Muscles of Mastication & Neck Flashcards
Temporalis
Origin: Temporal fossa
Insertion: Coronoid process of mandible
Innervation: Mandibular branch of Trigeminal Nerve
Function: elevate mandible, posterior fibres
Masseter
Origin: Zygomatic bone and arch
Insertion: ramus and angle of mandible
Innervation: Mandibular branch of Trigeminal Nerve
Function: elevates mandible (closes jaw)
Lateral Pterygoid
Origin: superior fibres - sphenoid bone. Inferior fibres - posterior surface of maxilla & sphenoid bone
Insertion: superior head - Intra articular disk of TMJ. Inferior - neck of condylar process of mandible
Innervation: Mandibular branch of Trigeminal Nerve
Function: protrude mandible and side to side movement
Medial pyterygoid
Origin: superior - sphenoid bone l, inferior - posterior surface of maxilla
Insertion: ramus of mandible
Innervation: Mandibular branch of Trigeminal Nerve
Function: run posterior and inferior to elevate and protrude mandible
Sternocleidomastoid
Origin: sternal head - manibrium of sternum. Clavicular head - medial third of clavicle
Insertion: mastoid process and superior nuchal line
Innervation: Cranial nerve 11
Function: unilateral: ipsilateral side flexion and contralateral rotation
Bilateral: forward head movement
Levator scapulae
Origin: upper cervical vertebrae
Insertion: superopr angle of scap and upper medial border
Innervation: Dorsal scapular nerve (branch from brachial plexus)
Function: elevate scap
Splenuis capitus
Origin: lower cervical and upper thoracic spine and nuchal ligament
Insertion: mastoid process and superior nuchal line
Innervation: 3rd and 4th cervical spinal nerve
Function: unilateral: ipsilateral side flexion and ipsilateral rotation of head and neck
Bilateral: extension of head and neck
Anterior scalene
Origin: lower cervical vertabrae
Insertion: 1st rib
Innervation: direct branch of brachial plexus
Function: elevates 1st and 2nd rib. If ribs stabilized, contraction causes ipislatersal side bend and ipsi lateral rotation
middle scalene
Origin: C2-C7
Insertion: 1st rib
Innervation: direct branch of brachial plexus
Function: elevates 1st rib. If ribs stabilized, contraction causes ipislatersal side bend and rotation
Posterior scalene
Origin: lower cervical vertabrae
Insertion: 1st rib
Innervation: direct branch of brachial plexus
Function: elevates 1st and 2nd rib. If ribs stabilized, contraction causes ipislatersal side bend and rotation
Longus capitus
Origin: ltransverse process c3-c6
Insertion: occipital bones
Innervation: direct branch of lateral rami from cervical spinal nerve
Function: head flexion
Longus cervicis
Origin: upper thoracic and lower cervical vertabrae
Insertion: upper cervical
Innervation: direct branch of ventral rami from cervical spinal nerve
Function: head flexion
Stylo hyoid
Origin: styloid process
Insertion: lesser horn of hyoid bone
Innervation: cranial nerve 7
Function: elevate hyoid bone
Digastric bellies
Origin: posterior: mastoid process
Insertion: continues as intermediate tendon passing through insertion of stylo hyoid muscle. Tendon continues as anterior belly that attaches to mandible.
Innervation: anterior: cranial nerve 5 mandibular division, posterior: cranial nerve 7
Function: elevate hyoid bone or depress mandible
Mylo hyoid
Origin: mylo hyoid line of mandible (forms floor of mouth)
Insertion: hyoid bone
Innervation: mandibular division of cranial nerve 5
Function: elevate hyoid or depress mandible. Lift tongue
Genio hyoid
Origin: 2 small bony elevations behind body of mandible
Insertion: hyoid bone (
Innervation: direct branch of C1
Function: elevate hyoid or depress mandible.
Omo hyoid
Origin: inferior belly: superior border of scapular. continues as intermediate tendon to then form superior belly
Insertion:superior belly inserts to hydroid bone
Innervation: ansa cervicalis (branch of brachial plexus)
Function: depress hyoid bone
Sterno hyoid
Origin: manubrium of sternum
Insertion: hyoid bone
Innervation: ansa cervicalis (branch of brachial plexus)
Function: depress hyoid bone
Sterno thyroid
Origin: manubrium of sternum
Insertion: thyroid cartilage of larynx
Innervation: ansa cervicalis (branch of brachial plexus)
Function: depress thyroid cartilage
Thyro hyoid
Origin: thyroid cartilage of larynx
Insertion: hyoid bone
Innervation: direct branch of C1
Function: elevated thyroid cartilage or depress hyoid
function of infrahyoid muscles in jaw movement
Depress and stabilize hyoid bone so Supra hyoid can perform their reverse function and open the jaw
Mandibular branch of trigeminal nerve Innervation
Masseter, temporalis, lateral and medial pterygoid, anterior belly of digastric muscle, mylohyoid
Cranial nerve 11 Innervation
Trapezius, SCM
