Dorsal Interossei Of The Hand

"Anatomy and Physiology", The Joints of the Body, The Lower Arm and Hand

Order: Reorder
Duration: 1:20
Published: 17 Feb 2011
Uploaded: 17 Feb 2011
Author: MyCyberCollege

The Elbows' movement is dependent upon the skeletal and muscular structures of the upper and lower arm working together. The Skeletal components of the Elbow include the Humerus of the upper arm, and the Radius and Ulnar bones of the lower arm. The Muscles of both the lower arm (the Flexor and Extensor Groups, the Radial Group) and the upper arm (the Deltoid, Biceps, Triceps) work in concert to permit the elbow to produce complex pronation, supination, and torsional/rotational movements. The Hand has a vast network of fine muscles that respond to in-puts from the peripheral nervous system, and acts willfully via the directives from the central nervous system. The Hand has tremendous fine-motor potential. Some of the primary muscles of the Hand include the Thenar, the Hypothenar, the Interossei palmares. The true potential of the fine motor movement of the Hand is demonstrated in the extraordinary skills of surgeons and professional musicians.

Dorsal interossei of the hand

The dorsal interossei of the hand are muscles that occupy the space between the metacarpals.

Structure

There are four dorsal interossei in each hand. They are specified as 'dorsal' to contrast them with the palmar interossei, which are located on the anterior side of the metacarpals.

The dorsal interosseous muscles are bipennate, with each muscle arising by two heads from the adjacent sides of the metacarpal bones, but more extensively from the metacarpal bone of the finger into which the muscle is inserted. They are inserted into the bases of the proximal phalanges and into the extensor expansion of the corresponding extensor digitorum tendon. The middle digit has two dorsal interossei insert onto it while the first digit (thumb) and the fifth digit (little finger) have none.

The first dorsal interosseous muscle is larger than the others. Between its two heads, the radial artery passes from the back of the hand into the palm.

Between the heads of dorsal interossei two, three, and four, a perforating branch from the deep palmar arch is transmitted.

Innervation

All interosseous muscles of the hand are innervated by the deep branch of the ulnar nerve.

Actions

The primary action of the dorsal interossei is to: flex the metacarpophalangeal joint (MCP) and to extend the interphalangeal joints and thus assist the lumbricals. In addition, a secondary function is to abduct the fingers away from the middle finger. This is in contrast to the palmar interossei, which adduct the fingers. This is often remembered by the mnemonic DAB PAD, short for "Dorsal ABducts, Palmar ADducts".

Additional images

References

External links

Category:Muscles of the upper limb Category:Hand

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