Major Muscle Actions

Triceps brachii

• extends elbow

• flexes elbow

• extends arm

• horizontal adduction of arm

Zygomaticus major and minor

• raises eyebrows

• closes mouth

• raises corner of mouth

• puckers lips

Fibularis longus

• eversion and plantar flexion of foot

• dorsiflexion of foot

• flexes hip

• adducts leg

Frontalis

• closes eyes

• closes mouth

• raises eyebrows

• flexes elbow

Pectoralis major

• abducts arm

• horizontal adduction of arm

• extends elbow

• extends arm

Gluteus medius

• abducts leg

• adducts leg

• plantar flexion of foot

• flexes knee

Masseter

• elevates corner of mouth

• elevates mandible

• puckers lips

• raises eyebrows

Sternocleidomastoid

• horizontal adduction of arm

• flexes arm

• extends arm

• one - turns head; two-flexes neck & raises sternum

Orbicularis oris

• closes eyes

• puckers lips

• raises eyebrows

• elevates mandible

Trapezius

• flexes back/tenses abdominal wall

• horizontal adduction of arm

• elevates scapula/shoulder, pulls scapula medial/downward

• one-turns head; both - flexes neck & elevates sternum