Week 14 Foot - Nerves & Structures PDF

The Foot Cutaneous Innervation of the Sole of the Foot  skin of sole is thick, hairless and firmly bound to underlying deep fascia  medial calcaneal branches of tibial nerve supply most of the heel  medial plantar nerve (terminal branch of tibial nerve) and supplies medial ⅔ of so...

The Foot Cutaneous Innervation of the Sole of the Foot  skin of sole is thick, hairless and firmly bound to underlying deep fascia  medial calcaneal branches of tibial nerve supply most of the heel  medial plantar nerve (terminal branch of tibial nerve) and supplies medial ⅔ of sole of foot and medial 3½ toes  lateral plantar nerve (terminal branch of tibial nerve) and supplies lateral ⅓ of sole of foot and lateral 1½ toes  small area along medial border of foot is supplied by saphenous nerve  small area of lateral heel and lateral border of foot is supplied by sural nerve (lateral calcaneal and lateral dorsal cutaneous branches) Deep Fascia of the Sole of the Foot  thicker in center of sole of foot à plantar aponeurosis  thinner along medial and lateral parts of sole of foot (covers abductor muscles of great and little toes, respectively)  plantar aponeurosis:  attaches posteriorly to calcaneal tuberosity  distally, it divides into 5 digital bands and become continuous with fibrous flexor (digital) sheaths of corresponding toes  digital bands are connected to each other by transverse fibers at the level of metatarsal heads and superficial transverse metatarsal ligaments  functions: gives firm attachment to overlying skin, protects deeper structures (vessels, nerves, tendons, etc.), assists in maintaining longitudinal arches of foot Fibrous Flexor (Digital) Sheaths  begin at level of metatarsal heads and extend to bases of distal phalanges  together with inferior surfaces of phalanges, interphalangeal joints and metatarsophalangeal joints, create osteofibrous tunnels on inferior (plantar) aspects of toes   osteofibrous tunnel of great toe contains tendon of flexor hallucis longus  osteofibrous tunnels of lateral 4 toes contain tendons of flexor digitorum longus and flexor digitorum brevis  within tunnels, tendons are surrounded by synovial sheaths Medial Plantar Artery  smaller terminal branch of posterior tibial artery  enters sole of foot deep to abductor hallucis muscle and runs anteriorly between abductor hallucis and flexor digitorum brevis muscles (accompanied by medial plantar nerve) and ends distally by supplying medial side of great toe  gives o numerous muscular and cutaneous branches along its course Lateral Plantar Artery  larger terminal branch of posterior tibial artery  enters sole of foot deep to abductor hallucis muscle and runs anteriorly and laterally between flexor digitorum brevis and quadratus plantae muscles (along its course, it is accompanied by lateral plantar nerve)  at base of 5th metatarsal, it curves medially (passing deep to oblique head of adductor hallucis muscle) to form (deep) plantar arch  plantar arch terminates at proximal end of 1st interosseous (intermetatarsal) space (between 1st and 2nd metatarsals), where it anastomoses with deep plantar artery (branch of dorsalis pedis artery)  branches:  numerous muscular and cutaneous branches along its course  perforating branches: originate from (deep) plantar arch, pass dorsally, between metatarsals, to anastomose with dorsal metatarsal arteries (on dorsum of foot)  plantar metatarsal arteries: originate from (deep) plantar arch, run distally and give o plantar digital arteries that supply toes Medial Plantar Nerve  terminal branch of tibial nerve  enters sole of foot deep to abductor hallucis muscle and runs anteriorly between abductor hallucis and flexor digitorum brevis muscles (accompanied by medial plantar artery)  muscular innervation: abductor hallucis, flexor digitorum brevis, 1st lumbrical and flexor hallucis brevis  cutaneous innervation: medial ⅔ of sole of foot and plantar aspects of medial 3½ toes (also supplies nail beds and tips of corresponding toes)  its distribution is similar to that of median nerve in hand Lateral Plantar Nerve  terminal branch of tibial nerve  enters sole of foot deep to abductor hallucis muscle and runs anteriorly and laterally between flexor digitorum brevis and quadratus plantae muscles (accompanied by lateral plantar artery) and at base of 5th metatarsal, it divides into superficial and deep branches (deep branch accompanies [deep] plantar arch)  muscular innervation: abductor digiti minimi, quadratus plantae, 2nd, 3rd and 4th lumbricals, adductor hallucis, flexor digiti minimi brevis and all plantar and dorsal interossei  cutaneous innervation: lateral ⅓ of sole of foot and plantar aspects of lateral 1½ toes (also supplies nail beds and tips of corresponding toes)  its distribution is similar to that of ulnar nerve in hand Cutaneous Innervation of the Dorsum of the Foot  skin is thin, hairy and freely movable on underlying structures  superficial fibular nerve divides into medial and intermediate dorsal cutaneous branches: supply dorsum of foot, medial side of great toe and adjacent sides of 2nd to 5th toes  medial branch of deep fibular nerve: supplies adjacent sides of great and 2nd toes  saphenous nerve: supplies skin along medial border of foot as far as ball of great toe (1st metatarsophalangeal joint)  sural nerve continues in foot as lateral dorsal cutaneous nerve and supplies skin along lateral border of foot and lateral aspect of little toe Dorsal Venous Arch (Network)  lies in subcutaneous tissue (superficial fascia)  dorsal digital veins drain into dorsal metatarsal veins and dorsal metatarsal veins drain into dorsal venous arch  dorsal venous arch drains on medial side into great saphenous vein  dorsal venous arch drains on lateral side into small saphenous vein Dorsalis Pedis Artery  begins distal to ankle, as a continuation of anterior tibial artery  runs superficially on dorsum of foot, with medial branch of deep fibular nerve, between tendon of extensor hallucis longus (medial to artery) and tendons of extensor digitorum longus (lateral to artery) and pulsations of artery can be felt in this location  terminates at proximal end of 1st interosseous (intermetatarsal) space (space between 1st and 2nd metatarsals) by dividing into 1st dorsal metatarsal artery and deep plantar artery  branches:  medial and lateral tarsal arteries  arcuate artery: runs laterally, deep to tendons of extensor digitorum longus and brevis, across bases of metatarsals and gives o 2nd to 4th dorsal metatarsal arteries and give rise to dorsal digital arteries for lateral part of 2nd toe and both sides of 3rd to 5th toes  1st dorsal metatarsal artery: gives o dorsal digital arteries for both sides of great toe and medial side of 2nd toe  deep plantar artery: passes inferiorly (into sole of foot) between 2 heads of 1st dorsal interosseous muscle and completes (deep) plantar arch on medial side Deep Fibular Nerve  enters dorsum of foot on lateral side of dorsalis pedis artery and divides into medial and lateral branches  lateral branch: supplies extensor digitorum brevis  medial branch: supplies skin of adjacent sides of great toe and 2nd toe