The hip is often compared with the shoulder in that it is a triaxial joint, able to function in all three planes, and also the proximal link to its extremity. In contrast to the shoulder, which is designed for mobility, the hip is a stable joint, constructed for weight bearing. To carry out activities of daily living (ADL) in what is considered a "normal" manner, however, at least 120° of hip flexion and 20° each of abduction and external rotation are necessary.110 Forces from the lower extremities are transmitted upward through the hips to the pelvis and trunk during gait and other lower extremity activities. Conversely, the hips support the weight of the head, trunk, and upper extremities, and therefore, the function of the lumbopelvic and hip muscles influences the mechanics and function of the entire lower extremity.
This chapter is divided into three major sections. The first section briefly reviews highlights of the anatomy and function of the hip and its relation to the pelvis, lumbar spine, and knee. The second section then describes common disorders of the hip and provides guidelines for conservative and postoperative management, expanding on the information and principles of management presented in Chapters 10 through 13. The reader should be familiar with that material as well as the components of a comprehensive examination of the hip and pelvis before determining a diagnosis and establishing a therapeutic exercise program. The third section describes exercise interventions commonly used to meet the goals of treatment for the hip region.
Structure and Function of the Hip
The pelvic girdle links the lower extremity to the trunk and plays a significant role in the function of the hip as well as the spinal joints. The proximal femur and the pelvis comprise the hip joint (Fig. 20.1). The unique characteristics of the pelvis and femur that affect hip function are reviewed in this section. The function of the pelvis with respect to spinal mechanics is described in greater detail in Chapter 14.
Bones and joints of the pelvis and hip.
Anatomical Characteristics of the Hip Region
The structure of the pelvis and femur are designed for weight bearing and transmitting forces through the hip joint.
Each innominate bone of the pelvis is formed by the union of the ilium, ischium, and pubic bones and therefore, is a structural unit. The right and left innominate bones articulate anteriorly with each other at the pubic symphysis and posteriorly with the sacrum at the sacroiliac joints.86 Slight motion occurs at these three joints to attenuate forces as they are transmitted through the pelvic region, but the pelvis basically functions ...