nose)
- Innervated by CN 111
What is the inferior oblique? (eye muscle)
- Elevates the eye and turns it laterally
- Attaches to the inferior posterior part of the eye
- When you contract this muscle, it pulls the posterior part of the eye inferiorly
- Innervated by CN 111
What is the superior oblique? (eye muscle)
- Depresses the eye and turns it laterally
- This muscle passes through a pulley like loop called the trochlea in the anteromedial orbit
- Attaches to the superior posterior part of the eye
- When this muscle contracts it pulls the posterior part of the eye superiorly
- Innervated by CN IV (trochlear)
What are the muscles of mastication? (mandible muscle)
- Mastication means to chew
- These muscles move the mandible at the temporomandibular joint
- 4 pairs of muscles: temporalis, masseter, lateral and medial pterygoids
What is the temporalis? (mandible muscle)
- A broad, fan-shaped muscle
- Extends from the temporal lines of the skull
- Attaches to the coronoid process of the mandible
- Elevates and retracts (pulls posteriorly) the mandible
What is the masseter? (mandible muscle)
- Elevates and protracts (pulls anteriorly) the mandible
- Most powerful and important of the masticatory muscles
- Short, thick muscle that is superficial to the temporalis
What are the lateral and medial pterygoids? (mandible muscle)
- Arise from the lateral pterygoid plates of the sphenoid bone and attach to the mandible
- Both protract the mandible and move it from side to side
- Maximize the efficiency of the teeth while chewing
- The medial pterygoid also elevates the mandible
What are intrinsic muscles? (tongue muscle)
- Curl, squeeze, and fold the tongue during chewing and speaking
- Tongue itself acts like a big muscle
What are extrinsic muscles? (tongue muscle)
- Attach from the head and neck structures to the tongue
- These muscles end in the suffix glossus (tongue)
- Most of these muscles are innervated by CN X11 (hypoglossal nerve)
What are the genioglossus muscles? (tongue muscle)
- Left and right muscles that arise on the mandible and protract the tongue
- Use these muscles when you stick your tongue out
What are the styloglossus muscles? (tongue muscle)
- Left and right muscles that arise from the styloid processes of the temporal bone
- Elevate and retract the tongue (pull the tongue posteriorly, back into the mouth)
What are the palatoglossus muscles? (tongue muscle)
- Left and right muscles that originate on the soft palate and elevate the posterior portion of the tongue
What is the pharynx?
- Commonly called the throat
- Funnel shaped tube that lies posterior to and extends inferiorly from both the oral and nasal cavities
- Several muscles help form this muscular tube or attach to it and aid in swallowing
- Most are innervated by CN X (vagus nerve)
- Primary pharyngeal muscles are constrictors
What are pharyngeal constrictors? (pharynx muscle)
- Superior, middle and inferior
- When a bolus of food enters the pharynx, these muscles contract sequentially to initiate swallowing
- Force the bolus inferiorly into the esophagus
What is the levator veli palatini? (pharynx muscle)
- Elevates soft palate when swallowing
What is the tensor veli palatini? (pharynx muscle)
- Tenses soft palate and opens auditory tube when swallowing or yawning
What is the larynx?
- Area of the throat containing the vocal cords
- Used for breathing, swallowing and talking
- Also called the voicebox
What is the palatopharyngeus? (larynx and pharynx muscle)
- Elevates the larynx and pharynx superiorly
- Originates from the soft palate
What is the salpingopharyngeus? (larynx and pharynx muscle)
- Elevates pharynx and larynx superiorly
- Originates from the auditory tube and opens it
- Blends with palatopharyngeus on the lateral wall of the pharynx
What is the stylopharyngeus? (larynx and pharynx muscle)
- Elevates pharynx and larynx superiorly
- Originates from the styloid process of the temporal bone
- Inserts from the side of the pharynx and thyroid cartilage of the larynx
What are muscles of the anterior neck?
