2024-04-182024-04-182024-03-21https://hdl.handle.net/20.500.12503/32793This case report describes an atypical deltoid variant discovered during cadaveric dissection of a middle-aged male donor. The bilateral spinal segments of the deltoid muscle (DM) were found to be encased in a distinctive fascial compartment, disconjugate from the normal morphology. The spinal segments were found to be innervated by a branch of the axillary nerve and perfused by a branch of the posterior circumflex humeral artery. Divergences from expected anatomy are important clinically in respect to surgical interventions, as correctly identifying in situ anatomy is essential for the accurate diagnosis and treatment of shoulder pathologies. Unexpected anatomical variations can cause unanticipated surgical delays, and the misidentification of in situ anatomy can be a cause for iatrogenic injury –both of which can increase the probability of unfavorable outcomes in the care of the surgical patient.enposter