Which term is part of the right side structures in the anatomy provided?

The radial collateral ligament is a significant structure associated with the anatomy of the right side, particularly in the context of the elbow joint. This ligament connects the lateral epicondyle of the humerus to the annular ligament of the radius, contributing to the joint’s stability during movement. Understanding its role is crucial for comprehending the biomechanics of the elbow and its relevance in various motions and injuries associated with this area.

In contrast, other terms provided have different anatomical associations. The medial collateral ligament is found on the inner side of the knee joint and is not part of the right-side structures of the elbow. The sartorius muscle, while important in the context of the thigh and hip flexion, is not directly related to the right side structures of the elbow or wrist. The fibularis longus muscle primarily functions within the context of the lower leg and ankle, making it irrelevant to the discussion surrounding the right side structures of the upper extremity.

Thus, the radial collateral ligament's connection to the elbow and its function in providing lateral stability makes it the appropriate answer in this scenario.