Why Are Sensation and Pulses Checked After an Injury?

After a limb injury, assessment should not stop at the painful bone or joint: circulation and nerve function below the injury also need to be checked. A fracture, dislocation, large haematoma or overly tight immobilisation can compress a blood vessel or nerve. Detecting that problem early may be more urgent than assigning a precise fracture label.

Polish version · For Patients

What does an orthopaedic surgeon check during the examination?

A neurovascular examination combines several observations. The clinician compares colour and temperature between limbs, checks capillary refill after pressure on a nail bed, feels for pulses at appropriate sites, tests sensation in the territories of individual nerves and asks the patient to perform selected movements of the fingers, toes, hand or foot.

Each part answers a different question. A palpable pulse is reassuring, but it does not exclude every clinically important circulatory problem. Likewise, normal skin colour does not rule out injury to a specific nerve. The overall pattern and comparison with the opposite side matter.

Why is the examination repeated?

The condition of a limb can change after reduction of a fracture or dislocation, application of a cast, increasing swelling or secondary displacement. Neurovascular findings should therefore be documented before an intervention and checked again afterwards. This helps establish whether an abnormality was present from the outset or developed later.

This is also why patients are told to watch their fingers or toes after immobilisation. Swelling often increases during the first few days and a cast or splint that was initially comfortable may become too tight.

What can an abnormal finding mean?

• a cold, pale or blue limb may indicate impaired blood flow;
• delayed capillary refill has to be interpreted together with temperature and pulses;
• new numbness may reflect nerve compression or injury;
• inability to perform a movement can result from pain, tendon or muscle injury, or nerve dysfunction;
• pain that seems disproportionate to the injury and worsens with passive movement of the digits can be one warning sign of acute compartment syndrome.

Why is an X-ray not enough?

X-rays show bone position well, but they do not directly assess nerve function or blood flow. Good fracture alignment therefore does not automatically mean that all soft tissues are safe. Conversely, numbness does not necessarily mean that a nerve has been divided; swelling or pressure can cause temporary symptoms. Distribution, progression and the complete examination determine how concerning a finding is.

Which symptoms after injury or casting need urgent reassessment?

• increasing numbness or reduced ability to move the fingers or toes;
• digits that become clearly colder, pale or blue;
• severe and increasing pain despite elevation and prescribed analgesia;
• a rapidly increasing sense of pressure or tightness under a cast;
• marked swelling that makes finger or toe movement difficult.

In that situation, do not cut or alter the immobilisation yourself. Prompt reassessment is needed. Trying to check a pulse at home is not an adequate substitute: it may be difficult to locate reliably, and the presence of a pulse does not rule out every complication.

Sources

1. National Institute for Health and Care Excellence. Fractures (complex): assessment and management. NICE guideline NG37.
2. National Institute for Health and Care Excellence. Fractures (non-complex): assessment and management. NICE guideline NG38.

Content prepared by: Tomasz Poboży - orthopaedic surgeon.