Four dorsal interossei muscles are located between the |metatarsal bones|. They are bipenniform muscles (each muscle has two points of attachment). The heads arise from adjacent sides of the |metatarsal bones| near the ankle and are inserted in the base of the first |phalanges| (toe bones). In addition there are three plantar interossei that lie beneath the |metatarsal bones|. The plantar interossei are single muscles connected to only one metatarsal bone. When these muscles contract, they stiffen the central part of the foot. You can feel this when you hook your toes under something and try to lift it by bending your knee.
