1. Introduction
- The knee
joint is the largest and most complex synovial joint in the
body.
- Type: Hinge
type of synovial joint.
- Function:
Allows flexion, extension, and slight rotation when
flexed.
- Formed
between: Femur, Tibia, and Patella.
2. Articular Surfaces
- Lower end
of femur (medial & lateral condyles)
- Upper end
of tibia (medial & lateral condyles)
- Posterior
surface of patella
Note: These surfaces are covered by hyaline
cartilage.
3. Ligaments of the
Knee Joint
Extracapsular ligaments
(outside the joint capsule):
- Patellar
ligament
- Medial
(tibial) collateral ligament
- Lateral
(fibular) collateral ligament
- Oblique
popliteal ligament
- Arcuate
popliteal ligament
Intracapsular ligaments
(inside the capsule):
- Anterior
cruciate ligament (ACL) – prevents forward movement
of tibia
- Posterior
cruciate ligament (PCL) – prevents backward
movement of tibia
- Menisci (medial
and lateral) – fibrocartilage pads for shock absorption
4. Relations of the
Knee Joint
Anterior:
- Skin,
patella, quadriceps tendon, patellar ligament, prepatellar bursa
Posterior:
- Popliteal
artery, vein, tibial nerve
- Popliteus
muscle
Medial:
- Sartorius,
gracilis, semitendinosus (Pes anserinus)
- Medial
collateral ligament
Lateral:
- Biceps
femoris, iliotibial tract
- Lateral
collateral ligament
Superior:
- Femur
Inferior:
- Tibia
5. Blood Supply
- Branches
of genicular arteries (from popliteal artery)
- Also
contributions from:
- Femoral
artery
- Anterior
tibial artery
6. Nerve Supply
- Supplied
by Hilton's law (nerves that supply muscles acting on a joint also
supply the joint)
- Nerves:
- Femoral
nerve
- Tibial
nerve
- Common
peroneal nerve
- Obturator
nerve
7. Movements of the
Knee Joint
- Flexion: by
hamstrings (biceps femoris, semitendinosus, semimembranosus)
- Extension: by
quadriceps femoris
- Medial
rotation (when flexed): semitendinosus, semimembranosus
- Lateral
rotation (when flexed): biceps femoris
Locking mechanism: Knee "locks" during final
degrees of extension for stability during standing.
8. Clinical Anatomy
- ACL Injury: common
in athletes; causes instability
- Meniscus
Tear: often due to twisting injury
- Osteoarthritis:
degeneration of cartilage, common in elderly
- Bursitis:
inflammation of knee bursae (e.g., prepatellar = "housemaid’s
knee")
- Genu
valgum ("knock knees") and Genu varum ("bow
legs")
Tags
ANATOMY