Sem 2 - K - Anterior/lateral leg & dorsum of foot - Interosseous membrane, superior tibiofibular joint, extensor retinaculum Flashcards
How many compartments are there in the leg?
What surface of the tibia is only covered by skin and fascia and has no muscle layer for protection?
We have
- Anterior compartment
- Lateral compartment
- Superficial posterior compartment
- Deep posterior compartment
The anteromedial surface of the tibia is only covered by skin and fascia
The fibrous structure spanning the length of the tibia and fibula is the interosseous membrane What direction do the fibres off the interosseus membrane travel and why is this orientation of the fibres important?
The majority of the interosseous membrane fibres travel in an inferolateral direction from the tibia to fibula
This is important to help resist the downward pull of the muscles attached to the fibula - only one muscle pulls the fibula upwards - biceps femoris
What artery pierces the interosseous membrane between tibia and fibula? What nerve does this artery run with?
The anterior tibial artery is one of the terminal branches of the popliteal artery and passes through a small opening in the interosseous membrane to come anteriorly
The anterior tibial artery descends in the anterior leg with the deep peroneal nerve
What are the two tibiofibular joints? State what type of joint each is
Superior (proximal) tibiofibular joint is a synovial plane joint
Inferior (distal) tibiofibular joint is a syndesmosis - a type of fibrous joint
What are the articulating surfaces of the superior tibiofibular joint?
What movement does this synovial plane joint allow for?
The articulating surfaces are between the articular facet on the head of the fibula and the articular facet on the lateral condyle of the tibia
During dorsiflexion of the ankle, the talus tends to wedge between the tibia and fibula causing slight movement of the superior tibiofibular joint
What ligaments help to stabilize the superior tibofibular joints?
Which muscle provides support to this joint?
These all help the joint capsule of this joint
The anterior and posterior ligaments of the head of fibula (attaching from head of fibula to lateral tibial condyle)
As well as the lateral collateral ligament (lateral epicondyle of femur to lateral head of tibia)
Biceps femoris provides additional support to the superior tibiofibular joint
What movements are possible at the ankle joint and state the muscles that can carry out each movement?
Dorsiflexion - Tibialis anterior, extensor digitorum longus, extensor hallucis longus, fibularis tertius
Plantarflexion - Gastrocnemius, soleus, plantaris, tibialis posterior, flexor digitorum longus, flexor hallucis longus, peroneus longus, peroneus brevis
How many muscles are in the anterior and lateral compartments of the leg?
What is the main function of the muscles?
Where do the tendons of the compartments pass at the ankle?
4 muscle in anterior compartment of leg
- Extension of ankle joint and digits are the main function
- Tendons pass anterior to the ankle joint
2 muscles in lateral compartment of the leg
- Eversion of the foot is the main function
- Tendons pass posterior to the lateral mallelous
Anterior compartment go anterior to the ankle joint and therefore this movement is dorsiflexion (ankle extension) Eversion of the foot is where you twist the foot so that the sole is facing laterally (opposite would be inversion where you twist the foot so the sole moves medially)
Are inversion and eversion movements of the foot or ankle? What muscles bring about these movements?
Inversion and eversion are not movements of the ankle joint but are movements of the foot
- Invertors of the foot Tibialis anterior and tibialis posterior
- Evertors of the foot Fibularis (peroneus) longus, brevis and tertius
We will now discuss the muscles in the lateral compartment of the leg
- What are the muscles in this compartment?
- What is the nerve supply to these muscles?
- What movements do these muscles allow for?
Peroneus longus and peroneus brevis both supplied by the superficial peroneal nerve (L5, S1, S2 roots) All muscles with Peroneus (fibularis) cause eversion of the foot Because the tendons of the peroneus longus and brevis pass posterior to the lateral malleolus and therefore posterior to the ankle joint, they will also allow for plantarflexion of the ankle joint
What are the attachments of the peroneus longus?
Peroneus longus attaches from head and upper 2/3rds of lateral fibula to the base of the 1st metatarsal and medial cuneiform
Describe the course of the tendon of the peorneus longus?
The tendon passes posterior to the lateral mealleolus and then passes on the inferior side of the peroneal trochlea of the calcaenous before passing inferior to the cuboid bone (forming a groove) to travel to the medial side of the foot - base of 1st metatarsal and medial cuneiform
What are the attachments of the peroneus brevis? (include the pathway for its tendon)
Peroneus brevis attaches to the inferior 2/3rds of the lateral fibula and its tendon passes posterior to the medial malleolus and then superior to the peroneal trochlea of the calcaneous to insert onto the tuberosity on the lateral side of the base of the 5th metatarsal
What are the two tendons of the lateral compartment of the leg separated by?
What bone does the tendons of the peorneus muscles form a groove in?
The two tendons are separated by the peroneal trochlea of the calcaneous - peroneus brevis runs superior, peroneus longus runs inferior
The two tendons form a groove on the lateral malleolus - lateral malleolar sulcus Peroneus longus also forms a groove on the inferior surface of the cuboid bone
What are the muscles of the anterior compartment of the leg and what is the nerve supply?
Tibialis anterior Extensor digitorum longus Extensor hallucis longus Fibularis tertius
All supplied by deep peroneal nerve (L4,5)
Lateral comparmtent - superficial fibular nerve (L5, S1,2) Anterior compartment - deep fibular nerve (L4,5) Largest anterior compartment muscle is the tibialis anterior What are the attachments of this muscle?
