Begin the examination with a full cardiovascular (CVS) examination.

What else should you assess?

The examination should be performed in particular to detect cardiac arrhythmias or possible valve disease as a source of emboli.

What should you assess in the abdomen?

The abdomen should be assessed for evidence of an abdominal aortic aneurysm.

It is essential to fully examine both legs; the comparison between the normal and abnormal leg will often aid both diagnosis and determining probable aetiology.

Look at the colour of the leg – white suggests acute ischaemia (Fig 1). Fixed mottling of the leg is a poor prognostic sign and implies irreversible ischaemia (Fig 2).

Chronically ischaemic legs may appear pink or blue. Dry gangrene (black tissue) is also a late sign and consistent with chronic irreversible ischaemia (more than two weeks) (Fig 3).

Patients with classical emboli have a white leg (with a normal leg on the opposite side); in patients with thrombotic occlusions the signs may be more subtle since collaterals may have formed due to pre-existing peripheral arterial disease.

Look for scars of previous surgery. Surgery on the abdominal aorta may be via a midline or transverse incision. Patients who have had an endovascular abdominal aneurysm repair (EVAR) will only have scars on the groin. Do not forget behind the knee – patients who have had a popliteal aneurysm repair may have a vertical scar behind the knee.


Click on the images to enlarge.
When carrying out palpation check the following:


Always compare to the opposite leg. It may also be helpful to assess the temperature of other peripheries (hands) and check the core temperature.


It is particularly important to determine whether the patient has a palpable femoral pulse.


Is the limb tender? This again is a poor prognostic sign as it suggests muscle ischaemia.

Is there pain on passive movement? This suggests compartment syndrome and requires immediate vascular referral for urgent intervention.

Neurological function

Test sensory and motor function. Loss of sensation is common. Loss of motor function is a poor prognostic sign. Any neurological deficit suggests the need for emergency intervention.

A Doppler examination should be performed on all patients with suspected acute limb ischaemia. It is very important to compare the results of the Doppler examination with the opposite leg of the patient. The ankle-brachial pressure index (ABPI) can be measured to help assess the severity of ischaemia when Doppler signals are audible.

ABPI is the systolic pressure in the pedal arteries divided by the brachial artery pressure. A manual sphygmomanometer cuff is placed around the lower leg and inflated until there is no audible pedal Doppler signal. The cuff is then slowly deflated until the arterial Doppler signal is audible – this is the ankle pressure.

Brachial pressure

The brachial pressure must be measured in the same way:

  • Normal ABPIs range from 1.0 to 1.2
  • Most claudicants will have an ABPI of 0.6-0.8
  • Patients with critical ischaemia (rest pain or tissue loss) usually have an ABPI of 0.2-0.4
  • Diabetics may have falsely elevated ABPIs due to calcified incompressible arteries

Learning bite

When examining a patient always compare with the contralateral leg.