Muscles of Mastication, Tongue, and Pharynx

Vocabulary practice flashcards covering origins, insertions, actions, innervations, and clinical considerations of the muscles of mastication, hyoid muscles, muscles of the tongue, pharynx, and soft palate.

Masseter Muscle

A muscle of mastication whose superficial head originates from the zygomatic process of the maxilla and anterior two-thirds of the inferior border of the zygomatic arch, and whose deep head originates from the posterior one-third and medial surface of the zygomatic arch. It inserts into the lateral surface of the angle and ramus of the mandible, is innervated by the masseteric nerve of $V_3$, and elevates the mandible during jaw closure.

Masseter Hypertrophy

An enlargement of the masseter muscle detectable by visual inspection and palpation, often indicative of parafunctional habits such as clenching.

Temporalis Muscle

A fan-shaped muscle of mastication originating from the temporal fossa (bounded by the inferior temporal line superiorly and infratemporal crest of the sphenoid bone inferiorly) and inserting into the coronoid process of the mandibular ramus. Innervated by deep temporal nerves of $V_3$, it elevates the mandible when the entire muscle contracts and retracts the mandible when its posterior portion contracts.

Medial Pterygoid Muscle

A muscle of mastication originating via a deep head from between the pterygoid plates of the sphenoid bone and a superficial head from the palatine bone and maxillary tuberosity. It inserts into the medial surface of the mandibular ramus and angle up to the mandibular foramen, is innervated by the medial pterygoid nerve of $V_3$, and acts bilaterally to elevate the mandible.

Lateral Pterygoid Muscle

A muscle of mastication originating via a superior head from the infratemporal surface and crest of the sphenoid bone and an inferior head from the lateral pterygoid plate. It inserts into the neck of the mandibular condyle at the pterygoid fovea and the TMJ disc/capsule, is innervated by the lateral pterygoid nerve of $V_3$, and acts to protrude or depress the mandible (bilateral contraction) or cause lateral deviation to the contralateral side (unilateral contraction).

Suprahyoid Muscles

A group of muscles located superior to the hyoid bone consisting of the digastric, mylohyoid, stylohyoid, and geniohyoid muscles.

Digastric Muscle

A suprahyoid muscle comprising an anterior belly originating on the intermediate tendon of the greater cornu and inserting into the digastric fossa on the medial mandible, and a posterior belly originating on the mastoid notch of the temporal bone and inserting on the intermediate tendon; acts to elevate the hyoid bone or depress the mandible.

Mylohyoid Muscle

A suprahyoid muscle originating along the mylohyoid line on the medial surface of the mandible and inserting into the body of the hyoid bone; acts to elevate the hyoid bone, depress the mandible, or elevate the tongue.

Stylohyoid Muscle

A suprahyoid muscle originating from the styloid process of the temporal bone and inserting onto the body of the hyoid bone; acts to elevate and retract the hyoid bone.

Geniohyoid Muscle

A suprahyoid muscle originating on the medial surface of the mandible at the genial tubercles and inserting into the body of the hyoid bone; acts to elevate and protrude the hyoid bone or depress the mandible.

Infrahyoid Muscles

A group of four paired muscles located inferior to the hyoid bone, comprising the omohyoid, sternohyoid, sternothyroid, and thyrohyoid muscles.

Omohyoid Muscle

A two-bellied infrahyoid muscle whose inferior belly originates from the scapula and connects to the superior belly, which inserts into the lateral border of the hyoid bone; acts to depress the hyoid bone.

Sternohyoid Muscle

An infrahyoid muscle originating from the posterior surface of the sternum close to where it meets the clavicle and inserting into the body of the hyoid bone; acts to depress the hyoid bone.

Sternothyroid Muscle

An infrahyoid muscle originating from the posterior surface of the sternum parallel with the 1st rib and inserting onto the thyroid cartilage; acts to depress the thyroid cartilage and larynx.

Thyrohyoid Muscle

An infrahyoid muscle originating from the thyroid cartilage and inserting into the body of the hyoid bone; acts to depress the hyoid bone while elevating the thyroid cartilage and larynx.

Dysphagia

Difficulty swallowing, which can be observed in patients following a stroke and requires clinical accommodations such as frequent suctioning and chair repositioning.

Tardive Dyskinesia

A neurological condition characterized by abnormal hyperkinetic involuntary movements of the head and neck, including grimacing, tongue protrusion, lip smacking, puckering, and rapid eye blinking.

Superior and Inferior Longitudinal Muscles

Intrinsic tongue muscles originating at the base of the tongue and inserting at the apex; they work together to shorten, thicken, and curl the tongue (elevating the apex).

Transverse Muscle of the Tongue

An intrinsic muscle originating from the median septum/dorsal surface and inserting into the lateral/ventral surfaces; acts together with the vertical muscle to elongate and narrow the tongue.

Vertical Muscle of the Tongue

An intrinsic muscle originating from the dorsal surface/median septum and inserting into the lateral surface; acts in conjunction with the transverse muscle to elongate and narrow the tongue.

Styloglossus Muscle

An extrinsic tongue muscle originating on the styloid process of the temporal bone and inserting into the lateral surface of the tongue at the apex; acts to retract the tongue superiorly and posteriorly.

Genioglossus Muscle

A fan-shaped extrinsic tongue muscle originating from the genial tubercles of the mandible and inserting into the tongue from base to apex; acts to depress and protrude the tongue.

Hyoglossus Muscle

An extrinsic tongue muscle originating from the greater cornu and body of the hyoid bone and inserting into the lateral surface of the tongue; acts to depress the tongue.

Stylopharyngeus Muscle

A pharyngeal muscle originating on the styloid process of the temporal bone and inserting into the lateral and posterior pharyngeal walls; acts to elevate and widen the pharynx.

Superior Pharyngeal Constrictor Muscle

A pharyngeal muscle originating from the hamulus of the medial pterygoid plate of the sphenoid bone, mandible, and pterygomandibular raphe, inserting into the median pharyngeal raphe; acts to raise the pharynx and larynx and push food down the esophagus during swallowing.

Middle Pharyngeal Constrictor Muscle

A pharyngeal muscle originating from the hyoid bone and stylohyoid ligament, inserting into the median pharyngeal raphe; acts to raise the pharynx and larynx and push food down the esophagus during swallowing.

Inferior Pharyngeal Constrictor Muscle

A pharyngeal muscle originating from the thyroid and cricoid cartilage of the larynx, inserting into the median pharyngeal raphe; acts to raise the pharynx and larynx and push food down the esophagus during swallowing.

Palatoglossus Muscle

A muscle of the soft palate originating from the median palatine raphe and inserting into the lateral surface of the tongue; acts to elevate and arch the tongue while depressing the soft palate toward the tongue.

Palatopharyngeus Muscle

A muscle of the soft palate originating from the soft palate and inserting into the laryngopharynx and thyroid cartilage; acts to close off the nasopharynx and elevate the pharynx.

Levator Veli Palatini Muscle

A muscle of the soft palate originating from the temporal bone and inserting into the median palatine raphe; acts to close off the nasopharynx during swallowing and speech.

Tensor Veli Palatini Muscle

A muscle of the soft palate originating from the pharyngotympanic tube and inferior surface of the sphenoid bone, wrapping around the pterygoid hamulus to insert into the median palatine raphe; acts to tense and lower the soft palate.

Muscle of Uvula

An intrinsic soft palate muscle originating from the posterior soft palate with no bony insertion; it adapts to the posterior pharyngeal wall to close off the nasopharynx.