The femoral neck has two angular relationships with the femoral shaft that are important to hip joint function ; In most adults, this angle is approximately 125˚, but it can vary from 90 to 135˚.
- An angle exceeding 125˚ produces a condition known as coxa valga.
- An angle less than 125˚ result in coxa vara.
Angle of Inclination
The proximal femur is shown ; A, normal angle of inclination; B, coxa vara; and C, coxa valga. The pair of red dots in each figure indicates the different alignments of the hip joint surfaces. Optimal alignment is shown in A.
The Angle of Anteroversion
The angle of anteroversion is formed as a projection of the long axis of the femoral head and the transverse axis of the femoral condyles. In adults, this angle averages approximately 12˚, but it varies a great deal.Anteroversion of more than 12˚ causes a portion of the femoral head to be uncovered and creates a tendency toward internal rotation of the leg during gait to keep the femoral head in the acetabular cavity.
An angle of less 12˚(retroversion) produces a tendency toward external rotation of the leg during gait.
The angle of torsion is shown between the neck and shaft of the femur
A, normal anteversion; B, excessive anteversion; and C, retroversion. The pair of red dots in each figure indicates the different alignments of the hip joint surfaces. Optimal alignment is shown in A.
Excessive Anteroversion of the proximal femur
A, Offset red dots indicate malalignment of the hip while standing in the anatomic position. B, As evident by the alignment of the red dots, standing with the hip internally rotated (“in toeing”) improves the joint congruity.