Dorsal Interossei of the Hand

Original Editor - Kate Sampson

Top Contributors - Kate Sampson, Olajumoke Ogunleye, Kim Jackson, Tomer Yona and Joao Costa

Description

Dorsal interossei of the hand.png

In the hand, there are four dorsal Interossei which lie superficially, in between the metacarpals on the dorsum of the hand. Each muscle is bipennate in shape and extends from the proximal ends of adjacent metacarpals to the proximal phalanx and dorsal digital expansion of the appropriate finger. The position of the insertion site is dependent on which digit is involved. On the first and second digit, the muscle lies on the lateral side and in the third and fourth digit, it lies off the medial side. [1]


Origins and Insertions [2]

Muscle
Origin
Insertion
1st 

The medial side of the proximal end of the first metacarpal and lateral side of the second metacarpal

Lateral side of the base of the second proximal phalanx and the extensor expansion (Extensor Hood)
2nd
Medial side of the second metacarpal and lateral side of the third metacarpal
Lateral side of the base of the third proximal phalanx and the extensor expansion
3rd
Medial side of the third metacarpal and lateral side of the fourth metacarpal
Medial side of the base of the third proximal phalanx and the extensor expansion
4th
Medial side of the fourth metacarpal and lateral side of the fifth metacarpal
Medial side of the base of the fourth proximal phalanx and the extensor expansion


Nerve Supply

The Dorsal Interossei muscles of the hand are all supplied by the deep branch of the ulnar nerve (C8, T1) [1].

Blood Supply

The Dorsal Interossei muscles of the hand are supplied by the dorsal and palmar interossei artery [1].

Function

The dorsal interossei muscles are muscles that abduct the second, third and fourth digits. The first digit and the fifth digit have their own abductor muscles in the thenar and hypothenar eminence and so do not have interossei musculature [2].

Functional contributions

As the dorsal interossei muscles attach to the extensor expansion (extensor hood) of the digits, it also assists in addition to the lumbricals in producing flexion and extension of the metacarpophalangeal and interphalangeal joints [2].

Assessment

The dorsal interossei muscles can be palpated in the dorsum of the hand on resisted abduction of the fingers between the metacarpals[1].

The first dorsal interosseous muscle can be tested by placing the patient's palm flat on a table and asking the patient to abduct his/her index finger against the examiner's resistance. The muscle belly can be both seen and palpated and is a reliable test for the ulnar nerve.

[3]

References

  1. 1.0 1.1 1.2 1.3 Palastanga N, Field D, Soames R. Anatomy and human movement. Structure and function. 5th ed. London: Butterworth Heinemann Elsevier, 2006.
  2. 2.0 2.1 2.2 Drake RL, Vogl W, Mitchell AWM. Gray's anatomy for students. London: Churchill Livingstone.
  3. KenHub. Dorsal interossei muscles of the hand- Human anatomy. Available from: https://www.youtube.com/watch?v=cn1Vp9FawKI (last accessed 14/2/2016).