What is the name of the position where a client is lying on one side at a 45-degree angle to the mattress?

The position described, where a client is lying on one side at a 45-degree angle to the mattress, is known as Sims' position. This position is commonly used in various healthcare settings for procedures such as administering enemas or during examinations due to its ability to provide access to different areas of the body while also maintaining comfort for the patient.

In Sims' position, the client typically lies on their left side with the left arm extended behind them and the right knee bent and brought forward. This unique arrangement helps with drainage and can facilitate better access for healthcare providers while ensuring that the patient is supported and stable. The emphasis on a 45-degree angle differentiates it from other lateral positions, as traditional lateral positioning may have the individual fully on their side without that specific angle.

Other options listed do not appropriately match the description. The lateral position typically describes a general side-lying position without specifying the 45-degree angle or the additional leg positioning characteristic of Sims' position. Fowler's position refers to a seating arrangement where the person is sitting at an angle, usually greater than 45 degrees, supporting activities like eating or breathing. The sitting position simply describes someone who is upright and does not pertain to the side-lying orientation described.