anatomy terms

Epicranius (occipitofrontalis)

Epicranius (occipitofrontalis)

origin

frontal belly: epicranial \n aponeurosis; occipital belly: \n occipital and temporal bones

insertion

frontal belly: skin of eyebrows \n and bridge of nose; \n occipital belly: epicranial \n aponeurosis

action

frontal belly: raises eyebrows \n and wrinkles forehead; \n occipital belly: tenses and \n retracts scalp

Nasalis

origin

maxillary bone; alar cartilage of \n nose

insertion

bridge of nose

Action

compresses and dilates nostrils

Orbicularis oculi

origin

medial aspect of bony orbit \n

insertion

skin around eyelids \n

action

closes eyes

orbicularis oris

origin \n maxillary bone; mandible

insertion

lips

action

closes mouth; protrudes lips

Levator labii superioris

origin

inferior aspect of bony orbit \n

insertion

skin and muscle of upper lip \n

action \n elevates upper lip

zygomaticus minor

origin

zygomatic bone

insertion

upper lip

action

elevates upper lip

zygomatic major

origin

zygomatic bone

insertion

angle of mouth

action

elevates lateral corners of mouth \n for smiling

buccinator

origin

maxillary bone; mandible \n

insertion

blends with fibers of orbicularis oris \n

action \n compresses cheek

depressor angle oris

origin

anterolateral surface of mandible \n

insertion

skin at angle of mouth

action

depresses angle of mouth

depressor labii inferoris

origin

anterolateral surface of mandible

insertion

skin of lower lip \n

action \n depresses lower lip

mentalis

origin

anterior surface of mandible

insertion

skin of chin

action

protrudes lower lip; wrinkles \n skin on chin

masseter

origin

zygomatic arch

insertion

lateral surface of mandibular \n ramus

action

elevates mandible to close jaw; \n protrudes mandible

temporalis

origin

temporal bone

insertion

coronoid process of mandible \n

action

elevates mandible to close jaw; \n retrudes mandible

lateral pterygoid

origin \n lateral pterygoid plate

insertion

neck of mandible

action

depresses mandible to open jaw; \n protrudes mandible; lateral \n excursion

Sternocleidomastoid

origin

manubrium; medial one-third of \n clavicle

insertion

mastoid process; occipital bone \n near mastoid process

action

flexion and lateral flexion of \n neck; rotates head so that face is \n turned superiorly and to the \n opposite side

scalenes (anterior, middle, posterior)

origin

transverse processes of cervical \n vertebrae

insertion

first two ribs

action

flexion, lateral flexion, and \n slight rotation of neck; elevation \n of first and second ribs

levator scapulae

origin \n transverse processes of superior four \n cervical vertebrae

insertion

medial border of scapula near \n superior angle

action

elevates scapula; inferior \n rotation of scapula

splenius

origin

spinous processes of inferior \n cervical and superior thoracic \n vertebrae

insertion

mastoid process, occipital bone \n and transverse processes of \n superior cervical vertebrae

action

laterally flexes, rotates, and \n extends head and neck

digastric

origin

anterior belly: inferior margin of \n mandible \n posterior belly: mastoid process

insertion

hyoid bone

action

anterior belly: inferior margin of \n mandible \n posterior belly: mastoid process

stylohyoid

origin \n styloid process of temporal bone \n

insertion

hyoid bone \n

action

elevates and retracts hyoid bone

mylohyoid

origin

mylohyoid line of mandible

insertion

hyoid bone \n

action \n elevates hyoid bone, tongue, \n and floor of mouth

Geniohyoid

origin \n inferior mental spine on posterior \n surface of mandible

insertion

hyoid bone

action

elevates and protracts hyoid \n bone; depresses mandible

hypoglossus

origin

hyoid bone

insertion

tongue

action \n depresses and retracts tongue

Sternohyoid

origin

manubrium and clavicle

insertion

hyoid bone

action

depresses larynx and hyoid bone

Sternothyroid

origin

posterior surface of manubrium \n

insertion

thyroid cartilage \n

action

depresses larynx and hyoid bone

Thyrohyoid

origin

thyroid cartilage of larynx \n

insertion

hyoid bone

action \n depresses hyoid bone; elevates \n larynx

Omohyoid

origin

superior border of scapula \n

insertion

hyoid bone \n

action

depresses and retracts hyoid \n bone

Pectoralis major

origin \n medial half of clavicle; sternum; \n costal cartilages of ribs 1-6 \n

insertion

lateral lip of intertubercular \n groove on humerus \n

action

flexion, medial rotation, and \n adduction of the arm

Pectoralis minor

origin

external surfaces of ribs 3-5 \n

insertion

coracoid process of scapula \n

action

depression and inferior rotation \n of scapula

Serratus anterior

action

external surfaces of ribs 1-8 \n

insertion

medial border of scapula

action

protraction and superior rotation \n of scapula; holds scapula against \n thoracic wall

