Arteries Blood supply to the foot is by branches of the posterior tibial and dorsalis pedis (dorsal artery of the foot) arteries. The posterior tibial artery enters the sole and bifurcates into lateral and medial plantar arteries. The lateral plantar artery joins with the terminal end of the dorsalis pedis artery (the deep plantar artery) to form the deep plantar arch. Branches from this arch supply the toes. The dorsalis pedis artery is the continuation of the anterior tibial artery, passes on the dorsal aspect of the foot and then inferiorly, as the deep plantar artery, between metatarsals I and II to enter the sole of the foot. Dorsalis pedis artery The dorsalis pedis artery is the continuation of the anterior tibial artery and begins as the anterior tibial artery crosses the ankle joint. It passes anteriorly over the dorsal aspect of the talus, navicular, and intermediate cuneiform bones, and then passes inferiorly, as the deep plantar artery, between the two heads of the first dorsal interosseous muscle to join the deep plantar arch in the sole of the foot. The pulse of the dorsalis pedis artery on the dorsal surface of the foot can be felt by gently palpating the vessel against the underlying tarsal bones between the tendons of extensor hallucis longus and the tendon of extensor digitorum longus to the second toe. Branches of the dorsalis pedis artery include lateral and medial tarsal branches, an arcuate artery, a first dorsal metatarsal artery: Posterior tibial artery and plantar arch The posterior tibial artery enters the foot through the tarsal tunnel on the medial side of the ankle and posterior to the medial malleolus. Midway between the medial malleolus and the heel, the pulse of the posterior tibial artery is palpable because here the artery is covered only by a thin layer of retinaculum, by superficial connective tissue, and by skin. Near this location, the posterior tibial artery bifurcates into a small medial plantar artery and a much larger lateral plantar artery. Tibial nerve The tibial nerve enters the foot through the tarsal tunnel posterior to the medial malleolus. In the tunnel, the nerve is lateral to the posterior tibial artery, Midway between the medial malleolus and the heel, the tibial nerve bifurcates with the posterior tibial artery into: a large medial plantar nerve; a smaller lateral plantar nerve. Medial plantar nerve The medial plantar nerve is the major sensory nerve in the sole of the foot. It innervates skin on most of the anterior two-thirds of the sole and adjacent surfaces of the medial three and one-half toes, which includes the great toe. In addition to this large area of plantar skin, the nerve also innervates four intrinsic muscles-abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, and the first lumbrical. The medial plantar nerve supplies a digital branch (proper plantar digital nerve) to the medial side of the great toe and then divides into three nerves (common plantar digital nerves) on the plantar surface of flexor digitorum brevis, which continue forward to supply proper plantar digital branches to adjacent surfaces of toes I to IV. The nerve to the first lumbrical originates from the first common plantar digital nerve. More than you ever wanted to know about the foot FUNCTIONS OF FOOT Support body weightSupport body weight Serves as a lever to propel the body forward in walking & runningServes as a lever to propel the body forward in walking & running FUNCTIONS OF FOOT IF THE FOOT POSSESSED A SINGLE BONE It cannot adapt itself to uneven surfacesIt cannot adapt itself to uneven surfaces Its propulsive action depends entirely on gastrocnemius & plantarisIts propulsive action depends entirely on gastrocnemius & plantarisBUT Gastrocnemius & plantaris FUNCTIONS OF FOOT IF THE FOOT IS FORMED OF SMALL BONES & MANY JOINTS It can adapt itself to uneven surfacesIt can adapt itself to uneven surfaces Long flexors & small muscles of foot assist in propulsive actionLong flexors & small muscles of foot assist in propulsive action WHY THERE ARE ARCHES? A segmented structure