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Overview of the Knee Anatomy

  • Bones of the Knee

    • Femur: Thigh bone, forms the upper part of the knee joint.

    • Tibia: Shinbone, supports most of the weight.

    • Fibula: Smaller bone next to the tibia, provides stability to the ankle and supports muscles.

    • Patella: Knee cap, protects the knee joint.

  • Ligaments

    • Anterior Cruciate Ligament (ACL): Prevents forward movement of the tibia.

    • Posterior Cruciate Ligament (PCL): Prevents backward movement of the tibia.

    • Medial Collateral Ligament (MCL): Stabilizes the inner knee.

    • Lateral Collateral Ligament (LCL): Stabilizes the outer knee.

  • Menisci

    • Medial Meniscus: C-shaped cartilage on the inner side.

    • Lateral Meniscus: C-shaped cartilage on the outer side.

Femur Anatomy

  • Patellar Surface: The area on the femur that interacts with the patella.

  • Medial and Lateral Grooves: Channels for ligament attachment.

  • Epicondyles: Medial and Lateral epicondyles serve as attachment sites for ligaments.

Tibia and Fibula Anatomy

  • Tibia: Main weight-bearing bone of the lower leg.

  • Fibula: Lateral to the tibia; less weight-bearing and mainly provides muscle attachment.

  • Tibial Tuberosity: Point of attachment for the patellar tendon.

Cruciate Ligaments Structure

  • Characteristics: Form an X shape within the knee joint.

  • Quadriceps Muscles: Primary muscles that extend the knee; their tendon attaches to the patella.

  • Articular Cartilage: Covers the ends of bones in the knee joint to allow smooth movement.

Anterior Cruciate Ligament (ACL)

  • Location: Extends from the lateral femoral condyle to the anterior tibia.

  • Function: Resist anterior movement of the tibia.

Posterior Cruciate Ligament (PCL)

  • Location: Extends from the medial femoral condyle to the posterior aspect of the tibia.

  • Function: Resists posterior movement of the tibia.

Collateral Ligaments Functions

  • Lateral and Medial Bands: Resist valgus (MCL) and varus (LCL) deformities, maintaining knee stability during movement.

Valgus and Varus Deformities

  • Valgus Deformity (Knock-kneed): Lower leg is abducted from the midline of the body.

  • Varus Deformity (Bow-legged): Lower leg is adducted toward the midline.

Menisci Structure

  • Function: Two crescent-shaped pads between the tibia and femoral condyles, providing cushioning and stability.

Knee Injuries

  • Common Types: Tears of ligaments (ACL, PCL, MCL, LCL) or menisci.

  • Symptoms: Swelling, instability, and a sensation that the knee may give out.

ACL Injuries

  • Common Causes: Non-contact injuries during sports involving running, jumping, cutting, or pivoting.

  • Clinical Signs: Often sensed as a "pop" at the time of injury.

  • Tests: Anterior Drawer Test and Lachman Test to assess ACL integrity.

PCL Injuries

  • Common Causes: Often results from trauma, particularly a dashboard injury in vehicle accidents.

  • Tests: Posterior Drawer Sign to evaluate posterior tibial translation.

MCL Injuries

  • Causes: Valgus stress due to contact or twisting injuries.

  • Symptoms: Pain, swelling, and abnormal abduction of the knee.

Unhappy Triad Injury

  • Description: Common injury pattern in contact sports involving simultaneous injury of the ACL, MCL, and typically a meniscus (often the medial meniscus).

LCL Injuries

  • Characteristics: Rarely injured in isolation; often associated with medial knee trauma.

Meniscal Tears

  • Mechanism of Injury: Common during sports involving twisting movements with weight on the knee.

  • Symptoms: Pain, swelling, and limited range of motion.

Diagnostic Tests for Menisci

  • McMurray Test: Detects meniscal tears by flexing and extending the knee while rotating the foot.

Bursitis of the Knee

  • Types: Prepatellar Bursitis (Housemaid’s knee) may arise from repetitive kneeling.

Baker's Cyst**

  • Description: Accumulation of fluid in the popliteal area, often related to joint disease or injury.

Osgood-Schlatter Disease

  • Characteristics: Overuse condition in children causing pain at the tibial tuberosity.

Patellar Fractures

  • Description: Result from trauma, often indicated by inability to extend the knee against gravity.

Conclusion

  • Knee Health: Understanding the anatomy and common injuries is crucial for effective injury prevention and treatment.