The top of the great trochanter is the guide in an operation recently introduced by Mr. Adams, namely, the ‘subcutaneous section of the neck of the femur.’ ‘The puncture should be made one inch above and nearly one inch in front of the top of the trochanter. The neck of the bone is to be sawn through at right angles to its axis, the saw working parallel to Poupart’s ligament, and about one inch below it.’ =Spine of the ilium.=--The anterior superior spine of the ilium is the point from which we measure the length of the lower limb. By looking at the spines of opposite sides we can detect any slant in the pelvis. By pressure on both spines simultaneously we examine if there be a fracture of the pelvis, or disease at the sacro-iliac joint. 100. ‘In reducing a dislocation of the hip by manipulation it is important to bear in mind that, in every position, the head of the femur faces nearly in the direction of the inner aspect of its internal condyle.’[8] 101. =Compression of femoral artery.=--About a point midway between the spine of the ilium and the symphysis pubis, the femoral artery can be felt beating, and effectually compressed, against the pubes. How should the pressure be applied when the patient lies on the back? In accordance with the slope of the bone--that is, with a slight inclination upwards. A want of attention to this point is the reason why so many fail when they undertake to command the circulation through the femoral artery in an amputation, or to cure an aneurysm by digital compression. If the Italian tourniquet be used, we should be careful to adjust the counter-pad well under the tuberosity of the ischium. If digital pressure be used, it is easy to command the femoral by slight pressure of the thumb, provided the fingers have a firm hold on the great trochanter. 102. =Sartorius.=--The sartorius is the great fleshy landmark of the thigh, as the biceps is of the arm, and the sterno-cleido-mastoideus of the neck. Its direction and borders may easily be traced by asking the patient to raise his leg, a movement which puts the muscle in action. The same action defines the boundaries of the triangle (of Scarpa) formed by Poupart’s ligament, the adductor longus and sartorius. =Line of femoral artery.=--To define the course of the femoral artery, draw a line from midway between the anterior superior spine of the ilium and the symphysis pubis to the (spur-like) tubercle for the adductor magnus on the inner side of the knee. The femoral artery lies under the upper 2/3 of this line. The sartorius begins to cross the artery, as a rule, from three to four inches below Poupart’s ligament. The point at which the profunda artery arises is about one and a half or two inches below the ligament. Therefore the incision for tying the femoral in Scarpa’s triangle should commence about a hand’s breadth below Poupart’s ligament, and be continued for three inches in the line of the artery.