Posterior shoulder instability

Posterior shoulder instability was first described by Sir Ashley Cooper in 1839 1 Cooper A. On the dislocations of the os humeri upon the dorsum scapulae and upon fractures near the shoulder joint. Guys Hosp Rep. 1839; 4: 265-284 Google Scholar in patients with epileptic seizures. In 1855, Malgaigne 2 Malgaigne J.F. Traite des fractures et des luxations. JB Balliere, Paris1855 Google Scholar described until recently the largest series of patients with posterior instability. He discussed 37 patients with this condition, all before the advent of radiography.