Muscles of Mastication & Neck

Question 1

Temporalis

Answer 1

Origin: Temporal fossa
Insertion: Coronoid process of mandible
Innervation: Mandibular branch of Trigeminal Nerve
Function: elevate mandible, posterior fibres

Question 1

Masseter

Answer 1

Origin: Zygomatic bone and arch
Insertion: ramus and angle of mandible
Innervation: Mandibular branch of Trigeminal Nerve
Function: elevates mandible (closes jaw)

Question 2

Lateral Pterygoid

Answer 2

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

Question 3

Medial pyterygoid

Answer 3

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

Question 4

Sternocleidomastoid

Answer 4

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

Question 5

Levator scapulae

Answer 5

Origin: upper cervical vertebrae
Insertion: superopr angle of scap and upper medial border
Innervation: Dorsal scapular nerve (branch from brachial plexus)
Function: elevate scap

Question 6

Splenuis capitus

Answer 6

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

Question 7

Anterior scalene

Answer 7

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

Question 8

middle scalene

Answer 8

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

Question 9

Posterior scalene

Answer 9

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

Question 10

Longus capitus

Answer 10

Origin: ltransverse process c3-c6
Insertion: occipital bones
Innervation: direct branch of lateral rami from cervical spinal nerve
Function: head flexion

Question 11

Longus cervicis

Answer 11

Origin: upper thoracic and lower cervical vertabrae
Insertion: upper cervical
Innervation: direct branch of ventral rami from cervical spinal nerve
Function: head flexion

Question 12

Stylo hyoid

Answer 12

Origin: styloid process
Insertion: lesser horn of hyoid bone
Innervation: cranial nerve 7
Function: elevate hyoid bone

Question 13

Digastric bellies

Answer 13

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

Question 14

Mylo hyoid

Answer 14

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

Question 15

Genio hyoid

Answer 15

Origin: 2 small bony elevations behind body of mandible
Insertion: hyoid bone (
Innervation: direct branch of C1
Function: elevate hyoid or depress mandible.

Question 16

Omo hyoid

Answer 16

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

Question 17

Sterno hyoid

Answer 17

Origin: manubrium of sternum
Insertion: hyoid bone
Innervation: ansa cervicalis (branch of brachial plexus)
Function: depress hyoid bone

Question 18

Sterno thyroid

Answer 18

Origin: manubrium of sternum
Insertion: thyroid cartilage of larynx
Innervation: ansa cervicalis (branch of brachial plexus)
Function: depress thyroid cartilage

Question 19

Thyro hyoid

Answer 19

Origin: thyroid cartilage of larynx
Insertion: hyoid bone
Innervation: direct branch of C1
Function: elevated thyroid cartilage or depress hyoid

Question 20

function of infrahyoid muscles in jaw movement

Answer 20

Depress and stabilize hyoid bone so Supra hyoid can perform their reverse function and open the jaw

Question 21

Mandibular branch of trigeminal nerve Innervation

Answer 21

Masseter, temporalis, lateral and medial pterygoid, anterior belly of digastric muscle, mylohyoid

Question 22

Cranial nerve 11 Innervation

Answer 22

Trapezius, SCM