LEG IN 15 QUESTIONS Kaan Yücel M.D., Ph.D. 1.March.2013 Friday

INTRODUCTION TO LEG Regio cruris - Leg between knee & ankle joint includes most of tibia & fibula Distally, structures pass between the leg & foot mainly through tarsal tunnel on the posteromedial side of the ankle, Except anterior tibial artery & ends of the deep and superficial fibular nerves

INTRODUCTION TO LEG Deep fascia of the leg Crural fascia Two intermuscular septa pass, together with the interosseous membrane, divide the leg into 3 compartments Anterior compartment Lateral compartment Posterior compartment

INTRODUCTION TO LEG Inferiorly, two band-like thickenings of the fascia form retinacula that bind the tendons of the anterior compartment muscles, preventing them from bowstringing anteriorly during dorsiflexion of the joint: Superior extensor retinaculum Inferior extensor retinaculum

INTRODUCTION TO LEG Flexor Retinaculum Between medial malleolus & calcaneus Binds posterior leg’s deep muscles’ tendons to medial malleolus Superior Peroneal Retinaculum Connects the lateral malleolus to calcaneus Binds the tendons of peroneus longus & brevis to lateral malleolus Inferior Peroneal Retinaculum Binds the tendons of the peroneus longus and brevis muscles to calcaneus

ANTERIOR COMPARTMENT OF THE LEG IN 5 QUESTIONS

1… anterior compartment of the leg Dorsiflexor (extensor) compartment Located anterior to the interosseous membrane between the lateral surface of the shaft of tibia and medial surface of shaft of the fibula anterior to the intermuscular septum that connects them. Bounded anteriorly by the deep fascia of the leg and skin.

2. Which muscles are in the anterior part of the leg? Tibialis anterior Extensor hallucis longus Extensor digitorum longus Fibularis tertius

3… functions of the muscles in the anterior part of the leg? Tibialis anterior Dorsiflexes the foot at the ankle joint and inverts the foot at the intertarsal joints. During walking, provides dynamic support for the medial arch of the foot. Extensor hallucis longus Extends lateral four digits and dorsiflexes ankle Extensor digitorum longus Extends great toe and dorsiflexes ankle Fibularis tertius Dorsiflexes ankle and aids in eversion of foot

Anterior tibial artery 4. Which arteries are in the anterior part of the leg? Anterior tibial artery Passes forward into the anterior compartment of leg through an aperture in the interosseous membrane. Begins at the inferior border of the popliteus muscle @ ankle joint midway between the malleoli Name change  dorsalis pedis artery (dorsal artery of the foot).

Anterior tibial artery 4. Which arteries are in the anterior part of the leg? Anterior tibial artery Distally, gives rise to anterior medial malleolar artery anterior lateral malleolar artery pass posteriorly around the distal ends of the tibia and fibula, respectively.

5. Which nerves are in the anterior part of the leg? Deep fibular (peroneal nerve) anterior tibial artery innervates all muscles in the anterior compartment; [continues into the dorsal aspect of the foot] innervates the extensor digitorum brevis, first two dorsal interossei muscles, and supplies the skin between the great and second toes.

LATERAL COMPARTMENT OF THE LEG IN 3 QUESTIONS

1. Which muscles are in the lateral part of the leg? Fibularis longus Fibularis brevis

2… functions of the muscles in the lateral part of the leg? Everts foot and weakly plantarflexes ankle Neurological Examination

3. Which nerves are in the lateral part of the leg? Superficial fibular (peroneal) nerve Fibularis longus & fibularis brevis Skin on the distal part of the anterior surface of the leg and dorsal areas of the foot and toes except for: the web space between the great and second toes,

POSTERIOR COMPARTMENT OF THE LEG IN 7 QUESTIONS

1. superficial muscles of the posterior part of the leg Gastrocnemius Soleus Plantaris

2. ..deep muscles of the posterior part of the leg? Popliteus Flexor digitorum longus Flexor hallucis longus Tibialis posterior

3… functions of the superficial muscles in posterior leg Gastrocnemius: Plantarflexes ankle when knee is extended; raises heel during walking; flexes leg at knee joint Soleus: Plantarflexes ankle independent of position of knee; steadies leg on foot

4… functions of the deep muscles in the posterior leg Popliteus acts on the knee joint Unlocking the extended knee @ the initation of flexion Others plantarflex the ankle with two continuing on to flex the toes. Tibialis posterior: Plantarflexes ankle; inverts foot

5… arteries in the posterior part of the leg Popliteal artery Major blood supply to the leg and foot Passes into the posterior compartment of leg between the gastrocnemius and popliteus muscles. under the tendinous arch formed between the fibular and tibial heads of the soleus muscle @ posterior compartment of leg divides into anterior tibial artery & posterior tibial artery

5… arteries in the posterior part of the leg Posterior tibial artery two major branches, the circumflex fibular artery and fibular artery: Nutrient artery of tibia Largest nutrient artery in the body Arises from the origin of the anterior or posterior tibial artery.

6… nerves in the posterior part of the leg Tibial nerve Passes under the tendinous arch formed between fibular and tibial heads of the soleus muscle vertically through the deep region of the posterior compartment of leg on the surface of tibialis posterior muscle with the posterior tibial vessels.

6… nerves in the posterior part of the leg Tibial nerve Leaves the posterior compartment of leg at the ankle via tarsal tunnel behind the medial malleolus. Enters the foot to supply most intrinsic muscles and skin.

6… nerves in the posterior part of the leg Tibial nerve In the leg, gives rise to: • branches that supply all the muscles in the posterior compartment of leg • 2 cutaneous branches sural nerve & medial calcaneal nerve