Week 13 Leg - Other Structures PDF

The Leg Cutaneous Innervation of the Leg  anterior surface:  superolateral: lateral sural cutaneous nerve  inferolateral: superficial fibular (peroneal) nerve  medially: saphenous nerve  posterior surface:  superolateral: lateral sur...

The Leg Cutaneous Innervation of the Leg  anterior surface:  superolateral: lateral sural cutaneous nerve  inferolateral: superficial fibular (peroneal) nerve  medially: saphenous nerve  posterior surface:  superolateral: lateral sural cutaneous nerve  inferolateral: sural nerve  medially: saphenous nerve Compartments of the Leg  crural fascia: deep fascia of leg and surrounds leg like a stocking and continuous superiorly with fascia lata  anterior and posterior intermuscular septa pass from crural fascia to fibula  interosseous membrane: fibrous membrane connecting interosseous borders of tibia and fibula and binds tibia and fibula together and provides attachment for neighboring muscles  crural fascia, intermuscular septa and interosseous membrane divide leg into 3 compartments: anterior, lateral and posterior (each with its own muscles, vessels and nerves)  posterior compartment is divided into superficial and deep parts by transverse intermuscular septum Retinacula of the Ankle  crural fascia thickens in ankle region to form retinacula and hold long tendons close to bones, preventing them from bowstringing  there are 2 extensor retinacula on anterior aspect of ankle  superior extensor retinaculum: attaches to distal parts of anterior borders of tibia and fibula  inferior extensor retinaculum:   Y-shaped: stem of “Y” is directed laterally and attaches to superior surface of calcaneus  upper limb of “Y” attaches to medial malleolus  lower limb of “Y” reaches medial border of foot and becomes continuous with deep fascia of sole of foot Flexor Retinaculum  located on medial side of ankle  extends from medial malleolus to medial surface of calcaneus (runs posteriorly and inferiorly)  space under flexor retinaculum is referred to by some authors as “tarsal tunnel” and allows structures (tendons, blood vessels and nerves) to pass from deep part of posterior compartment of leg into sole of foot There are 2 fibular (peroneal) retinacula on lateral side of ankle:  superior fibular retinaculum: extends from lateral malleolus to lateral surface of calcaneus (runs posteriorly and inferiorly)  inferior fibular retinaculum: attaches at both ends to lateral surface of calcaneus Posterior Tibial Artery  terminal branch of popliteal artery  begins at lower border of popliteus muscle  runs inferiorly in deep part of posterior compartment of leg accompanied by posterior tibial veins and tibial nerve  passes posterior to medial malleolus, under flexor retinaculum and at this point it is only covered by skin and fasciae and its pulse can be palpated approximately halfway between heel and medial malleolus  terminates by dividing into medial and lateral plantar arteries, deep to flexor retinaculum  branches:  fibular artery: originates from proximal part of posterior tibial artery and it is its largest branch and descends posterior to fibula, within flexor hallucis longus or between it and tibialis posterior and supplies muscles in posterior and lateral compartments of leg and ends distally giving o branches to arterial anastomosis  around ankle (posterior lateral malleolar branch) and to heel (lateral calcaneal branches) and it also gives o a perforating branch that pierces lower part of interosseous membrane to enter anterior compartment of leg and anastomose with a branch of anterior tibial artery  circumflex fibular artery: passes around neck of fibula and participates in arterial anastomosis around knee joint (may originate from anterior tibial artery)  muscular branches to muscles in posterior compartment of leg  posterior medial malleolar branch: participates in arterial anastomosis around ankle  medial calcaneal branches: supply medial aspect of heel  medial and lateral plantar arteries (terminal branches) Tibial Nerve  terminal branch of sciatic nerve in lower ⅓ of posterior thigh  descends through popliteal fossa and passes under tendinous arch of soleus  runs inferiorly in deep part of posterior compartment of leg accompanied by posterior tibial artery and veins  passes posterior to medial malleolus, under flexor retinaculum  terminates by dividing into medial and lateral plantar nerves under flexor retinaculum  branches (in posterior