Lecture 13 - SQ Flashcards
- What are the locations of the suprapatellar and prepatellar bursae of the knee?
1) There are many bursae in the region of the knee. Two major ones of clinical importance are
the prepatellar and suprapatellar bursae. The prepatellar bursa is found in front of the lower
part of the patella. The suprapatellar bursa is a large saccular extension of the joint cavity and
is found behind the patella, between the body of the femur and the tendon of quadriceps.
- List all muscles that extend and flex the leg
2) FLEXION:
- hamstrings
- sartorius
- gracilis
- gastrocnemius
- plantaris
- popliteus
EXTENSION:
-quadriceps
- With the leg flexed to 90 degrees, what muscles laterally rotate the leg? With the leg flexed
to 90 degrees, what muscles medially rotate the leg?
3) Rotation of the flexed knee: MEDIAL: -semitendinosus -semimembranosus -sartorius -gracilis -popliteus (with foot off the floor) [Note: The knee cannot normally be rotated when the leg is fully extended.
LATERAL:
-biceps femoris
- What are the boundaries and contents of the superfical and deep muscle compartments of the
calf?
4) The superficial and deep muscle compartments of the calf are separated from each other by the
transverse crural fascia. The muscles of the superficial compartment of the calf are
gastrocnemius, soleus and plantaris. The muscles of the deep calf are the tibialis posterior, the
flexor digitorum longus, the flexor hallucis longus and the popliteus. The deep muscles are
bordered by the tibia medially, the fibula laterally, the interosseous membrane anteriorly, and
the deep transverse fascia posteriorly.
- What is the course and motor distribution of the tibial nerve?
5) After leaving the popliteal fossa, the tibial nerve dives between the two heads of the
gastrocnemius and courses down the middle of the calf within the deep compartment. Upon
reaching the ankle, it passes posteriorly and inferiorly to the medial malleolus along with the
“Tom, Dick and Harry” tendons. During its journey, the tibial nerve innervates the flexors of
the knee, the flexors of the ankle, and the flexors of the toes (both the extrinsic and the
intrinsic muscles).
- Describe the course and motor distribution of the common peroneal nerve.
6) The common peroneal nerve normally arises within or just superior to the popliteal fossa and
passes lateral to the neck of the fibula. It has two terminal branches: the superficial peroneal
nerve, which is motor to the muscles of the lateral compartment of the leg, and the deep
peroneal nerve, which is motor to the muscles of the anterior compartment of the leg.
- What are the attachments and relationships of the medial (tibial) collateral and lateral (fibular)
collateral ligments of the knee?
7) The tibial (medial) collateral ligament is part of the joint capsule. It crosses the medial side of
the knee joint and is attached to the medial condyles of the femur and tibia. The deep fibres of
this ligament are attached to the medial meniscus, thus limiting its ‘freedom’ during
movements of the knee. The fibular (lateral) collateral ligament is not part of the joint capsule
and is therefore extracapsular. It is cord-like, attached superiorly to the lateral femoral condyle
and inferiorly to the head of the fibula. This ligament has no attachment to the lateral
meniscus.
- What are the attachments, relationships and functions of the cruciate ligaments?
8) The cruciate ligaments cross each other, hence the name cruciate, and their primary function is
to provide stability to the knee joint by preventing the femur from sliding either anteriorly or
posteriorly off of the tibial table. The anterior cruciate ligament (ACL) is attached inferiorly to
the anterior intercondylar area of the tibia and extends upward, posterolaterally. It attaches
superiorly to the medial surface of the lateral femoral condyle. The ACL prevents the femur
from sliding posteriorly in relation to the tibia. The posterior cruciate ligament (PCL) is
attached inferiorly to the posterior intercondylar area of the tibia and passes upward and
anteromedially. It is attached superiorly to the lateral surface of the medial femoral condyle.
The PCL prevents the femur from sliding anteriorly off the tibial plateau.
- What are the attachments and functions of the medial and lateral menisci?
9) The menisci are kidney-shaped (medial) and semilunar-shaped (lateral) fibrocartilaginous
discs that lie between the condyles of the femur and tibia. The menisci are attached to the
irregular central part of the tibial table by each of their two horns. The medial meniscus is
partly fixed by its attachment to the medial collateral ligament, whereas the lateral meniscus is
not attached to the lateral collateral ligament, but to the popliteus muscle which controls its
movements.
The menisci deepen the articular surfaces of the tibia and help to spread the synovial fluid
between the thrust-bearing surfaces of the femur and tibia. The lateral meniscus is very
important in the locking and unlocking action of the knee. It acts as a wedge blocking (i.e.,
locking) the knee. When the knee is to be ‘unlocked’ the popliteus pulls the lateral meniscus
posteriorly and thus allows the knee to be freely flexed.
- What is the nerve supply of the flexors and extensors of the knee joint?
10) The extensors of the knee are supplied by the femoral nerve. The flexors of the knee are
supplied primarily by the tibial component of the sciatic nerve. However, the gracilis assists in
flexion and it receives its supply from the obturator nerve, and half of biceps femoris is
supplied by the common peroneal.
- What structural and/or functional changes result in, or contribute to, chronic lateral
displacement (dislocation) of the patella?
11) The more acute the angle between the long axes of the femur and tibia, the more likely the
patella will dislocate laterally. Each time the patella dislocates, the more likely it becomes that
it will occur again (i.e., recurrent dislocation) because of stretch in the tendons and ligaments
that normally resist this dislocation.
