A resident aspirates a grossly swollen knee joint for suspected septic arthritis using the standard lateral approach. Through which soft tissue window should the needle be introduced into the joint cavity?
- A At the midpoint of the lateral edge of the patella, between the patella and the lateral femoral condyle ✓
- B Below the inferior pole of the patella through the patellar ligament
- C Just below the lateral tibial plateau through Gerdy's tubercle
- D Medial to the patellar ligament at the level of the joint line
Correct answer: A. At the midpoint of the lateral edge of the patella, between the patella and the lateral femoral condyle
Explanation
The standard arthrocentesis route enters at the midpoint of the lateral border of the patella, passing between the patella and the lateral femoral condyle directly into the synovial cavity, where fluid distends the capsule. Entering through the patellar ligament below the patella risks damaging the infrapatellar fat pad and gives poor access to the suprapatellar recess, while Gerdy's tubercle is the attachment of the iliotibial tract and lies outside the joint capsule.
Reference: Moore's Clinically Oriented Anatomy, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.