Bones of foot
•The bones of the foot include the tarsus, metatarsus, and phalanges. There are 7 tarsal bones, 5 metatarsal bones, and 14 phalanges
Bones of foot
•Tarsus: made up of 7 tarsal bones arranged in two rows. In proximal row, there is talus above, and calcaneus below. In distal row, there are four tarsal bones lying side by side. From medial to lateral, there are medial cuneiform,intermediate cuneiform.lateral cuneiform and cuboid. B/w talus and 3 cuneiform bones , navicular bone is interposed.
•These tarsal bones are much larger and stronger than the carpal bones because they have to support and distribute the body weight
Talus
•It is 2nd largest tarsal bone. It lies b/w tibia above and calcaneum below gripped on sides by malleoli
•It has a head, neck and a body
•Side determination:
•Head is directed forward
•Trochlear articular surface of body is directed upwards and concave articular surface downward
•Body bears a large triangular facet laterally and comma faced facet medially
•Head:
•Directed forwards and slightly downwards and medially
•Ant, surface is oval and convex . It articulates with the posterior surface of navicular bone
•Inferior surface is marked by 3 articular areas. Posterior facet is large ,oval ,convex and articulates with the middle facet on sustentaculum tali of calcaneum. The anterolateral facet articulates with the ant facet of calcaneum. Medial facet with the spring ligament.
•Neck:
•Constricted part b/w head and neck
•It is set obliquely on the body so that inferiorly it extends further backwards on medial side than on lateral side
•Medial part of its planter surface is marked by deep groove termed as sulcus tali
•Body: cuboidal in shape and has 5 surfaces
•Superior surface which articulate with lower end of tibia to make ankle joint. Also called trochlear sufrace
•Inferior surface has oval concave articular surface which articulate with posterior facet of calcaneum to form subtalar joint
•Medial surface
•Lateral surface has a triangular articular surface for lateral malleolus
•Posterior process is small and is marked by oblique groove which is bounded by medial and lateral tubercles .
Attachments on talus
•Devoid of muscular attachments
•Many ligaments are attached to it
•Distal part of dorsal surface provides attachment to capsular ligament of ankle joint and to dorsal talonavicular ligament
•Inferior surface provides attachment to interosseous talocalcanean and cervical ligaments
•Lateral part of neck provides attachment to anterior talofibular ligament
•Lower non articular part of medial surface of body gives attachment to deltoid fibres
•Groove on posterior surface has attachment of lexor hallucis longus. Medial tubercle provides attachment to deltoid above and medial talocalcanean ligament below
•Posterior talofibular ligament is attached to upper part of posterior process
calcaneus
•Largest tarsal bone
•Forms the prominence of heel
•Rougly cuboidal and has 6 surfaces
•side determination
•Ant.surface is small and bears a concavoconvex facet for cuboid.post surface is large and rough
•Dorsal or upper surface has a large convex articular surface in middle.
•planter surface is rough
•Lateral surface is flat and medial surface concave from above downwards
Features of Calcaneum
•Anterior surface is smallest, covered by concavocovex sloping articular surface for cuboid
•Post surface is divided into 3 areas, upper,middle and lower. Upper area is smooth while others are rough
•Dorsal or superior surface is divided to 3 areas. Post 1/3 is rough. Middle 1/3 is covered by post facet for articulation with facet on inferior surface of body of talus.Ant. 1/3 is articular in anteromedial part and non articular in posterolateral part.
•Planter surface is rough and marked by 3 tubercles. Medial and lateral are situated posteriorly , anterior tubercle lies in anterior part. Also in this surface there is large weight bearing prominence called calcaneal tuberosity
•Lateral surface is rough and in its anterior part there is small elevation termed as peroneal tubercle
•Medial surface is concave from above downwards. In it’s concavity there is shelf like projection of bone called sustentaculum tali, the upper surface of this process helps in formation of talocalcaneonavicular joint
Attachments of calcaneum
•Middle rough area on post surface has insertion of tendocalcaneus and plantaris. The upper area is covered by a bursa, lower area is covered by dense fibrofatty tissue and supports the body weight while standing
•Lateral part of non articular area on ant part of dorsal surface provide origin to extensor digitorum brevis, extensor retinaculum. Medial part forms sulcus calcanei and provides attachment to interosseous talocalcanean ligament medially and cervical ligament laterally
• medial tubercle of planter surface provides attachment to abductor hallucis, flexor retinaculum and planter aponeurosis
•Lateral tubercle gives origin to abductor digiti minimi. Ant tubercle gives attacment to short plantar ligament. The rough strip b/w three tubercles gives attachment to long plantar ligament
•On lateral surface, peroneal tubercle lies b/w tendons of peroneus brevis above and peronus longus below. It itself gives attachment to a slip from inferior peroneal retinaculum. Calcaneofibular ligament is attached 1cm behind the trochlea
•On medial surface, groove on lower surface of sustantaculum tali is occupied by tendon of flexor hallucis longus. Its medial margin is related to tendon of flexor digitorum longus and provides attachment to spring ligament anteriorly, slip of tibialis posterior in the middle, medial talocalcaneal ligament posteriorly.
