ABOVE KNEE AMPUTATION
ARTHROSCOPY
KNEE JOINT
Block 14
GNK 483
Anatomy
•
•
•
•
•
•
•
•
Classification
Bones
Capsule
Ligaments
Synovial membrane
Cruciate ligaments
Menisci
Nerve supply
•
•
•
•
Blood supply
Relationships
Bursae
Movements
Classification
• Synovial hinge joint
• Medially & laterally: femur & tibia (hinge and
rotation)
• Intermediate: Femur & patella (gliding joint
Capsule
• Absent anteriorly
• Synovial membrane protrudes to form the
bursa beneath the tendon of quadriceps
femoris
• It is anteriorly reinforced by the tendon of
quadriceps femoris, the patella and the patella
retinacula
Capsule
• Inferiorly, the capsule is fixed to the margins
of the tibia, except where the tendon of
popliteus passes
• The capsule is reinforced on both sides by the
expansions of vastus lateralis and medialis, as
well as behind by the oblique popliteal
ligament from the insertion of
semimembranosus
Ligaments
5 extracapsular
• Patellar ligaments –
quadriceps reflex L2,3,4
• Lateral collateral ligament
• Medial collateral ligament
• Oblique popliteal ligament
– is an expansion from the
insertion of
semimembranosus
• Arcuate popliteal ligament
– Y-shaped ligament posterior
that bridges the tendon of
popliteus
Ligaments
4 intracapsular
•
•
•
•
Synovial membrane
Cruciate ligaments
Menisci
Tendon of popliteus
Synovial Membrane
• Infrapatellar fold is a reflexion from the
posterior surface of the patella-forms a fold to
the intercondylar fossa
• The synovial membrane from the posterior
part of the capsule is reflected around the
front of the cruciate ligaments-they are
therefore intracapsular but extrasynovial
Cruciate Ligaments
Extrasynovial
• Anterior
– Taut in extension
– Prevents post
displacement of
femur on tibia
– Prevents
hyperextension of
the knee
Cruciate Ligaments
Extrasynovial
• Posterior
– Stronger
– Taut during flexion
– Prevents ant
displacement of
femur on tibia
– Prevents
hyperflexion of the
knee
Menisci - General
•
•
•
•
•
Medial & lateral
C-shaped
Fibrous cartilage
Upper surface concave
Outer margins thicker,
convex,attached to capsule
• Inner margins thinner,
concave,free border
• Transverse ligament extends
between the 2 ant parts of the
menisci
Menisci
• Medial meniscus
– Semicircular (oval)
– Wider at back than in
front
– Attached to medial
collateral ligament
– Most commonly
injured
Menisci
• Lateral meniscus
– Almost circular
– Even width front and
back
– Separated from lateral
collateral ligament via
popliteal tendon
Nerve Supply
• Br of femoral n to vastus medialis
• Obturator n (the br passes with the femoral a
thro the add hiatus to popliteus fossa
• Sciatic n
Blood Supply
• Genicular anatomosis formed by brrs of
popliteal a
• Middle genicular a pierces the capsule &
supplies cruciate lig’s, synovial mem, outer
margins of menisci
Relations
• Anterior femoris
quadriceps femoris & bursa
• Posterior
– popliteal fossa+contents, popliteal a+v, tibial+c.peroneal
nn
• Lateral
– Biceps femoris, lateral collateral ligament, tendon of
popliteus
• Medial
– Sartorius, gracilis,medial coll lig,semitendinosus
Bursae – Anterior (4)
• Suprapatellar
– Beneath quadriceps
femoris
• Prepatellar
– Housemaids knee
• Superficial infrapatellar
– Betw skin & patellar
ligament
– Clergyman’s knee
• Deep infrapatellar
– Betw patellar lig & tibia
Bursae – Posterior (2)
• Beneath popliteus
• Beneath
semimembranosus
Bursae – Posterior (2)
• Others:
Biceps femoris
Lateral head of
gastrocnemius
Medial head of
gastrocnemius
Anserine bursa below
insertion of:
– Sartorius
– Gracilis
– semitendinosus
Movements
• Flexion
– hamstrings+sartorius,gracilis,gastroc
• Extension
– quadriceps femoris+medial rotation
• Rotation
– Passive: screw home mechanism
– Active: medially in a flexed knee (SarGrTen)
laterally via Biceps femoris