Muscle  

Action 

Masseter 

Elevates and protracts mandible 

Digastric 

Depresses mandible and elevates hyoid bone 

during chewing and swallowing 

Sternocleidomastoid 

They laterally flex neck to same side, rotate 

head to opposite side and pull head forward  

and down    

Diaphragm 

Upon inhalation, the diaphragm contracts and  

flattens and the chest cavity enlarges 

Levator Scapulae 

Only elevates scapula 

Erector Spinae 

Extend the back, laterally flex the back, and  

maintain correct posture and curvature of  

the spinal column 

Latissimus Dorsi 

Extends shoulder, depresses and retracts  

shoulder and adducts, and rotates  

retracts shoulder + adducts, and rotates  

arm medially 

External Oblique 

Compresses abdomen, flexes and rotates 

vertebral column 

Rectus Abdominis  

Compresses abdomen, flexes 

vertebral column  

DOES NOT ROTATE  

Trapezius 

Rotates and retracts scapula 

Superior portion: elevates scapula 

Inferior portion: depresses scapula 

Rhomboid Major 

Retracts, elevates, and rotates 

scapula 

Rhomboid Minor 

Retracts and elevates scapula 

DOES NOT ROTATE 

Pectoralis Major 

Flexes shoulder, adducts, and rotates 

arm medially 

Pectoralis Minor 

Depresses and protracts scapula, 

elevates ribs during forceful 

inhalation 

Deltoid 

Lateral portion abducts arm  

Anterior portion flexes shoulder  

Posterior portion extends shoulder 

Supraspinatus 

Abducts arm (Move away from midline) 

Infraspinatus 

Rotates arm laterally 

Subscapularis 

Rotates arm medially 

Teres Minor 

Rotates arm laterally 

Biceps Brachii 

Flexes elbow and supinates forearm and 

hand 

Brachioradialis  

Flexes elbow 

Triceps Brachii 

Extends elbow 

Flexor Carpi Ulnaris 

Flexes wrist and adducts hand 

Palmaris Longus 

Flexes wrist 

Flexor Carpi Radialis 

Flexes wrist and abducts hand 

Extensor Carpi Ulnaris 

Extends wrist and adducts hand 

Extensor Digiti Minimi 

Extend the fifth digit at its  

metacarpophalangeal joint 

Extensor Carpi Radialis 

• Brevis + Longus 

Extends wrist and abducts hand 

Gluteus Maximus  

Extends hip 

Tensor Fascia Latae 

Abducts thigh, flexes hip, and rotates thigh 

medially 

Adductor Longus 

Adducts thigh and flexes hip 

Gracilis 

Adducts thigh and flexes knee 

Sartorius 

Flexes knee and hip, abducts and rotates 

thigh laterally, and rotates leg medially 

Rectus Femoris 

Extends knee, flexes hip 

Vastus Lateralis 

Extends knee 

Vastus Intermedius 

Extends knee 

Vastus Medialis 

Extends knee 

Biceps Femoris 

Flexes knee, rotates leg laterally, 

 and extends hip 

Semimembranosus 

Flexes knee, rotates leg medially,  

and extends hip 

Muscle  

Flexes knee, rotates leg medially,  

and extends hip 

Tibialis anterior 

Dorsiflexion and inversion of foot 

Gastrocnemius 

Plantar flexion of foot, flexes knee 

Soleus 

Plantar flexion of foot