Spinal Chord

2nd lumbar vertebrae

• Anterior & Posterior Median
• Gray Matter
• Gray Commissure
• Central Canal
• Anterior White Commissure
• Anterior & Posterior Gray Horns
• Lateral Gray Horns
• Columns
• Posterior Root Ganglion
• Spinal nerve
• Cauda equina

• Anterior White columns
• Posterior white Columns
• Lateral White Columns

• All Columns contain sensory(ascending) and
• motor(descending) tracts that extend long distances up or down the spinal chord

Anterior Gray Horns-contain cell bodies of somatic motor neurons that provide impulses for skeletal muscle contractions

Posterior Gray Horns-contains interneurons as well as axons of incoming sensory neurons

Lateral Horns-are between posterior and anterior gray horns, contain cell bodies of autonomic motor neurons that regulate the activity of cardiac muscle, smooth muscle and glands

White Columns-contain sensory and motor tracts that may extend long distances up or down the spinal chord

• Ascending(sensory)-propagate up the spinal chord to the brain along two main routes on each side(spinothalamic tract and posterior column)
•        spinothalamic tract-conveys impulses for sensing pain, itchiness and deep pressure
•        Posterior tract- convey impulses for discriminating touch, light pressure and deep pressure.

• Descending(motor)-motor output to skeletal muscles travel down the spinal chord in two types of pathways(direct and indirect)
•                Direct-convey impulses that originate in the cerebral cortex and are destined to cause voluntary movements of skeletal muscles
•                Indirect-impulses from the brain stem to cause automatic movements that maintain skeletal muscle tone

Posterior root-composed of sensory axons lying between a spinal nerve and the dorsolateral aspect of spinal chord

Anterior root-composed of motor neurons that emerge from anterior aspect of spinal chord extends laterally to join posterior root forming a spinal nerve

A dorsal and ventral nerve merged, mixed(sensory and motor)

group of cell bodies of sensory neurons and their supporting cell from posterior root spinal nerve

Anterior median fissure-wide groove on anterior side

Posterior median sulcus-narrow furrow on posterior side

Gray matter- shaped like an H or butterfly consists of cell body, unmeyilinated axons, dendrites and neuroglia

Gray commissure-forms crossbar of H connecting the gray matter on right and left sides

in center of gray commissure, passageway filled with cerebrospinal fluid that extends the length of the spinal chord

Anterior gray horns-contain cell bodies of somatic motor neurons that provide impulse for skeletal muscle contractions

Posterior gray horns-contain inter neurons as well as axons of incoming sensory neurons

a collection of spinal nerve toots hang inferiorly from the spinal chord in vertebral column