Muscles in Forearm

muscles in forearm

The muscles of the forearm are divided into two compartments by deep fascia and fibrous intermuscular septa. The tendons and muscles that extend and flex the forearm are referred to as extensors. There are five deep extensor muscles and seven superficial extensor muscles. This article will discuss the different types of forearm muscles and their functions. For further information, visit Muscles of the Forearm.

Extensor carpi ulnaris

The Extensor Carpi Ulnaris is one of the forearm’s most superficial muscles. It extends the wrist, and also helps angle the hand inward towards the little finger. This muscle is found in the posterior compartment of the forearm, and is related to the Extensor digitorum and the Extensor digiti minimi.

Palmaris longus

The palmaris longus muscles in the forearm are superficial flexor muscles located in the anterior compartment. They are attached to the medial epicondyle of the humerus and project over the transverse carpal ligament. Their tendon inserts into the palmar aponeurosis, which is the anchor for the skin and other fascia. The palmaris longus muscle plays an important role in wrist flexion and abduction.

Flexor digitorum profundus

The flexor digitorum profundus is a deep-seated fusiform muscle that stretches between the bones of the forearm and the phalanges. It is a member of the anterior compartment of the forearm and lies in the third layer. It originates on the upper third of the ulna, and it splits into four tendons that insert onto the second, middle, and ring phalanges.

Adductor pollicis

The adductor pollicis muscle is one of the largest intrinsic muscles in the hand. Its main function is to facilitate the adduction of the thumb, the movement of the thumb towards the index finger from its abducted position. Adduction is necessary for pinching and gripping, and it aids in opposition of the thumb, which is a combination of adduction and opposition. To test the strength of the adductor pollicis, you can push the thumb against the index finger, and pull the two apart.


Supinator muscles in the forearm attach to the bones of the forearm and form the floor of the cubital fossa. They are a major cause of entrapment during hand movements. These muscles are usually deep in the forearm, but some are superficial. The supinator muscle has several names. These include supinator longus, supinator brevis, and brachioradialis.

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