24 Muscle & Actions

Temporalis

Elevates mandible (shuts mouth)

Orbicularis oculi

Squints eyes shut

Orbicularis oris

Closes and purses lips

Zygomaticus major

Raises corners of mouth (smile)

Sternocleidomastoid

Flexes neck when both sides act together

Rectus abdominis

Compresses abdomen and flexes back

Serratus anterior

Thrusts (protracts) scapula forward

Pectoralis Major

Adducts the arm

Trapezius

Elevates the scapula

Diaphragm

Involved in normal respiration

Latissimus dorsi

Extends and adducts the arm

Deltoid

Abducts arm (raises to ask a question)

Rotator Cuff muscles

Contract to prevent sliding of the head

Biceps Brachii

Flexes elbow and supinates forearm

Sartorius

Abducts the leg

Gracilis

Adducts the leg

Rectus Femoris

Assists with thigh flexion

Biceps femoris (lateral)

Involved in movement at both hip and knee joints

Semitendinosus

Extends at the hip and flexes at the knee

Semimembranosus

Causes knee flexion and internal rotation

Gastrocnemius

Plantar flexes the foot at the ankle

Soleus

Also plantar flexes the foot

Tibialis anterior

Dorsiflexes the foot