Final answer:
The correct origin of the obturator externus is from the margins of the obturator foramen and not the ischial tuberosity. The correct insertion is on the greater trochanter of the femur, not the lateral epicondyle.
Step-by-step explanation:
The obturator externus is a muscle located in the hip region. Its origin is from the outer surfaces of the obturator membrane, pubic bone, and ischium, particularly the margins of the obturator foramen. As for the insertion of the obturator externus, it is not the gluteal tuberosity of the femur, the iliotibial tract, nor the lateral epicondyle of the femur. The insertion is on the greater trochanter of the femur. This muscle is involved in the lateral rotation of the thigh at the hip joint and aids in stabilizing the hip joint.
The options provided to answer the question can be evaluated as follows:
a) The origin of the obturator externus is the ischial tuberosity. - This statement is incorrect because the ischial tuberosity is not the site of origin for this muscle. The muscle originates from the margins of the obturator foramen.
b) The insertion of the obturator externus is the greater trochanter of the femur. - This statement is correct.
c) The origin of the obturator externus is the anterior superior iliac spine. - This statement is incorrect because the anterior superior iliac spine is not the origin point for the obturator externus.
d) The insertion of the obturator externus is the lateral epicondyle of the femur. - This statement is incorrect as the insertion of the obturator externus is the greater trochanter, not the lateral epicondyle.