Palmar interossei muscles

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Palmar interossei muscles

The palmar interossei muscles are a group of muscles located in the hand. These muscles are responsible for the adduction of the fingers, meaning they bring the fingers towards the middle finger. There are three palmar interossei muscles, each associated with the second, fourth, and fifth fingers.

Anatomy

The palmar interossei muscles originate from the metacarpal bones of the hand. Specifically:

• The first palmar interosseous muscle originates from the ulnar side of the second metacarpal.
• The second palmar interosseous muscle originates from the radial side of the fourth metacarpal.
• The third palmar interosseous muscle originates from the radial side of the fifth metacarpal.

Each muscle inserts into the base of the proximal phalanx and the extensor expansion of the corresponding finger.

Function

The primary function of the palmar interossei muscles is to adduct the fingers towards the middle finger. This action is essential for various hand movements, including gripping and manipulating objects. Additionally, these muscles assist in flexing the metacarpophalangeal joints and extending the interphalangeal joints of the fingers.

Innervation

The palmar interossei muscles are innervated by the ulnar nerve, specifically the deep branch of the ulnar nerve. This nerve provides the necessary motor signals for the muscles to contract and perform their functions.

Blood Supply

The blood supply to the palmar interossei muscles is primarily provided by the palmar metacarpal arteries, which are branches of the deep palmar arch.

Clinical Significance

Injury or damage to the ulnar nerve can result in weakness or paralysis of the palmar interossei muscles, leading to difficulties in finger adduction and impaired hand function. Conditions such as ulnar nerve entrapment or cubital tunnel syndrome can affect these muscles.

See Also

• Dorsal interossei muscles
• Hand anatomy
• Ulnar nerve
• Metacarpal bones