TBL7 - Anterior and Lateral Leg Flashcards
The anterior compartment of the leg is adjacent to what and enclosed by what?
The anterior compartment of the leg is adjacent to the lateral surface of the tibial shaft (aka the shin) and enclosed by deep fascia
What does the fascia of the anterior compartment of the leg separate it from?
The fascia of the anterior compartment of the leg separates it from the lateral compartment of the leg, which is lateral to the fibula and enclosed by deep fascia.
What are compartment syndromes and how are prolonged symptoms relieved?
1) Trauma to muscles and/or vessels in the compartments from burns, sustained intense use of muscles, or blunt trauma may produce hemorrhage, edema, and inflammation of the muscles
2) Because the septa and deep fascia of the leg forming the boundaries of the leg compartments are strong, the increased volume consequent to any of these processes increases intracompartmental pressure
3) Increased pressure in a confined anatomical space adversely affects the circulation and threatens the function and viability of tissue within or distally, constituting compartment syndromes
4) A fasciotomy (incision of overlying fascia or a septum) may be performed to relieve the pressure in the compartment(s) concerned
How are tibialis anterior muscle strains and deep fibular nerve entrapment distinguished by their symptoms?
1) Shin splints—edema and pain in the area of the distal
two thirds of the tibia—result from repetitive microtrauma of the tibialis anterior which causes small tears in the periosteum covering the shaft of the tibia and/or of fleshy attachments to the overlying deep
fascia of the leg
2) Shin splints are a mild form of the anterior compartment syndrome. Shin splints commonly occur during traumatic injury or athletic overexertion of muscles in the anterior compartment, especially TA, by untrained persons. Muscles in the anterior compartment
swell from sudden overuse, and the edema and muscle–
tendon inflammation reduce the blood flow to the muscles. The swollen muscles are painful and tender to pressure
3) Excessive use of muscles supplied by the deep fibular
nerve (e.g., during skiing, running, and dancing) may result in muscle injury and edema in the anterior
compartment. This entrapment may cause compression
of the deep fibular nerve and pain in the anterior compartment. Pain occurs in the dorsum of the foot and
usually radiates to the web space between the 1st and 2nd toes
Compare dorsiflexion and plantarflexion of the foot and distinguish inversion and eversion of the foot
1) Dorsiflexion: Flex foot superiorly
2) Plantarflexion: Flex foot inferiorly
3) Inversion: Rotate foot medially
4) Eversion: Rotate foot laterally
What does the tibialis anterior muscle attach to proximally and distally? Where do the extensor digitorum longus and the extensor hallucis longus attach to proximally and distally?
1) In the anterior leg, the tibialis anterior muscle attaches proximally to the tibia and distally to the plantar surface (aka sole) of the medial foot
2) The extensor digitorum longus and extensor hallucis longus attach proximally on the tibia and fibula and distally to the dorsum of the toes
What are the common innervations of the three anterior leg muscles? What are their actions?
1) Deep fibular nerve (L4, L5)
2) Tibialis anterior: Dorsiflexes ankle and
inverts foot
3) Extensor digitorum longus: Extends lateral four digits and dorsiflexes ankle
4) Extensor hallucis longus: Extends great toe and dorsiflexes ankle
Where do the fibularis longus and fibularis brevis attach to proximally and distally?
1) In the lateral leg, the fibularis longus and fibularis brevis attach proximally to the fibula
2) The fibularis longus attaches distally to the plantar surface of the foot
3) The fibularis brevis attaches distally to the lateral side of the foot
What is the common innervation of the fibularis longus and brevis? What are their functions?
1) Superficial fibular nerve (L5, S1, S2)
2) Everts foot and weakly plantarflexes ankle
What are terminal branches of the common fibular (peroneal) nerve? Where does this nerve originate? Where does it travel?
1) The superficial fibular (peroneal) and deep fibular (peroneal) nerves are terminal branches of the common fibular (peroneal) nerve
2) The common fibular (peroneal) nerve originates in the posterior thigh and courses around the neck of the fibula into the anterolateral leg
How is the popliteal artery formed? What does the popliteal artery bifurcate into?
1) The femoral artery diagonally crosses the distal femur and becomes the popliteal artery
2) In the proximal leg, the popliteal artery bifurcates into the anterior tibial artery and posterior tibial artery
What does the anterior tibial artery supply? Where does the anterior tibial artery travel and what artery is its continuation?
1) The anterior tibial artery supplies the anterior and lateral leg
2) The anterior tibial artery continues onto the dorsum of the foot as the dorsal pedis artery
3) The dorsal pedis artery extends to the first interosseous space to provide digital arteries to the big toe
Why is the common fibular (peroneal) nerve frequently injured and what are the symptoms after its injury?
1) Because of its superficial position, the common fibular is the nerve most often injured in the lower limb, mainly because it winds subcutaneously around the fibular neck, leaving it vulnerable to direct trauma
2) Severance of the common fibular nerve results in flaccid paralysis of all muscles in the anterior and lateral compartments of the leg (dorsiflexors of ankle and evertors of foot)
3) The loss of dorsiflexion of the ankle causes footdrop, which is further exacerbated by unopposed inversion
of the foot
Where is the dorsal pedis pulse palpated and what is the most common cause of its diminution or absence?
1) Dorsalis pedis pulses may be palpated with the feet slightly dorsiflexed. The pulses are usually easy to palpate because these dorsal arteries are subcutaneous and pass along a line from the extensor retinaculum to a point just lateral to the EHL tendons
2) A diminished or absent dorsalis pedis pulse usually suggests vascular insufficiency resulting from arterial disease
