The apical ectodermal ridge (AER) produces a fibroblast growth factor (Fgf), which promotes the outgrowth of the limb buds by stimulating mitosis. Retinoic acid is a global organizing gradient that initiates the production of transcription factors that specify regional differentiation and limb polarization. Several factors influence the formation of the limb bud vasculature and musculature including retinoic acid, sonic hedgehog (SHH), HOX genes, apical ectodermal ridge (AER) and the zone of polarizing activity (ZPA). The limb buds of the embryo begin to form about 5 weeks after fertilization as the lateral plate mesoderm migrates into the limb bud region and condenses along the central axis to eventually form the vasculature and skeletal components of the lower limb. Two of the muscles of the anterior compartment of the lower limb also invert the foot (tibialis anterior, flexor hallucis longus) and one weakly everts the foot (fibularis tertius). The key function of the muscles of the anterior compartment of the lower limb is dorsiflexion of the ankle and extension of the toes. The anterior compartment is the most common site for acute compartment syndrome and is a medical emergency that requires fasciotomy of the involved compartment.

The anterior compartment of the lower limb is susceptible to several pathologies including acute compartment syndrome resulting in foot drop, atherosclerotic plaque buildup of the arteries, and deep vein thrombosis. The anterior compartment muscles function as the primary extensors of the ankle (dorsiflexion) and extensors of the toes. The anterior compartment contains the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and fibularis tertius muscles, innervated by the deep peroneal nerve and supplied by the anterior tibial artery. The lower leg subdivides into four compartments which are the anterior, lateral, superficial posterior and deep posterior compartments.

Compartments of leg vasculature