8 CEUs. 51 Muscles of Arm and Hand

The muscles of the upper limb are responsible for the movements of the shoulder, arm, forearm, wrist, hand, and fingers. They can be divided into four groups based on their location and function.

- **Muscles of the scapula**: These muscles attach the scapula (shoulder blade) to the thorax (chest wall) and help stabilize and position the scapula. They include the **supraspinatus**, **infraspinatus**, **teres minor**, **subscapularis**, **teres major**, **serratus anterior**, **levator scapulae**, **rhomboid major**, and **rhomboid minor**. The first four muscles form the **rotator cuff**, which surrounds and supports the shoulder joint.

- **Muscles of the shoulder**: These muscles attach the humerus (upper arm bone) to the scapula and move the arm in different directions. They include the **pectoralis major**, **pectoralis minor**, **deltoid**, **coracobrachialis**, and **latissimus dorsi**. The pectoralis major and latissimus dorsi are also involved in the movements of the chest and back.

- **Muscles of the arm**: These muscles are located in the upper arm and move the forearm and elbow. They include the **brachialis**, **biceps brachii**, **triceps brachii**, and **coracobrachialis**. The biceps brachii and triceps brachii are the most prominent muscles of the arm and are antagonists, meaning they perform opposite actions.

- **Muscles of the forearm and hand**: These muscles are located in the forearm and hand and move the wrist, hand, and fingers. They can be further subdivided into **forearm flexors**, **forearm extensors**, and **hand muscles**. The forearm flexors include the **pronator teres**, **flexor carpi radialis**, **palmaris longus**, **flexor carpi ulnaris**, **flexor digitorum superficialis**, **pronator quadratus**, **flexor pollicis longus**, and **flexor digitorum profundus**. The forearm extensors include the **supinator**, **extensor digitorum**, **extensor carpi ulnaris**, **extensor carpi radialis longus and brevis**, **extensor indicis proprius**, **extensor digiti minimi**, and **brachioradialis**. The hand muscles include the **thenar muscles**, **hypothenar muscles**, **interossei**, **lumbricals**, **adductor pollicis**, and **palmaris brevis**.

Each muscle of the upper limb has a specific name, origin, insertion, innervation, and action.