Vascularity of the hip labrum during the foetal period.

Tears of the hip labrum have been recognized as a cause of hip pain and clicking. It has been reported that labrum tears are associated with increased microvessel formation. The purpose of this study was to identify the regional vascularity of the acetabular labrum during late foetal development. The acetabular labrum was examined from 21 formalinized foetuses of the age 5th to 10th months of gestation (mean 6.4±0.99). The acetabulum of each specimen was anatomically prepared and divided into four quadrants. The number of blood vessels in labrum quadrants was counted during microscopic examination. A total of 599 of blood vessels were found in all specimens: 159 in quadrant I, 150 in quadrant II, 127 in quadrant III and 163 in quadrant IV. The capsular part of the labrum contained 357 vessels and the articular part contained 242. The total number of blood vessels within the capsular parts of all specimens (357) was significantly greater than the number within the articular parts (242) (p<0.028). There was some evidence to suggest that with increasing foetal age, the number of blood vessels in the labrum decreased. However, taking into consideration the number of vessels in particular quadrants of the labrum, the great frequency of labral tears in the anterosuperior part of the labrum could not be explained.