Topic 23 - M.splenius, M.semispinalis capitis and muscles of mastication

Question 1

M.masseter

Answer 1

O: Ventral border of zygomatic arch - it has three intersecting layers
I: Fossa masseterica of mandible
A: Closes jaw

Question 2

M.digastricus

Answer 2

O: Proc. paracondylaris
I: Ventral-ventromedial border of mandible
A: Opens mouth

Question 3

M.pterygoideus medialis

Answer 3

O: Fossa pterygopalatina
I: Fossa pterygoidea of mandible
A: Grinding movements, closes jaw

Question 4

M.pterygoideus lateralis

Answer 4

O: Ventral to canalis alaris and fissura orbitalis from sphenoid bone
I: Fovea pterygoidea
A: Grinding movements, closes jaw

Question 5

M.splenius

Answer 5

O: Proc.spinosus of Th.1-3, cau. end of lig.nuchae, raphe cervicis and by an aponeurosis from cran. border of thoracolumbar fascia
I: Crista nuchae, mastoid part of temporal bone
A: Extends neck and raises head. Unilateral contraction draws head lat.

Question 6

M.semispinalis capitis

Answer 6

It has two parts: 1.m.biventer cervicis (dors.) and 2.m.complexus (vent.)
O: 1. from proc.trans. of Th2-4 and its firmly connected to the median fibrous raphe, contains several tendinous inscriptions; 2. from cau. articular proc. of C3-Th1
I: Both attaches on occipital bone (crista nuchae, protuberancia occipitalis externa)
A: Bilateral cont. extends neck, unilat. cont. flexes head and neck lat.

Question 7

M.temporalis

Answer 7

O: Fossa temporalis and its borders: linea temporalis, crista sagittalis externa, crista nuchae, dorsal edge of zygomatic arch
I: Proc.coronoideus of mandible
A: Raises mandible, closes jaw

Question 8

M.mylohyoideus

Answer 8

O: Medial surface of the alveolar border of the mandible - linea mylohyoidea
I: Middle raphe beneath the tounge and the basihyoid
A: Acts like a sling to lift the tounge