The posterior tibial pulse serves as a direct indicator of the circulatory status in the lower extremities, reflecting the flow of blood to the foot. This pulse is one of the main peripheral pulses healthcare professionals check to assess overall vascular health. Accurately locating and palpating this pulse requires a precise understanding of the anatomy of the ankle area and is foundational to evaluating foot perfusion.
Precise Anatomical Location
The posterior tibial artery courses just behind and inferior to the prominent bony knob on the inner side of the ankle, known as the medial malleolus. The artery runs in a protective groove situated between this malleolus and the calcaneal tendon (Achilles tendon). This location is often described as being midway between the posterior edge of the medial malleolus and the heel point.
The artery follows a path approximately two to three centimeters superior to the heel bone, traveling deep to the flexor retinaculum within the tarsal tunnel. Pressing in this specific area allows the artery to be compressed against the underlying tibia bone, making the pulsation perceptible.
Proper Palpation Technique
To successfully locate the pulse, the patient should be positioned comfortably, ideally lying down with the foot slightly relaxed. This relaxation reduces tension in the soft tissues around the ankle, improving the ease of palpation. The examiner should use the pads of their index and middle fingers to search for the pulse, as the thumb has its own strong pulse that can be misleading.
The fingers should be placed in the depression just behind and slightly below the medial malleolus, in the space between the bony prominence and the Achilles tendon. Apply light but firm pressure, directing the force toward the tibia bone, which acts as a firm surface to compress the artery against. Applying too much pressure will compress and flatten the artery, which can obliterate the pulse and make it undetectable.
If the pulse is faint or difficult to locate, slight adjustments in the foot’s position may help, such as gently repositioning the foot into a slightly dorsiflexed or plantar-flexed position. Once found, the pulse should be assessed for its rate, rhythm, and strength, typically graded on a scale where 2+ indicates a normal pulse. Compare the strength and rhythm of the pulse to the same location on the opposite ankle to assess symmetry in blood flow.
Clinical Significance of Assessment
The assessment of the posterior tibial pulse provides immediate, non-invasive feedback about the blood flow reaching the foot. A normal, easily palpable pulse suggests that the major arteries supplying the lower leg are open and functioning well. This pulse is a fundamental component of the peripheral vascular examination, especially for individuals with risk factors like diabetes or a history of cardiovascular disease.
A pulse that is significantly weakened, often described as “thready,” or completely absent, can be a sign that blood flow to the lower limb is compromised. This finding is a common indicator of peripheral arterial disease (PAD), where plaque buildup narrows the arteries and reduces circulation. When a pulse is diminished, it suggests arterial insufficiency that requires further evaluation to prevent complications like limb ischemia.
The posterior tibial pulse is often assessed alongside the dorsalis pedis pulse to confirm the overall status of pedal circulation. While a diminished pulse is highly suggestive of a circulatory problem, a small percentage of healthy individuals may naturally have a non-palpable posterior tibial artery. Therefore, an absent pulse must be considered within the context of the patient’s overall symptoms and other findings, such as skin temperature or color changes.