The pulse is the measurable wave of pressure traveling through the arteries following each heartbeat, caused by blood being forcefully ejected from the heart. While a pulse can be felt at various points on the body, the carotid pulse is recognized as one of the most reliable and accessible sites for quickly assessing heart function. Its strength and location make it particularly useful when a peripheral pulse, such as the one in the wrist, cannot be easily located.
Location and Physiological Role
The carotid arteries are major blood vessels running up both sides of the neck, serving the purpose of supplying oxygenated blood directly to the brain. Because these arteries originate near the heart, receiving blood flow with significant force, the pulse felt here is typically stronger and easier to palpate than in other areas.
Located near the split of the common carotid artery are two specialized structures: the carotid sinus and the carotid body. The carotid sinus acts as a baroreceptor, monitoring the mechanical stretch of the artery wall caused by blood pressure. If pressure is sensed as too high, the sinus triggers a reflex response to help lower blood pressure and heart rate.
The adjacent carotid body functions as a chemoreceptor, constantly sampling the chemical composition of the blood flowing to the brain. This cluster of cells is highly sensitive to changes in oxygen, carbon dioxide, and the blood’s acidity (pH). When it detects imbalances, it signals the brainstem to adjust the respiratory rate. Applying undue pressure to this area can inadvertently trigger these reflexes.
Safe Technique for Checking the Carotid Pulse
To safely check the carotid pulse, first locate the correct position on one side of the neck. Begin by finding the Adam’s apple or the cricoid cartilage in the center of the throat. From that midline point, slide the pads of your index and middle fingers laterally into the soft groove between the windpipe and the large, rope-like muscle running vertically up the side of the neck, known as the sternocleidomastoid.
Use only the pads of two fingers for palpation, avoiding the thumb, which has its own strong pulse that can be confused with the one being measured. Apply the lightest pressure possible, only enough to feel the distinct, rhythmic beat against your fingertips. Excessive force can compress the artery, making the pulse undetectable, or, more dangerously, stimulate the carotid sinus. Stimulating the sinus can cause a reflex slowing of the heart rate and a drop in blood pressure, potentially leading to dizziness or fainting.
A fundamental safety rule is to never press on both carotid arteries at the same time. Compressing both sides simultaneously can significantly reduce or cut off the blood supply to the brain, which can cause fainting or serious neurological harm. Once the pulse is located, maintain light pressure and count the beats for a minimum of thirty seconds to accurately assess the rate and rhythm.
Understanding Pulse Rate and Rhythm
The number of beats counted over a specific period is translated into a standard measurement known as Beats Per Minute (BPM). If you count the beats for 30 seconds, you simply multiply that number by two to determine the full minute’s rate. In healthy adults at rest, the typical heart rate range is between 60 and 100 BPM. Highly physically fit individuals, such as endurance athletes, may naturally have a lower resting rate, sometimes dipping into the 40s, due to the efficiency of their heart muscle.
A resting rate consistently exceeding 100 BPM is known as tachycardia (a fast heart rate). Conversely, a resting rate below 60 BPM is referred to as bradycardia (a slow heart rate). While both conditions can be normal responses to factors like exercise or sleep, they may also indicate underlying health concerns if they occur without a clear cause.
Beyond the rate, the carotid pulse allows for an assessment of rhythm, which refers to the pattern of the beats. A normal rhythm is regular, with consistent time intervals between each beat. An irregular pulse, or arrhythmia, is characterized by variation in the spacing or strength of the beats. Detecting an irregular rhythm may signal a disturbance in the heart’s electrical system that warrants further medical evaluation.