Vastus Medialis: a Reappraisal of VMO and VML

Abstract

Abstract.[Purpose] The morphology and innervation pattern of the vastus medialis (VM) were investigated to determine if there was an anatomical distinction between the oblique (VMO) and longus (VML) parts. [Subjects and Methods] Forty lower limbs were dissected. The innervation pattern was observed in 39 specimens. Muscle length and fibre angles of 14 specimens were recorded.[Results] In 22 specimens there was a distinct separation between the VML and VMO (change in fibre angle, fibrofascial plane, vasculature or nerve branch). The mean fibre angle of VMO was 52°, and the mean VML fibre angle was 5° (relative to the shaft of the femur). Ten limbs (25.6%) had separate innervation to the VML. The separation between VMO and VML was found to be more proximal than expected, with the VMO on average accounting for 70% of the VM, in contrast to the much more distal point of separation reported elsewhere, leading us to raise the possibility that VML and vastus intermedius may have been misidentified in some previous studies. [Conclusions] In conclusion the VML/VMO division (when present) is much more proximal than has been previously reported, and there is no consistent pattern of innervation to the two parts of the muscle.

An investigation into the architecture of the vastus medialis oblique muscle in athletic and sedentary individuals: An in vivo ultrasound study

“…Previous studies have found average VMO angles ranging from 47 to 57 in cadaveric knees (Weinstabl et al, 1989;Nozic et al, 1997;Farahmand et al, 1998;Peeler et al, 2005;Skinner and Adds, 2012). Ultrasound studies on mildly active nonpathological individuals found an average VMO angle of 56.6 degrees (Engelina et al, in press) and 57.6 (Jan et al, 2009) with a weak positive correlation between VMO angle and insertion ratio.…”

“…Numerous cadaveric studies have been carried out to determine the architecture of the VMO, focusing on the fiber angle, insertion ratio, and location (e.g., Lieb and Perry, 1968;Peeler and Anderson, 2007;Skinner and Adds, 2012). However, there is still uncertainty as to how these results are related to patella tracking in vivo.…”

The interaction between the vastus medialis and vastus intermedius and its influence on the extensor apparatus of the knee joint

“…Most investigations deal primarily with the distal part of the VM, which is also termed vastus medialis obliquus (VMO) (Fig. 6) [3,14,26,40,46,48,50,53]. We were not able to find a separate innervation to the different sections of VM, nor a clearly distinct fascial plane between the two heads.…”

Rare Variant of Vastus Medialis Detected <i>in vivo</i> by Ultrasound and Confirmed by High-resolution MRI

“…There have been three reports in the literature of an unusual variant found in cadaveric specimens in which the VMO and VML are incontrovertibly separate entities, as the VML ran deep to a distal and superficial VMO, so that the VMO existed as a separate layer, superficial to the VML. This variation has been reported in 5 out of 22 cadaveric lower limbs5 ) , three out of “more than a hundred” dissected lower limbs3 ) , and bilaterally in one out of a sample of 200 Nigerian cadavers, which the authors called an “accessory quadriceps femoris muscle”4 ) . As far as we are aware, there have thus far been no reports of this unusual variation in living patients encountered in clinical practice.…”