3rd and 4th plantar layers of the foot (Latin)

The stratum tertium is composed of the m. flexor hallucis brevis, m. adductor hallucis and m. flexor digiti minimi brevis. The m. flexor hallucis brevis arises from the os cuboideum via its caput laterale and from the tendo musculi tibialis posterioris and septum intermusculare medialis via its caput mediale. Both heads (capita) run anteromedially towards the great toe (hallux), inserting onto each side of the base of the phalanx proximalis hallucis. The m. adductor hallucis similarly arises by way of two heads: a caput obliquum and caput transversum. The caput obliquum originates from the bases of ossa metacarpi 2-4, the os cuboideum, os cuneiforme laterale and the tendo musculi fibularis longi, while the caput transversum extends from the ligg. metatarsophalangea plantaria of the toes 3-5 and lig. metacarpeum transversum profundum to reach and attach onto the base of the phalanx proximalis hallucis. The m. flexor digiti minimi is part of the mm. plantares laterales and acts on the little toe (digitus minimus). It originates from the base of os metatarsi 5 and extends to insert onto the phalanx proximalis digiti minimi. The stratum quartum consists of the mm. interossei plantares and mm. interossei dorsales which are mm. plantares centrales pedis. The mm. interossei dorsales are best viewed from a dorsal perspective of the foot (see previous image). The mm. interossei plantares are three muscles which arise from the medial plantar aspect of the ossa metacarpi 3-5 and insert onto the medial aspect of the bases of the phalanges proximales and aponeurosis extensoria of digitorum 3-5.