compartment of leg):  muscular branches to soleus, flexor digitorum longus, flexor hallucis longus and tibialis posterior  medial calcaneal branches: supply skin over medial and inferior aspects of heel  articular branch to ankle joint  medial and lateral plantar nerves (terminal branches) Anterior Tibial Artery  terminal branch of popliteal artery  begins at lower border of popliteus muscle and passes forward, into anterior compartment of leg, through an opening in upper part of interosseous membrane  in upper ⅔ of leg is deeply located and descends on interosseous membrane covered by muscles of anterior compartment   in distal ⅓ of leg is superficial and passes anterior to distal end of tibia, covered only by skin and fasciae  at ankle, it is crossed anteriorly (from lateral to medial) by tendon of extensor hallucis longus  distal to ankle, it continues on dorsum of foot as dorsalis pedis artery  along its course, it is accompanied by anterior tibial veins and deep fibular nerve (nerve is lateral to artery)  branches:  muscular branches: supply muscles of anterior and lateral compartments of leg  anterior tibial recurrent artery: participates in arterial anastomosis around knee joint  branches that participate in arterial anastomosis around ankle joint (anterior medial and anterior lateral malleolar arteries) Deep Fibular (Peroneal) Nerve  terminal branch of common fibular nerve  begins deep to fibularis longus muscle, lateral to neck of fibula (in lateral compartment of leg)  pierces anterior intermuscular septum, which separates anterior and lateral compartments, and enters anterior compartment of leg  in anterior compartment, it descends with anterior tibial artery and veins (lateral to them)  continues onto dorsum of foot (does not change name like artery does)  branches:  muscular branches: supply muscles of anterior compartment of leg  articular branch: ankle joint Avulsion Fracture of the Tuberosity of the 5th Metatarsal  when foot is suddenly and forcibly inverted, tuberosity of 5th metatarsal may be avulsed (torn away) by tendon of fibularis brevis  common in basketball and tennis players  associated with severely sprained ankle  causes pain, edema and bruising at base of 5th metatarsal Blood Supply of the Lateral Compartment  no major artery passes vertically through lateral compartment of leg  main sources of blood supply: anterior tibial and fibular arteries  branches of anterior tibial artery perforate anterior intermuscular septum to supply lateral compartment  branches of fibular artery perforate posterior intermuscular septum to supply lateral compartment Superficial Fibular (Peroneal) Nerve  terminal branch of common fibular nerve  begins deep to fibularis longus muscle, lateral to neck of fibula (in lateral compartment of leg)  lies at first deep to fibularis longus and then descends between fibularis longus and brevis and extensor digitorum longus  in lower leg pierces deep fascia and becomes superficial  branches:  muscular branches: supply fibularis longus and fibularis brevis muscles  medial and intermediate dorsal cutaneous nerves: supply skin of inferolateral part of anterior leg, dorsum of foot and dorsal surfaces of toes, except adjacent sides of great and 2nd toes (supplied by deep fibular nerve) and lateral side of little toe (supplied by lateral dorsal cutaneous nerve and continuation of sural nerve) Structures that Pass Anterior to the Ankle, Superficial to the Inferior Extensor Retinaculum  saphenous nerve  great saphenous vein  branches of superficial fibular nerve Structures that Pass Anterior to the Ankle, Deep or Through the Inferior Extensor Retinaculum   tendon of tibialis anterior  tendon of extensor hallucis longus  tendons of extensor digitorum longus  tendon of fibularis tertius  anterior tibial artery and veins  deep fibular nerve Structures that Pass Through Tarsal Tunnel (posterior to the medial malleolus, deep to the flexor retinaculum [in order from anteromedial to posterolateral])  tendon of Tibialis posterior  tendon of flexor Digitorum longus  posterior tibial Artery and veins  tibial Nerve  tendon of flexor Hallucis longus  “Tom, Dick And Very Nervous Harry” Structures that Pass Posterior to the Lateral Malleolus, Superficial to the Superior Fibular  Retinaculum  sural nerve  small saphenous vein  Structures that Pass Posterior to the Lateral Malleolus, Deep to the Superior Fibular Retinaculum  tendon of fibularis brevis  tendon of fibularis longus