MUSCLES

Buccinator

• Origin: Maxilla and mandible

• Insertion: Orbicularis oris

• Action: Compresses cheeks

Pectoralis Major

• Origin: Clavicle, sternum, and costal cartilage of the upper ribs

• Insertion: Greater tubercle of the humerus

• Action: Flexes shoulder and adducts the humerus

Trapezius

• Origin: Occipital bone, spinous process of C7, and all thoracic vertebrae

• Insertion: Acromial extremity of clavicle and scapular spine

• Action: Elevates and adducts the scapula

Sternocleidomastoid

• Origin: Clavicle

• Insertion: Mastoid process

• Action: Flexes shoulder and neck; rotates head

Masseter

• Origin: Zygomatic arch

• Insertion: Mandible

• Action: Elevates mandible

Adductor Longus

• Origin: Pubis

• Insertion: Posterior femur

• Action: Adduction

Biceps Femoris

• Origin: Ischial tuberosity and femur

• Insertion: Fibular head

• Action: Flexes knee and extends hip

Deltoid

• Origin: Acromial and scapular spine

• Insertion: Deltoid tuberosity of humerus

• Action: Abducts the humerus

Triceps Brachii

• Origin: Scapula and humerus

• Insertion: Olecranon process of ulna

• Action: Extends elbow

Biceps Brachii

• Origin: Coracoid process and supraglenoid tubercle of scapula

• Insertion: Radial tuberosity

• Action: Flexes elbow and supinates hand and wrist

Supinator

• Origin: Lateral epicondyle of humerus and proximal ulna

• Insertion: Proximal radius

• Action: Supinates forearm