WBR0419

{{WBRQuestion |QuestionAuthor=Rim Halaby, M.D. [1] |ExamType=USMLE Step 1 |MainCategory=Embryology |SubCategory=Renal |MainCategory=Embryology |SubCategory=Renal |MainCategory=Embryology |SubCategory=Renal |MainCategory=Embryology |MainCategory=Embryology |SubCategory=Renal |MainCategory=Embryology |SubCategory=Renal |MainCategory=Embryology |SubCategory=Renal |MainCategory=Embryology |SubCategory=Renal |MainCategory=Embryology |MainCategory=Embryology |SubCategory=Renal |Prompt=A 19 year old male patient presents to the emergency department with abdominal pain. Appropriate history and physical examination are conducted. Abdominal and pelvic computed tomography (CT) scans are ordered to investigate the cause of the patient’s complaint. Based on the CT scan, no etiology of the abdominal pain is determined. However, an incidental finding is documented as seen in the CT scan image shown below. Which artery is involved in this patient’s incidental finding?

[[Image: |Explanation=Horseshoe kidney is a congenital disorder caused by renal fusion of the central portion. As the fused kidney ascends during embryological development, the inferior mesenteric artery (IMA) stops its ascend and the kidney remains low in the abdomen. Horseshoe kidney is commonly an incidental finding. The kidney function is generally not impaired.

Educational Objective: Horseshoe kidney is a congenital disorder caused by fusion of the two kidneys. Patients with horseshoe kidney often have normal renal function. During development, the fused kidney fails to ascend to its normal location in the abdomen due to obstruction by the IMA. As a result, horseshoe kidney lies lows in the abdomen.

|AnswerA=Umbilical artery |AnswerAExp=Umbilical artery is not involved in horseshoe kidney. |AnswerB=Superior mesenteric artery (SMA) |AnswerBExp=The superior mesenteric artery (SMA) is not involved in horseshoe kidney. |AnswerC=Inferior mesenteric artery (IMA) |AnswerCExp=The inferior mesenteric artery (IMA) stops the ascend of the horseshoe kidney and the latter remains low in the abdomen. |AnswerD=Descending aorta |AnswerDExp=Descending aorta is not involved in horseshoe kidney. |AnswerE=Renal artery |AnswerEExp=Renal artery is not involved in horseshoe kidney. |RightAnswer=C |Approved=No }}