Bones of foot
•Navicular Bone
• The tuberosity of the navicular bone can be seen and felt on the medial border of the foot 1 in. (2.5 cm) in front of and below the medial malleolus; it gives attachment to the main part of the tibialis posterior tendon
•. Cuboid Bone
• A deep groove on the inferior aspect of the cuboid bone lodges the tendon of the peroneus longus muscle.
• Cuneiform Bones
• The three small, wedge-shaped cuneiform bones articulate proximally with the navicular bone and distally with the first three metatarsal bones. Their wedge shape contributes greatly to the formation and maintenance of the transverse arch of the foot
•Metatarsal Bones and Phalanges
•The metatarsal bones and phalanges resemble the metacarpals and phalanges of the hand, and each possesses a head distally, a shaft, and a base proximally.
•The five metatarsals are numbered from the medial to the lateral side
• The first metatarsal bone is large and strong and plays an important role in supporting the weight of the body.
•The head is grooved on its inferior aspect by the medial and lateral sesamoid bones in the tendons of the flexor hallucis brevis.
• The fifth metatarsal has a prominent tubercle on its base that can be easily palpated along the lateral border of the foot. The tubercle gives attachment to the peroneus brevis tendon. Each toe has three phalanges except the big toe, which possesses only two.
Foot
•The foot supports the body weight and provides leverage for walking and running. It is unique in that it is constructed in the form of arches, which enable it to adapt its shape to uneven surfaces. It also serves as a resilient spring to absorb shocks, such as in jumping.
•The part/region of the foot contacting the floor or ground is the sole.
• The part directed superiorly is the dorsum of the foot
• The sole of the foot underlying the calcaneus is the heel or heel region and the sole underlying the heads of the medial two metatarsals is the ball of the foot.
•The great toe is also the 1st toe and the little toe is also the 5th toe.
Dorsum of foot
•Skin
•The skin on the dorsum of the foot is thin, hairy, and freely mobile on the underlying tendons and bones.
• The sensory nerve supply to the skin on the dorsum of the foot is derived from the superficial peroneal nerve, assisted by the deep peroneal, saphenous, and sural nerves.
• The superficial peroneal nerve emerges from between the peroneus brevis and the extensor digitorum longus muscle in the lower part of the leg . It now divides into medial and lateral cutaneous branches that supply the skin on the dorsum of the foot; the medial side of the big toe; and the adjacent sides of the second, third, fourth, and fifth toes.
• The deep peroneal nerve supplies the skin of the adjacent sides of the big and second toes
• The saphenous nerve passes onto the dorsum of the foot in front of the medial malleolus . It supplies the skin along the medial side of the foot as far forward as the head of the first metatarsal bone.
• The sural nerve enters the foot behind the lateral malleolus and supplies the skin along the lateral margin of the foot and the lateral side of the little toe. The nail beds and the skin covering the dorsal surfaces of the terminal phalanges are supplied by the medial and lateral plantar nerves.
•Dorsal Venous Arch (or Network)
• The dorsal venous arch lies in the subcutaneous tissue over the heads of the metatarsal bones and drains on the medial side into the great saphenous vein and on the lateral side into the small saphenous vein .
• The great saphenous vein leaves the dorsum of the foot by ascending into the leg in front of the medial malleolus.
• The small saphenous vein ascends into the leg behind the lateral malleolus.
• The greater part of the blood from the whole foot drains into the arch via digital veins and communicating veins from the sole, which pass through the interosseous spaces.
Muscles of the Dorsum of the Foot
Artery of the Dorsum of the Foot
•Dorsalis Pedis Artery (the Dorsal Artery of the Foot)
•The dorsalis pedis artery begins in front of the ankle joint as a continuation of the anterior tibial artery . It terminates by passing downward into the sole between the two heads of the first dorsal interosseous muscle, where it joins the lateral plantar artery and completes the plantar arch . It is superficial in position and is crossed by the inferior extensor retinaculum and the first tendon of extensor digitorum brevis . On its lateral side lie the terminal part of the deep peroneal nerve and the extensor digitorum longus tendons. On the medial side lies the tendon of extensor hallucis longus. Its pulsations can easily be felt.
•Branches :
•Lateral tarsal artery, which crosses the dorsum of the foot just below the ankle joint.
• Arcuate artery, which runs laterally under the extensor tendons opposite the bases of the metatarsal bones. It gives off metatarsal branches to the toes.
• First dorsal metatarsal artery, which supplies both sides of big toe
Nerve Supply of the Dorsum of the Foot
•Deep Peroneal Nerve :
•The deep peroneal nerve enters the dorsum of the foot by passing deep to the extensor retinacula on the lateral side of the dorsalis pedis artery.
•It divides into terminal, medial, and lateral branches.
•The medial branch supplies the skin of the adjacent sides of the big and second toes.
•The lateral branch supplies the extensor digitorum brevis muscle. Both terminal branches give articular branches to the joints of the foot.
