Anatomy of the Foot Arches

• An arch is a curved structure that spans a space and may or may not support weight above it.
• The foot is the terminal part of the lower limb that bears the weight of the entire body.
• The arches of the foot are formed by the tarsal and metatarsal bones, which are strengthened by ligaments and tendons.
• The bones of the foot are divided into Tarsus, Metatarsus and Phalanges.
• The bones are arranged in longitudinal and transverse arches to support the various muscles and ligaments.
• There are 26 bones in the skeletal structure of the foot.
• The tarsal joint is composed of the talocalcaneal and talocalcaneonavicular joints.
• The midtarsal joint is composed of the calcaneocuboid joint.
• Other joints include: tarsometatarsal joint, intermetatarsal joint, metatarsophalangeal joint, and interphalangeal joint.
• Ligaments hold the tendons in place and stabilize the joints.
• Ligaments allow the arch to curve or flatten, providing balance and foot strength for walking through stretching and contracting.

Important Ligaments

• Spring ligament extends from the sustentaculum tali to the navicular bone.
• Long plantar ligament connects the calcaneus to the cuboid.
• Short plantar ligament is located on the plantar surface of the calcaneus to the cuboid.
• Tendons concentrate the pull of a muscle on a small area of attachment in an inelastic but flexible manner.
• Examples of tendons in the foot include: tibialis anterior, tibialis posterior, and the tendon of flexor digitorum longus.
• The foot is a platform for supporting body weight
• The foot is also a lever to propel the body forward for running, walking, and jumping.
• The human foot is designed in the form of elastic arches to achieve these functions.

Classification of Arches

• Longitudinal arches, which include the medial and lateral arches.
• Transverse arch.

Arches Details

• Each arch consists of bones that form the arch, an anterior pillar, a posterior pillar, a summit, and a main joint.

Medial Longitudinal Arch

• Bones include the calcaneus, talus, navicular, three cuneiform bones, and their respective metatarsals.
• The anterior pillar shafts of the medial 3 metatarsals.
• The posterior pillar is the medial part of the calcaneum.
• The summit is the trochlear upper surface of the Talus.
• The main joint of the arch is the talocalcaneo-navicular joint.
• The visible arch is formed on the medial margin of the foot.
• The Medial Longitudinal Arch is a higher arch than its counterpart.
• This arch is extremely resilient due to its large number of component bones.
• The Medial Longitudinal Arch acts as a shock absorber for body weight.

Lateral Longitudinal Arch

• Bones consist of the calcaneus, cuboid, and the lateral two metatarsal bones.
• Anterior pillar shafts of the 4th & 5th metatarsals.
• The posterior pillar is the lateral part of the calcaneum.
• The summit is a facet on the superior surface of the Calcaneum.
• The main joint of the arch is the calcaneo-cuboid.
• The arch is flat and lies on the lateral margin of the foot.
• Contains less bones.
• Transmits weight and thrust to the ground.

Transverse Arch

• Bones consist of three cuneiform bones, cuboid, and the metatarsals.
• The anterior is heads of the metatarsals.
• A complete transverse arch forms when the medial borders of both feet meet.
• Pillars are medial and lateral parts of the longitudinal arches.
• It is an incomplete arch.
• Formed by the wedge shape of the three cuneiform bones.
• The bases of the three metatarsals accentuate the arch.

Mechanism of Arch Support

• The talus is the keystone of this the medial longitudinal arch
• Spring ligament, long plantar ligament, & dorsal ligaments provide the intersegmental ties
• The Medial part of the plantar aponeurosis, and the medial parts of flexor digitorum longus & flexor hallucis longus act as tie beams.
• Sling support is provided by the tibialis posterior, flexor hallucis longus, and digitorum longus

Maintenance of the Lateral Longitudinal Arch

• The calcanean angle of the cuboid forms the bones.
• Long & short plantar ligaments and dorsal ligaments act as intersegmental ties.
• Tie beams are lateral parts of the plantar aponeurosis and flexor digitorum longus.
• Peroneus longus and brevis offer sling support.

Support for the Transverse Arch

• Wedge shaped 3 cuneiforms & bases of middle 3 metatarsals act as support
• Deep transverse ligaments, dorsal interossei, and the adductor hallucis provide support to the intersegmental ties.
• The tendon of peroneus longus provide the tie beams.
• Tendons of peroneus brevis & tertius on lateral side, and the tendon of tibialis anterior on the medial side are the sling supports.

Functions of the Arches

• Distributing body weight to the weight-bearing areas
• Providing springs for walking.
• Acting as shock absorbers in stepping and jumping
• Protecting the soft tissues of the sole
• Providing resilience and rigidity

Pes Planus

• Is a condition where medial longitudinal arch is depressed.
• There is also lateral deviation of the forefoot.
• The head of the talus is forced downward & medially.

Club Foot

• The foot is inverted and the ankle is plantarflexed.
• Weight is borne on the lateral surface of the forefoot.
• Talipes Equinu involves a patient walking on the toes with the heel raised.
• Talipes calcaneus involves a patient walking on the heel with the forefoot raised.
• Talipes varus involves a patient walking on the outer border of the foot, which is inverted and adducted.