Crude touch is a sensory modality which allows the subject to sense that something has touched them, without being able to localise where they were touched (contrasting fine touch

Fine touch

Fine touch, , is a sensory modality which allows a subject to sense and localise touch. The form of touch where localisation is not possible is known as crude touch....

). Its fibres are carried in the spinothalamic tract

Spinothalamic tract

The spinothalamic tract is a sensory pathway originating in the spinal cord. It transmits information to the thalamus about pain, temperature, itch and crude touch...

.

As fine touch normally works in parallel to crude touch, a person will be able to localise touch until fibres carrying fine touch (Posterior column-medial lemniscus pathway

Posterior column-medial lemniscus pathway

The posterior column-medial lemniscus pathway is the sensory pathway responsible for transmitting fine touch, vibration and conscious proprioceptive information from the body to the cerebral cortex; as well as tactile pressure, barognosis, graphesthesia, stereognosis, recognition...

) have been disrupted. Then the subject will feel the touch, but be unable to identify where they were touched.