WINDSOR UNIVERSITY SCHOOL OF MEDICINE DEPARTMENT OF ANATOMY Lower limb LEG Dr. SREEKANTH THOTA

Fascial Compartments of the Leg The leg is that part of the lower limb between the knee joint and ankle joint . The leg is divided into anterior , posterior , and lateral (fibular) compartments by: 1. An interosseous membrane, which links adjacent borders of the tibia and fibula along most of their length. 2. Two intermuscular septa, which pass between the fibula and deep fascia surrounding the limb.

Compartments of leg 1. Muscles in the anterior compartment of leg dorsiflex the ankle, extend the toes, and invert the foot. 2. Muscles in the posterior compartment plantarflex the ankle, flex the toes, and invert the foot. 3. Muscles in the lateral compartment evert the foot.

Retinacula of the Ankle 1. Extensor retinacula :Two extensor retinacula strap the tendons of the extensor muscles to the ankle region and prevent tendon bowing during extension of the foot and toes . 1. Superior extensor retinaculum 2. Inferior extensor retinaculum: Y-shaped

Fibular retinacula Fibular (peroneal) retinacula bind the tendons of the fibularis longus and fibularis brevis muscles to the lateral side of the foot. 1. Superior fibular retinaculum 2. Inferior fibular retinaculum

Flexor retinaculum It attaches above to the medial malleolus and below and behind to the inferomedial margin of the calcaneus.

Anterior compartment of leg Muscles: The tibialis anterior, extensor digitorum longus, Fibularis tertius, and extensor hallucis longus Blood supply: Anterior tibial artery Nerve supply: Deep peroneal nerve Action: Dorsiflex the foot at the ankle joint, extend the toes, and invert the foot.

Tibialis anterior N. supply: Deep peroneal nerve Origin: Lateral surface of shaft of tibia and interosseous membrane Insertion :Medial cuneiform and base of first metatarsal bone N. supply: Deep peroneal nerve Action :Dorsiflexion of foot at ankle joint; inversion of foot.

Extensor digitorum longus Origin: Anterior surface of shaft of fibula Insertion :Extensor expansion of lateral four toes N. supply: Deep peroneal nerve Action :Extension of lateral four toes and dorsiflexion of foot

Extensor hallucis longus Origin: Anterior surface of shaft of fibula Insertion :Base of distal phalanx of great toe N. supply: Deep peroneal nerve Action :Extension of great toe and dorsiflexion of foot

Fibularis tertius N. supply: Deep peroneal nerve Origin: Anterior surface of shaft of fibula Insertion :Base of fifth metatarsal bone N. supply: Deep peroneal nerve Action :Dorsiflexion and eversion of foot

Artery of the Anterior Compartment of the Leg Anterior Tibial Artery: Terminal branch of the popliteal artery. It arises at the level of the lower border of the popliteus muscle and passes forward into the anterior compartment of the leg through an opening in the upper part of the interosseous membrane.

Pulse of anterior tibial artery Having passed behind the superior extensor retinaculum, it has the tendon of the extensor hallucis longus on its medial side and the deep peroneal nerve and the tendons of extensor digitorum longus on its lateral side. In front of the ankle joint, the artery becomes the dorsalis pedis artery.

Nerve Supply of the Anterior Compartment of the Leg Deep Peroneal Nerve: Terminal branch of the common peroneal nerve . Branches 1. Muscular branches :Tibialis anterior, the extensor digitorum longus, the peroneus tertius, and the extensor hallucis longus. 2. Articular branch to the ankle joint

Injury to common fibular nerve Footdrop and loss of eversion May cause sensory loss over lateral leg and dorsum of foot Causes Direct trauma as nerve passes superficially around neck of fibula

Foot drop Foot drop, sometimes called drop foot, is a general term for difficulty lifting the front part of the foot. The loss of dorsiflexion of the ankle causes footdrop.

Lateral Compartment of the Leg Muscles: Fibularis longus and Fibularis brevis Blood supply: Branches from the Fibular artery Nerve supply: Superficial peroneal nerve

Fibularis longus N. supply: Superficial fibular nerve Origin: Lateral surface of shaft of fibula Insertion :Base of first metatarsal and the medial cuneiform N. supply: Superficial fibular nerve Action :Eversion of foot

Fibularis brevis N. supply: Superficial Fibular nerve Origin: Lower two-thirds of lateral surface of shaft of fibula Insertion :Base of fifth metatarsal bone N. supply: Superficial Fibular nerve Action :Eversion of foot

Artery of the Lateral Compartment of the Leg Numerous branches from the fibular artery which lies in the posterior compartment of the leg, pierce the posterior fascial septum and supply the Fibularis muscles.

