Home » Health & Wellness » Orthopedics » Anatomic-physiological peculiarities of the lower extremities

Anatomic-physiological peculiarities of the lower extremities

© Mikhail Yegorov, Alexander Barinov

This article continues the articles circle about the orthopedic cosmetology. The basic role of the human lower extremities is providing for support and spatial transference of the body, which is achieved by the functional unity of all elements. Besides, the legs perform the static function stabilizing the body, and also they can shorten and lengthen the longitudinal axis of the body and turn it around in different directions. All this is possible only with lower extremities normally developed. In the process of growth and development of the organism, their form changes.

According to a number of researchers, a baby is born with an insignificant varus deformity of the lower extremities (genu varum), which, by the age of 2-4 years old, is transformed into physiological valgus curving of the knee. Some researchers observations demonstrated that the valgus position of the knee is quite clearly manifested by the first year of life, and it increases up to the age of 10. Value of the physiological valgus with adults ranges between 0 - 14 degrees.

Physiological valgus of the knee is associated with the adduction of the femur inside. The adduction of the femur inside is caused by the physiological lateroposition of the quadriceps femoris which performs not only the function of straightening in the knee joint, but, to some extent, abduction, as well. Despite the fact that the distal section of the femur is brought to the middle line of the body, the chink of the knee joint is horizontally oriented. It is conditioned by a great standing out of the medial condyle downwards, in comparison with the lateral one.

The skeleton of the lower limb is represented by the foot bones and by the femur, tibia and fibula. The distal metaepiphysis of the femur and the proximal metaepiphysis of the tibia consist of many systems of osseous trabeculae crossing each other at right angles and situated perpendicularly to the joint surface. The mentioned areas are propitious spots for performing corrective osteotomies, for the costeous bone is easy to cross with a osteotom, and a large contact area of fragments provides for their post-operational stability. The line connecting the center of the hip joint to the center of the ankle joint makes the mechanical axis of the lower limb. Normally, it is projected onto the center of the knee joint, the static load being evenly distributed over the whole joint surface of the tibia. The lines drawn through the centers of the femur and the tibia correspondingly make up the anatomical axes of the femur and shin. The mechanical axis coincides with the anatomical axis of the shin and forms an angle of 7-8 degrees with the anatomical axis of the femur (fig.1; A - anatomical axis, B - mechanical axis).

The copyright of the article Anatomic-physiological peculiarities of the lower extremities in Orthopedics is owned by Mikhail Yegorov, Alexander Barinov. Permission to republish Anatomic-physiological peculiarities of the lower extremities in print or online must be granted by the author in writing.