Pyramidal signs indicate that the pyramidal tract is affected at some point in its course. Pyramidal tract dysfunction can lead to various clinical presentations such as spasticity, weakness, slowing of rapid alternating movements, hyperreflexia, and a positive Babinski sign.

The pyramidal tract completes development and myelinization between 2 and 3 years of age. Pyramidal signs occur as a normal phenomena until the age of 2, when the myelinization is finished, and so under this age they aren't considered pathological.

The upper motor neurons from the central nervous system descend through the pyramidal tracts (i.e., corticospinal tracts), connecting the brain and spinal cord and help in controlling voluntary movement of muscles.

The irritative phenomena are present if there is visible flection of the thumb, which goes to opposition:

Extension phenomena are positive if the great toe dorsiflexes (goes up) following the stimulus:

These phenomena are positive if the toes of the foot flex:

Pyramidal signs can be a result from different types of damage to the brain or spinal cord, such as strokes, infections, tumors, hemorrhagic events, multiple sclerosis, or trauma.

Parkinsonian-Pyramidal syndrome (PPS) is a combination of both pyramidal and parkinsonian signs that manifest in various neurodegenerative diseases.