Neck and Facial muscles

Question 1

Suprahyoid muscles

Answer 1

Mylohyoid
Geniohyoid
Stylohyoid
Digastric

Question 2

Infrahyoid

Answer 2

Sternohyoid
Omohyoid
Sternothyroid
Thyrohyoid

Question 3

Mylohyoid

Answer 3

Origin: mylohyoid line of mandible
Insertion : mylohyoid raphe and body of hyoid
Innervation: nerve to mylohyoid, branch of inferior alveolar nerve (from mandibular nerve, CN V3)
Action : elevates hyoid, floor of mouth, and tongue during swallowing

Question 4

Geniohyoid

Answer 4

Origin : inferior mental spine of mandible
Insertion : body of hyoid
Innervation: C1 via hypoglossal nerve (CN XII)
Action: pulls hyoid anterosuperiorly; shortens floor of mouth; widens pharynx

Question 5

Stylohyoid

Answer 5

Origin : styloid process of temporal bone
Insertion : body of hyoid
Innervation: stylohyoid branch of facial nerve (CN VII)
Action : elevates and retracts hyoid, elongating floor of mouth

Question 6

Digastric

Answer 6

Origin : anterior belly- digastric fossa of mandible
posterior belly - mastoid notch of temporal bone
Insertion : intermediate tendon to body and greater horn of hyoid
Innervation : anterior belly : nerve to mylohyoid, branch of inferior alveolar nerve
posterior belly : digastric branch of facial nerve (7)

Question 7

Sternohyoid

Answer 7

Origin : manubrium of sternum and medial end of clavicle
Insertion : body of hyoid
Innervation : C1-C3 by branch of ansa cervicalis
Action: depresses hyoid after elevation during swallowing

Question 8

Omohyoid

Answer 8

Origin : superior border of scapula near suprascapular notch
Insertion : inferior border of hyoid
Innervation : C1-C3 by branch of ansa cervicalis
Action : depresses, retracts, and steadies hyoid

Question 9

Sternothyroid

Answer 9

Origin : posterior surface of manubrium of sternum
Insertion : oblique line of thyroid cartilage
Innervation : C2 and C3 by branch of ansa cervicalis
Action : dieresis hyoid and larynx

Question 10

Thyrohyiod

Answer 10

Origin : oblique line of thyroid cartilage
Insertion : inferior border of body and greater horn of hyoid
Innervation : C1 via hypoglossal nerve
Action : depresses hyoid and elevates larynx

Question 11

Trapezius

Answer 11

Origin : nuchal ligaments, external occipital protuberance, medial third of superior nuchal line, spinous process of C1-C7
Insertion - spine of scapula, acromion, lateral third of clavicle
Innervation - spinal accessory nerve
- C3 & C4 spinal nerves
Action - ascending fibers - depress scapula
- descending fibers - elevates scapula
- middle - retract fibers
- ascending and descending work together to rotate glenoid cavity superiorly

Question 12

Platysma

Answer 12

Origin : inferior border of mandible, skin, and subcutaneous tissue of lower face
Insertion : fasciae covering superior parts of pectoralis major and deltoid
Innervation : cervical branch of facial nerve (CN VII)
Action : draws corners of mouth inferiorly and widens it as in expression of sadness and fright; draws skin of neck superiorly when teeth are clenched, indicating tension

Question 13

Sternocleidomastoid

Answer 13

Origin : lateral surface of mastoid process of temporal bone and lateral half of superior nuchal line
Insertion : sternal head - anterior surface of manubrium of sternum
Clavicular head - superior surface of medial third of clavicle
Innervation : spinal accessory nerve; motor
C2 and C3 nerves (pain and proprioception)
Action - unilateral - lateral flexion and contralateral rotation of neck
- bilateral - extends neck at atlanto-occipital joints
- flexes cervical vertebrae so that chin approaches
manubrium
- extends superior cervical vertebrae while
flexing inferior so that chin is thrust forward and head
is kept level

