Final answer:
The oblique popliteal ligament is not considered an intrinsic ligament of the knee because it is an expansion of a muscle that reinforces the posterior capsule. The correct answer is fourth option.
Step-by-step explanation:
The question 'Which of the following would NOT be considered an Intrinsic ligament of the knee?' requires identifying which of the listed ligaments is not categorized as an intrinsic ligament. Intrinsic ligaments are those that are contained within the articular capsule of the joint.
The anterior cruciate and the posterior cruciate ligament are intracapsular ligaments, meaning they are within the joint capsule, and thus are considered intrinsic. On the contrary, the oblique popliteal ligament, while related to the knee joint capsule, is an expansion of the semimembranosus muscle and reinforces the posterior capsule but is not an intrinsic ligament. As such, the correct answer is the oblique popliteal ligament, which is not an intrinsic ligament of the knee.