How to assess the Glasgow coma scale(GCS) clinically?

The Glasgow coma scale:

Assessment of the Glasgow coma scale clinically:

Eye-opening:

• The patient’s eyes may already open (spontaneous)
• Eyes may open in response to the observer saying or calling the patient’s name (To name)
• Eyes may open in response to a standard painful stimulus (To pain)
• Eyes may not open at all (None)

Best verbal response: 

Following the completion of eye-opening observation, the observer presents a standard verbal stimulus to the patient by saying clearly, “Mr X, do you know where you are now? “

• The patient may give an orientated answer or response (Orientated)
• He may be confused as to where he is (Confused)
• He may deliver an answer which is inappropriate to the question (Inappropriate)
• The answer may be incomprehensible (Incomprehensible)
• There may be no answer (None)

Best motor response:

Mainly the arms are tested as they are better windows on cerebral function than are the lower limbs. The best response of each arm should be recorded separately if they are found to be different.

• The patient is first asked to squeeze the observer’s fingers with both hands. This will determine if one or both limbs are obeying.
• Failure of a limb to obey will result in the application of a standard painful stimulus to the sternum (Some textbooks advise avoiding sternum rub as it may cause bruising); if a limb is brought up to where the stimulus is being applied, it is classified as localising or purposeful movement.
• If a limb fails to obey or localise, then a standard painful stimulus is applied to the limb itself, and the observer records whether the limb undergoes an apparently coordinated withdrawal or
• Just spastic flexion or
• Just decerebrate extension or
• No movement at all (None)

Image showing method of the GCS assessment:

[Image from Davidson's Principles and practice of medicine 23rd Edition; Fig 10.5]