Articular muscle of the knee: a muscle seldom recognized on MR imaging.
OBJECTIVE
We studied the MR imaging characteristics of the articular muscle of the knee, an important but seldom recognized structure of the distal thigh and knee.


METHODS
We used a 1.5-T system to prospectively evaluate the articular muscle of the knee in five healthy volunteers (10 knees); then we retrospectively studied the knee examinations of 24 patients (30 knees). One reader made duplicate readings to prospectively assess the sagittal proton density-weighted and axial T1-weighted images of the healthy volunteers. Three independent readers retrospectively evaluated the sagittal proton density-weighted images of the 24 patients.


RESULTS
The articular muscle of the knee was identified in 100% of prospective studies (10/10) and in 83% of retrospective studies (25/30). For the prospective study group, measurements (mean +/- SEM) were as follows: number of bundles, 2.4 +/- 0.68 (range, 1-4); length of uppermost bundle, 47.2 +/- 4.06 mm; width of origin, 8.6 +/- 0.79 mm; angle of origin, 11.4 degree +/- 1.29 degree; and cross-sectional bundle width, 19.8 +/- 2.05 mm2.


CONCLUSIONS
The articular muscle of the knee can usually be identified by MR imaging as an independent entity, separate from the great (vastus) muscle group.
Puig
S
S
Universitätsklinik für Radiodiagnostik, Vienna, Austria.
Dupuy
D E
DE
Sarmiento
A
A
Boland
G W
GW
Grigoris
P
P
Greene
R
R
D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D005260:Female; D006801:Humans; D007717:Knee / Q000033:anatomy & histology* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000473:pathology; D011446:Prospective Studies; D012016:Reference Values; D012189:Retrospective Studies; D000070600:Tibial Meniscus Injuries