This patient has suffered an inferior shoulder dislocation (luxatio erecta). This is a rare type of shoulder dislocation, representing only about 0.5% of all shoulder dislocations. Anterior and posterior dislocations are much more common but don't present with a shoulder fixed in abduction or flexion such as this case. The cited articles by Seweckee and Fung report that this condition can be diagnosed by physical exam alone due to its unique presentation, but radiographs should be obtained to evaluate for concomitant injuries.
Since Pubmed does not have abstracts on these articles, the Fung article can be accessed at www.amjorthopedics.com/pdfs/037050097e.pdf
Sewecke JJ, Varitimidis SE. Bilateral luxatio erecta: a case report and review of the literature. Am J Orthop. 2006 Dec;35(12):578-80.
PMID:17243409 (Link to Abstract)
Wirth MA, Rockwood CA Jr: Subluxations and dislocations about the glenohumeral joint, in Bucholz RW, Heckman JD (eds): Rockwood and Green’s Fractures in Adults, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 1109-1207
Fung DA, Menkowitz M, Chern K. Asymmetric bilateral shoulder dislocation involving a luxatio erecta dislocation. Am J Orthop. 2008 May;37(5):E97-8.
PMID:18587510 (Link to Abstract)