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