Lower Limb 4: The Leg Flashcards
What is acute osteomyelitis?
Bone infection caused by bacteria
affects the long bones of the legs
Why is the tibia the commonest long bone to be fractured?
very superficial antero-medially
particularly slender in its lower 1/3
What is a compound injury?
an open fracture
occurs where there is a break in the skin around a broken bone
Function of the interosseus membrane?
unites the tibia and fibula
separates the muscles of the anterior and posterior compartment
serves as a site for muscle attachement
What is the function of the two foramina in this membrane?
to allow anterior tibial vessels through
allow perforating branch of fibular artery through
what are the compartments of the leg and what structures separate them?
Anterior (extensor), Posterior (flexor), Lateral (fibular)
separated by interosseus membrane
2 intermusclar septae between fibula and deep fascia
attachment of deep fascia to periosteum of anterior and posterior borders of the tibia
what are the specific functions of the compartments of the leg?
Anterior - dorsiflex ankle, extend toe, invert foot
Posterior - plantarflex ankle, flex toes, invert foot
Lateral - evert foot
What are the muscles of the anterior compartment of the leg?
Tibialis Anterior
Extensor Digitorum Longus
Extensor Hallucis Longus
Fibularis Tertius (aka Peroneus Tertius)
What is the innervation and blood supply of the anterior compartment of the leg?
Deep Fibular Nerve L4, L5, S1
Anterior Tibial artery
What is the function of a retinaculum in a limb?
Hold tendons in place and stabilise them
What is the origin and insertion of Tibialis Anterior?
Origin: Lateral tibial condyle, upper 2/3 of tibial shaft, interosseus membrane
Insertion: medial and intermediate cuneiform, base of 1st metatarsal
What is the action of Tibialis Anterior?
Dorsiflex ankle
invert foot
support medial arch
What is the origin and insertion of Extensor Hallucis Longus
Origin: Middle medial fibula and interosseus membrane
Insertion: Upper surface of base of distal phalynx of great toe
What is the function of Extensor Hallucis Longus?
Extend big toe
dorsiflex ankle
What is the origin and insertion of Extensor Digitorum Longus?
Origin: Lateral fibular condyle, upper 2/3 medial fibula, interosseus membrane
Insertion: 4 tendons come from inferior extensor retinaculum and extend to middle and distal phalanges of toes 2-5
What is the function of Extensor Digitorum Longus?
Extend toes 2-5
Dorsiflex ankle
Where is Fibularis Tertius?
deep and lateral to extensor hallucis longus and extensor hallucis brevis
this muscle is not present in all individuals
What is the function of Fibularis Tertius?
Assist in dorsiflexion and eversion of the foot
What happens to the popliteal artery in the leg?
Bifurcates in anterior tibial and posterior tibial
anterior tibial enters into anterior compartment through a hiatus in the interosseus membrane
How does the deep fibular nerve arise?
In popliteal fossa, tibial nerve gives off a branch, the common fibular nerve
this in turn gives off a branch in the lateral leg, the deep fibular nerve, which supplies the anterior compartment
What does the deep fibular nerve innervate?
all muscles of anterior compartment of the leg
muscles of dorsum of the foot (EDB, EHB)
first 2 dorsal interossei
skin between 1st and 2nd toes
What are the muscles of the lateral compartment of the leg?
Fibularis (peroneus) Longus
Fibularis (peroneus) Brevis
Where do the tendons of the lateral compartment pass?
Posterior to the lateral malleolus
What are the functions of fibularis longus and brevis?
Longus: Eversion + plantarflexion of the foot
also supports transverse arch of the foot
Brevis: Eversion of the foot
What is the innervation of the lateral compartment of the leg?
Superficial Fibular Nerve L5, S1, S2
a branch of the common fibular nerve
What is the origin and insertion of fibularis longus?
Origin: Superior lateral fibula +lateral tibial condyle
Insertion: Under surface of distal medial cuneiform + base of 1st metatarsal
What is the origin and insertion of fibularis brevis?
Origin: Lower 2/3 lateral fibular shaft
Insertion: lateral tubercle of metatarsal 5
why is the common fibular nerve prone to injury?
What are the consequences of such an injury?
Becomes quite superficial as it passes around the neck of the fibula
paralysis of dorsiflexion muscles resulting in foot drop, alteration of gait to compensate
loss of sensation on dorsum of foot and lateral leg
paralysis of anterior and lateral compartments of the leg
How is the posterior compartment of the leg divided?
Separated into superficial and deep compartments by the transverse intermuscular septum
What are the muscles of the superficial posterior compartment?
Gastrocnemius
Soleus
Plantaris
What is the innervation to the superficial posterior compartment?
Tibial Nerve, L5, S1, S2
What is the origin of gastrocnemius?
2 heads: upper lateral femoral condyle and medial femoral condyle
What is the origin of soleus?
It is deep to gastrocnemius
soleal line and medial tibia, posterior fibula, neck and shaft
What is the common insertion of gastrocnemius and soleus?
They unite to form the calcaneal (achilles) tendon, inserts onto posterior of calcaneus
What is the origin and insertion of plantaris?
Origin: lateral supracondylar ridge of femur
Insertion: Medial to calcaneal tendon
What is the common action of the superficial posterior compartment?
Plantarflex foot at ankle
flex leg at knee (apart from soleus)
What are the contents of the deep posterior compartment?
4 Muscles: Popliteus Flexor Hallucis Longus Flexor Digitorum Longus Tibialis posterior
Posterior tibial artery
Tibial nerve
What is the origin and insertion of Popliteus?
Origin: Popliteal groove on lateral femoral condyle
Insertion: Posterior surface of medial proximal tibia, attached to lateral meniscus
What is the action of popliteus?
Medially rotate tibia on the femur if the femur is fixed (sitting)
Laterally rotates femur on tibia if tibia is fixed (standing)
unlocks the knee to allow flexion
What is the origin and insertion of flexor hallucis longus?
Origin: Posterior, inferior lower 2/3 fibula + interosseus membrane
Insertion: Plantar surface, distal phalanx of great toe
What is the action of flexor hallucis longus?
Flex great toe
What is the origin and insertion of flexor digitorum longus?
Origin: Medial Posterior tibia
Insertion: 4 tendons into plantar surface bases of distal 2-5 phalanges
What is the action of flexor digitorum longus?
Flex toes 2-5
What is the origin and insertion of tibialis posterior?
Origin: Posterior 2/3 interosseus membrane
Insertion: tuberosity of navicular, medial 1st cuneiform
What is the function of tibialis posterior?
Invert foot
Plantarflex foot
support medial arch when walking
How do the tendons of the deep posterior compartment travel to the foot?
Pass posterior to the medial malleolus Tom, Dick and Nervous Harry Tibialis Posterior (tom) flexor Digitorum Longus (Dick) posterior tibial Artery (and) tibial Nerve (nervous) flexor Hallucis Longus (Harry)
Tom closest to medial malleolus, Harry furthest posterior