Attaches from the lateral condyle of tibia, superior 1/2 of lateral surface of tibia and interosseous membrane
Crosses ankle joint anterior before heading to medial aspect of foot Inserts at the medial and inferior surfaces of the medial cuneiform and the base of the 1st metatarsal
State again the attachments of the tibialis anterior and what is its function?
Tibialis anterior
Attaches
- from the lateral condyle of the tibia, superior 1/2 of the lateral tibial surface and interosseus membrane and inserts into the medial and inferior surfaces of the medial cuneiform and the base of the 1st metatarsal
Function -
- dorsiflexes the ankle and inverts the foot
State again the attachments of the extensor digitorum longus and its function
EDL attaches from the lateral condyle of tibia, superior 3/4 of medial surface of the fibula and interosseous membrane to insert onto the middle and distal phalanges of the lateral 4 digits
- Function - extension of the lateral 4 digits, dorsiflexes the ankle
State again the attachment of the extensor hallucis longus and its function?
Extensor hallucis longus attaches from the middle anterior surface of the fibular and interosseous membrane and inserts into the dorsal aspect of the distal phalnyx of the hallux
Function - Extension of the big toe and dorsiflexion of the ankle joint
State again the attachments of the peroneus tertius and its function
Attaches from the inferior 1/3rd of the anterior fibula and interosseous membrane Inserts onto the dorsal aspect of the base of the 5th metatarsal Function - dorsiflexion of the ankle, assists in eversion of the foot
There is a retinaculum associated with the ankle joint (both an extensor and flexor retinaculum) What are the two extensor retinaculum?
We have the superior and inferior extensor retinaculum
Where does the inferior extensor retinaculum attach from?
Inferior extensor retinaculum is Y shaped with a common origin from the calacaneous laterally
- The upper limb attaches to the medial malleolus
- The lower limb passes round the medial border of the foot and blends with dense fascia over the abductor hallucis (medial part of plantar fascia)
What are the two intrinsic muscle of the dorsum of the foot and what is their common origin? What is their nerve supply?
Extensor digitorum brevis and Extensor hallucis brevis
- These muscles originate from the superior surface of the calcaneous and the inferior extensor retinaculum
- Both supplied by the deep peroneal nerve (L5,S1)
- Anterior compartment of leg muscle - deep fibular nerve (L4,5)
- Lateral compartment of leg muscles- superficial fibular nerve (L5, S1,2)
- Dorsum of foot muscles - deep fibular nerve (L5, S1)
What is the attachment of the extensor digitroum brevis, its function and nerve supply?
Extensor digitorum brevis arises from the superior surface of the calcaneous and inferior extensor retinaculum and inserts onto the long extensor tendons of toes 2-4
- Function - extension of digits 2-4
- Nerve supply - deep peroneal nerve (L5,S1)
What is the attachment of the extensor hallucis brevis, its function and nerve supply?
Extensor hallucis brevis arises from the superior surface of calcaneous and inferior extensor retinaculum inserts onto the base of the proximal phalnyx of the big toe
- Function - it extends the big toe
- Nerve supply - deep peroneal nerve (L5, S1)
Where does the common peroneal nerve branch?
The common peroneal nevre branches between the nec of the fibula and the peroneus longus (attaches at head and upper 2/3rds of lateral fibula) to form the superficial and deep peroneal nerve
describe the route of the superificial fibular nerve?
The superficial fibular nerve runs in the lateral compartment of the leg supply the peroneus longus and brevis (L5, S1, S2) before continuing as a cutaneous nerve innervating distal anterior leg and most of the dorsum of the foot
Describe the route of the deep peroneal nerve after its formation?
The deep peroneal nerve pierces/passes through the EDL and travels with the anterior tibial artery initially between EDL and tibialis anterior but more distally between EHL and tibialis anterior
The deep peorneal nerve crosses the ankle joint to innervate the EHB and EDB and provides cutaneous innervation to the 1st web space
- What supplies most of the cutaneous innervation to the lateral and anterior leg?
- What supplies most of the cutaneous innervation to the dorsum of the foot?
- What supplies cutaneous innervation to the 1st web space?
- Most of cutaneous innervation to lateral leg is the sural nerve (medial and lateral cutaenous branches)
- Most of cutaneous innervation to anterior leg is the saphenous nerve
- Most of cutaneous innervation to dorsum of the foot - superficial peroneal nerve
- Cutaneous innervation to 1st web space - deep peroneal nerve
Describe the arterial supply to the leg?
- Popliteal artery divides to form anterior and posterior tibial artery
- Posterior tibial artery supplies the posterior leg and gives a fibular artery branch which remains in posterior leg and gives perforating branches to the lateral compartment
- Anterior tibial artery travels through the interosseous membrane and descends on this with the deep peroneal nerve
What does the arcuate artery anastamose with? What branches does it give?
The arcuate artery runs across the metatarsal giving metatarsal and digital arteries to anastamose with the lateral tarsal artery
What does the deep plantar artery branch of the dorsalis pedis artery anastamose with?
Deep plantar artery passes to the sole of the foot to anastamose with the lateral plantar artery to form the deep plantar arch between layers 3 and 4 of the sole of the foot
