OBJECTIVETo discuss the imaging manifestation and clinical value in herniation pit of femoral neck.

METHODSOne case proved by operation and pathology and twenty cases with typical imaging manifestation described by Pitt were reviewed retrospectively. There were 17 males and 4 females with an average age of 53 years old(ranging from 30 to 85 years). All cases were examined by X-ray films and CT, and 13 cases were performed with MRI.

RESULTSTwenty-nine lesions were found in the 21 cases, 9 cases were in right side, 8 cases were in left side, 4 cases were in both sides. The lesions were all located in the superior lateral part of the femoral neck and anterior lateral base of femoral head. The lesions were round or oval, and most of their greatest diameter was less than 16 mm. X-ray films showed a central radiolucency with a thin clear sclerotic rim or simple sclerotic loop. CT scans showed a well-defined lesion of soft-tissue attenuation with sclerotic margin. The lesions had focal cortical perforation. On MRI images,most lesions showed uniformly long T1 and long T2 fluid signal intensity.

CONCLUSIONHerniation pit of femoral neck have some specific imaging features, CT can make accurate diagnosis. X-ray and MRI are helpful to diagnosis.