PMC7203533_01
A 28-year-old woman who presented with low back pain for a month without neurological symptoms: (a) axial and (b) coronal T1-weighted images of the pelvis show congenital absence of the left piriformis muscle (yellow arrows point to the expected location).
SAJR-24-1838-g001.jpg
PMC7203533_01_SAJR-24-1838-g001.jpg
F0001
Given the history of perineal discomfort, MR neurography of the pelvis was subsequently performed to evaluate the pudendal nerve and demonstrated absence of the left piriformis muscle (Figure 1).
(a) Axial T2 fat-saturated (b) and coronal short tau inversion recovery images again reveal the same findings.
SAJR-24-1838-g002.jpg
PMC7203533_01_SAJR-24-1838-g002.jpg
F0002
The sciatic nerve and lumbosacral plexuses were normal in configuration and signal intensity with no signs of neuritis (Figure 2).