The abdominal mass in pyloric stenosis in a new born child can be best palpated:

Ref. Sabiston Textbook of Surgery. Pg. 1869   Background Hypertrophy of the pyloric sphincter causes narrowing of the gastric outlet Most common cause of gastric obstruction in patients 2-12 weeks old Risk factors include male (4:1); firstborn (2:1); white/caucasian; term infants; bottle-fed babies Presentation Usually present around 3-6 weeks with a history of progressively worsening non-billious vomiting (may be projectile) Associated with poor weight gain, decreased urine output (fewer wet nappies) and stools, excessive hunger, dry mucous membranes and depressed fontanelle Examination of the abdomen may reveal an epigastric ‘olive-shaped’ mass Management Fluid resuscitation- correct any electrolyte disturbance (particularly hypokalaemia) prior to surgery Nil by mouth and nasogastric drainage or suction prior to surgery and between feeds Surgery – Pyloromyotomy