“Looking down to sign a hotel register, I felt a spasm like an electric current move along my back from the base of my skull to my toes. Every time I repeated the movement, the spasm recurred.”
The causes of Lhermitte sign include multiple sclerosis (MS), radiation damage to the spinal cord), cervical spondylosis (degeneration of the disc spaces between the vertebrae), herniation of a cervical disc, a cervical spinal cord tumor, and subacute combined degeneration (caused by vitamin B12 deficiency).
Shocks radiating up the spine are sometimes referred to a reverse Lhermitte sign.
The sign is named for a French neurologist, Jean Lhermitte (1877-1959) who originally described it in a patient with multiple sclerosis (MS). It is a classic sign of MS.
- Sign, Macewen
A sign to detect hydrocephalus and brain abscess. Percussion (tapping) on the skull at a particular spot (near the junction of the frontal, temporal and parietal bones) yields an unusually resonant sound in the presence of hydrocephalus or a brain abscess. Named for Sir William Macewen (1848-1924), a surgeon in Glascow, Scotland who also described […]
- Sign, Tinel's
An examination test that is used by doctors to detect an irritated nerve. Tinel’s sign is performed by lightly banging (percussing) over the nerve to elicit a sensation of tingling or “pins and needles” in the distribution of the nerve. For example, in a person with carpal tunnel syndrome where the median nerve is compressed […]
- Sign, toe
Joseph Francois Felix Babinski (1857-1932). His name will never be forgotten in medicine, thanks to the toe sign he described.
- Signal transduction
A basic process in molecular cell biology involving the conversion of a signal from outside the cell to a functional change within the cell. A signal (such as a hormone or neurotransmitter) interacts with a receptor on the cell surface; this interaction causes a change in a second messenger (such calcium); and, eventually, a change […]
- Signal transduction pathway
The course by which a signal from outside a cell is converted to a functional change within the cell.