Chapter 8 (5)

• The ankle consists of tarsal bones that differ from carpal bones due to their load-bearing role. The calcaneus is the largest tarsal bone that forms the heel and serves as the point of attachment for the calcaneal (Achilles) tendon. The talus is the most superior tarsal bone that forms the ankle joint with the tibia and fibula, sitting upon the calcaneus and articulating with the navicular. The proximal row of tarsal bones consists of the talus, calcaneus, and navicular, while the distal row includes the medial, intermediate, lateral cuneiforms, and cuboid.
• The foot bones are divided into two groups: the metatarsals and the phalanges
• Metatarsals are five long bones that run from the mid-foot to the toes
• The first metatarsal is the bone closest to the big toe, while the fifth metatarsal is the bone closest to the little toe
• Each metatarsal has a base, a shaft, and a head
• Phalanges are the bones of the toes
• The big toe has two phalanges, while the other four toes have three
• Each phalanx has a base, a middle section, and a tip
• During the seventh week of embryonic development, the rotation of the upper and lower limbs in opposite directions begins. It is interesting to note that the largest digit is medial in the foot and lateral in the hand. Each limb rotates about 90° in opposite directions, and this rotation also explains why the elbow flexes posteriorly and the knee flexes anteriorly.
• The foot's sole is not flat on the ground. It has three springy arches that absorb stress. The medial longitudinal arch runs from heel to hallux and is formed by the calcaneus, talus, navicular, cuneiforms, and metatarsals I and III. The lateral longitudinal arch runs from heel to little toe and includes calcaneus, cuboid, and metatarsals IV and V.
• The transverse arch of the foot is located across the middle of the foot. It consists of the cuboid, cuneiforms, and proximal heads of metatarsals. The arches are held together by short, strong ligaments. Pes planus, also known as flat feet, can occur due to excessive weight, repetitious stress, or congenital weakness.
• The arches of the feet: