Dorsal Interossei of the Hand
Original Editor - Kate Sampson
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. 
Origins and Insertions 
|| Insertion |
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)|
|| 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 |
|| 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 |
|| 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 |
The Dorsal Interossei muscles of the hand are supplied by the dorsal and palmar interossei artery .
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 .
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 .
The dorsal interossei muscles can be palpated in the dorsum of the hand on resisted abduction of the fingers between the metacarpals.
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.
- Palastanga N, Field D, Soames R. Anatomy and human movement. Structure and function. 5th ed. London: Butterworth Heinemann Elsevier, 2006.
- Drake RL, Vogl W, Mitchell AWM. Gray's anatomy for students. London: Churchill Livingstone.
- KenHub. Dorsal interossei muscles of the hand- Human anatomy. Available from: https://www.youtube.com/watch?v=cn1Vp9FawKI (last accessed 14/2/2016).