A&P Lab: Axial muscles (muscles of head and trunk)

epicranius

frontalis and occipitalis and the aponeurosis

what does the epicranius muscles do

elevates eyebrows and skin of forehead

orbicularis oculi

close and squint your eyes

what muscle is this 

orbicularis oculi 

orbicularis oris

purses your lips (kissy face)

what muscle is this

orbicularis oris

buccinator

pulls cheeks inward to produce sucking and whistling movement

buccinator is a 

trumpeter muscle 

what muscle is this 

buccinator 

platysma

depresses mandible (opens jaw) and tightens skin of neck

what muscle is this

platysma

zygomaticus major

pull corners of the mouth laterally and superiorly in smiling

origin of zygomaticus major

zygomatic bone

insertion of zygomaticus major

angle of mouth, blends with muscle fibers of orbicular oris and several others

what muscle is this

zygomaticus major

zygomaticus minor 

elevates upper lip 

what is this muscle

zygomaticus minor

risorius

pulls corner of mouth laterally (smirking)

what is this muscle 

risorius

muscles of mastication (chewing)

all innervated by Trigeminal nerve (V) and are some of the strongest muscles

temporalis

elevates and retracts mandible as in closing mouth, biting

origin of temporalis

temporal fossa

temporal fossa

insertion of coronoid process and ramus of mandible

what muscles is this

temporalis

masseter

elevates mandible as in chewing, biting

what muscle is this

masseter

lateral pterygoid

moves mandible from side to side, protrudes and depresses mandible

what muscle is this

lateral petrygoid

medial pterygoid

protrudes, and moves mandible side to side

what muscle is this

medial pterygoid

digastric

elevates hyoid bone and stabilizes it during swallowing and speech

what muscle is this

digastric

mylohyoid

elevates hyoid and floor of mouth and pushes food toward pharynx

what muscle is this

mylohyoid

sternohyoid

most superficial muscle of neck- depressed larynx and hyoid bone if mandible is fixed (during swallowing and talking)

what muscle is this

sternohyoid

sternocleidomastoid

flex head and neck when both sides contract (rotate head toward opposite side when contract separately)

origin of sternocleidomastoid

sternum and clavicle

insertion of sternocleidomastoid

mastoid process of temporal bone

what muscle is this

sternocleidomastoid

trapezius

holds head upright and hyperextends head and neck

origin of trapezius

posterior occipital bone and C7-T4

insertion of trapezius

clavicle, acromion, and spine of scapula

what muscle is this

trapezius

erector spinae group

iliocostalis, longissimus, spinalis

iliocostalis

extends and laterally flexes vertebral column

longissimus

extends and laterally flexes vertebral column

spinalis

extends vertebral column

what muscle is this

iliocostalis

what muscle is this

longissimus

what muscle is this

spinalis

muscles of ventilation

external intercostals, internal intercostals, diaphragm, pectoralis minor

external intercostals

inspiration (inhaling)

internal intercostals

nearest to the sternum; expiration (exhaling)

diaphragm

inspiration (inhaling) also

pectoralis minor

important in forced inspiration and expiration

what muscle is this

external intercostals

what muscle is this

internal intercostals

what muscle is this

diaphragm

what muscle is this

pectoralis minor

muscles of the abdominal wall

move trunk and increase intra-abdominal pressure

rectus abdominis

flexes trunk

origin of rectus abdominis

crest of pubis, pubic symphysis

insertion of rectus abdominis

cartilage of 5th, 6th, and 7th ribs and xiohoid process

external oblique

rotate and laterally flex the trunk

internal oblique

rotate and laterally flex the trunk also

transversus abdominis

squeeze abdominal contents and increase intra-abdominal pressure

what muscle is this

rectus abdominis

what muscle is this

external oblique

what muscle is this

internal oblique

what muscle is this

transversus abdominis

what muscle is this

linea alba