Trapezius

origin

posterior surface of occipital bone; \n ligamentum nuchae; spinous \n processes of thoracic vertebrae

insertion

lateral third of clavicle; \n acromion process; spine of \n scapula \n

action

descending part: elevates scapula \n transverse part: retracts scapula \n ascending part: depresses \n scapula

Latissimus dorsi

origin

spinous processes of vertebrae T6- \n T12; thoracolumbar fascia; iliac \n crest; inferior three ribs

insertion

intertubercular groove of \n humerus \n

action

extension, adduction, and \n medial rotation of arm

Rhomboid minor

origin

ligamentum nuchae; spinous \n processes of vertebrae C7 and T1 \n

insertion

medial border of scapula

action

retracts scapula; elevates \n scapula; inferior rotation of \n scapula

Rhomboid major

origin

spinous processes of vertebrae of T2- \n T5 \n

insertion

medial border of scapula

action

retracts scapula; elevates \n scapula; inferior rotation of \n scapula

Deltoid

origin

lateral third of clavicle; acromion \n process; spine of scapula \n

insertion

deltoid tuberosity of humerus

action

anterior fibers: medial rotation \n and flexion of arm \n middle fibers: abduction of arm \n posterior fibers: lateral rotation \n and extension of arm

Subscapularis

origin

subscapular fossa of scapula \n

insertion

lesser tubercle of humerus \n

action \n adduction and medial rotation of \n arm

Supraspinatus

origin

supraspinous fossa of scapula \n

insertion

greater tubercle of humerus \n

action

abduction of arm

Infraspinatus

origin

Infraspinous fossa of scapula \n

insertion

greater tubercle of humerus \n

action

lateral rotation of arm

Teres minor

origin

lateral border of scapula \n

insertion

greater tubercle of humerus \n

action

lateral rotation of arm

Teres major

origin

inferior angle of scapula \n

insertion

medial lip of intertubercular \n groove of humerus

action

extension, adduction, and \n medial rotation of arm

Rectus abdominis

origin

pubic crest; pubic symphysis \n

insertion

xiphoid process; costal \n cartilages of ribs 5-7

action

flexion of vertebral column; \n stabilizes pelvis during walking; \n increases intraabdominal \n pressure during forced expiration

External oblique

origin

external surfaces of inferior eight \n ribs

insertion

linea alba; pubic crest; pubic \n tubercle; iliac crest

action

rotation and lateral flexion of \n trunk; increases intraabdominal \n pressure during forced expiration

Internal oblique

origin

thoracolumbar fascia; inguinal \n ligament; costal cartilages of \n inferior six ribs; iliac crest

insertion

linea alba; pubic crest \n

action

increases intraabdominal \n pressure during forced expiration

Erector spinae

action \n iliac crest; posterior surface of \n sacrum; processes of cervical, \n thoracic, and lumbar vertebrae \n

insertion

ribs and transverse processes of \n vertebrae about 6 segments \n above origin

action

extension and lateral flexion of \n vertebral column and neck

Quadratus lumborum

origin

iliac crest; iliolumbar ligament

insertion

inferior border of 12th rib and \n transverse processes of lumbar \n vertebrae

action

lateral flexion of vertebral \n column

External intercostals

origin

inferior border of superior rib \n

insertion

superior border of inferior rib \n

action \n elevates the ribs during normal \n inspiration

Internal intercostals

origin

superior border of inferior rib \n

insertion

inferior border of superior rib \n

action

depresses the ribs during forced \n expiration

Diaphragm

origin

xiphoid process; lower six costal \n cartilages; anterior surface of lumbar \n vertebrae L1-L3

insertion

central tendon of diaphragm \n

action

flattens to increase the volume \n of the thoracic cavity