Muscles (O, I, A) P. 3-5

Question 1

M. temporalis

Answer 1

O: Fossa temporalis, linea temporalis, crista saggitalis ext, crista nuchae & dorsal edge of arcus zygomaticus

I: Proc. coronoideus of mandibula

A: Raises mandible, closes jaw

Question 2

M. masseter

Answer 2

O: ventral border of arcus zygomaticus

I: Fossa massaterica of mandible

A: Closes jaw

Question 3

M. digastricus

Answer 3

O: Proc. paracondylaris of Os occipitale

I: ventromedial border of mandible

A: Opens mouth

Question 4

M. pterygoideus med.

Answer 4

O: Proc. pterygopalatina (from sphenoid, palatine, and pterygoid bones)

I: Fossa pterygoidea (medially, below for. mandibulae)

A: Grinding movements, closes jaw

Question 5

M pterygoideus lat.

Answer 5

O: Ventral to can. alaris and fissura orbitalis (sphenoid bone)

I: Fovea pterygoidea (next to proc. condylaris of mandible)

A: Grinding movements, closes jaw

Question 6

M. sternocleidomastoideus

(M. sternocephalicus)

Answer 6

• m. sternocephalicus
  O: Manubrium sterni

I:
> m. sternomastoideus: mastoid part of Os temporale
> m. sternooccipitalis: crista nuchae of Os occipitale

A:
~ Unilateral contraction (draws head and neck to one side)
~ Bilateral contraction (draws head down)

Question 7

M. sternocleidomastoideus

(M. brachiocephalicus)

Answer 7

> m. cleidobrachialis
O: distal cranial surface of humerus + crista humeri

I: Intersectio clavicularis

> m. cleidocephalicus
O: Intersectio clavicularis

I:
* m. cleidocervicalis: raphe of neck
* m. cleidomastoideus: mastoid part of Os temporale

A (both):
~ Forelimb fixed - unilateral contraction (moves head & neck) in lateral direction, bilateral contraction: bend head & neck downwards and backwards
~ Limb free (elevated position) - move forelimb cranially

Question 8

M. omotransversarius

Answer 8

O: Distal part of spina scapula, then runs under M. sternocleidomastoideus

I: Caudal border of Ala atlantis

A:
~ If limb is fixed - flexes neck laterally
~ If limb is free - draws shoulder cranially

Question 9

M. splenius

Answer 9

O: Proc. spinosus of Th1-3, caudal end of lig. nuchae, raphe of neck, and cranial border of fascia thoracolumbalis

I: Crista nuchae + mastoid part of Os temporale

A: Extends neck and raises head

Question 10

M. serratus dorsalis cran.

Answer 10

O: Fascia thoracolumbalis + proc. spinosus of Th1-7

I: prox on ribs 2-10

A: Inspiratory muscle

Question 11

M. semispinalis capitis

Answer 11

O:
> M. biventer cervicis: Proc. transversus of Th2-4
> M. complexus: Proc. articularis caud. of C3-Th1

I: Crista nucha, external occipital protuberance

A:
~ Unilaterally contraction - flexes head and neck laterally
~ Bilaterally contraction - extends neck