Subacute traumatic arterial pseudoaneurysms involving the infragenicular arteries are rarely discussed in the literature because they tend to be asymptomatic or manifest clinically subtle symptoms even at late stages. We describe the case of a 25-year-old patient with a perforation injury to the lower limb from a shard of glass, who, after two weeks, developed pain and swelling in the limb, which suggested deep vein thrombosis. Venous Doppler ultrasound ruled out thrombosis but revealed heterogeneous echogenicity in the anterior wall of the middle third of the anterior tibial artery with internal flow, suggesting a pseudoaneurysm. We opted for conventional surgical treatment and, after proximal and distal control of the artery, drainage of the local hematoma and primary suturing of the lesion were performed. Pseudoaneurysm of the infrapatellar arteries, although rare, is a challenging clinical entity that requires early diagnosis.