Functions of muscles

Covers ALL muscles of posterior trunk and lower extremity muscles

Trapezius

Allows you to shrug your shoulders or extend your head

Deltoid

Prime mover of shoulder abduction

Latissimus dorsi

Prime mover of shoulder extension, also adducts the shoulder

Teres major

synergist of latissimus dorsi in extension and adduction of shoulder

Rhomboids

Pull the scapulae medially

Levator scapulae

Elevate the scapula; act to flex the head to the same side (with scapulae fixed)

Semispinalis

Extends the head; rotates the head to the opposite sideE

Erector spinae

Prime movers of back extension

Splenius

As a group, extend or hyperextend the head; when only one side is active, head is rotated and bent toward the same side

Quadratus lumborum

Forms the posterior abdominal wall; helps to maintain upright posture

Gluteus maximus 

powerful extensor of the hips, used when climbing the stairs

Gluteus medius

Abducts and medially rotates the thigh; commonly used as an injection site

Gluteus minimus

Abducts and medially rotates the thigh

Biceps femoris

One of the hamstring muscles that extends the thigh and flexes the knee

Semitendinosus

One of the hamstring muscles that extends the thigh and flexes the knee

Semimembranosus

One of the hamstring muscles that extends the thigh and flexes the knee

Illiopsoas

A strong hip flexor

Sartorius

Flexes and laterally rotates the thigh; brings about the cross-legged sitting position; “the tailor’s muscle”

Adductors (longus and magnus)

Adduct, flex, and rotate the thigh

Pectineus

Adduct, flex, and rotate the thigh

Gracilis

Adduct, flex, and rotate the thigh

Rectus femoris

One of the quadriceps; extends the knee

Vastus lateralis

One of the quadriceps; extends the knee

Vastus medialis

One of the quadriceps; extends the knee

Gastronemius

Produces plantar flexion of the ankle

Soleus

Produces plantar flexion of the ankle

Fibularis (peroneus) longus

Plantar flexes and everts the foot

Tibialis anterior

prime mover of dorsiflexion

Tibialis posterior

prime mover of foot inversion

Extensor digitorum longus

Prime mover of toe extension

Flexor digitorum longus

Prime mover of toe flexion