Supralaryngeal Anatomy 1 Muscles of Face • Facial muscles are devoid of facial sheaths (characteristic of skeletal muscle) • Size, shape & extent of development depend on – age – dentition – sex • Lips are most mobile 2 Facial Muscles Levator Labii Superioris Risorius Orbicularis Oris Depressor Anguli Mentalis Oris 3 Orbicularis Oris • Principal muscle acting on the lips • Oval ring of muscle encircling mouth • Paired: upper & lower muscles (superior & inferior), functional differentiation • Acts as point of insertion for many other muscles • Function: Protrude & close lips, compress, contract, extend, rounding 4 Obicularis Oris 5 Buccinator • “Bugler’s muscle” • • • • Lies deep to the risorius Originates on the pterygomandibular ligament Inserts into the lower orbicularis oris Function: Compresses the lips & cheeks against the teeth & draws the corners of mouth laterally; primarily involved in mastication, moves food onto grinding surface of the molars, contraction constricts the oropharynx 6 Buccinator Pterygomandibular Ligament 7 Levator Anguli Oris • Arises from the canine fossa of the maxilla (lower part of orbit) • Inserts into upper & lower lips • Function: Draws the corner of the mouth up and medial-ward (spreads lips) 8 Levator Anguli Oris Canine Fossa of Maxilla 9 Levator Labii Superioris • Originates from the infraorbital margin of the maxilla (lower part of orbit) • Insertion into the mid-lateral region of the upper lip • Function: Elevation of the upper lip 10 Levator Labii Superioris Infraorbital margin of Maxilla 11 Zygomatic Major • Arises on the zygomatic bone • Courses obliquely • Inserts into the corner of the obicularis oris • Function: Elevates and retracts the angle of the mouth, as in the gesture of smiling 12 Depressor Labii Inferioris • Originates oblique line of mandible, runs upward • Insert into the lower lip and orbicularis oris • Function: Depresses the corners of the mouth and, by virtue of attachment to lower lip, help compress the lower lip to the upper lip 13 Depressor Labii Inferioris 14 Mentalis • Origin from incisive fossa of mandible, inserting into skin of chin below (lower gum in area of mandibular teeth) • Function: contraction elevates and wrinkles the chin and pulls the lower lip out 15 Masseter • Originates for zygomatic arch • Insert into angle & lateral surface of the ramus of the mandible • Function: Closes jaw & retracts the mandible 16 Masseter 17 Facial Muscles • Obicularis oris, inferior & superior muscles: – Lip protrusion, closure, retraction, elevation & depression • Risorius & Buccinator: – Assist in retraction of the lips & support entrapment of air within the oral cavity • Levator labii superioris, zygomatic minor: – Elevate upper lip • Depressor labii inferioris: – Depresses lower lip • Zygomatic major: – Elevates & contracts corners of mouth 18 Muscles of the Mouth • Extrinsic & intrinsic muscles of the tongue • Muscles for soft palate elevation 19 Tongue • Occupies the floor of the mouth • Extrinsic muscles: moves tongue into different positions or regions in the mouth • Intrinsic muscles: Shapes tongue into contours; fine graded control of the articulatory gestures • Primarily involved in mastication & deglutition – Movement of food – Position food for chewing – Propel it backward for swallowing 20 Tongue • • • • Dorsum: Superior surface Tip or Apex: Anterior-most portion Base: In oropharynx Palatine surface: Portion of surface in oral cavity; 2/3 of tongue • Lingual Frenulum: Underside of tongue; Joins inferior tongue & mandible; stabilizing tongue during movement 21 Intrinsic Tongue Muscles • Two pairs of muscles running longitudinally, transversely & vertically • Interact in a delicate fashion to produce the rapid, delicate articulations for speech & nonspeech activities 22 Intrinsic Tongue Muscles • Superior Longitudinal: – Courses along the length of tongue – Upper layer of tongue – Originates from fibrous submucous layer near epiglottis – Fibers fan forward & outward to insert into the lateral margins of the tongue & apex region – Function: Elevate tongue tip, pulls tongue to one side (toward side of contraction) 23 Superior & Inferior Longitudinal Muscles Superior Inferior 24 Intrinsic Tongue Muscles • Inferior Longitudinal Muscle: – Originates at the root of the tongue & corpus hyoid – Fibers course to apex of tongue – Occupies lower sides of tongue (absent in medial tongue base) – Function: Depresses tongue tip; assist in retraction of the tongue; Contraction to one side pulls tongue in that direction & downward 25 Intrinsic Tongue Muscles • Transverse Muscles: –Function: to narrow tongue; Pulls edges toward midline –Fibers originate at the median fibrous septum & course laterally to insert into side of the tongue 26 Transverse & Vertical Muscles 27 Intrinsic Tongue Muscles • Vertical Muscles: – Run at right angles to the transverse muscles – Course from base of tongue and insert into the membranous cover – Function: Flatten tongue; Pulls tongue down into the floor of the mouth 28 Intrinsic Tongue Muscles Superior Longitudinal Coronal Vertical Muscles Inferior Longitudinal Transverse Muscles 29 Extrinsic Muscles • Genioglossus: – Prime mover, most of deeper bulk – Arises from inner mandibular surface and fans to insert into the tip & dorsum of the tongue – Medial position – Function: • • • • 1. Withdraw tongue into mouth 2. Pull tongue tip down, lower the tongue 3. Protrude the tongue 4. Pull tongue root & dorsum anteriorly 30 Genioglossus 31 Extrinsic Muscles • Hyoglossus: – Arises from greater cornu & lateral body of the hyoid – Inserts into the sides of the tongue between the styloglossus & inferior longitudinal – Function: Pulls sides of tongue down 32 Hyoglossus 33 Extrinsic Muscles • Styloglossus: – Originates from antero-lateral margin of styloid process – Inserts into inferior sides of tongue; divides to insert into inferior longitudinal & hyoglossus – Function: Draws tongue back & up 34 Styloglossus 35 Extrinsic Muscles • Palatoglossus: – Muscle of the tongue & velum – Function: Depress the soft palate or elevating the back of the tongue 36 Palatoglossus 37 Velopharyngeal Anatomy • Soft palate & its relationship with the pharyngeal wall • Muscles here run from skull and insert somewhere in palate • Muscles important for speech-Cleft palate • Three sounds in English that require velum to be depressed- n, m, ing 38 Reading/Assignments • Seikel: Pgs. 305-319 • Dickson: Pgs. 222-250 39