Nerve of the Lateral Compartment of the Leg Superficial Fibular Nerve: The superficial fibular nerve is one of the terminal branches of the common fibular nerve. It arises in the substance of the Fibularis longus muscle on the lateral side of the neck of the fibula. Branches Muscular branches : Fibularis longus and brevis

Injury to superficial fibular nerve Loss of eversion Fibularis longus and brevis

Posterior compartment of leg Muscles in the posterior (flexor) compartment of leg are organized into two groups, superficial and deep. Blood supply: Posterior tibial artery. Nerve supply: Tibial nerve

Muscles of the Posterior Compartment of the Leg Superficial group of muscles 1.Gastrocnemius 2.Soleus 3.Plantaris Deep group of muscles 1.Popliteus 2.Tibialis posterior 3.Flexor digitorum longus 4.Flexor hallucis longus Muscles mainly plantarflex, invert the foot and flex the toes.

Gastrocnemius Soleus Plantaris Superficial group Gastrocnemius and plantaris cross knee joint and thus also flex knee . All three contribute to calcaneal tendon.

Gastrocnemius Origin: Lateral head from lateral condyle of femur Medial head from above medial condyle Insertion:Via tendo calcaneus into posterior surface of calcaneum Innervation: Tibial nerve Function: Plantarflexes foot and flexes knee

Plantaris Origin: Lateral supracondylar ridge of femur Insertion: Posterior surface of calcaneum Innervation: Tibial nerve Function: Plantarflexes foot and flexes knee

Soleus Origin: Shafts of tibia and fibula Insertion: Posterior surface of calcaneum Innervation: Tibial nerve Function: Plantarflexes the foot

Deep group of muscles Popliteus Origin: Lateral surface of lateral condyle of femur Insertion: Posterior surface of shaft of tibia above soleal line Innervation: Tibial nerve Function: Flexes leg at knee joint “Unlock the knee” popliteus contracts rotating the femur laterally so that flexion of the knee can occur

Flexor digitorum longus Origin: Posterior surface of shaft of tibia Insertion: Bases of distal phalanges of lateral four toes Innervation: Tibial nerve Function: Flexes distal phalanges of lateral four toes; plantar flexes foot at ankle joint

Flexor hallucis longus Origin: Posterior surface of shaft of fibula Insertion: Base of distal phalanx of big toe Innervation: Tibial nerve Function: Flexes distal phalanx of big toe; plantar flexes foot at ankle joint

Tibialis posterior Origin: Posterior surface of shafts of tibia and fibula and interosseous membrane Insertion: Tuberosity of navicular bone Innervation: Tibial nerve Function: Inversion and plantarflexion of foot

Nerve supply Tibial nerve: Supplies all muscles in posterior compartment. Divides into medial and lateral plantar nerves inferior and posterior to medial malleolus.

Blood supply: Posterior tibial artery: Fibular artery: Largest branch of popliteal artery. Divides into medial and lateral plantar arteries. Fibular artery: Most important branch of posterior tibial artery. Supplies lateral compartment.

Arteries in the posterior compartment of leg.

Tarsal tunnel The 'tarsal tunnel' is formed on the posteromedial side of the ankle by a depression formed by the medial malleolus of the tibia, the medial and posterior surfaces of the talus, the medial surface of the calcaneus and overlying flexor retinaculum.

Contents of Tarsal tunnel Structures That Pass Behind the Medial Malleolus Beneath the Flexor Retinaculum From Medial to Lateral 1.Tibialis posterior tendon 2.Flexor digitorum longus 3.Posterior tibial artery 4.Tibial nerve 5.Flexor hallucis longus ( TOM DICK AND HARRY)

Tibial Nerve Entrapment Tarsal tunnel syndrome Tarsal tunnel syndrome is caused by compression of the tibial nerve in the canal formed by the flexor retinaculum and the foot bones. Causes: 1. Tenosynovitis (swelling of the synovial membrane lining the tendons) 2. Fractures of the talus, tibia or calcaneum bones Symptoms Abnormal sensation such as tingling and numbness in the sole or toes Treatment non-operative and operative. .

Posterior Tibial Pulse The posterior tibial pulse can usually be palpated between the posterior surface of the medial malleolus and the medial border of the calcaneal tendon.