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Flashcards in Mod 3 - Lecture 3: Knee Deck (23)
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Distal Femur: Anterior Side

- Patellar Surface
---- a smooth groove at the bottom of the bone in between the medial and lateral condyle
---- where the patella sits to form the knee
- Medial and Lateral Epicondyles
---- medial condyle is on same side as femoral head
---- smoother than the condyles


Distal Femur: Posterior Side

- Intercondylar Fossa
---- a deep groove between the medial and lateral condyle
- Medial and Lateral Condyle
---- stick out more, rounded, a clear projection



- Lateral and Medial Condyle
---- lateral is closest to fibula
---- at the top of the tibia
---- articular surfaces can be seen on top in a posterior view
- Tibial Tuberosity: a roughened bump near the top of the tibia on the anterior side
---- a site for muscle attachment
- Medial Malleolus: a pointed projection at the bottom of the tibia
--- points toward the body's midline, not toward the fibula



- Head: the small rounded end
---- connects to the tibia
- Lateral Malleolus: the pointed bottom end of the bone
- the fibula is lateral to the tibia in anatomical position



- sesamoid bone
- provide a congruent articular surface opposing the femur
- provide a fulcrum to augment quads efficiency in knee extension
---- provide an angle to the connection between femur and tibia which allows the muscles to use more force
- serving as a strong linkage within the quadriceps tendon
- protecting the knee from direct trauma


Articulations of the Knee Region

- Tibiofemoral
- Patellofemoral
- Tibiofibular (proximal and distal)


Tibiofemoral Joint

- primary joint of the knee
- hinge/condyloid
--- move primarily in one plane, but have some ability to move in another plane
- distal end of femur and proximal end of tibia
---- femoral articular surfaces
---- tibial articular surfaces


Patellofemoral Joint

-Knee flexion: patella glides on the patellar surface of the anterior distal femur
- congruent fit between patella and femur
---- patella has a groove with a middle ridge on its posterior side which allows it to fit and move smoothly in the groove on the femur


Tibiofibular Joint: Proximal/ Superior

- synovial joint
---- plane type
- between the head of the fibula and the lateral condyle of the tibia
- Movement: slight movement occurs during dorsiflexion
---- more movement than at the distal joint


Tibiofibular Joint: Distal/Inferior

- fibrous joint
--- syndesmosis type
- between the inferior ends of the tibia and fibula
- Movement: slight movement occurs to accommodate the talus during dorsiflexion of the foot
---- less movement than at the proximal joint



- during the last twenty degrees of knee extension, the anterior tibial glide persists on the tibia's medial condyle bc its articular surface is longer in that dimension than the lateral condyle's
- prolonged anterior glide on the medial side produces external rotation
---- the "screw home" mechanism or the "locking mechanism" of the knee


Stability of the Knee

- Primary Stabilizers
---- Collateral and Cruciate Ligaments
- Secondary Stabilizers
---- joint capsule, menisci, muscles


Collateral Ligaments of the Knee Joint

- on the sides of the knee, outside the joint capsule
- Lateral Collateral (Fibular Collateral) - resists varus stress
---- varus: the ankle is too far in
---- that would require this ligament to stretch and lengthen more than it can
- Medial Collateral (Tibial Collateral) - resists valgus stress
---- attaches to joint capsule
---- valgus: angle is too far out
--- that would require this ligament to stretch and lengthen more than it can


Cruciate Ligaments

- inside the joint capsule
- cruciate means cross
---- ligament goes from one side of the femur to the other side of the tibia
- Posterior Cruciate: inserts on the posterior border of the tibia
---- prevents posterior displacement of the tibia
---- prevents the proximal tibia from falling back during extension bc the ligament holds it to the femur
- Anterior Cruciate: inserts on the anterior border of the tibia
---- prevents anterior displacement of tibia
---- the proximal tibia can't fall forward away from the knee during flexion bc the ligament holds it to the femur



- fibrous cartilaginous discs
located within the joint capsule
---- lateral and medial: like a figure eight over the articulating surface of the tibia
- increase congruence
---- improve fit between femur and tibia
- reduce friction
- shock absorption
---- weight bearing


Muscles of the Anterior Thigh

- All innervated by the Femoral Nerve
- Iliopsoas
- Quadriceps
---- Rectus Femoris
---- Vastus Intermedius
---- Vastus Medialis
---- Vastus Lateralis
- Sartorius


Adductor Muscles

- the inner thigh
- Obturator Nerve
---- Adductor Magnus
---- Adductor Longus
---- Adductor Brevis
---- Gracilis
- Femoral Nerve
---- Pectineus


Posterior Thigh Muscles

- Hamstrings
---- Biceps Femoris
---- Semimembranosus
---- Semitendinosus
- Sciatic Nerve
---- tibial and peroneal divisions


Femoral Triangle

- Borders:
---- superior: inguinal ligament
---- oblique: sartorius
---- medially: adductor longus
- Contents:
----from lateral to medial: femoral nerve, artery, and vein


Popliteal Fossa

- back of the knee
- Borders:
---- medial: biceps femoris
---- lateral: semimembranosus
---- inferior: gastrocnemius
---- roof: skin and fascia
---- floor: popliteal surface of the femur, popliteus muscle
- Contents:
---- popliteal arteries and veins
---- tibial and common fibular nerves
---- sural nerve (cutaneous)


Knee Joint Pathology: Ligament Strains/Tears

- excessive force in the anterior or posterior direction
---- femur and tibia/fibula twist in opposite directions under full body weight
- ACL: tibia rotates anteriorly
- PCL: tibia rotates posteriorly


Meniscal Tear

- Degenerative
- Traumatic
---- blow to the side of the knee
---- twisting of the knee
- Meniscus if fibrocartilage so it does not have a dedicated blood supply
---- does not heal well on its own
---- torn piece needs to be removed so that it doesn't cause more damage
---- excessive damage --> total knee replacement


Total Knee Replacement

- articular surfaces of the femur and tibia are removed and replaced with prosthetics