Palpation and Sensory Adaptation

Sensory receptors
Thermoreceptors are the nervous system’s temperature sensors.

Mechanoreceptors are the nervous system’s pressure sensors.

Sensory adaptation
Both types of nervous system receptors adapt to constant stimuli by switching off. This is essential to prevent the overload of the nervous system. It also allows us to screen out non-essential information so that we can focus on what’s changing in our environment (e.g. the car moving towards us, the ground shifting under our feet, the heat of an element on the stove as our hand nears it, etc.).

Sensory adaptation is of benefit to our palpatory sense because it allows us to filter out unnecessary information so that we can focus on the tissues that we intend to engage.

However sensory adaptation also limits palpation because we are unable to effectively palpate relatively superficial structures after the palpation of deep structures (which place more pressure on our mechnoreceptors).

It is worthwhile noting that nervous receptors return to normal fairly quickly after the original stimulus is removed. This is the reason that it is advisable to keep moving while palpating, albeit slowly.