Final answer:
The brachial artery is used to obtain a blood pressure reading in adults, as it is easily accessible for the placement of a blood pressure cuff and provides accurate measurements of central blood pressure.
Step-by-step explanation:
In an adult patient, the brachial artery is commonly used to obtain a blood pressure reading. This is due to its accessibility and the convenience it provides when using a blood pressure cuff, also known as a sphygmomanometer.
A mercury manometer or another type of blood pressure measuring device is attached to an inflatable cuff, which is then placed around the upper arm at the level of the heart. The cuff is inflated until the pressure it exerts exceeds the blood pressure in the brachial artery, effectively occluding blood flow. As air is slowly released from the cuff, the clinician listens with a stethoscope for the sounds of blood flow resuming. The point at which the sounds are first heard is recorded as the systolic pressure, and when the sounds become continuous, this is noted as the diastolic pressure. A pulse can also be manually palpated at the radial artery in the wrist or the carotid artery in the neck, but these are not typically used for blood pressure measurement due to various risks and practicality issues.
The brachial artery is preferred because it has a consistent location, it is near the surface of the arm, and its pulse can be readily palpitated or auscultated. Additionally, using the brachial artery aligns the cuff at heart level, providing a more accurate reflection of central blood pressure.