Hip motion is dependent on

• A. The position of the joints above and below it (due to the many two-joint muscles attached to it) and the lumbar spine position
• B. The position of the knee
• C. The strength of the neck muscles
• D. The length of the fibula

Answer: (A)

Hip motion is governed by how the joints connected to the hip are aligned, especially the joints of the trunk. The muscles that cross the hip often span two joints, so the position of joints above the hip—like the pelvis and lumbar spine—and the angle of the lumbar spine itself determine how those muscles lengthen or shorten. That pelvic tilt driven by the lumbar spine changes the orientation of the hip socket and the tension in hip flexors and extensors, which in turn sets how far the hip can move in a given direction. Because many hip muscles cross both the hip and another joint, the knee position also affects their length and how smoothly the hip can move, but the dominant influence described here is the state of the joints above the hip and the lumbar spine. Other factors like neck muscle strength or fibula length don’t typically limit hip range in standard movements.