dendritic spines

den·drit·ic spines

variably long excrescences of nerve cell dendrites, varying in shape from small knobs to thornlike or filamentous processes, usually more numerous on distal dendrite arborizations than on the proximal part of dendritic trunks. Dentritic spines are a preferential site of synaptic axodendritic contact; they are sparse or absent in some types of nerve cells (motor neurons, the large cells of the globus pallidus, and stellate cells of the cerebral cortex), and exceedingly numerous in others such as the pyramidal cells of the cerebral cortex and the Purkinje cells of the cerebellar cortex. Synonym(s): dendritic thorns, gemmule (2)

den·drit·ic spines

(den-drit'ik spīnz) Variably long excrescences of nerve cell dendrites, varying in shape from small knobs to thornlike or filamentous processes, usually more numerous on distal dendrite arborizations than on the proximal part of dendritic trunks; they are a preferential site of synaptic axodendritic contact; sparse or absent in some types of nerve cells (motor neurons, the large cells of the globus pallidus, stellate cells of the cerebral cortex), exceedingly numerous in others such as the pyramidal cells of the cerebral cortex and the Purkinje cells of the cerebellar cortex.
Synonym(s): gemmule (2) .