A resident who is lying flat on his back with his head and shoulders supported by a pillow is in the _________ position.

The resident described as lying flat on his back with his head and shoulders supported by a pillow is in the supine position. This position refers specifically to someone who is on their back, which is the defining characteristic. The use of a pillow to support the head and shoulders may provide comfort and alignment but does not change the classification of the position as supine.

Understanding the differences in positional terminology is important in nursing care, as each position has specific implications for patient comfort, safety, and medical needs. The supine position is frequently used for various medical examinations and treatments, and it allows for easy access to the front of the body.