Plantar interossei muscles
In human anatomy, plantar interossei muscles are three muscles located between the metatarsal bones in the foot. == Structure == The three plantar interosseous muscles are unipennate, as opposed to the bipennate structure of dorsal interosseous muscles, and originate on a single metatarsal bone.
Source: Wikipedia — Plantar interossei muscles (CC BY-SA 4.0)