Muscles in the Arm

muscles in the arm

The muscles in the arm connect to the shoulder on one side and the elbow joint on the other. The elbow joint is made up of two bones, the ulna and the radius. These two bones help you bend and straighten your arm. These two bones are also called the biceps brachii.


The coracobrachialis muscle originates from the lateral cord of the brachial plexus, with fibers arising from the fifth, sixth, and seventh cervical nerves. These nerves pierce the coracobrachialis and continue into the forearm as the lateral antibrachial cutaneous nerve. This nerve innervates the coracobrachialis and the biceps brachii.

Biceps brachii

The Biceps brachii muscles are a pair of elongated muscles in the arm. These muscles originate in the supraglenoid tubercle of the scapula, and have two heads. The long head runs over the head of the humerus, while the shorter head is attached to the radial tuberosity. Both heads contain blood vessels. The muscles function as a pair to help the arm flex and the shoulder.

Triceps brachii

The biceps brachii muscles in the arm are the prime mover of the arm. They are positioned on the anterior side of the humerus and insert on the radius bone. In addition to the biceps brachii, the arm also has two synergist muscles: the brachioradialis on the forearm and the brachialis on the upper arm.

Flexor pollicis longus

The flexor pollicis longus muscle is located in the lower half of the arm. It aids in the flexion of the thumb. This muscle is bordered on the side by the supinator muscle. It runs down the forearm and attaches to the interosseous membrane. This tendon then traverses the hand.

Palmaris longus

The palmaris longus is a pair of muscles that are located at the base of the forearm. The researchers have studied how this muscle works in humans. According to them, the muscles’ roles are complementary and may differ in different people. In addition, there are several variations within the palmaris longus, including duplication, accessory slips, and substitute structures. As such, the location of these muscles and their origin and insertion may also vary. These variations have clinical implications. In some cases, they can mimic soft tissue tumors.

Extensor carpi ulnaris

The extensor carpi ulnaris is one of the extensor muscles in the arm. It is located on the medial side of the forearm, and receives its vascular supply from the ulnar artery, which branches from the brachial artery near the antecubital fossa. This muscle is related to the digiti minimi and the extensor digitorum and is part of the superficial extensor muscle group.

Extensor carpi radialis

The Extensor Carpi Radialis (ECRL) is a group of muscles that help extend the wrist and hand. These muscles are used for a variety of actions, including throwing a ball and picking up objects. They are found in the posterior compartment of the forearm, partly overlapped by the brachioradialis. They are usually palpable inferoposterior to the elbow.

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