Anterio-Lateral Compartment of Leg PDF

LEG  Leg   Extends between the knee joint to the ankle joint.  The bony framework of the leg consists of two parallel bones, the tibia medially and fibula laterally.  Leg Compartments  The leg is divided into  a) anter...

LEG  Leg   Extends between the knee joint to the ankle joint.  The bony framework of the leg consists of two parallel bones, the tibia medially and fibula laterally.  Leg Compartments  The leg is divided into  a) anterior (extensor) b) posterior (flexor) c) lateral (fibular) compartments by:  interosseous membrane  two intermuscular septa  direct attachment of the deep fascia to the periosteum of the anterior and medial borders of the tibia.  Anterior Compartment   Muscles: Ankle dorsiflexors (extensors)  Blood Vessels: Anterior Tibial Vessels  Nerves: Deep Fibular Nerve  Muscles   There are four muscles that dorsiflex the foot at the ankle joint, extend the toes, and invert the foot.  All are innervated by the deep fibular nerve. 1. Tibialis anterior 2. Extensor hallucis longus 3. Extensor digitorum longus 4. Fibularis tertius  INSERTIO NERVE MUSCLE ORIGIN ACTION N SUPPLY Lateral surface Deep Dorsiflexion of of tibia and Medial foot at ankle Tibilis cuneiform and fibular adjacent base of first joint and Anerior interosseous nerve inversion of membrane metatarsal [L4,L5] foot Bases of distal Extension of Extensor Proximal one- lateral four and middle Digitorum half of medial phalanges of toes and foot surface of fibula Longus lateral four toes dorsiflexion Dorsal surface Deep Extension of Extensor Middle one-half of medial of base of distal fibular great toe and Hallucis phalanx of great dorsiflexion of Longus surface of fibula toe nerve foot [L5,S1] Distal part of Dorsiflexion Fibularis Base of fifth medial surface and eversion Tertius metatarsal of fibula of foot  Anterior Tibial Artery   It originates from the popliteal artery in the posterior comp. of the leg and passes forward into the anterior comp. through an aperture in the interosseous membrane.  In the distal leg, it lies between the tendons of the tibialis anterior and extensor hallucis longus muscles.  It leaves the leg by passing anterior to the ankle joint and continues onto the dorsal aspect of the foot as the dorsalis pedis artery.  Anterior Tibial Artery   Branches 1. Recurrent branch: anastomosis around knee joint. 2. Muscular branches 3. Anterior medial malleolar A. 4. Anterior lateral malleolar A. 5. Dorsalis Pedis A.  Deep Fibular Nerve  It originates in the  lateral compartment of leg as one of the two divisions of the common fibular nerve arising between the fibularis longus muscle and the neck of the fibula.  It passes deep to the extensor digitorum longus and reaches the anterior interosseous membrane where it meets and descends with the anterior tibial artery.  Deep Fibular Nerve  The deep fibular nerve:   innervates all muscles in the anterior compartment ( T.A., E.H.L., E.D.L., F.T.)  then continues into the dorsal aspect of the foot where it innervates the extensor digitorum brevis, contributes to the innervation of the first two dorsal interossei muscles, and supplies the skin between the great and second toes.  Lateral Compartment  Muscles:  2 Evertors of ankle joint.  Blood Vessels: No major artery found, but supplied by perforating branches of Fibular artery from the post. Comp.  Nerves: Superficial Fibular Nerve  Muscles  Fibularis longus  originates from anterolateral surface of upper fibula and adjacent region of the lateral tibial condyle. Distally it passes posterior to the lateral malleolus in a shallow bony groove. It swings under the foot to cross the sole and attach to the inferior surfaces of bones on the medial side of the foot (lateral sides of the base of the first metatarsal and the medial cuneiform). Action: Eversion and plantar flexion of foot.  Muscles  Fibularis Brevis  Originates from the lower two- thirds of the lateral surface of the fibula The tendon passes behind the lateral malleolus across the lateral surface of the calcaneus to attach to a tubercle on the lateral surface of the base of fifth metatarsal. Action: assists in eversion of the foot  Superficial Fibular Nerve   This nerve originates from common fibular nerve, which enters the lateral compartment of leg from the popliteal fossa near the neck of fibula.  It supplies the two fibular muscles and then penetrates deep fascia in the lower leg and enters the foot where it divides into medial and lateral branches, which supply dorsal areas of the foot and toes except for: a) the web space between the great and second toes, which is supplied by the deep fibular nerve b) the lateral side of the little toe, which is supplied by the sural branch of the tibial nerve.  Ankle Retinacula   Thickening of deep fascia on the lower parts of the leg.  They are five retinacula: a. Two extensor retinacula (upper and lower) b. Two fibular retinacula (upper and lower) c. One flexor retinaculum  They help to maintain the structures passing from the leg into the foot in their position and prevent their displacement.  Extensor Retinacula   Superior extensor retinaculum is a thickening of deep fascia in the distal leg just superior to the ankle joint and attached to the anterior borders of the fibula and tibia.  inferior retinaculum is Y-shaped, attached by its base to the lateral side of the upper surface of the calcaneus, and crosses medially over the foot to attach by one of its arms to the medial malleolus, while the other arm wraps medially around the foot and attaches to the medial side of the plantar aponeurosis.  Structures deep to extensor retinacula From lateral to medial:  1. Tendon of fibularis tertius 2. Tendon of extensor digitorum longus 3. dorsalis pedis artery 4. tendon of the extensor hallucis longus 5. tendon of the tibialis anterior  Fibular Retinacula  Superior Fibular  retinaculum extends between the lateral malleolus and the calcaneus.  Inferior Fibular retinaculum attaches to the lateral surface of the calcaneus around the fibular trochlea and blends above with the fibers of the inferior extensor retinaculum.  At the fibular trochlea, a septum separates the compartment for the tendon of the fibularis brevis muscle above from that for fibularis longus below. THANK YOU