gross anatomy on skeletal muscle

origin

Attachment on the less movable bone

insertion

Attachment on the bone that moves

head

One point of origin (ex. biceps = two heads)

belly

Thick middle portion of a muscle

tendon

Connects muscle to bone

aponeurosis

Broad, flat tendon

Agonist (Prime mover)

Muscle responsible for the main movement

Antagonist

Opposes the agonist

Antagonist

Opposes the agonist

Synergist

Assists the agonist

fixator

Stabilizes a joint while another muscle moves

circular

Surrounds an opening

parallel

fibers run parallel

fusiform

thick middle, narrow ends

convergent

broad origin, narrow insertion

pennante

fibers attach to tendon

types of pennate

• unipennate

• bipennate

• Multipennate

4 muscles of the quadriceps femoris

• Rectus femoris

• Vastus lateralis

• Vastus medialis

• Vastus intermedius

function of the quadriceps femoris

extension of the knee, rectus femoris also flexes the hip

3 muscles of hamstring

• Biceps femoris

• Semitendinosus

• Semimembranosus

function of the hamstring muscles

flex knee and extension of hip

Orbicularis oris

closes and purses lips

Trapezius

Elevates, depresses, retracts, rotates scapula and Extends neck

Digastric

Depresses mandible and Elevates hyoid

Masseter

Elevates mandible (strong chewing muscle)

Pterygoids Medial

Elevates mandible (strong chewing muscle)

Pterygoids Medial

Elevates mandible

Pterygoids Lateral

Depresses and protracts mandible and Side-to-side chewing

Superior rectus

moves up and medially

Inferior rectus

moves down and medically, controlled by

Medial rectus

Moves eye inward

lateral rectus

moves eye outwardly

superior oblique

moves down and laterally

inferior oblique

moves up and laterally

Supraspinatus

Abducts arm

Infraspinatus

Lateral rotation

Teres minor

Lateral rotation

Subscapularis

Medial rotation

rotator cuff muscles

• Supraspinatus

• Infraspinatus

• Teres minor

• Subscapularis

shoulder and arm actions

• flexion

• extension

• abductions

• adduction

• medial rotation

• lateral rotation

thenar ( thumb ) muscles

• abductor pollicis

• flexor pollicis

• opponents pollicis

• adductor pollicis

hypothenar ( little finger )

• abductor digiti minimi

• flexor digiti minimi

• opponents digiti minimi

Gastrocnemius

Plantar flexion and Flexes knee

Soleus

Plantar flexion only