

Muscles and Their Actions on the Body
Back Muscles
- Latissimus dorsi
Action: Adducts, extends, internally rotates, and horizontally abducts the arm -
Rhomboideus major
Action: Adduction and downward rotation of the scapula -
Rhomboideus minor
Action: Adduction and downward rotation of the scapula
-
Teres minor
Action: External rotation and horizontal abduction of the arm -
Levator scapulae
Action: Extension of neck, downward rotation and elevation of the scapulae -
Trapezius
Action: Elevates, depresses (depends on area of muscle being activated), adducts and upwardly rotates the scapulae -
Erector spinae
Action: Extension, lateral flexion and rotation of the head and neck
Shoulder, Chest and Arm Muscles
-
Pectoralis major
Action: Adducts, flexes, extends (depends on fibers being recruited), internally rotates and horizontally adducts the arm -
Pectoralis minor
Action: Depresses protracts and downwardly rotates the scapulae - Deltoid
-
Anterior
Action: Abducts, flexion, internally rotates and horizontally adducts the arm -
Medial
Action: Abducts the arm -
Posterior
Action: Abducts, extends, externally rotates and horizontally abducts the arm -
Coracobrachialis
Action: Flexes and horizontally adducts the arm
-
Rotator Cuff
-
Subscapularis
Action: Internally rotates the arm -
Infraspinatus
Action: Externally rotates the arm -
Teres Minor
Action: Externally rotates the arm -
Supraspinatus
Action: Abduction of the arm
-
-
Biceps brachii
Action: Flexion of the elbow and shoulder, supination of the forearm -
Brachialis
Action: Flexion of the elbow -
Pronator teres
Action: Pronates the forearm -
Triceps brachii
Action: Extends the elbow, adducts and extends the shoulder (long head) -
Anconeus
Action: Extends the elbow -
Supinator
Action: Supinates the forearm -
Pronator quadratus
Action: Pronates the forearm -
Flexor carpi radialis
Action: Flexes and abducts the wrist -
Flexor carpi ulnaris
Action: Flexes and adducts the wrist -
Palmaris longus
Action: Flexion of the wrist -
Extensor carpi radialis longus
Action: Extends and adducts the wrist -
Extensor digitorum
Action: Extends the wrist
Legs
- Quadriceps
-
Rectus femoris
Action: hip flexion and knee extension -
Vastus lateralis
Action: knee extension -
Vastus medialis
Action: knee extension -
Vastus Intermedius
Action: knee extension -
Sartorius
Action: flexion, external rotation, and abduction at the hip, flexion and internal rotation at the knee -
Gracilis
Action: abduction, flexion, and internal rotation at the hip, internal rotation of the knee -
Pectineus
Action: adduction, flexion, and horizontal adduction at the hip -
Adductor longus
Action: adduction, flexion, and horizontal adduction at the hip -
Adductor magnus
Action: adduction, flexion, and horizontal adduction at the hip - Hamstrings
-
Semimembranosus
Action: extension a the hip, and flexion and internal rotation at the knee -
Semitendinosus
Action: extension and internal rotation at the hip, flexion and internal rotation at the knee -
Biceps Femoris
Action: extension at the hip, external rotation and flexion at the knee -
Gluteus maximus
Action: extension, external rotation, horizontal abduction, and adduction at the hip -
Gluteus medius
Action: abduction, horizontal abduction, internal rotation (anterior fibers), and external rotation (posterior fibers) at the hip -
Gluteus minimus
Action: abduction, horizontal abduction, and internal rotation at the hip
Lower Leg
-
Tibialis anterior
Action: dorsiflexion and inversion of the foot -
Extensor digitorum longus
Action: dorsiflexion and eversion of the foot -
Extensor hallucis longus
Action: inversion of the foot -
Peroneus longus
Action: plantarflexion and eversion of the foot -
Soleus
Action: plantarflexion -
Gastrocnemius
Action: plantarflexion of the foot, flexion of the knee
Trunk/Abdomen
-
Rectus abdominis
Action: flexion and lateral flexion of the trunk -
External oblique
Action: flexion of the trunk, lateral flexion (same side), and rotation (opposite side) -
Internal oblique
Action: flexion of the trunk, lateral flexion (same side), rotation (same side) -
Serratus anterior
Action: protraction and upward rotation of the shoulder girdle -
Tranversalis abdominis
Action: compresses the abdominal/pelvic cavity.