Muscles of the hand

Muscles of the Hand

The hand is a complex structure that is made up of numerous muscles. These muscles are responsible for the hand's ability to perform a wide range of movements, from fine motor skills like writing and sewing to more gross motor skills like gripping and lifting. The muscles of the hand can be divided into two main groups: the extrinsic muscles, which are located in the forearm but control the movements of the hand and fingers, and the intrinsic muscles, which are located within the hand itself.

File:Hand muscles front.png

Front view of the muscles of the hand

Extrinsic Muscles

The extrinsic muscles of the hand are further divided into two groups: the flexors, which enable the fingers and thumb to bend, and the extensors, which enable them to straighten.

Flexors

The flexor muscles include the flexor digitorum superficialis, flexor digitorum profundus, and flexor pollicis longus. These muscles originate in the forearm and insert into various points on the fingers and thumb, allowing them to bend at the joints.

File:Flexor muscles of the hand.png

Flexor muscles of the hand

Extensors

The extensor muscles include the extensor digitorum, extensor indicis, and extensor pollicis longus and brevis. These muscles also originate in the forearm and insert into various points on the fingers and thumb, allowing them to straighten after they have been bent.

File:Extensor muscles of the hand.png

Extensor muscles of the hand

Intrinsic Muscles

The intrinsic muscles of the hand are located within the hand itself and are responsible for the fine motor movements of the fingers and thumb. These muscles are divided into three groups: the thenar muscles, the hypothenar muscles, and the interossei muscles.

Thenar Muscles

The thenar muscles are located in the fleshy mound at the base of the thumb, known as the thenar eminence. They include the abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis. These muscles allow the thumb to move in a wide range of directions, enabling it to oppose the fingers and perform precise movements.

File:Thenar muscles of the hand.png

Thenar muscles of the hand

Hypothenar Muscles

The hypothenar muscles are located in the fleshy mound at the base of the little finger, known as the hypothenar eminence. They include the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi. These muscles allow the little finger to move and oppose the thumb.

File:Hypothenar muscles of the hand.png

Hypothenar muscles of the hand

Interossei Muscles

The interossei muscles are located between the metacarpal bones of the hand. They include the dorsal interossei and the palmar interossei. These muscles allow the fingers to spread apart (abduct) and come together (adduct).

File:Interossei muscles of the hand.png

Interossei muscles of the hand

See Also

• Anatomy of the hand
• Muscular system
• Hand surgery