The Parents of a 6-Week-Old Boy Come to the Clinic

The parents of a 6-week-old boy come to the clinic for evaluation because the infant has been vomiting. The parents report that the vomiting has been increasing in frequency and forcefulness over the last week. The mother says, "Sometimes, it seems like it just bursts out of his mouth." A diagnosis of hypertrophic pyloric stenosis is suspected. When performing the physical examination, which of the following would the nurse most likely find?

A) Sausage-shaped mass in the upper midabdomen
B) Hard, moveable, olive-shaped mass in the right upper quadrant
C) Tenderness over the McBurney point in the right lower quadrant
D) Abdominal pain in the epigastric or umbilical region