موسى صالح عبد الرحمن الحنبلي أحمد سلمان

8 موسى صالح عبد الرحمن الحنبلي أحمد سلمان 1 P a g e

Today we will talk about a new region, which is the leg. And as always, we will start with studying the sensory innervation of the leg. What is the importance of the sensory innervation in general? It is important in the neurological examination, the neurologist test the patient s motor and sensory activity, so in sensory examination the neurologist takes a pin/needle for example and start testing a specific region for sensation response, if there is a sensation then everything is fine, but if there is a sensation loss then there is a problem in this region s nerve (maybe it has been cut, or maybe the patient is diabetic which may lead to nerve damage ). Diabetic patients usually have a lot of sensation loss, causing a bigger problem which is the diabetic foot, so the patient got poked by a pin and didn t feel it, this may lead to an infectionin his foot, the infection may lead to ulceration then a formation of wound, it may take up to six months for the wound to heal and it may not heal at the end. So if the patient has sensory loss,it is important that you shouldhave the ability to identify the nerve that causing it. The sensory innervation of the leg 1. The saphenous nerve :posteromedial andanteromedial surface of the skin supplied by it, until it reaches the ball of the big toe (the big toe is not supplied by it).so the medial region supplied only by the saphenous nerve. 2. Lateral cutaneous nerve of the calf (branch of the common peroneal): supplies the skin on the upper part of the anterolateral and posterolateral (small part) surface of the leg. 2 P a g e

3. The superficial peroneal nerve (branch of the common peroneal), supplies the skin of the lower part of the anterolateral surface of the leg(all the dorsum of the foot),except a small region between the big and the second toe which is supplied by the deep peroneal. 4. The sural nerve (branch of the tibial nerve): supplies the skin on the lower part of the posterolateralsurface of the leg(and a small lateral region in the foot). 5. The medial calcaneal branches of the tibial nerve: supplies the heel of the foot. *for example the third toe supplied by which nerve? The superficial peroneal *The little toe supplied by which nerve? The sural nerve from the lateral side and the superficial peroneal nerve *The big toe supplied by the superficial peroneal *And as we said the deep peroneal supplies the cleft between the big toe and the second toe. 3 P a g e

Fascial compartment of the leg The deep fascia of the leg forms Two intermuscular septa (anterior and posterior) which are attached to the fibula. These, together with the interosseous membrane, divide the leg into three compartments:anterior, lateral and posterior. in the posterior compartment, a superficial and deep transverse septum further divide the posterior compartment into layers of superficial and deep muscles. Is there any difference between the compartments in the thigh and the leg? Yes, in the leg we have anterior, posterior and lateralcompartments where in the thigh we have anterior, posterior and medial compartments. The action of the compartments of the leg Anterior: dorsiflexion of the ankle, extension of the toes. Lateral: eversion of the foot, planter flexion. Posterior: planterflexion of the ankle, flexion of the toes. 4 P a g e

*the subtailor and transverse tarsal joint give the eversion and inversion actions of the foot. so when you see the word peroneus you should know that the action of the muscle is eversion, and when you see the word tibialis you should know that the action of the muscle is inversion. The motor nerve supply of the leg: The sciatic nerve is divided into two nerves: The tibial nerve: supplies the posterior compartment The common peroneal nerve: divided into two nerves : 1. Superficial peroneal: supplies the lateral compartment 2. Deep peroneal: supplies the anterior compartment. The anterior compartment: We have 4 muscles in the anterior compartment: 1. Tibialis anterior 2. Extensor hallucis longus 3. Extensor digitorum longus 4. Peroneus tertius Origin: the tibialis originates from the lateral surface of the tibia, The rest of the anterior muscles are originating from the fibula. 5 P a g e