can hold up weight only if it is built in the form of archesA segmented structure can hold up weight only if it is built in the form of arches Weight will be distributed on: 1) the heel (behind) & 2) heads of metatarsal bones (in front): pressure will be minimized on nerves & vessels in soleWeight will be distributed on: 1) the heel (behind) & 2) heads of metatarsal bones (in front): pressure will be minimized on nerves & vessels in sole Forward propulsive action will be easierForward propulsive action will be easier ARCHES OF FOOT MEDIAL LONGITUDINAL ARCH: Higher than lateral archHigher than lateral arch Formed of: calcaneum, talus (key stone), navicular, three cuneiform & first three metatarsal bonesFormed of: calcaneum, talus (key stone), navicular, three cuneiform & first three metatarsal bones ARCHES OF FOOT LATERAL LONGITUDINAL ARCH: Lower than medial archLower than medial arch Formed of: calcaneum, cuboid (key stone), fourth & fifth metatarsal bonesFormed of: calcaneum, cuboid (key stone), fourth & fifth metatarsal bones ARCHES OF FOOT TRANSVERSE ARCH: It is only half an archIt is only half an arch It is formed of: bases of metatarsal bones, cuboid & three cuneiform bonesIt is formed of: bases of metatarsal bones, cuboid & three cuneiform bones FACTORS MAINTAINING ARCHES OF FOOT Shape of bonesShape of bones Strength of ligamentsStrength of ligaments Tone of musclesTone of muscles MECHANISM OF ARCH SUPPORT SHAPE OF BONES Bones are wedge- shaped with the thin edge lying inferiorlyBones are wedge- shaped with the thin edge lying inferiorly This applies particularly to the bone occupying the center of the arch keystoneThis applies particularly to the bone occupying the center of the arch keystone MECHANISM OF ARCH SUPPORT INFERIOR EDGES OF BONES ARE TIED TOGETHER MECHANISM OF ARCH SUPPORT INFERIOR EDGES OF BONES ARE TIED TOGETHER Medial longtitudinal arch: plantar calcaneonavicular ligament, tibialis posteriorMedial longtitudinal arch: plantar calcaneonavicular ligament, tibialis posterior Lateral longtitudinal arch: long & short plantar ligamentsLateral longtitudinal arch: long & short plantar ligaments Transverse arch: deep transverse ligaments, transverse head of adductor hallucis, dorsal interosseiTransverse arch: deep transverse ligaments, transverse head of adductor hallucis, dorsal interossei MECHANISM OF ARCH SUPPORT TYINGTHE ENDS OF THE ARCH TOGETHER TYING THE ENDS OF THE ARCH TOGETHER MECHANISM OF ARCH SUPPORT TYINGTHE ENDS OF THE ARCH TOGETHER TYING THE ENDS OF THE ARCH TOGETHER Medial longtitudinal arch: plantar aponeurosis, medial part of flexor digitorum longus & brevis, flexor hallucis longus, flexor hallucis brevis, abductor hallucisMedial longtitudinal arch: plantar aponeurosis, medial part of flexor digitorum longus & brevis, flexor hallucis longus, flexor hallucis brevis, abductor hallucis Lateral longtitudinal arch: plantar aponeurosis, lateral part of flexor digitorum longus & brevis, abductor digiti minimi, flexor digiti minimiLateral longtitudinal arch: plantar aponeurosis, lateral part of flexor digitorum longus & brevis, abductor digiti minimi, flexor digiti minimi Transverse arch: peroneus longusTransverse arch: peroneus longus MECHANISM OF ARCH SUPPORT SUSPENDING THE ARCH FROM ABOVE MECHANISM OF ARCH SUPPORT SUSPENDING THE ARCH FROM ABOVE Medial longtitudinal arch: tibialis anterior, tibialis posterior, medial ligament of ankle jointMedial longtitudinal arch: tibialis anterior, tibialis posterior, medial ligament of ankle joint Lateral longtitudinal arch: peroneus longus, peroneus brevisLateral longtitudinal arch: peroneus longus, peroneus brevis Transverse arch: peroneus longusTransverse arch: peroneus longus PES PLANUS (FLAT FOOT) A condition in which the medial longitudinal arch is depressedA condition in which the medial longitudinal arch is depressed The forefoot is evertedThe forefoot is everted The head of talus is forced downward & mediallyThe head of talus is forced downward & medially The causes are both congenital and acquiredThe causes are both congenital and acquired