Articulation L3 - The Tongue, Mandible, Velopharynx Moodle.pptx

Muscles  You should learn about the following muscles in detail (origin, course, insertion, and function).  For the remaining muscles of articulation (i.e., any muscle not on this list), you should know just the function of the muscles. • orbicularis oris, buccinator, superior longitudinal, inferi...

Muscles  You should learn about the following muscles in detail (origin, course, insertion, and function).  For the remaining muscles of articulation (i.e., any muscle not on this list), you should know just the function of the muscles. • orbicularis oris, buccinator, superior longitudinal, inferior longitudinal, transverse, vertical, genioglossus, styloglossus, palatoglossus, hyoglossus, masseter, temporalis, tensor veli palatini, levator veli palatini, palatopharyngeus The Tongue • Primary biological functions are in taste, mastication, and deglutition • Nonbiological function: tongue is the most important and the most active of the articulators • Tongue is – “slung” by muscles from the roof of the mouth and the base of the skull – fastened to the inner surface of the mental symphysis, to the hyoid bone, and the pharynx – attached to the epiglottis through ligaments • The sides and tip of the tongue can move independently of each other The Tongue Two Parts 1. Blade - Tip: the portion of the tongue nearest the front teeth - Blade: part just below the upper alveolar ridge - Front: part just below the hard palate - Back: part beneath the soft palate 2. Root - Root: below visible portion of tongue The Tongue – Surface Anatomy • Dorsum is divided by a longitudinal medial sulcus which runs from the tip posteriorly to a pit called the foramen cecum • From the foramen cecum, a shallow V-shaped grooved called the sulcus terminalis courses anteriorly and laterally to the margins of the tongue; this landmark separates the anterior two-thirds of the dorsum from the posterior one-third The Tongue – Surface Anatomy • Surface of tongue in front of sulcus terminalis (front 2/3) is called the palatine surface; has papillae (4 types) which give the surface a certain roughness (they contain taste buds) • Surface of tongue in back of sulcus terminalis (back 1/3) is smoother; it’s somewhat nodular as it contains many mucous membranes and lymph nodes (comprise the lingual tonsil) • Lingual frenulum extends from the floor of the mouth at midline to the underside of the tongue The Tongue – Mucous Membrane • Outer surface of tongue is a mucous membrane that is continuous with the mucous membrane of all other structures in the oral cavity • Mucous membrane has a “basement layer” of connective tissue called the corium • The corium is dense and can be thought of as the “skeleton” of the tongue corium The Tongue – Deep Structures • 8 muscles of the tongue divided into intrinsic and extrinsic groups • It is difficult to trace the path of a particular extrinsic muscle once it enters the tongue; it’s even difficult to determine whether individual fibers are from intrinsic or extrinsic muscles • The tongue is divided into two lateral halves by its median fibrous septum • All the lingual musculature is regarded as paired • The two halves are individually supplied by motor and sensory nerves and blood vessels Muscles of the Tongue Intrinsic Muscles of the Tongue Inferior Longitudinal Superior Longitudinal Transverse Vertical Extrinsic Muscles of the Tongue Genioglossus Styloglossus Palatoglossus Hyoglossus Inferior Longitudinal Muscle • A bundle of muscle fibers located on the undersurface of the tongue Origin: root of the tongue and hyoid bone Course: horizontal toward front Insertion: tip & front edges of tongue (inferior half) and styloglossus Innervation: hypoglossal nerve (CN XII) Function: protrudes/retracts tongue, depress tongue tip, moves tip side to side Superior Longitudinal Muscle • It occupies a substantial portion of the tongue Origin: tongue root & septum Course: horizontal, toward front Insertion: tip & front edges of the tongue (superior half) Innervation: hypoglossal nerve (CN XII) Function: retract/protrudes tongue, turns tip and/or edges upward, moves tip from side-to-side Transverse Muscle Origin: median fibrous septum of tongue Course: lateral Insertion: edges of tongue Innervation: hypoglossal nerve (CN XII) Function: narrows and elongates tongue, elevates posterior part of tongue Vertical Muscle Origin: upper lateral surfaces of entire length of tongue Course: vertically downward and somewhat laterally Insertion: inferior & lateral surface of entire length of tongue Innervation: hypoglossal nerve (CN XII) Function: flattens the tongue, protrudes tongue, creates longitudinal groove along middle of tongue Genioglossus Muscle • Forms the bulk of the tongue tissue • Strongest & largest of the extrinsic tongue muscles Origin: mental spine (inside mandible) Course: posteriorly & upward in fanlike pattern Insertion: body of hyoid, dorsum of tongue, upper pharynx Innervation: hypoglossal nerve (CN XII) Function: protrude, retract, and depress the tongue Hyoglossus Muscle Origin: greater cornua and corpus of hyoid Course: upward Insertion: sides of posterior half of tongue Innervation: hypoglossal nerve (CN XII) Function: depress and retract the tongue Styloglossus Muscle Origin: styloid process of the temporal bone Course: down and forward Insertion: sides of the tongue Innervation: hypoglossal nerve (CN XII) Function: elevate & retract tongue Palatoglossus Muscle (Also discussed with muscles of the palate; same muscle) Origin: anterior surface of the velum Course: downward & laterally Insertion: sides of tongue, towards the back Innervation: vagus (CN X, spinal accessory XI Function: lowers soft palate (with tongue anchored), or raises the back of the tongue Palatoglossus The Mandible: TMJ & Muscles • Principle function is mastication • Contributes to speech production by modifying the resonant characteristics of the vocal tract; also houses the lower teeth which are important articulatory structures • Lower lip and tongue postures are somewhat dependent upon jaw movement • Although jaw movement is slight during normal speech production, inadequate, inappropriate, or sluggish movements may contribute to articulatory defects • Primary movements of the jaw are elevation and depression; it may also be protruded and retracted as well as moved laterally in a grinding motion • Normal mobility of the lower jaw is dependent on the temporomandibular joint • There are 4 mandibular depressors (various innervations) and 3 mandibular elevator muscles (trigeminal nerve) Temporomandibular Joint • The mandible, the only moveable bone in the face, articulates with the temporal bone by means of the temporomandibular joint • Temporomandibular joint is formed by the indirect articulation of the condyle of the mandible and the anterior part of the mandibular fossa of the temporal bone Temporomandibular Joint - Condyle of the mandible rests in the mandibular fossa - Articular disc or meniscus: - separates the condyle from the fossa - Articular capsule: a thin envelope completely surrounding the joint - Condyle is held in place by a series of ligaments (temporomandibular (or lateral), sphenomadibular, and stylomandibular) Temporomandibular Joint Disorder https://www.youtube.com/watch?v=Dd3aT9c_08M https://ahcnweb.net/patient-information/injury-by-body-part-or-region/tempero-mandibular-pain-tmj/ Muscles of the Mandible Mandibular Elevators • Masseter • Medial (Internal) Pterygoid • Temporalis Mandibular Depressors • Digastric • Mylohyoid • Geniohyoid • Lateral (External) Pterygoid Masseter Muscle • Most powerful muscles of mastication • Along with the medial (internal) pterygoid forms the mandibular sling muscular sling in which the angle of the mandible rests and which straps the ramus to the skull • Internal and external fibers Origin: zygomatic arch Course: down and back Insertion: outside surface of the ramus at the angle & coronoid process of mandible Innervation: trigeminal nerve Function: closes and retracts jaw; may assist in lateral movement Medial (Internal) Pterygoid Muscle • Along with the masseter forms the mandibular sling muscular sling in which the angle of the mandible rests and which straps the ramus to the skull Origin: pterygoid fossa and the lateral pterygoid plate Course: down and back Insertion: medial surface of the ramus and angle of mandible Innervation: trigeminal nerve Function: elevates mandible; assists in protruding the mandible Temporalis Muscle • Built for speed Origin: temporal fossa (a very shallow depression between the superior and inferior temporal lines) Course: down and forward Insertion: coronoid process and ramus of mandible Innervation: trigeminal nerve Function: raise mandible; assists in retracting mandible and in lateral movement of mandible Digastric Muscle (last time) • Consists of two fleshy bellies Anterior Belly of the Digastric Origin: inside surface of mandible, near its symphysis Course: down and toward back Insertion: intermediate tendon which is attached to the hyoid bone near