Muscles

the attachment of a muscle to the stationary bone

origin

the attachment of a muscle to the movable bone

insertion

the movements that occur when the muscle contracts; usually pulling one bone towards or away from another

action

epicranial aponeurosis

origin of frontalis

skin superior to orbit

insertion of frontalis

• draws scalp anteriorly

• raises eyebrows

• wrinkles skin horizontally (surprise)

action of frontalis

occipital bone and mastoid process of temporal bone

origin of occipital belly

epicranial aponeurosis

insertion of occipital belly

draws scalp posteriorly

action of occipital belly

medial wall of orbit

origin of orbicularis oculi

circular path around orbit

insertion of orbicularis oculi

closes eye

action of orbicularis oculi

zygomatic bone, more superiorly

origin of zygomaticus minor

upper lip

insertion of zygomaticus minor

raises upper lip, exposing upper teeth

action of zygomaticus minor

zygomatic bone, more inferiorly

origin of zygomaticus major

skin at angle of mouth and orbicularis oris

insertion of zygomaticus major

draws angle of mouth superiorly and laterally, (smiling)

action of zygomaticus major

maxilla and zygomatic arch

origin of masseter

angle and ramus of mandible

insertion of masseter

elevates mandible, as closing mouth

action of masseter

muscle fibers surrounding opening of mouth

origin of orbicularis oris

skin at corner of the mouth

insertion of orbicularis oris

closes and protrudes lips (kissing), compresses lips against teeth, and shapes lips during speech

action of orbicularis oris

sternal head: manubrium of sternum

clavicular head: medial 1/3 of clavicle

origin of sternocleidomastoid

mastoid process of the temporal bone

insertion of sternocleidomastoid

bilateral: flex the cervical portion of the vertebral column

unilateral: laterally rotate and flex head to opposite side of contracting muscle

action of sternocleidomastoid

superior nuchal line of occipital bone, spines of C7-T12

origin of trapezius

clavicle, acromion, and spine of scapula

insertion of trapezius

Reverse Muscle Action

RMA

superior fibers: rotate scapula upward

middle fibers: adduct scapula

inferior fibers: depress and rotate scapula upward; stabilize scapula

RMA: extends head at neck

action of trapezius

spines of T7-L5 vertebrae, sacral crest, iliac crest, ribs 9-12 via thoracolumbar fascia

origin of latissimus dorsi

intertubercular sulcus of humerus

insertion of latissimus dorsi

extends, adducts, and medially rotates arm at shoulder

RMA: elevates vertebral column and torso

action of latissimus dorsi

acromion and spine of scapula

origin of deltoid

deltoid tuberosity of humerus

insertion of deltoid

anterior fibers: flexes and medially rotate arm at shoulder

lateral fibers: abduct arm at shoulder

posterior fibers: extends and laterally rotate arm at shoulder

action of deltoid

clavicle, sternum, and costal cartilages of ribs 2-6

origin of pectoralis major

greater tubercle of humerus; upper limb muscle

insertion of pectoralis major

adducts and medially rotates arm at shoulder

action of pectoralis major

long head: supraglenoid tubercle of scapula

short head: coracoid process of scapula

origin of biceps brachii

radial tuberosity of radius and bicipital aponeurosis

insertion of biceps brachii

• flexes arm at shoulder

• flexes forearm at elbow

• supinates forearm at radioulnar joints

action of biceps brachii

long head: infraglenoid tubercle of scapula

lateral head: lateral and posterior surface of humerus

medial head: posterior surface of humerus

origin of triceps brachii

olecranon of ulna

insertion of triceps brachii

• extends forearm at elbow

• extends arm at shoulder

action of triceps brachii

supraspinatus fossa of scapula

origin of supraspinatus

greater tubercle of humerus; most superior muscle of the rotator cuff

insertion of supraspinatus

assists deltoid in abducting arm at shoulder

action of supraspinatus

infraspinatus fossa of scapula

origin of infraspinatus

greater tubercle of humerus; between the supraspinatus and teres minor muscles of the rotator cuff

insertion of infraspinatus

laterally rotates arm at shoulder

action of infraspinatus

inferior, lateral border of scapula

origin of teres minor

greater tubercle of humerus, most inferior muscle of the rotator cuff

insertion of teres minor

laterally rotates and extends arm at shoulder

action of teres minor

subscapular fossa of scapula

origin of subscapularis

lesser tubercle of humerus

insertion of subscapularis

medially rotates arm at shoulder

action of subscapularis

pubic crest and pubic symphysis

origin of rectus abdominus

cartilage of ribs 5-7 and xiphoid process

insertion of rectus abdominus

flexes vertebral column; compresses abdomen

RMA: flexes pelvis on the vertebral column

action of rectus abdominus

ribs 5-12

origin of external oblique

iliac crest of ilium

insertion of external oblique

bilateral: flexes vertebral column; compresses abdomen

unilateral: laterally flexes and rotates vertebral column

action of external oblique

iliac crest of ilium; cartilages of ribs 5-10

origin of transverse abdominus

xiphoid process, linea alba, and pubis

insertion of transverse abdominus

compresses abdomen

action of transverse abdominus

iliac crest of ilium, sacrum, and coccyx

origin of gluteus maximus

gluteal tuberosity and linea aspera of femur

insertion of gluteus maximus

extends and laterally rotates thigh at hip

action of gluteus maximus

anterior superior iliac spine of ilium; pelvic/thigh muscle

origin of sartorius

medial surface of body of tibia; anterior muscle of the pelvis and thigh

insertion of sartorius

weakly flexes leg at knee

weakly flexes, abducts, and laterally rotates thigh at hip

action of sartorius

body and inferior ramus of pubis

origin of gracilis

medial surface of body of tibia; medial muscle of the pelvis and thigh

insertion of gracilis

• adducts and medially rotates thigh at hip

• flexes leg at knee

action of gracilis

anterior inferior iliac spine of ilium (A.I.I.S)

origin of rectus femoris

tibial tuberosity via patellar tendon; most superficial quadricep muscle

insertion of rectus femoris

flexes thigh at hip; extends leg at knee

action of rectus femoris

greater trochanter and linea aspera of femur

origin of vastus lateralis

tibial tuberosity via patellar tendon; most lateral quadricep muscle

insertion of vastus lateralis

extends leg at knee

action of vastus lateralis

linea aspera of femur

origin of vastus medialis

tibial tuberosity via patellar tendon; medial quadricep muscle

insertion of vastus medialis

extends leg at knee

action of vastus medialis

anterior and lateral surfaces of body of femur

origin of vastus intermedialis

tibial tuberosity via patellar tendon; quadricep muscle deep to the rectus femoris

insertion of vastus intermedialis

extends leg at knee

action of vastus intermedialis

long head: ischial tuberosity of ischium

short head: linea aspera of femur

origin of biceps femoris

head of fibula and lateral condyle of tibia

insertion of biceps femoris

extends thigh at hip, most lateral hamstring muscle

action of biceps femoris

ischial tuberosity

origin of semitendinosus

proximal part of tibia medial to tibial tuberosity

insertion of semitendinosus

“half tendon” extends thigh at hip

action of semitendinosus

ischial tuberosity

origin of semimembranosus

medial condyle of tibia

insertion of semimembranosus

flexes leg at knee; extends thigh at hip

action of semimembranosus

lateral condyle and body of tibia; interosseous membrane

origin of tibialis anterior

metatarsal I and medial cuneiform

insertion of tibialis anterior

dorsiflexes foot at ankle; inverts foot at intertarsal joints

action of tibialis anterior