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.