Except in thin subjects, the constituent elements of the hip-joint cannot be palpated through the skin. A line drawn vertically downwards from the middle of Poupart's ligament passes over the centre of the joint, which in adults lies on the same level as the tip of the great trochanter. In children it is somewhat higher.
For purposes of clinical diagnosis it is necessary to locate certain bony prominences, the most important being—(1) The anterior superior iliac spine, which is most readily recognised by running the fingers along Poupart's ligament towards it. (2) The ischial tuberosity, which in the extended position of the limb is overlapped by the lower margin of the gluteus maximus muscle, and is therefore not easily located with precision. By flexing the limb and making pressure from below upwards in the gluteal fold, the smooth, rounded prominence can usually be detected. (3) The quadrilateral great trochanter is readily recognised on the lateral aspect of the hip. Its highest point or tip can best be felt by pressing over the gluteal muscles from above downwards.
Clinical Tests.—If a line is drawn from the anterior superior iliac spine to the most prominent part of the ischial tuberosity, it just touches the tip of the great trochanter. This is known as Nélaton's line ([Fig. 58]).
Fig. 58.—Nélaton's Line.
Bryant's test ([Fig. 59]) is applied with the patient lying on his back, and consists in dropping a perpendicular AB from the anterior superior iliac spine, and drawing a line CD from the tip of the great trochanter to intersect the perpendicular at right angles. This is done on both sides of the body, and the length of the lines CD compared. Shortening on one side indicates an upward displacement of the trochanter, lengthening a downward displacement. The third side AC of the triangle indicates the distance between the anterior spine and the tip of the trochanter.
Fig. 59.—Bryant's Line.