Knowledge · Clinical Examination

Peripheral Vascular Examination for MRCS Part B: Pulses, ABPI and Buerger's Test

By Dr Richard Miller, MBChB FRCS with the MRCS Part B Questions Team · Reviewed 15 September 2026

In brief

Examine both legs together: inspect for tissue loss and colour change, assess temperature, capillary refill and sensation, palpate every pulse from the aorta down, then perform Buerger's test and measure the ABPI.

The peripheral vascular examination compares both legs at once. Inspect for tissue loss, ulceration and colour change, assess temperature, capillary refill and sensation, palpate the aorta, femoral, popliteal, posterior tibial and dorsalis pedis pulses, then perform Buerger's test and measure the ankle brachial pressure index.

Key takeaways

Expose both legs and the abdomen, and compare side with side at every step.
NICE CG147 recommendation 1.3.2 lists examining the femoral, popliteal and foot pulses and measuring the ABPI as the assessment of suspected peripheral arterial disease.
CG147 calculates the index by dividing the highest ankle pressure by the highest arm pressure, using a Doppler probe in preference to an automated system.
CG147 also warns not to exclude peripheral arterial disease in a person with diabetes on the basis of a normal or raised ABPI alone.
In Buerger's test, the poorer the arterial supply, the smaller the angle at which the raised leg turns pale.

How is this station marked in MRCS Part B?

A physical examination station is marked out of 20 across four domains: clinical and technical skill carries 8 marks, and clinical knowledge and its application, communication, and professionalism carry 4 marks each. The examiner also gives the station a separate global rating of pass, borderline or fail.

Two things follow from that split. More than half the marks sit outside your knowledge of the condition, so a silent, technically correct examination scores poorly. And you are signalled at six minutes of the nine to present your findings, so the sequence has to finish inside six.

How do I start the peripheral vascular examination?

Gel your hands, introduce yourself, gain consent and ask about pain, particularly rest pain in the foot at night. Lie the patient flat with both legs exposed from the groin down and the abdomen accessible.

Look around the bay for the equipment the station expects you to use: a hand-held Doppler, ultrasound gel and a blood pressure cuff.

What am I looking for on inspection?

Tissue loss: ulcers, gangrene, amputated toes and pressure areas, including between the toes and on the heel.
Colour: pallor, cyanosis, or the dusky rubor of a dependent ischaemic foot.
Trophic change: hair loss, shiny atrophic skin, thickened nails and muscle wasting.
Scars: a long saphenous vein harvest scar, groin incisions and previous bypass scars.
Arterial ulcers are typically on the tips of the toes, the heel or over the lateral malleolus, with a punched out edge and a deep pale base.

What do I assess on palpation?

Compare the two limbs at every point, working from proximal to distal.

Temperature with the back of your hand, working up the leg until it becomes warm.
Capillary refill time in the pulp of the great toe.
Sensation and movement, because sensory and motor loss mark the threatened limb in acute ischaemia.
Abdominal aorta above the umbilicus, feeling for expansile pulsation.
Femoral pulse at the mid-inguinal point, then popliteal with both hands behind the flexed knee.
Posterior tibial behind the medial malleolus and dorsalis pedis between the first and second metatarsals.

Say that you would also check for radiofemoral delay and auscultate for femoral and aortic bruits.

What is Buerger's test and what does it show?

**Buerger's test** assesses the adequacy of the arterial supply to the leg by raising it until it turns pale, then letting it hang down. With the patient supine, raise both legs to about 45 degrees and hold them for one to two minutes, watching the colour of the soles.

GPnotebook describes the interpretation: the poorer the arterial supply, the less the angle to which the legs must be raised before they become pale. Then sit the patient up and hang the legs over the edge of the bed.

On dependency the ischaemic foot first becomes blue, as blood is deoxygenated passing through ischaemic tissue, and then red, from reactive hyperaemia due to post-hypoxic vasodilatation. A normal leg simply returns to its usual colour.

