Exam #5: Leg Flashcards
What are the two bones of the leg? Which of these bones is weight-bearing?
1) Tibia*
2) Fibula
*Weight bearing
What connects the two leg bones?
Interosseous membrane
What are the four compartments of the leg?
1) Anterior
2) Lateral
3) Superficial Posterior
4) Deep Posterior
What is the major function of the muscles in the anterior compartment?
Dorsiflexion of the ankle & extension of the toes
What nerve innervates the anterior compartment?
Deep Peroneal Nerve
What artery supplies the structures of the anterior compartment?
Anterior tibial artery
What are the four muscles of the anterior compartment?
1) Tibialis anterior
2) Extensor digitorum longus
3) Extensor hallucis longus
4) Peroneus tertius
Where is the anterior compartment?
Anterior to the interosseous membrane, between the anterior intermuscular septum & tibia
What is the origin of the Tibialis Anterior?
Tibia & interosseous membrane
What is the insertion of the Tibialis Anterior?
Medial cuneiform and base of the 1st metatarsal
What is the origin of the Extensor Hallucis Longus (EHL)?
Fibula & interosseous membrane
What is the insertion of the Extensor Hallucis Longus (EHL)?
Base of the distal phalanx of the great toe (hallux)
What is the origin of the Extensor Digitorum Longus (EDL)?
Tibia, fibula, & interosseous membrane
What is the insertion of the Extensor Digitorum Longus (EDL)?
Middle & distal phalanges of toes 2-5 (lateral 4)
What is the origin of the Peroneus Tertius?
Fibula & interosseous membrane
What is the insertion of the Peroneus Tertius?
Base of the 5th metatarsal
What is the deepest muscle of the anterior compartment?
Extensor Hallucis Longus (EHL)
Where does the Anterior Tibial artery enter the anterior compartment?
Branches from the Popliteal artery & passes through a hole in the interosseous membrane
What are the branches of the Anterior Tibial artery?
1) Tibial recurrent
2) Anterior medial malleolar
3) Anterior lateral malleolar
4) Dorsalis pedis
What are shin splints? What anatomical structures are involved?
Shin splints are pain and edema to the distal 2/3 of the tibia caused by repetitive microtrauma to the anterior tibialis m.
What nerve is most commonly injured in the lower leg?
Common peroneal nerve
Why is the common peroneal nerve the most commonly injured nerve in the lower leg?
- It has a superficial & lateral position
- It winds around the fibular neck, leaving it vulnerable to direct trauma
What is the clinical manifestation of severance of the common peroneal nerve?
“Footdrop”
- Loss of innervation to BOTH the anterior & lateral compartments of the LE
- Loss of dorsiflexion (and eversion) results in classic “footdrop”
What is compartment syndrome?
Increased pressure within a compartment compromises the circulation and function of the tissues within that space
- Anterior compartment is most commonly effected
- Most cases of “Acute Compartment Syndrome (ACS)” are the result of tibial fracture
What is the major function of the lateral compartment?
Eversion of the foot
What nerve innervates the lateral compartment?
Superficial peroneal nerve
What arteries supply the lateral compartment?
The lateral compartment DOES NOT have an artery coursing through it; rather, it is supplied by perforating branches from:
- Anterior compartment’s Anterior Tibial a.
- Posterior compartment’s Peroneal a.
What muscles are contained within the lateral compartment?
1) Peroneus Longus
2) Peroneus Brevis
Where is the lateral compartment?
Bounded by the lateral surface of the fibula & the atnerior & posterior intermuscular septa
What is the origin of the Peroneus Longus?
Lateral Fibula