Final answer:
A patient lying on their back for an abdominal examination is in the supine position, which allows healthcare providers to effectively examine the abdominal regions and quadrants.
Step-by-step explanation:
A patient lying on his or her back for an abdominal examination is in the supine position. When a patient is supine, their upper limbs, including palms, may be touching their sides and lower limbs touching at sides, which is conducive to an abdominal exam. Healthcare providers utilize this position to effectively communicate and examine regions and quadrants of the abdomen, crucial for identifying issues such as abdominal pain or masses.