Insertion : - Tibialis anterior: Medial cuneiform &1st metatarsal bone - Extensor hallucis longus: Distal Phalanx of the big toe - Extensor digitorum longus: Extensor expansion of lateral four toes. - Peroneus tertius: Base of 5th metatarsal bone. Action: - All dorsiflexion of the ankle of the foot. - Hallucis :Extends big toe - Dgitorum : Extends four toes - Tibialis : inversion of the foot - Peroneus : eversion of the foot Muscles of dorsum of foot Extensor digitorum brevis Origin :Calcaneus Insertion :Extensor expansion of medial four toes, unusual insertion because it is digitorum and inserts on the big toe, it is the only digitorum muscle that does this. Nerve Supply :Deep fibular nerve 6 P a g e

Ankle Retinacula The retinacula are thickenings of thedeep fascia that keep the long tendonsaround the ankle joint in position. Extensor Retinaculum It has 2 parts: 1. Superior: between the leg bonesabove the malleoli 2. Inferior: it is Y-shaped originates from the lateral surface of the calcaneus separates into two bands: a) Upper - passes to the medial malleolus b) Lower to the navicular and medial cuneiform bones Structures passes below Extensor retinaculum(from medial to lateral): - Tom: Tibialis Anterior - Has: Extensor hallucis - Very:Vessels(Anterior tibial) - Nice: Nerve (Deep fibular nerve) - Dog: Extensor Digitorum - Pig: Peroneus tertius 7 P a g e

Lateral Compartment 1. Fibularis (peroneus) longus 2. Fibularis (peroneus) brevis Origin : lateral surface of the fibula Insertion : - Fibularis (peroneus) longus: 1st metatarsal - Fibularis (peroneus) brevis: 5th metatarsal Nerve supply : superficial peroneal Action : planterflexion (attached to the foot from below) and eversion (peroneus) of foot. Peroneal (Fibular) Retinaculum It has 2 parts: 1. Upper: - from the lateral malleolus to the calcaneus, - transmits the common synovial sheath of theperoneus longus and brevis muscles 8 P a g e

2. Lower: located on the lateral surfaceof Calcaneus. Posterior Compartment Superficial 1. Gastrocnemius, origin: Lateral head from lateral condyle of femur and medial head from above medial condyle. 2. Soleus, antigravity muscle, initiates the movement,origin: posterior surface of the tibia and fibula. 3. Plantaris: very thin muscle and maybe absent, origin: lateral supracondylar ridge of femur. Insertion : All into calcaneum via tendon calcaneus(tendon Achilles). Action: planter flexion of the ankle, the gastrocnemius may help in the flexion of the knee, gastrocnemius help in jumping and running, soleus help in walking. Gastrocnemius and soleus together called the heart of the lower limb, the venous blood move toward the gravity (downwards) in the leg, when those muscles contract the pump the blood upwards, so the movement of the blood will be against the gravity. So if someone broke his leg and a cast has been applied, he may develop a deep venous thrombosis (DVT), so firstly a thrombus happens in the veins after that in the deep vein after that this may be developed into pulmonary embolism. to avoid this especially after the complicated surgical operations are done,doctors advise their patients to move their legs and they prescribe to them anticoagulants. 9 P a g e

How to know if the tendon calcaneus (tendon Achilles) has been cut or not? The patient lays on the abdomen, you pinch the calf muscles all at once, the action should be planter flexion of the ankle if the tendon is intact. Deep 1. Tibialis Posterior 2. Flexor digitorum longus 3. Flexor halluces longus 4. Popliteus: Origin - lateral condyle femur Insertion popliteal surface of tibia Action,flexion and unlocking the knee, sowe have two conditions in this muscle: - If the insertion is immobile the femur will rotate laterally (lateral rotation) - If the origin is immobile the tibia will rotate medially (medial rotation) Locking and unlocking of the knee In the tibia, the medial condyle is deeper than the lateral condyle, and the same in the femur, so when the femur rotates medially, as if it falls in a hole and couldn t get out from it, this is called locking of the knee, the unlocking of the knee done by a small rotation of the knee (so the femur can get out of the hole)and then flexion can be done. So the locking of the knee means medial rotation of the femur, or lateral rotation of the tibia 10 P a g e

And unlocking of the knee means lateral rotation of the femur or medial rotation of the tibia Best of luck Done by : Mousa Suboh 11 P a g e