the juncture of its corpus and greater horn Innervation: trigeminal nerve Function: elevate the hyoid bone or depresses the jaw Posterior Belly of the Digastric Origin: mastoid process of temporal bone Course: down and forward Insertion: intermediate tendon (same as anterior belly) Innervation: facial nerve Function: elevate the hyoid bone or depresses the jaw Mylohyoid Muscle (last time) • A thin, trough-like sheet of muscle that forms the muscular floor of the mouth Origin: mylohyoid line along each side of the inner surfaces of the mandible Course: medially and downward Insertion: in a mid-line raphe on a tendon that runs from the mental symphysis to the hyoid bone Innervation: mylohyoid nerve Function: elevate the hyoid bone, depresses the mandible Geniohyoid Muscle (last time) • A paired cylindrical muscles located above the superior surface of the mylohyoid muscle • These two muscles often lie in direct contact with each other, but on opposite sides of midline; they may also be a single muscle fiber Origin: lower mental symphysis of mandible Course: back and down Insertion: anterior surface of the body of the hyoid bone Innervation: hypoglossal nerve Function: pull the hyoid bone up and forward or depresses the mandible Lateral Pterygoid Muscle Origin: two heads: 1 from greater wing of sphenoid bone and 1from lateral pterygoid plate Course: backward Insertion: pterygoid fossa on condyle of the mandible Innervation: trigeminal nerve Function: depresses and protrudes mandible; unilateral contraction moves jaw in a grinding fashion Faucial Pillars • Two folds of skin lateral to each side of the uvula of velum – anterior and posterior faucial pillars • Contain muscle fibers o Anterior – palatoglossus (palatoglossal folds) o Posterior – palatopharyngeous (palatopharyngeal folds) • Between the two folds is a space referred to as the tonsillar fossa Anterior and posterior faucial pillars with intermediate tonsillar fossa The Tonsils • Masses of lymphoid tissue; probably a defense mechanism against bacterial invasion of the body • Complete ring of tonsillar tissue surrounds entrance to oropharynx; ring is referred to as Waldeyer’s ring • Waldeyer’s ring consists of palatine tonsils, pharyngeal tonsils/adenoids, & lingual tonsils Posterior view The Tonsils Lingual tonsils: covers much of the root of the tongue, found on the tongue at the level of the faucial pillars (tonsillar fossae space) The Tonsils Pharyngeal Tonsils (Adenoids) located in the posterior wall of the nasopharynx; are usually greatly enlarged in childhood and the early teens; by adulthood these adenoids have usually completely atrophied anterior posterior Pharyngeal Tonsils (Adenoids) The Tonsils Palatine tonsils Found laterally within each tonsillar fossa; easily seen in an oral exam; relatively large in young children, but shrink after puberty Palatine tonsils Palatine tonsils The Tonsils Relevance to speech: • adenoids contribute to velopharyngeal closure (closure between the soft palate and the pharyngeal walls) • when the palate is too short or the pharynx is too deep, inadequate velopharyngeal closure will result in hypernasality The Velopharyngeal Mechanism The Velopharyngeal Mechanism • Varies the degree of acoustic coupling between oral & nasal cavities – controlled by velum and posterior pharyngeal wall • Regulates communication between oral and nasal cavities; important for both digestive and speech functions; assists in swallowing • Velopharyngeal closure is a very important articulatory gesture • Inadequate closure may result in nasalized speech or the inability to impound air pressure within the oral cavity for the production of consonants • Inappropriate or excessive velopharyngeal closure can result in the familiar “stuffy nose” quality – denasalized speech The Velopharyngeal Mechanism • Adequacy of velopharyngeal closure and appropriate timing of the valving action are two important parameters of articulation • Velopharyngeal closure is achieved by elevating and retracting the soft palate and at the same time constricting the walls of the pharynx • The posterior pharyngeal wall may move anteriorly to meet the soft palate in some individuals and may be seen as a compensatory gesture in instances of a short palate • Muscles that mediate movement of velum and pharynx work together to achieve velopharyngeal closure Effects of Enlarged Adenoids VPI Velopharyngeal Insufficiency https://www.youtube.com/watch?v=CfQOCVyt0Jw Post-Op for VPI surgery (start at 3:00) https://www.youtube.com/watch?v=TqpA-T9K1jQ