ANAT 3001 axial muscles

muscles of facial expression

1. orbicularis oculi

2. orbicularis oris

3. buccinator

4. platysma

orbicularis oculi

orbicularis oculi ORIGIN

outer surface of bony orbit

orbicularis oculi INSERTION

skin surrounding eyelids

orbicularis oculi ACTION

closes eyes

orbicularis oris

orbicularis oris ORIGIN

maxilla and mandible

orbicularis oris INSERTON

skin surrounding mouth

orbicularis oris ACTION

purses lips

buccinator

buccinator ORIGIN

maxilla and mandible

buccinator INSERTION

orbicularis oris

buccinator ACTION

compresses cheeks, holds food inbetween teeth

platysma

platysma ORIGIN

skin of shoulder and chest

platysma INSERTION

skin of mandible and cheek

platysma ACTION

tenses skin of neck

muscles of mastification

1. temporalis

2. masseter

3. medial pterygoid

4. lateral pterygiod

temporalis

temporalis ORIGIN

lateral side of neurocranium

temporalis INSERTION

coronoid process of mandible

temporalis ACTION

elevates and retracts mandible

masseter

masseter ORIGIN

zygomatic arch

masseter INSERTION

lateral surface of mandibular ramus

masseter ACTION

elevates and protracts mandible

sternocleidomastoid

sternocleidomastoid ORIGIN

sternum and clavicle

sternocleidomastoid INSERTION

mastoid process of temporal bone

sternocleidomastoid ACTION

unilaterally: ipsilaterally bends the neck and contralaterally rotates the head

bilaterally: flexes neck

supra- and infrahyoid muscles

suprahyoid muscles ACTION

elevate hyoid with larynx and pharynx during swallowing, open mouth

infrahyoid muscles ACTION

depress hyoid with larynx and pharynx during swallowing

erector spinae

muscles of erector spinae

1. spinalis (along spine, most medial)

2. longissimus (longest, middle layer)

3. illiocostalis (along ribs, most lateral)

erector spinae muscles ORIGIN

spinous processes, sacrum and ilium

erector spinae muscles INSERTION

vertebrae and ribs

erector spinae muscles ACTION

extends the spine (maintain posture)

muscles of the abdominal wall

1. rectus abdominis

2. external oblique

3. internal oblique

4. transversus abdominis

muscles of the abdominal wall ACTION

flexes and compresses the trunk and abdomen

oblique muscle layers

oblique muscle layers

1. external oblique (most superficial layer, down and in)

2. internal oblique (middle layer, up and in)

3. transversus abdominis (deepest layer, side to side)

oblique muscle layers ORIGIN

inferior ribs and iliac crest

oblique muscle layers INSERTION

linea alba

oblique muscle layers ACTION

flex and rotate trunk, compress abdomen

rectus abdominis

rectus abdominis ORIGIN

pubic bone

rectus abdominis INSERTION

xiphopid process and inferior ribs

rectus abdominis ACTION

flex trunk; compress abdomen

muscles of breathing

1. respiratory diaphragm

2. intercostal muscles

respiratory diaphragm

respiratory diaphragm ORIGIN

internal surface of ribs, xiphoid process, lumbar vertebrae 

respiratory diaphragm INSERTION

central tendon

respiratory diaphragm ACTION

diaphragm flattens of inhalation

*active for breathing at rest and forced

intercostal muscles

intercostal muscles ORIGIN

ribs

intercostal muscles INSERTION

adjacent rib

intercostal muscles ACTION

assists with breathing

*active during forced inhalation and exhalation