A football offensive lineman takes his three-point stance. The base of support (BOS) includes 1 upper extremity (hand placed on ground) and both lower extremities with his right elbow in 30 ° of flexion

Which of the following would best resist a valgus stress applied to the humeroulnar joint
a. Lateral collateral ligament
b. Anterior medial collateral ligament
c. Lateral ulnar collateral ligament
d. Posterior medial collateral ligament

ANS: B
The lateral collateral ligaments primarily resist varus force; therefore, that would not be a suitable answer. Both the anterior medial collateral ligament and posterior collateral ligament resist valgus stress; however, the posterior medial collateral ligament is a better resistor of valgus stresses after 55 ° of flexion.