Lower Limb - Class 10A Anatomy PDF

Revision: superficial veins & nerves of leg  Compartments of leg Bones of the leg are in magenta boxes. Anterior Crural fascia, connective tissue septa and the inteross...

Revision: superficial veins & nerves of leg  Compartments of leg Bones of the leg are in magenta boxes. Anterior Crural fascia, connective tissue septa and the interosseous membrane are in blue boxes. Lateral Medial Extensor compartment Peroneal compartment The terms ’peroneal’ and ’fibular’ Flexor compartment Posterior are interchangeable.  Compartments of leg II. This figure shows labels for the bones, connective tissue structures (crural fascia, anterior & posterior intermuscular septa, interosseous membrane), as well as superficial nerves and blood vessels of the leg only. Deep neurovascular structures are not labelled, and muscles Anterior are not shown. The deep layer of the crural fascia is indicated by an asterisk. The terms ’peroneal’ and ’fibular’ are interchangeable. 1. Extensor compartment 2. Peroneal compartment 3. Deep layer of flexor compartment Posterior 4. Superficial layer of flexor compartment  Regions of leg: anterior & posterior regions of leg Bones of the leg are in magenta boxes. Crural fascia, connective tissue septa and the interosseous membrane are in blue boxes. Anterior region of leg (= extensor + peroneal compartments) The terms ’peroneal’ and ’fibular’ Posterior region of leg (= flexor compartment) are interchangeable.  Muscles of anterior region of leg The three muscles in the extensor compartment (mediolateral sequence) are tibialis anterior, extensor hallucis longus & extensor digitorum longus muscles. Extensor hallucis longus emerges from between the neighbouring muscles at the distal part of the region. There are two muscles in the peroneal compartment: peroneus/fibularis longus (superficial) and peroneus/fibularis brevis muscles (deep). Blood vessels & nerves of anterior region of leg The anterior tibial artery enters the extensor compartment through the interosseous membrane. Distally, it continues as the dorsalis pedis artery. The artery is accompanied by a vein with the same name. The common fibular nerve pierces the posterior intermuscular septum and it splits into a superficial and a deep fibular nerve in the peroneal compartment. The former stays in the peroneal compartment and innervates the peroneal muscles. The latter pierces the anterior intermuscular septum and supplies the extensor muscles. Its terminal branches supply the skin. Key blood vessels and nerves are highlighted by blue boxes. Anterior region of leg Key structures in the region are highlighted by blue boxes. Do not transect tendons.  Tendons around the lateral malleolus Tendons around the lateral malleolus form a sling-like structure around the distal end of the fibula and the lateral part of the tarsus. This is referred to as the lateral malleolar sling: directly posterior to the ankle is the tendon of peroneus brevis, in front of it is the lateral-most tendon of extensor digitorum, also known as peroneus tertius, inserting on the base of the 5th metatarsal bone. The lateral sling is marked with a yellow broken line. The lateral malleolus and the lateral part of the tarsus are marked with a grey ellipsoid (just like a sling-stone). Tendons are held in place by peroneal and extensor retinacula. Transect and reflect the retinacula along the edges. Lateral malleolar region The small saphenous vein and the sural nerve pass superficially, posterior to the lateral malleolus. The peroneal retinaculum (superior & inferior), local thickenings of the crural fascia, form a canal for the passage of the tendons of the peroneal muscles. This is known as the lateral malleolar canal. The extensor retinaculum (superior & inferior) holds the extensor tendons in place. Superficial structures of dorsum of foot There is a dorsal venous network on the dorsum of foot, which gives rise to the long and short saphenous veins. Sensory innervation to the skin is provided by the saphenous nerve, the deep and the superficial fibular nerves (terminal branches: medial & intermediate dorsal cutaneous nerves of foot), and the sural nerve (terminal branch: lateral dorsal cutaneous nerve of foot). The dorsal fascia of foot is situated deep to the superficial structures. Key structures are typed in boldface and highlighted by blue boxes.  Muscles of dorsum of foot Long tendons over the dorsum of foot are highlighted by magenta boxes. Small muscles arising & inserting on the dorsum of foot are highlighted by blue boxes.  Blood vessels & nerves of dorsum of foot The anterior tibial artery, which runs in the extensor compartment of the leg, continues as the dorsalis pedis artery on the foot. The artery supplies the ankles and the tarsus. One of its branches, the arcuate artery, which arises at the level of the base of the metacarpal bones, anastomoses with the lateral tarsal artery. The arterial arch thus formed gives rise to the dorsal metatarsal arteries, which give dorsal digital arteries to the toes. The A. tarsea lateralis terminal branch of the dorsalis pedis artery is the deep plantar artery, which heads towards the sole. Arteries are accompanied by veins with the same name. The anterior tibial artery & vein are accompanied by the deep fibular nerve, which supplies the intrinsic muscles of the dorsum of foot. It splits into its terminal branches between the first and second toes. The skin is supplied by Aa. metatarseae dorsales nerves listed on the previous page. Key blood vessels and nerves are highlighted by blue boxes.  References and image sources Sobotta: Atlas of Human Anatomy Gray’s Basic Anatomy Szentágothai – Réthelyi: Functional Anatomy Tömböl: Regional Anatomy