Marcelo Bordalo-Rodrigues MD, Presenter: Nothing to Disclose

Zehava Sadka Rosenberg MD, Abstract Co-Author: Nothing to Disclose

Mark E. Schweitzer MD, Abstract Co-Author: Nothing to Disclose

Leon David Rybak MD, Abstract Co-Author: Nothing to Disclose

The goals of our study were to describe: 1) the normal MRI and 2) strains of the musculotendinous junction of the proximal rectus femoris muscle. To the best of our knowledge these have not been described in detail in the radiology literature.

A retrospective study of hip and thigh MR studies was performed in 20 asymptomatic patients (15 women, 5 men, mean age 48y, range 28-80y) and 22 patients with strains at the rectus femoris musculotendinous junction (8 women, 14 men, mean age 36y, range 12-62y). The MR studies were performed with a 1.5 T magnet, (axial & coronal T1W and T2W fat-suppressed and sagittal T2W fat-suppressed images). The proximal musculotendinous junction of the rectus femoris was followed from the hip origin down to the distal thigh. The location, extent and signal characteristics of the strains were recorded in the symptomatic group.

Normal anatomy: The direct and indirect tendons of the rectus femoris were optimally visualized on axial and coronal images. The tendons joined just below their respective origins from the anterior inferior iliac spine and from the ilium, above the acetabulum. The anterior portion of the conjoined tendon blended with the proximal anterior fascia while the posterior portion coursed deep within the muscle almost down to the distal thigh. Rectus femoris strain: Of the 16 acute strains, 14 occurred at the thigh level and depicted longitudinally oriented, intrasubstance musculotendinous separation, deep within the muscle belly. In 2 cases the strains were located in the hip region, at the level of the conjoined tendon. In 6 chronic injuries a hypointense, rope-like, low signal tissue around the intramuscular tendon, compatible with fibrous encasement, was noted.

Unlike most musculotendinous junction strains elsewhere in the body, which occur at the junction of the muscle belly with the tendon, most rectus femoris strains occur at the thigh level, deep within the muscle, and are longitudinal in orientation. Less commonly they occur at the hip region, at the junction of the proximal muscle belly with the conjoined tendon.

Bordalo-Rodrigues, M, Rosenberg, Z, Schweitzer, M, Rybak, L, Normal anatomy and strains of the musculotendinous junction of the proximal rectus femoris: MR features.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4412390.html