Dissection 5/6- Knee and Anterior/Lateral Leg Flashcards
What type of joint is the knee?
Synovial hinge joint
How many articulations does the knee joint have? What are they?
- 3 articulations
- 2 femero-tibial and 1 femero-patellar
Does the fibula take part in the knee joint?
No
What are the 2 major and 2 minor movements of the knee joint?
Major: flexion and extension
Minor: medial and lateral rotation
What muscles and what nerves take part in flexion of the knee?
- Hamstrings and gastrocnemius via the tibial and common fibular nerves
What muscles and nerve take part in extension of the knee?
Quadriceps muscles via the femoral nerve
What muscles and nerves are associated with medial rotation of the knee?
Hamstrings and gracilis via the tibial and obturator nerves
What muscles and nerves are associated with lateral rotation of the knee?
Biceps femoris via the tibial and common fibular nerves
What are the external and internal layers of the knee joint capsule?
External: fibrous layer/capsule
Internal: synovial membrane
What does the internal synovial membrane of the knee joint line?
All surfaces of the articular cavity not covered with articular cartilage
What is the infra patellar fat pad? Where is it located?
A cylindrical piece of fat which is under and behind the. patellar bone
What structure can be purposely removed in arthroscopic surgery to allow better access to the knee joint?
Infrapatellar fat pad
What are the bursa of the knee?
Fluid filled sacs and synovial pockets that sometimes communicate with the joint
What are bursae filled with?
Synovial fluid
What do the bursae represent within a joint?
Weak points
Which bursa is an extension of the synovial cavity?
The supra patellar bursa
What is the function of the supra patellar bursa?
Reduces friction on the quadriceps tendon during knee movements
Abnormal fluid within the knee joint can fill the supra patellar bursa, causing swelling where?
The inferior third of the anterior thigh
What are the important ligaments of the knee joint?
Medial and lateral collaterals, anterior and posterior cruciates and the iliotibial tract
The lateral collateral ligament extends in which direction?
Inferiorly
Where does the LCL attach to and from?
Lateral epicondyle of femur to the lateral surface of the head of fibula
The tendon of what muscle passes deep to the LCL?
Popliteus
The tendon of which muscle is split in two by the LCL?
Biceps femoris
Which of the collateral ligaments is rounded, cord like and strong?
LCL
Which of the collateral ligaments is a strong flat band?
MCL
Where does the MCL extend to and from?
Medial epicondyle of femur to the medial surface of tibia
Cruciate ligaments are named anterior and posterior according to their site of attachment to where?
Intercondylar eminence of the tibia
Which is the weaker of the two cruciate ligaments?
ACL
The ACL passes out in which directions?
Superiorly, laterally, posteriorly
The ACL attaches where proximally?
Lateral femoral condyle
What action does the ACL prevent?
Anterior displacement of the tibia on the femur, hyperextension of the knee joint
What test is used for the ACL?
Anterior drawer test
Which is the stronger of the two cruciate ligaments?
PCL
Where does the PCL lie in relation to the ACL?
Medial
What directions does the PCL pass in?
Superiorly and anteriorly
Where does the PCL attach proximally?
Medial femoral condyle
What movement does the PCL prevent?
Posterior displacement of the tibia on the femur, prevents hyperflexion of the knee
What test is used for the PCL?
Posterior drawer test
What is the main function of the menisci?
Shock absorbers
Menisci are crescentic discs made of what?
Fibrocartilage
The menisci assist with stabilisation of what?
Curved femoral condyles upon the flatter tibial condyles
Where are the menisci thickest?
Peripherally (where they are attached to the fibrous capsule)
The medial meniscus is attached to which ligament of the knee? What is the clinical relevance of this?
MCL
Makes the medial meniscus more susceptible to injury
An injury to the medial meniscus would occur after a blow to what side of the knee?
Lateral
An injury to what 3 structures makes up the unhappy triad?
