The second dorsal interosseous abducts the second toe laterally, toward the third toe. Because the second toe has two dorsal interossei acting on it (first abducts medially, second abducts laterally), it has the greatest active range of abduction of any lesser toe. The second dorsal interosseous occupies the second intermetatarsal space.
| Origin | Adjacent surfaces of the second and third metatarsals (bipennate) |
|---|---|
| Insertion | Lateral base of the proximal phalanx of the second toe and extensor hood |
| Nerve Supply | Lateral plantar nerve (deep branch) |
| Blood Supply | Second plantar metatarsal artery |
| Actions | Abducts the second toe laterally (away from the midline); Assists MTP flexion of the second toe |
|---|
The second dorsal interosseous is assessed in peripheral neuropathy evaluation alongside the first. Wasting of the second intermetatarsal space is visible in advanced diabetic neuropathy and Charcot-Marie-Tooth disease. Second MTP joint plantar plate tears produce dorsal subluxation of the second toe, which the second dorsal interosseous cannot oppose due to denervation or fibrosis in chronic cases.
Palpated in the second intermetatarsal space on the dorsum of the foot, between the second and third metatarsal shafts, during active lateral deviation of the second toe.
Denervation wasting of the second dorsal interosseous producing a visible depression in the second intermetatarsal space, associated with peripheral neuropathy or second MTP joint chronic instability.
