vegetative neuron

Vegetative neurons – location and type

Sympathetic preganglionic in lateral horn

→ form shoal-like structure

located in intermediolateral gray matter (Rexed lamina VII).

Columns of vegetative neurons

Intermediomedial (C1–L2) and intermediolateral (C4–C7 and L3–S2)

Pelvic parasympathetic nucleus

Intermediate position between columns

coordinates pelvic smooth muscles.

Somatic neurons – location and types

Anterior horn; Rexed lamina VIII and IX; types: α, β, γ.

Anterior horn columns

Medial column, Central column, Lateral column.

Medial column – features

Receives anterior corticospinal fibers

innervates axial muscles

subcolumns: ventromedial (axial muscles) and dorsomedial (trunk wall via ventral branches/intercostal nerves).

Central column – nuclei

Found at cervical and lumbar intumescences

accessory nucleus (C1–C5)

phrenic nucleus (C3–C5)

lumbosacral nucleus (S2–S4).

Lateral column – general features

At intumescences

receives corticospinal fibers

innervates girdles and limbs.

Lateral column – nuclei

Ventral (girdles)

ventrolateral (shoulder & hip joints)

dorsolateral (elbow & knee)

retrodorsolateral (hand & foot, ankle).

Functional organization of lateral column nuclei

Anterior aspect → extensors

posterior aspect → flexors.

Association neurons (interneurons) – location

Remain within spinal cord; do not leave the cord.

Commissural neurons

Axons cross midline.

Association tracts

Ipsilateral, contralateral, or bilateral.