M: Leg Flashcards
What is the tibia in cross section, what surfaces does it have?
Triangular in cross section
Has medial, lateral and posterior surfaces
Is the tibial tuberosity located anteriorly or posteriorly?
Anteriorly
Where is the intercondylar eminence located on the tibia, which 2 things make it up?
Located between the 2 tibial plateaus - made up of the medial and lateral intercondylar tubercles
What is acute osteomyelitis?
Infection of the bone which develops following an injury, infection or underlying condition
What is a compound injury?
When the bone breaks in such a way that bone fragments stick out through the skin or a wound penetrates down to the bone
Why is the tibia a highly accessible donor sight for bone grafts?
Has an extensive subcutaneous surface anteriorly
What is the interosseous membrane?
A form of fibrous joint which units the tibia and fibula
What is the functions of the interosseous membrane in terms of the musculature of the leg? 2
Seperates the anterior and posterior compartments of the leg
Provides a sight for muscle attachment
What are the function of the 2 foramina in the interosseous membrane?
Allow vessels to pass between the posterior and anterior compartments of the leg
What four muscles are found in the anterior compartment of the leg?
1) Tibialis anterior
2) Extensor hallucis longus
3) Extensor digitorum longus
4) Fibularis tertius
(from medial to lateral)
What is the function of a retinaculum in a limb?
Stabilize muscle tendons, holding them in place to allow them to perform there function
Which is the most medial muscle in the anterior compartment of the leg?
Tibialis anterior
What are the origins and insertions of tibialis anterior?
Origin - lateral surface of tibia and adjacent interosseous membrane
Insertion - medial and inferior surfaces of medial cuneiform and base of metacarpal 1
What movements may be produced at the ankle joint by contraction of tibialis anterior?
Dorsiflexion of the foot at the ankle joint
Does tibialis produce inversion or eversion of the foot?
Inversion
What is the difference between intrinsic and extrinsic muscles of the foot?
Extrinsic - have origins in the leg but insertions in the foot
Intrinsic - have origins and insertions in the foot
What are the 2 extrinsic extensors of the toes?
1) Extensor digitorum longus
2) Extensor hallucis longus
What are the attachments of extensor hallucis longus?
Origin - Middle 1/2 of medial surface of fibula and adjacent interosseous membrane
Insertion - Dorsal surface of base of distal phalynx of great toe
What are the attachments of extensor digitorum longus?
Origin - proximal 1/2 of medial surface of fibula and related surface of lateral tibial condyle
Insertion - via dorsal digital expansions into bases of distal and middle phalanges of lateral 4 toes
Where does fibularis tertius lie in relation to the other muscles in the anterior compartment of the leg, is it always present?
Lies deep and lateral to extensor hallucis longus and extensor hallucis brevis
Fibularis tertius is not present in all individuals
What is the function of fibularis tertius?
Dorsi flexion and eversion of the foot
Which muscle has to be retracted in order to expose the anterior tibial artery?
Extensor digitorum longus
Where does the anterior tibial artery arise from?
The popliteal artery
How does the anterior tibial artery pass from the posterior to anterior compartment of the leg?
Via a hiatus in the interosseous membrane
What are the 2 muscles in the lateral compartment of the leg?
1) Fibularis (peroneus) longus
2) Fibularis (peroneus) brevis
Where do the tendons of fibularis longus and brevis pass relative to the lateral malleolus?
Pass posterior to the lateral malleolus
Where does the tendon of fibularis longus insert on the plantar surface of the foot?
Undersurface of lateral sides of distal end of medial cuneiform and base of metatarsal 1
What are the 3 actions of fibularis longus?
1) Eversion of foot
2) Plantar flexion of the foot
3) Supports arches of foot
What is the 1 action of fibularis brevis?
Eversion of the foot
What is the innervation of the muscles in the lateral compartment of the leg?
Superficial fibular nerve
At which point in the common fibular nerve vulnerable to injury?
As it courses around the neck of the fibular
What would be the motor consequence of injury the common fibular nerve as it coursed around the neck of the fibula and why?
Lose ability to dorsiflex the foot at the ankle joint, the foot will appear permanently plantar flexed - this is foot drop
- due to loss of nerve supply to muscles of anterior compartment (supplied by deep fibular nerve)
May also present with a characteristic gait as a result of foot drop
What would be the sensory consequences of injury to the common peroneal nerve as it courses around the neck of the fibula?
Loss of sensation to the dorsum of the foot and lateral side of leg (supplied by lateral sural nerve from the common fibula and sural communicating nerve from common fibula and tibia)
What 2 sub-compartments is the posterior compartment of the leg divided into and by what?
1) Superficial posterior
2) Deep posterior
Divided by the transverse intermuscular septum
The deep posterior sub compartment of the leg contains what neurovasculature?
1) Posterior tibial artery
2) Tibial nerve
Which 4 muscles are located in the deep posterior compartment of the leg?
1) Popliteus
2) Flexor digitorum longus
3) Flexor hallucis longus
4) Tibialis posterior
What are the attachments of popliteus?
Origin - lateral femoral condyle
Insertion - posterior proximal tibia
What are the 2 actions of popliteus?
1) Stabilizes knee joint (resists lateral rotation of tibia on femur)
2) Unlocks knee joint (laterally rotates femur on fixed tibia)
What are the attachments of flexor digitorum longus?
Origin - medial posterior tibia
Insertion - plantar surfaces of bases of distal phalanges of lateral 4 toes
What is the 1 action of flexor digitorum longus?
Flexes the lateral 4 toes
What are the attachments of flexor hallucis longus?
Origin - posterior surface of fibula and adjacent interossesous membrane
Insertion - Plantar surface of distal phalynx of great toe
What is the 1 action of flexor hallucis longus?
Flexes the great toe
What are the attachments of tibialis posterior?
Origin - posterior surface of interosseous membrane and adjacent regions of tibia and fibula
Insertion - tuberosity of navicular and adjacent region of medial cuneiform
What are the 3 functions of tibialis posterior?
1) Inversion of foot
2) Plantarflexion of foot
3) Support of medial arch during walking
Which 3 tendons pass posterior to the medial malleolus?
1) Tibialis posterior
2) Flexor digitorum longus
3) Flexor hallucis longus
Where do the 3 muscles tendons lie posterior to the medial malleolus from most anterior to most posterior?
Tom Dick and Harry
1) Tibialis posterior
2) flexor Digitorum longus
3) flexor Hallucis longus
What artery and nerve also pass posterior to the medial malleolus?
Tibial nerve
Posterior tibial artery
Which 2 muscle tendons do tibial nerve and posterior tibial artery pass between when passing posterior to the medial malleolus?
Between tendons of flexor digitorum longus and flexor hallucis longus
(Tom, Dick and Nervous Harry)
Why is the tibis the commonest long bone to be fractured and to suffer a compound injury?
Shaft of the tibia is subcutaneous and unprotected anteromedially throughout its course and particularly slender in its lower third
