Musculi interossei manus

Musculi interossei would be found located in the spaces between the metacarpals, in spatia interossea metacarpi. They are divided into two layers:


 * musculi interossei palmares (I.-III.)
 * musculi interossei dorsales (I.-IV.)

Musculi interossei palmares
These are three palmar muscles (I.–III.). Due to the axis, guided by the third finger it lies on the sides facing the third finger. The third finger has no palmar muscles.

Beginning: Attachment:
 * start at the bases of the 2nd, 4th and 5th metacarpals always on the sides facing the axis running through the third toe.
 * they attach to the base of the first phalanges and to the lower aponeurosis of the fingers (2nd, 4th and 5th toes).

Innervation:
 * nervus ulnaris (ramus profundus).

Function:
 * clutch the 2nd, 4th and 5th fingers to the third finger. They clench a fan of fingers.

Musculi interossei dorsales
These are four dorsal muscles (I.–IV). The course of the muscles goes towards the axis going through the third finger. The third finger (II. and III.) is clamped from both sides. So the third finger has two mm. interossei dorsales. While on the second finger the interosseus dorsalis muscle is only on the radial side, on the fourth finger only on the ulnar side.

Between the heads of the mm. interosseus dorsalis I. passes into the palm a. radialis.

Beginning:
 * they start double, i.e. as feathered muscles always coming from two sides of the adjacent metacarpals facing each other.

Attachment:
 * they attach to the base of the first phalanges and to the dorsal aponeurosis of the 2nd–4th finger.

Innervation:
 * ulnar nerve (ramus profundus).

Function:
 * move the 2nd and 4th fingers away from the third finger. They clench a fan of fingers.

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