Computed tomography provides a non-invasive method for studying anatomy
in live subjects. The abductor muscles of the hip were studied by using
computed tomography to describe their position, size, and orientation. The
outlines of the muscles were clearly identifiable; patterns that are
associated with trauma, arthritis, and so on, differed from normal. The
patterns in eighteen normal hips in twelve adults were mapped in detail.
The cross-sectional areas of the abductor muscles were measured and vectors
representing the total pull of the abductor muscle in the frontal and
sagittal planes were constructed for each hip. The variations in individual
and composite muscular anatomy were recorded. The inclination of the axis
of the abductor muscle ranged from 17 to 26 degrees (standard deviation,
2.9 degrees) in the frontal plane and from -2 to 14 degrees (standard
deviation, 4.2 degrees) in the sagittal plane.