Lumbricals of the foot phalanges. All four lumbricals insert into extensor hoods of the phalanges, thus creating extension at the inter-phalangeal (PIP and DIP) joints. However, as the tendons also pass inferior to the metatarsal phalangeal (MTP) joints it creates flexion at this joint. Absence of one or more; doubling of the third or fourth even the fifth. Insertion partly or wholly into the first phalanges. The most medial lumbrical is innervated by the medial plantar nerve while the remaining three lumbricals are supplied by the lateral plantar nerve. Lumbricals of the foot The lumbricals are four small skeletal muscles, accessory to the tendons
Dorsal interossei of the hand 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. Each finger is provided with two interossei (palmar or dorsal), with the exception of the little finger, in which the abductor digiti minimi muscle takes the place of