Lateral part of longitudinal arch of foot

The lateral part of longitudinal arch of foot is lower as compared to its medial counterpart. It has limited mobility but still help in weight transmission to the ground.

The bony structure can be divided into anterior and posterior pillars. The anterior pillar is long but weak, formed by the cuboid bone and the 4th and 5th metatarsals. The posterior pillar is short but strong, formed by the lateral half of the calcaneus. It’s important to note that the phalanges do not contribute to the formation of the longitudinal arches.

Due to the arch-like alignment of the bones, the foot does not lie flat on the ground. Only the anterior end (heads of the 4th and 5th metatarsals) and the posterior end (lateral tubercle of the calcaneus) of the lateral part of the longitudinal arch touch the ground. The highest point of the arch is located at the level of the articular facet on the superior surface of the calcaneus, around the subtalar joint. A significant joint within the arch is the calcaneocuboid joint.

Various factors support the lateral part of longitudinal arch of foot, including:

• The long and short plantar ligaments

• The plantar aponeurosis and muscles of the first layer of the sole, which act as tie beams, pulling the anterior and posterior ends of the arch towards each other and preventing it from collapsing flat on the ground

• Muscles of the lateral leg compartment (peroneus longus and brevis), which pull the summit of the lateral longitudinal arch upwards

• The tendons of peroneus longus and tibialis anterior together form a stirrup-like ring that provides support to the longitudinal arches