According to Weisl (1955), the first medical practitioners to express an interest in the pelvic girdle were Hippocrates (460-377BCE), Vesalius (1543CE) and Pare (1643CE). Research over the last 50 years has revealed significant information pertaining to the anatomy and function of the pelvic girdle.
Henry Gray (1918) Anatomy of the Human Body. Bartleby.com: Gray's Anatomy, Plate 319. Image sourced from Wikimedia Commons. Available here.