The neurologist who tested nerve pain on himself

What a Regrowing Nerve Revealed

Pain from nerve damage can be difficult to describe: a patient may feel a sharp prick, burning, or touch in the wrong place, while a clinician has no direct way to experience those sensations. Henry Head’s experiment made that problem unusually personal. As sensation returned after his radial nerve was cut, he repeatedly tested the skin it served and recorded what each stimulus felt like and where he seemed to feel it.

The radial nerve carries signals from the arm and hand toward the brain. When it is severed, those signals stop; as the nerve regrows, sensation can return unevenly. Head’s careful testing let him follow that recovery in stages instead of treating “feeling” as one ability that simply switched back on.

Sensation Returned in Different Stages

Head distinguished between two broad kinds of sensory information. Protopathic sensation—an older term—covered basic warnings such as pain and extremes of temperature. Epicritic sensation meant finer discrimination, including locating a touch precisely and telling two nearby touches apart.

His records showed that these capacities did not return together. Basic pain and temperature responses could appear before the more precise ability to identify where the skin had been touched. The distinction helped neurologists think of sensation as a set of functions carried and processed in different ways, rather than a single signal.

The Cost of Making Symptoms Observable

Head’s self-experiment turned subjective reports into a systematic record: the same area could be tested again and again as the nerve healed. That made a hidden process—the changing quality of sensation during nerve recovery—available for clinical study.

The lasting point is not that pain can be reduced to a neat chart. It is that careful, repeated observation can reveal meaningful stages inside an experience patients may struggle to put into words. In Head’s case, the record followed recovery not just as the return of feeling, but as the gradual return of different kinds of feeling.