The lateral compartment is that part of the knee where the femur articulates with the tibia  - but referring only to the outer or lateral side.

lateral compartment of the knee
The lateral side is easy to spot if you just look for the small fibula bone on the side - that is always the lateral side. The lateral 'compartment' comprises the articulation of the rounded condyle and the flattened tibia and the lateral meniscus on that side.

Dr Sheila Strover (Editor)
BSc (Hons), MB BCh, MBA

See biography...