- Divided into suprahyoid muscles (superior to the hyoid bone) and infrahyoid muscles (inferior to the hyoid bone)
What is the digastric muscle? (suprahyoid muscle)
- Associated with the floor of the mouth
- Elevate the hyoid bone while speaking or swallowing
- Also can depress the mandible
- Has 2 bellies: anterior and posterior
- One extends from the mental protuberance to the hyoid
- One continues from the hyoid to the mastoid portion of the temporal bone
- 2 bellies are united by an intermediate tendon that is held in position by a dense connective tissue sling
What is the geniohyoid? (suprahyoid muscle)
- Arises from the mental spines of the mandible and attaches to the hyoid bone
- Elevates the hyoid bone
What is the mylohyoid? (suprahyoid muscle)
- Broad and flat muscle that provides a muscular floor to the mouth
- When contracted, it both elevates the hyoid bone and raises the floor of the mouth
- Left and right sides align in a v shape
What is the stylohyoid? (suprahyoid muscle)
- Attaches to the styloid process of the skull and hyoid
- When contracted, it elevates the hyoid bone, causing the floor of the oral cavity to elongate during swallowing
What is the omohyoid? (infrahyoid muscle)
- Contains 2 thin muscle bellies anchored in place by a connective tissue sling
- Lateral to the sternohyoid and extends from the superior border of the scapula to the hyoid
- Depresses the hyoid bone
What is the sternohyoid? (infrahyoid muscle)
- Extends from the sternum to the hyoid
- Depresses the hyoid bone
What is the sternothyroid? (infrahyoid muscle)
- Deep to the sternohyoid
- Extends from the sternum to the thyroid cartilage of the larynx
- Depresses the thyroid cartilage to return it to its original position after swallowing
What is the thyrohyoid? (infrahyoid muscle)
- Extends from the thyroid cartilage of the larynx to the hyoid
- Depresses the larynx during swallowing
- The omohyoid, sternohyoid, and thyrohyoid help anchor the hyoid so the digastric can depress the mandible
What are the anterolateral neck muscles?
- Flex the head and/or neck
- Main muscles in this group are the sternocleidomastoid and the 3 scalenes
What is the sternocleidomastoid? (anterolateral muscle)
- A thick, cordlike muscle
- Extends from the sternum and clavicle to the mastoid process posterior to the ear
- Contraction of both is called a bilateral contraction (flexes the neck)
- Contraction of just one is called a unilateral contraction (lateral flexion of the neck and rotation of the head to the opposite side of the muscle)
What are the scalene muscles? (anterolateral muscle)
- Anterior, middle and posterior
- Work with the sternocleidomastoid to flex the neck
- Elevate the first and second ribs during forced inhalation
What are the posterior neck muscles?
- The trapezius attaches to the skull and helps extend the head and/or neck
- Primary action is to help move the pectoral girdle
What is the splenius capitis and cervicis? (posterior muscle)
- For unilateral action: turns head to the same side as the contracted muscle
- For bilateral action: extends the head/neck
- Superiorly attached to the occipital bone and mastoid process of temporal bone
- Inferiorly attached to the ligamentum nuchae
What is the longissimus capitis? (posterior muscle)
- For unilateral action: rotates head towards the same side as contracted muscle
- For bilateral action: extends the head/neck
- Superiorly attached to the mastoid process of the temporal bone
- Inferiorly attached to the transverse process of T1-T4 and articular processes of C4-C7 vertebrae
What is the obliquus capitis superior? (posterior muscle)
- Turns head to the same side of contracted muscle
- Superiorly attached to the inferior nuchal line of the occipital bone
- Inferiorly attached to the transverse process of the atlas
What is the obliquus capitis inferior? (posterior muscle)
- Turns head to the same side of contracted muscle
- Superiorly attached to the transverse process of the atlas
- Inferiorly attached to the spinous process of the axis
What is the rectus capitis posterior major? (posterior muscle)
- Extends head/neck
- Superiorly attached to the nuchal line of the occipital bone
- Inferiorly attached to the spinous process of the axis
What is the rectus capitis posterior minor? (posterior muscle)
- Extends head/neck
- Superiorly attached to the inferior nuchal line of the occipital bone
- Inferiorly attached to the posterior tubercle of the atlas
