Anatomy Bones and Muscles · MU Pleven

21. Knee joint

Covers the knee as the body's largest and most complex synovial joint, classed as a modified hinge. It goes through the articular surfaces and cartilage, the medial and lateral menisci, and the capsule, then lists the extracapsular and intracapsular ligaments with their attachments and functions. It also describes the synovial membrane and bursae, the movements including the locking and unlocking mechanism, and the blood and nerve supply, with the Rule of Hilton.

Inside: 11 sections · 2 labelled pictures · 12 flashcards · 2 min

Topic 21 of 236 in the MU Pleven syllabus for Anatomy Bones and Muscles (Medicine, Year 2). The free AceMed note covers it in 11 sections, about 308 words (2 min of reading), with 12 flashcards.

In this note

  1. Knee joint.
  2. Type
  3. Articular Surfaces
  4. Articular Cartilage
  5. Menisci (Semilunar cartilages)
  6. Capsule
  7. Ligaments of Knee Joint
  8. Synovial Membrane
  9. Movements
  10. Blood Supply
  11. Nerve Supply

Type

  • Largest and most complex synovial joint in the body.
  • Compound synovial joint:
  • Modified hinge joint (mainly flexion/extension, with slight rotation).

Articular Surfaces

  • Femur: medial & lateral condyles (convex).
  • Tibia: medial & lateral condyles (flat, with fibrocartilaginous menisci).
  • Patella: posterior surface articulates with patellar surface of femur.

Articular Cartilage

  • Hyaline cartilage covers all articular surfaces.
  • Menisci deepen the tibial articular surface.

Menisci (Semilunar cartilages)

  • Medial meniscus:
  • C-shaped, attached to medial collateral ligament, less mobile → more injured.
  • Lateral meniscus:
  • O-shaped, more mobile.
  • Function: shock absorption, improve congruence, aid lubrication

Capsule

  • Thin, fibrous capsule surrounding joint.
  • Absent anteriorly (replaced by quadriceps tendon, patella, patellar ligament).

Ligaments of Knee Joint

A. Extracapsular

  1. 1. Patellar ligament – continuation of quadriceps tendon to tibial tuberosity.
  2. 2. Medial (tibial) collateral ligament (MCL):
  • From medial epicondyle of femur → medial tibial condyle.
  • Firmly attached to medial meniscus.
  1. 3. Lateral (fibular) collateral ligament (LCL):
  • From lateral epicondyle of femur → head of fibula.
  • Separated from lateral meniscus by popliteus tendon.
  1. 4. Oblique popliteal ligament: expansion of semimembranosus tendon (posterior capsule).
  2. 5. Arcuate popliteal ligament: posterior, strengthens posterolateral capsule.

B. Intracapsular (but extrasynovial)

  1. 1. Anterior cruciate ligament (ACL):
  • From anterior intercondylar area of tibia → medial surface of lateral femoral condyle.
  • Function: prevents anterior displacement of tibia on femur, stabilizes in extension.
  1. 2. Posterior cruciate ligament (PCL):
  • From posterior intercondylar area of tibia → lateral surface of medial femoral condyle.
  • Function: prevents posterior displacement of tibia, stabilizes in flexion.

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