The brachial pulse is the rhythmic expansion and recoil of the brachial artery, a major blood vessel supplying blood to the arm and forearm. This palpable beat provides direct information about the heart rate and the efficiency of blood circulation in the upper extremity. While the pulse is often checked at the wrist, the brachial site holds specific significance in both emergency and routine medical assessments. Learning how to locate and assess this pulse is foundational for understanding the body’s vascular status.
Anatomical Landmarks for Location
The brachial artery runs along the inner side of the upper arm, nestled between the biceps and triceps muscles. To locate the pulse, focus on the antecubital fossa, the shallow triangular area at the front of the elbow (the elbow crease). The artery is situated on the medial side of the arm, running down toward the elbow.
To pinpoint the location, identify the prominent tendon of the biceps muscle as it crosses the elbow crease. The pulse is found just above the crease, one to two inches up the arm, positioned slightly inward (medially) from the biceps tendon. Compression against the underlying humerus bone makes the pulse easier to feel.
Proper Technique for Assessment
To begin the assessment, the arm should be extended slightly and supported, with the palm facing upward, ensuring the muscles are relaxed. Use the pads of the index and middle fingers, placing them gently on the inner arm just above the elbow crease. Avoid using the thumb, as it possesses its own detectable pulse, which can lead to an inaccurate reading.
Apply firm but gentle pressure until a steady, rhythmic pulsation is felt. The brachial artery lies deeper than the radial artery at the wrist, so slightly more pressure may be necessary. Count the number of beats for 15 or 30 seconds. Multiplying the 15-second count by four, or the 30-second count by two, yields the estimated heart rate in beats per minute.
If the pulse rhythm is irregular, count the beats for a full 60 seconds to capture the variation. Consistent pressure must be maintained throughout the count to avoid obstructing blood flow. If the pulse is weak or difficult to find, repositioning the fingers slightly along the inner arm may help locate the strongest point of the beat.
Primary Medical Uses
The brachial pulse is the standard site for checking circulation in infants under one year of age during emergency situations, such as Cardiopulmonary Resuscitation (CPR). In babies, the carotid and radial pulses are often too small or difficult to access quickly. Placing two or three fingers on the inner upper arm is the preferred method for assessing an infant’s pulse for five to ten seconds.
The brachial artery is also fundamental in the accurate measurement of blood pressure, especially when using a manual cuff and a stethoscope. The cuff is placed around the upper arm, and the stethoscope is positioned directly over the artery at the elbow crease. The sounds heard as the cuff deflates—known as Korotkoff sounds—are the result of blood flow turbulence within the brachial artery.
The first sound heard indicates the systolic pressure, which is the maximum pressure exerted when the heart contracts. The last sound heard before silence indicates the diastolic pressure, which is the minimum pressure when the heart is relaxed. The brachial artery serves as the precise point of auscultation (listening) that allows for the determination of both the upper and lower blood pressure readings.