The neck is about 5cm long and makes an angle of 125 ° with the shaft in males and in females (about 110° ). This is called the angle of inclination. It is widest at birth and diminishes with age till adolescence.
Femoral neck anteversion (FNA) describes the normal torsion or twist present in the femur. Femoral neck anteversion is the angle between the axis of the femoral neck and the frontal surface of the femur (ie, the coronal plane of the human body). In adults without pathology, the femur is twisted so the head and neck of the femur are angled forward between 15 and 20 degrees from the frontal plane of the body.
The torsion angle refers to the rotation of a distal or proximal end of a certain part of the human body along the longitudinal axis of the limb during the development of a certain part of the human body. By rotation the faral and the proximal of the limb is not on the same coronal plane, the angle between the two coronal planes twist . The angle of the femoral neck torsion is the angle between the coronal plane of the femoral neck and the coronal plane of the femur (ie, the coronal plane of the human body). The torsion angle is always greater than angle of anteversion.
This is a line between the anterior superior iliac spine and the ischial tuberosity, with the patient in the supine position. This line passes through the apex of the greater trochanter. If the apex of the greater trochanter is higher than this line by 1 cm, it means that the greater trochanter is displaced upwards, which is often used to diagnose posterior dislocation of the ankle or femoral neck fracture.
Drop a perpendicular from the anterior superior iliac spine to the horizontal
Project a second line upwards from the tip of the greater trochanter to meet the first line at 90°
Join the anterior superior iliac spine to the tip of the greater trochanter.
A line projected on each side of the body from the greater trochanter beyond the anterior superior iliac spine. The two lines normally meet in the midline at or above the umbilicus. If one femur is displaced upwards, the lines meet away from the midline. If both are displaced upwards the lines meet below the umbilicus.