The pedal pulse represents the rhythmic expansion of arteries in the foot as the heart pumps blood through the body. Assessing this pulse is a non-invasive method used to gauge the adequacy of blood circulation in the lower extremities. Since the feet are the furthest point from the heart, the strength and presence of this pulse directly indicate overall circulatory health. A routine check of the pedal pulse provides valuable insight into a person’s peripheral vascular status.
Defining the Pedal Pulse and Its Locations
The pedal pulse refers to the palpable measurement of blood flow in two distinct arteries of the foot: the dorsalis pedis and the posterior tibial arteries. These two locations are the most distal points routinely checked in a vascular assessment. The presence of a palpable pulse at both sites suggests that blood is successfully reaching the end of the limb.
Dorsalis Pedis (DP) Pulse
The Dorsalis Pedis (DP) pulse is found on the top, or dorsum, of the foot. To locate it, one generally feels along the line between the first and second toes, just lateral to the extensor tendon of the great toe, near the ankle joint.
Posterior Tibial (PT) Pulse
The Posterior Tibial (PT) pulse is located on the inner side of the ankle, specifically behind and slightly below the medial malleolus. It lies within the groove between this bony prominence and the Achilles tendon. Assessing both the DP and PT pulses provides a comprehensive evaluation, as one artery may be congenitally absent in a small percentage of otherwise healthy individuals.
Technique for Locating and Assessing the Pulse
Proper assessment of the pedal pulse requires a light touch and specific positioning to ensure accuracy. The patient’s foot should be relaxed and supported, and any socks or coverings must be removed to fully expose the skin. The assessor should use the pads of the index and middle fingers, not the thumb, as the thumb contains its own strong pulse that can lead to misinterpretation.
Gentle pressure is applied to the skin over the artery site, gradually increasing pressure until a pulsation is felt or determined to be absent. Applying too much force can compress the artery and obliterate a faint pulse, making it falsely appear absent. Once located, the pulse is evaluated for its rate, rhythm, and strength.
The strength, or intensity, of the pulse is graded on a simple scale, which helps standardize the findings:
- 0: Absent or non-palpable.
- 1+: Diminished, weak, or thready.
- 2+: Normal, easily palpable, and not easily obliterated by pressure.
- 3+ (or 4+): Bounding, feeling stronger than normal.
What Changes in the Pedal Pulse Indicate
Variations from the normal 2+ pulse strength provide significant information about the circulatory system. A weak or absent pulse (graded 0 or 1+) is often the primary clinical sign of poor blood flow to the lower extremities. This finding strongly suggests the possibility of a blockage or narrowing in the arteries supplying the limb.
The most common underlying cause for a diminished pedal pulse is Peripheral Artery Disease (PAD), a condition where plaque buildup restricts blood flow in the peripheral arteries. Since the pedal arteries are the most distant from the heart, they are often the first to show reduced flow when blockages are present higher up the leg. An absent pulse is highly specific for detecting significant PAD, though a formal diagnosis often requires additional testing like the Ankle-Brachial Index (ABI).
Conversely, a bounding pulse (graded 3+) can indicate a state of high blood flow or a hyperdynamic circulation. This may be observed in conditions such as severe anemia, fluid overload, or certain types of shock where the heart is pumping forcefully. While less common than a diminished pulse, a bounding pulse still warrants investigation to determine the underlying systemic cause.
The assessment of peripheral circulation extends beyond just the pulse strength and includes observation of the surrounding tissues. If a pulse is weak, associated signs like a cool skin temperature in the foot or a delayed capillary refill time provide supporting evidence of reduced perfusion. Capillary refill is checked by pressing on the toenail and noting how quickly the color returns, with a sluggish return indicating poor microcirculation.
Regular monitoring of the pedal pulse is particularly important for individuals with risk factors such as diabetes, a history of smoking, or high blood pressure. In patients with diabetes, a diminished pedal pulse can be an early warning sign of vascular complications that may lead to non-healing wounds and tissue damage. The simple assessment of pedal pulses can therefore serve as an early marker for systemic vascular disease, indicating a need for more comprehensive diagnostic evaluation.