Question 14

Buccinator

Answer 14

Origin : mandible, alveolar processes of maxilla and mandible, pterygomandibule raphe
Insertion: angle of mouth (modiolus); orbicularis oris
Innervation: facial nerve
Action : presses cheek against molar teeth; works with tongue to keep food between occlusal surfaces and out of oral vestibule; resists distension (when blowing)

Question 15

Orbicularis oculi (orbital sphincter)

Answer 15

Origin : medial orbital margin; medial palpebral ligament; lacrimal bone
Insertion : skin around margin of orbit; superior and inferior tarsi (tarsal plates)
Innervation : facial nerve
Action : closes eyelids; palpebral part does so gently; orbital part tightly (winking)

Question 16

Orbicularis oris (oral sphincter)

Answer 16

Origin: medial maxilla and mandible; deep surface of peri-oral skin; angle of mouth
Insertion : mucous membrane of lips
Innervation : facial nerve
Action : tonus closes mouth; phasic contraction compresses and protrudes lips (kissing) or resists distension (when blowing)

Question 17

Occipito frontalis - frontal belly

Answer 17

Origin: epicranial aponeurosis
Insertion : skin and subcutaneous tissue of eyebrows and forehead
Innervation : facial nerve
Action : elevates eyebrows and wrinkles skin of forehead; protracts scalp (indicating surprise or curiosity)

Question 18

Occipito frontalis - occipital belly

Answer 18

Origin : lateral two thirds of superior nuchal line
Insertion : epicranial aponeurosis
Innervation : facial nerve
Action : retracts scalp; increasing effectiveness of frontal belly

Question 19

Masseter

Answer 19

Origin : quadrate muscle attaching to inferior border and medial surface of maxillary process of zygomatic bone and zygomatic arch
Insertion : angle and lateral surface of ramus of mandible
Innervation : anterior trunk of mandibular nerve via masseteric nerve
Action : elevates mandible; superficial fibers makes limited contribution to protrusion of mandible

Question 20

Temporalis

Answer 20

Origin : triangular muscle with broad attachment to floor of temporal fossa and deep surface of temporalis fasciae
Insertion : narrow attachment to tip and medial surface of coronoid process and anterior border of ramus of mandible
Innervation : anterior trunk of mandibular nerve via deep temporal nerves
Action : elevates mandible, closing jaws; posterior, more horizontal fibers are retractors of mandible

Question 21

Lateral pterygoid

Answer 21

Origin : triangular two headed muscle from (1) infratemporal surface and crest of greater wing of sphenoid (2) lateral surface of lateral pterygoid plate
Insertion : superior head attaches primarily to joint capsule and articular disc of TMJ; inferior head attached primarily to pterygoid fovea on neck and condylar process of mandible
Innervation : anterior trunk of mandibular nerve via nerve to lateral pterygoid
Action : bilaterally - protracts mandible and depresses chin
unilaterally - swings jaw towards contralateral side; alternate unilateral contraction produced larger lateral chewing movements

Question 22

Medial pterygoid

Answer 22

Origin : quadrangular space (1) medial surface of lateral pterygoid plate and pyramidal process of palatine bone (2) tuberosity of maxilla
Insertion : medial surface of ramus of mandible; inferior to mandibular foramen
Innervation : anterior trunk of mandibular nerve via nerve to medial pterygoid
Action : acts with masseter to elevate mandible; contributes to protrusion

Question 23

Cricothyroid

Answer 23

Origin: anterolateral part of crichoid cartilage
Insertion : inferior margin and inferior horn of thyroid cartilage
Innervation : external laryngeal nerve (CN X)
Action : stretches and tenses vocal ligament

Question 24

Posterior crico-arytenoid

Answer 24

Origin : posterior surface of lamina of cricoid cartilage
Insertion : vocal process of arytenoid cartilage
Innervation : inferior laryngeal nerve (terminal part of recurrent laryngeal nerve, from CN X)
Action : abducts vocal folds

Question 25

Stylopharyngeus

Answer 25

Origin : styloid process of temporal bone
Insertion : posterior and superior borders of thyroid cartilage with palatopharyngeus
Innervation : glossopharyngeal nerve
Action : elevate (shorten and widen) pharynx and larynx during swallowing and speaking