The Anatomy of the Extensor Mechanism and its Clinical Relevance

Anatomic dissections of 15 lower limbs demonstrated that the quadriceps tendon consists basically of three laminae. These were the RF tendon, the fused aponeuroses of the VML and VLL, and the aponeurosis of the VI (from superficial to deep). The VM and VL were seen to consist of long and oblique components that had different origins and insertions and different fibre alignments. In the case of the VM, the two parts were separated by a fascial plane that contained a branch of the femoral nerve. The laminar arrangement of the quadriceps tendon indicates that in ACL reconstruction the part of the extensor mechanism that is affected most is the RF tendon. The VMO and VLO play an important role in the stability and alignment of the patella. The fibres of the VMO were seen to arise from the tendon of the adductor magnus and this provides anatomical evidence in favour of McConnell's rehabilitation program in the management of chondromalacia patellae.