Week 12 Anatomy

Anterior compartment of the leg

  •  all supplied by deep peroneal nerve
  • Tibialis anterior-L4, L5 –  lateral surface of tibia, IO membrane–> medial and inf surface of medial cunieform and base of 1st metatarsal, strongest dorsiflexor,
  • extensor Hallucis longus – L5, S1 middle fibula and IO membrane –> dorsal base of distal phalynx of big toe.
  • extensor Digitorum longus – L5, S1 small part of lateral tibial condyle, IO membrane, and 3/4 medial fibula–> middle and distal phalynx of lateral 4 toes – common synovial sheath with PT
  • Peroneus tertius – L5, S1 – inferior 1/3 of fibula, IO membrane –> base of 5th metatarsal
  • Deep vessels and nerves run on IO membrane.



Lateral compartment of the leg

  • All supplied by superficial peroneal
  • Peroneus Longus – L5, S1, S2 fibula head and superior 2/3 of fibula–> base of 1st metatarsal and medial cunieform
  • Peroneus Brevis –  L5, S1, S2 inferior 2/3 of fibula –> lateral side of base of 5th metatarsal
  • Both have common synovial sheaths at superior retinaculum but separate at inferior fibular retinaculum, brevis goes above the peroneal trochlea(on clacaneus) while longus goes under and runs along  grove in inferior cuboid.
  • Eversion occurs at subtalar and transverse tarsal joints



Posterior compartment of the leg

  • Separated by transverse intermuscular septum
  • Superficial – all supplied by tibial nerve – S1, S2 all insert vial calcaneal tendon to calcaneal tuberoscity. Plantarflexors.
    • Gastrocnemeus – Power generator. Lateral condyle of femur, superior to medial condyle of femur
    • Soleus – the workhorse. Posterior head of fibula, soleal line, medial tibia.
    • Plantaris – small muscle, long belly. Inferior lateral supracondylar line of femur, oblique pop ligament.
    • Calcaneal tendon – largest and strongest in the body, 15cm long. There is a superficial and deep bursa to allow gliding
  • Deep – all by tibial nerve
    • Popliteus = L4, L5, S1 lateral condyle of femur and meniscus–> posterior tibia superior to soleus – knee unlocker
    • Flexor Halucis longus – S2, S3 inferior 2/3 of post fibula, inferior IOM–> base of distal phalynx of hallux
    • Flexor digitorum longus – S2, S3 medial posterior tibia, fibula–> base of distal phalanx of lateral 4 digits.
    • Tibialis posterior – L4 L5 IOM, post tibia and fibula–> tuberosity of navicular, cuneiform and cuboid, base of 2-4 metatarsals.



Structures crossing the ankle joint

Extensor retinaculum of ankle – Timothy has a very nasty disease, paratyphi

  • Tibialis anterior
  • extensor Hallucis longus
  • Artery – anterior  tibial
  • Vein
  • Nerve – deep peroneal
  • extensor Digitorum
  • Peroneus tertius




Structures passing behind the medial malleolus.

Tom Did A Night at Home.

  • Tibialis posterior.
  • Flexor Digitorum longus.
  • Posterior tibial Artery.
  • Posterior tibial Nerve.
  • Flexor Hallucis longus.


Lateral maleolus

  • Peroneus longus and brevis in common sheath. Brevis on top.
  • At trochlea – separate sheaths. Brevis goes over, longus goes under.


Nerves of Leg

  • Saphenous – from femoral nerve, accompanies great saphenous vein, supplies skin on medial side of ankle and foot.
  • Sural – arises from both tibial and common fibular nerve, descends between heads of gastroc and becomes superficial midway down, with small saphenous vein, passes inferior to lat maleolus- supplies skin of posterior and lateral leg and lateral foot.
  • Tibial – from sciatic, apex of politeal, descends and lies on politeus, runs inferiorly on tibialis posterior, terminates below flexor retinaculum into medial and lateral plantar nerves. – supplies posterior muscles of leg and knee joint.
  • Common fibular – from pop apex follows biceps femoris, posterior aspect of fibula head, neck of fibula, deep to peroneus longus and splits into deep and superficial. – supply knee joint and lateral posterior part of leg. Fracture of fibula–> Loss leads to foot drop and loss of eversion with unopposed inversion and variable loss of sensation.
  • Superficial peroneal – pierces deep fascia at distal third of leg to become superficial- supply lateral compartment and skin of distal third of ant leg and dorsum of foot
  • Deep fibular – after arising from common fibular it passes through EDL and descends on IOM, between TA and EDL then between TA and EHL –> enters dorsum of foot – supplies ant muscles of leg, dorsum of foot, 1st digital cleft, articular branches.


Arteries of leg

  • Popliteal – superior and inferior, medial and lateral genicular branches.
  • Ant Tibial – from popliteal at top of IOM -pierces it and runs down the front – ant tibial recurrent, perforating peroneal, medial and lateral malleolar, dorsalis pedis and ends as deep plantar arch. 1st interosseus space
  • Posterior tibial – continuation of politeal, terminates at flexor retinaculum by spliting into medial and lateral plantar arteries.
  • Fibular – from Post tibial, in posterior compartment with perforators supplying lateral compartment.



Ankle joint

  • Hinge synovial joint – tibia, fibula and talus. Allows flexion and extension.
  • Fibula articulates in one place, Tibia articulates in two places.
  • Unstable during plantar flexion.
  • 3 lateral collateral ligaments – ant and post talofibular ligament, calcaneofibular ligament.
  • Large strong medial collateral – deltoid ligament – 4 parts.



Tibio fibular joints

  • Superior one is a plane synovial joint
  • Inferior one is a compound fibrous joint
  • Slight movement occurs at both joints.



Foot joints

  • Sub talar – plane synovial – inversion/eversion
  • Talocalcaneonavicular – synovial ball and socket – gliding and rotation
  • Calcaneocuboid – plane synovial – inversion, eversion, circumduction
  • Cuneonavicular – plane synovial – little movement
  • TMT – plane synovial – gliding or sliding
  • Inter metatarsal – plane synovial joint – little movement
  • MTP – condyloid synovial – flexion, extension, abduction, adduction and circumduction – lumbricals and interossi flex, DAB, PAD
  • IP – hinge synovial – flexion, extension.