Gerdy's tubercle is a smooth facet on the lateral aspect of the upper part of the tibia, just below the knee joint and adjacent to the tibio-fibular joint, where the iliotibial tract runs down the outside part of the thigh.
It is used as a site for the insertion of a periosteal needle by which intramedullary fluids may be infused in neonates. It can be fractured along with the tibial tuberosity.
^Yoo JH, Hahn SH, Yang BK et al. (June 2007). "An en bloc avulsion fracture of tibial tuberosity and Gerdy's tubercle in an adolescent basketball player: a case report". Knee Surg Sports Traumatol Arthrosc15 (6): 781–5. doi:10.1007/s00167-006-0213-8. PMID17024477.CS1 maint: Explicit use of et al. (link)