Regio cruris - Leg o between knee & ankle joint
o 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
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
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
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
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.
Lateral condyle of tibia
Superior ¾ of medial surface of
fibula and interosseous membrane
Middle and distal phalanges of lateral 4 digits
Lateral condyle of tibia
Superior half of lateral surface of
tibia and interosseous membrane
Medial cuneiform Base of 1st metatarsal
Middle part of anterior surface of
fibula and interosseous membrane
Dorsal aspect of base of distal phalanx of great toe (hallux)
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
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).
Distally, gives rise to anterior medial malleolar artery anterior lateral malleolar artery pass posteriorly around the distal ends of the tibia and fibula, respectively.
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.
Head and superior 2/3 of lateral surface of fibula
Base of 1st metatarsal and medial cuneiform
Inferior 2/3 of lateral surface of fibula
Dorsal surface of tuberosity on lateral side of base of 5th metatarsal
Everts foot and weakly plantarflexes ankle
Neurological Examination
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
Lateral aspect of lateral condyle of femur
Posterior surface of calcaneus via calcaneal tendon
Popliteal surface of femur superior to medial condyle
Posterior aspect of head and superior ¼ of posterior surface of fibula Soleal line and middle 1/3 of medial border of tibia Tendinous arch extending between the bony attachments
Posterior surface of calcaneus via calcaneal tendon
Inferior end of lateral supracondylar line of femur Oblique popliteal ligament
Posterior surface of calcaneus via calcaneal tendon
Lateral surface of lateral condyle of femur Lateral meniscus
Posterior surface of tibia Superior to soleal line
Medial part of posterior surface of tibia inferior to soleal line
by a broad tendon to fibula
Bases of distal phalanges of lateral four digits
Inferior 2/3 of posterior surface of fibula Inferior part of interosseous membrane
Base of distal phalanx of great toe (hallux)
Interosseous membrane Posterior surface of tibia inferior to soleal line
Posterior surface of fibula
Tuberosity of navicular Cuneiform, cuboid, and sustentaculum tali of calcaneus Bases of 2nd, 3rd, and 4th metatarsals
Plantarflexes ankle when knee is extended
Plantarflexes ankle independent of position of knee
Plantaris Weakly assists gastrocnemius in plantarflexing ankle Tibialis posterior Plantarflexes ankle Fibularis longus- Fibularis brevis Weakly plantarflexes ankle
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
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
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
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.
Tibial nerve
Passes o under the tendinous arch formed
between fibular and tibial heads of the soleus muscle
o vertically through the deep region of the posterior compartment of leg on the surface of tibialis posterior muscle with the posterior tibial vessels.
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.
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