The 'close-packed position' of the knee joint (maximum ligamentous tautness and congruence) is:

• A 90 degrees of flexion
• B Full flexion with medial rotation of the tibia
• C Full extension with lateral (external) rotation of the tibia ✓
• D 30 degrees of flexion (mid-range)

Explanation

The close-packed position of the knee is full extension with slight lateral (external) rotation of the tibia — the 'screw-home' mechanism. At full extension, all ligaments (ACL, PCL, collaterals) become taut, the menisci are compressed, and joint surfaces are maximally congruent, effectively 'locking' the knee. To unlock the knee for flexion to begin, the popliteus muscle medially rotates the tibia (or laterally rotates the femur on the fixed tibia). The knee is most stable and least likely to be injured in close-packed position; most injuries occur in mid-flexion (loose-packed).

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.