Rarely does anterior dislocation of the shoulder, which represents about 45% of all dislocations, cause vascular lesions; actually, there have been very few cases described in literature. The diagnosis in often delayed due to the bone and muscle structure in the chest and shoulder which tends to disguise the signs of lesion; an efficient collateral circulation will help maintain a normal radial pulse. The inconsistent and unpredictable behavior of false aneurysms can lead to sudden and severe hemorrhaging, to slowly developing anemia, or remaining hidden for weeks, even month before manifesting themselves in the form of pulsating hematomas. Furthermore, these factors render difficulties in compiling a standard protocol for diagnosis and thus potentially create serious consequences for patient. The authors detail a clinical case of pseudoaneurysm involving the axillary artery resulting from an anterior dislocation of the shoulder. The authors also research eventual risk factors, investigate diagnostic difficulties an considering the high frequency of this form of dislocation, the possibility of resulting vascular lesion and consequences associated from late or misdiagnosis.