- Medial Meniscus
- MCL
- ACL
Both menisci are point anchored anteriorly and posteriorly by attachment to where?
The tibial intercondylar area
What is genu varum?
Bow legged
What is genu valgum?
Knock kneed
Genu varum results in extra stress on what side of the knee?
Medial
Genu valgum results in extra stress on what side of the knee?
Lateral
Genu valgum/varum may result in the loss of which structures completely?
Lateral and medial menisci respectively
The anterior compartment of the leg is bound anteriorly by what?
Deep fascia of the leg and the skin
What are the bindings of deep fascia found inferior to the anterior compartment of the leg that bind the tendons of the compartment known as?
Retinacula
What is the purpose of the retinacula?
Prevents tendons from bow-stringing anteriorly during dorsiflexion of the ankle
Where is the superior extensor retinaculum found?
Passing from the tibia to fibula, proximal to the malleoli
What does the inferior extensor retinaculum attach to laterally?
Anterior calcaneus
What does the inferior extensor retinaculum attach to medially?
Medial malleolus and medial cuneiform
The inferior extensor retinaculum forms a strong loop around the tendons of which muscles?
Fibularis tertius and extensor digitorum longus
The muscles of the anterior leg compartment are supplied by what nerve?
Deep fibular nerve
The muscles of the anterior leg compartment all attach proximally to which structures?
Tibia, fibula, interosseus membrane
What is the distal attachment of the tibialis anterior?
base of 1st metatarsal and medial cuneiform
What is the function of the tibialis anterior?
Dorsiflexes ankle and inverts foot
What is the distal attachment of the EHL?
Dorsal aspect of the base of distal phalanx of great toe
What is the function of the EHL?
Dorsiflexes ankle and great toe
What is the distal attachment of the EDL?
Middle and distal phalanges of lateral 4 digits
What is the function of the EDL?
Dorsiflexes ankle and lateral 4 digits
Where does the fibulas tertius attach to distally?
Dorsal of base of 5th metatarsal
What is the function of fibulas tertius?
Dorsiflexes ankle, everts foot
What are the muscles of the anterior compartment of the leg?
Tibialise anterior
Extensor hallucis longus
Extensor digitorum longus
Fibularis tertius
What does the superficial fibular nerve supply?
Muscles of the lateral leg and the skin/fascia of the dorsum of foot
What does the deep fibular nerve supply?
Muscles of the anterior leg and the skin of the 1st interdigital cleft
What other structure does the deep fibular nerve accompany in the anterior compartment of the leg?
Anterior tibial artery
What does the anterior tibial artery supply?
Structures in the anterior leg compartment
What two muscles in the anterior compartment does the anterior tibial artery pass down between?
Tibialis anterior and EDL
Where does the anterior tibial artery end? What does it become?
The ankle, between the malleoli. It becomes the dorsalis pedis artery
What is the other name for the lateral compartment of the leg?
Evertor compartment
What separates the lateral leg compartment from the anterior leg compartment?
Anterior intermuscular septum
What is the smallest of the leg compartments?
Lateral
What are the muscles of the lateral compartment of the leg?
Fibularis longus and fibulas brevis
What bone do the muscles of the lateral leg compartment attach to proximally?
Fibula
Where does the fibularis longus attach distally?
Plantar surface of the base of the 1st metatarsal
Where does the fibularis brevis attach distally?
Plantar surface of the base of the 5th metatarsal
What is the main action of the lateral leg muscles?
Eversion of the foot
What are the lateral leg muscles supplied by?
Superficial fibular nerve
After supplying the lateral leg muscles, what does the superficial fibular nerve continue as? What does it supply?
A cutaneous nerve- skin on the distal part of the anterior surface of the leg and nearly all the dorsum of the foot
Does the lateral compartment of the leg have an artery running through it?
No
What is the blood supply to the lateral leg muscles?
Proximally- branches of the anterior tibial artery
Distally- branches of the fibular artery