How is the ABPI measured?

The **ankle brachial pressure index** is the ratio of the highest ankle systolic pressure to the highest arm systolic pressure in that person. NICE CG147 recommendation 1.3.3 sets out the method.

The person should be resting and supine if possible.
Record the systolic pressure with an appropriately sized cuff in both arms.
Record it in the posterior tibial, dorsalis pedis and, where possible, peroneal arteries.
Take the measurements manually with a Doppler probe of suitable frequency, in preference to an automated system.
Document the nature of the Doppler signals in the foot arteries.
Divide the highest ankle pressure by the highest arm pressure for each leg.

Stanford Medicine 25 gives the interpretation used at the bedside: a normal index is about 1.0 to 1.4, a value below 0.9 is diagnostic of peripheral arterial disease, a value below 0.5 suggests severe disease, and a value above 1.4 suggests a non-compressible calcified vessel.

How do I complete the examination and present?

Say that you would complete the assessment with a full cardiovascular examination, a check for atrial fibrillation, blood pressure, blood glucose and lipids, and duplex ultrasound of the arterial tree.

Present the limb as a whole: whether it is acutely or chronically ischaemic, which pulses are present, the ABPI, and whether the limb is threatened.

What are the most common mistakes at this station?

Examining one leg only, so there is nothing to compare against.
Palpating the dorsalis pedis with a thumb, so the candidate's own pulse is felt.
Skipping Buerger's test because it takes a minute of standing still.
Quoting an ABPI band without being able to say how the index is calculated.
Excluding arterial disease on a normal ABPI in a diabetic patient, which CG147 explicitly warns against.
Forgetting sensation and movement, which are what separate a threatened limb from a stable one.

MRCS Part B Questions has a peripheral arterial examination station with a marked checklist at /Sample-Questions. Reviewed and updated 15 September 2026.

Key evidence

Peripheral arterial disease: diagnosis and management (CG147), recommendations — NICE (2020)
Ankle Brachial Index — Stanford Medicine 25
Buerger's test — GPnotebook

FAQ

What is Buerger's test?

It is a two-part bedside test of arterial sufficiency in the leg. The leg is raised until the sole turns pale, which happens at a smaller angle the worse the arterial supply, and is then hung down over the edge of the bed. An ischaemic foot turns blue and then red as reactive hyperaemia follows the period of hypoxia.

Why does the foot turn red when it hangs down?

Because the arterioles in the ischaemic tissue have dilated in response to the accumulated metabolic products of hypoxia. When the leg becomes dependent and blood returns, it flows through those dilated vessels and produces the deep red flush of reactive hyperaemia, often described as a sunset foot.

Can I trust the ABPI in a patient with diabetes?

Not on its own. NICE CG147 recommendation 1.3.4 says not to exclude a diagnosis of peripheral arterial disease in people with diabetes on the basis of a normal or raised ankle brachial pressure index alone, because arterial calcification makes the vessels incompressible. Recommendation 1.3.5 also says not to use pulse oximetry to diagnose it in diabetes.

Which pulse should I use for the ABPI?

Record the pressure at the posterior tibial, dorsalis pedis and where possible the peroneal artery, then use the highest of those ankle pressures as the numerator. The denominator is the higher of the two brachial pressures, not an average, and the whole measurement should be taken manually with a Doppler probe.

How do I recognise an acutely ischaemic limb?

By the six Ps: pain, pallor, pulselessness, perishing cold, paraesthesia and paralysis. The last two matter most, because sensory and motor loss indicate a threatened limb that needs immediate vascular assessment rather than an outpatient duplex scan.

The MRCS Part B Questions Team

Written and maintained by doctors who have sat and scored well at this interview, and reviewed against the current published guideline in each case. Guidance changes — check the source before you rely on a threshold.

Last reviewed 15 September 2026

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