Hip Anatomy and Movement Quiz

• Hip Joint: 1. Degrees of movement for hip abduction, adduction, medial and lateral rotations. 2. Axis of motion and range of motion (ROM) for hip rotations. 3. Flexor muscles of the hip, their location, and functions: produce flexion, abduction, and medial rotation. 4. Extensor muscles of the hip, their location, and functions: inserted into the femur or the vicinity of the knee joint. 5. Abductor muscles of the hip, their location, and functions: generally lie lateral to the sagittal plane. 6. Adductor muscles of the hip, their location, and functions: generally lie medial to the sagittal plane. 7. Rotator muscles of the hip, their functions: lateral rotators and medial rotators.
• Knee Joint: 1. A complex, synovial modified hinge joint with three bones, two degrees of freedom (DOF), and three articulating surfaces. 2. Functions: withstands large forces, provides great stability, and enables a large ROM. 3. The knee joint capsule comprises passive and active connections among the menisci, ligaments, retinacula, bones, muscles, and the capsule itself. 4. The articular surfaces of the femur and tibia, their functions, and modifications for axial rotation. 5. The complex nature of the knee joint capsule, including the proximal tendon of the popliteus muscle, semimembranosus muscle, oblique popliteal ligament, and arcuate popliteal ligament. 6. The role of collateral ligaments in strengthening the articular capsule and providing transverse stability during extension.

 The head of the femur forms an angle of 10-30 degrees with the femoral plane (angle of anteversion).  Increased femoral anteversion can lead to in-toeing and genu valgum.  Acetabulum is a hemispherical cavity bounded by the acetabular rim, which is deeper and non-articular in the central part.  Acetabular labrum is a fibrocartilaginous ring inserted into the acetabular rim and deepens the acetabulum.  The strong ligamentum teres of the head of the femur arises from the acetabular notch and carries the vascular supply to the femoral head.  The hip joint capsule is a cylindrical sleeve running from the hip bone to the upper end of the femur, strengthened by powerful ligaments anteriorly and posteriorly.  The iliofemoral ligament is a Y-shaped ligament covering the hip joint anteriorly and superiorly, and the pubofemoral ligament is anterior and inferior, limiting lateral rotation and abduction.  The fibrous layer of the hip joint capsule consists of parallel fibers that link the two discs and become increasingly oblique when the femur rotates relative to the acetabulum, increasing the stability of the joint.  In standing, a horizontal axis is used for flexion and extension of the hip, with the common hip axis representing the line connecting the centers of the two femoral heads.  Active hip flexion with the knee extended is limited to 70-90 degrees, while passive hip flexion with the knee extended is less than 90 degrees due to hamstring stretching.  Hip abduction is 45 degrees and is usually accompanied by pelvis elevation, while hip adduction is 0 degrees but is possible up to 30-40 degrees with crossed legs in the standing position.