Final answer:
The angle of torsion is the relationship between the femoral head and the femoral shaft in the transverse plane, affecting the alignment of the knee and hip joints.
Step-by-step explanation:
The relationship between the femoral head and the femoral shaft in the transverse plane is known as the angle of torsion. This angle represents the amount of twist between the proximal end (with the femoral head) and the distal end of the femur, which impacts the alignment of the knee and hip joints, as well as the overall biomechanics of the lower limb. An abnormal angle of torsion can lead to conditions such as femoral anteversion or retroversion, affecting an individual's gait and leading to hip or knee pain. Understanding the angle of torsion is crucial for professionals involved in diagnosing and treating musculoskeletal conditions.