Leg

Posterior compartment of leg

- Tibial nerve - Posterior tibial artery - Fibular artery

What happens if sesamoid bones are gone?

Flexor hallucis brevis "slips" off and, at a new angle, can only adduct toe - no longer can flex. Result: bunion

Describe the paths, relationships and functions of the nerves, arteries and *veins* supplying the muscles and skin of the leg

Great saphenous vein Small saphenous vein

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Fibularis brevis

Origin: Fibula (more distal than longus) Insertion: lateral plantar side of foot; 5th metatarsal base Action: Weak plantarflexion and eversion Innervation: Superficial fibular nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Flexor hallucis longus

Origin: Fibula and interosseus membrane Insertion: Plantar surface of the distal phalanx of the great toe Action: Flexion of the great toe; weak plantar flexion Innervation: Tibial nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Extensor digitorum longus

Origin: Fibula and interosseus membrane Insertion: distal phalanges of the lateral four digits (dorsal) Action: dorsiflex the foot; extend the digits Innervation: Deep fibular nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Extensor hallucis longus

Origin: Mid-fibula and interosseus membrane Insertion: distal phalanx of the great toe (dorsal) Action: dorsiflex the foot; extend the great toe Innervation: Deep fibular nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Fibularis longus

Origin: Proximal fibula Insertion: medial plantar side of foot; medial cuneiform and first metatarsal Action: weak plantarflexion, eversion Innervation: Superficial fibular nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Flexor digitorum longus

Origin: Tibia Insertion: Plantar surface of the distal phalanges Action: Flexion of the 2-5th digits; weak plantar flexion Innervation: Tibial nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Soleus

Origin: Tibia and fibula Insertion: Calcaneus Action: Plantarflexion of the ankle Innervation: Tibial nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Tibialis posterior

Origin: Tibia, fibula, and interosseus membrane Insertion: plantar surface of several tarsals and metatarsals Action: Plantarflexion, inversion of the ankle Innervation: Tibial nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Gastrocnemius

Origin: posterolateral and posteromedial aspects of the distal femur Insertion: calcaneus Action: crosses two joints: Flexion of the knee, plantarflexion of the ankle Innervation: Tibial nerve

Describe the muscles of the leg by compartment; be able describe their attachments, actions and innervations Tibialis anterior

Origin: tibia and interosseus membrane Insertion: medial plantar foot (medial cuneiform and first metatarsal) Action: dorsiflex the foot; invert the foot Innervation: Deep fibular nerve

Bursa / Retinacula

Synovial tendon sheaths that prevent muscles and tendons from sliding out of place

Describe the paths, relationships and functions of the *nerves*, arteries and veins supplying the muscles and skin of the leg

The *common fibular nerve* is a terminal branch of the sciatic nerve that arises in the popliteal fossa and wraps around the head and neck of the fibula to split again. The common fibular nerve splits into the *superficial fibular nerve* and the *deep fibular nerve*. The superficial fibular nerve serves all of the muscles of the lateral compartment and cutaneous innervation for the distal lateral leg and most of the dorsum of the foot, and the deep fibular nerve serves the muscles of the anterior compartment as well as cutaneous innervation between the first and second toes. The *tibial nerve*, a terminal branch of the sciatic nerve that arises in the popliteal fossa, serves the posterior compartment muscles. It descends from the popliteal fossa, traveling with the posterior tibial artery and piercing through soleus to lie on posterior tibialis. NB: Tibial nerve supplies CUTANEOUS innervation of the sole of the foot!!!!

Describe the paths, relationships and functions of the nerves, *arteries* and veins supplying the muscles and skin of the leg

The anterior compartment is serviced by the *anterior tibial artery*, which splits off from the popliteal artery in the popliteal fossa and moves anteriorly through the interosseus membrane. It runs alongside the deep fibular nerve. After this vessel crosses the ankle joint, it is called *dorsalis pedis*. The lateral compartment is served by penetrating vessels from the *fibular artery* in the posterior compartment. The *posterior tibial artery*, a terminal branch of the popliteal artery that arises in the popliteal fossa, descends to supply the muscles of the posterior compartment. It splits to form the *fibular artery* (below the split to form anterior and posterior tibial); the fibular artery travels adjacent to the lateral compartment to provide perforating branches to those muscles.

Describe the function, location, composition and maintenance of the arches of the foot

The arches of the foot serve to absorb shock, adapt to the surface they are standing on, and to distribute weight. Ex: sesamoid bones - create a tunnel for long flexor tendon to great toe - protects great toe The medial longitudinal arch is formed from the talus, the navicular, the cuneiforms, and the medial metatarsals. The lateral longitudinal arch is formed from the calcaneus, the cuboid, and the lateral metatarsals. The transverse arch is formed from the cuneiforms, the cuboid, and the metatarsal bases. The arches of the foot are maintained by the interlocking shape of the bones, the plantar ligaments, the plantar aponeurosis, and muscles and tendons.

Describe the arrangement of the crural fascia and discuss its role in compartment syndromes

The crural fascia surrounds the leg muscles and forms the anterior, lateral, and posterior (deep and superficial) compartments. The fascia is very snug and is not stretchy. It prevents muscle bulging. If injury causes any swelling in the muscle, however, there is nowehere for the swelling to go, and it can crush nerves and blood vessels, causing further damage. This compartment syndrome requires cutting of the fascia to relieve pressure.