ANAT

1) Posterior Funiculus - Medial Lemniscal Pathway: general sensation (bundle of axons carry information to the opposite side of the body).

2) Anterolateral Pathway: pain/temperature

3) Spinocerebellar Pathway: Proprioception (knowing where w/o looking); diverges to right & left side of cerebellum.

4) Corticospinal (Motor) Pathway (pyramidal system): controls precise & voluntary movements (85%/15%).

1) Posterior column pathway: proprioception, pressure, fine touch, vibration.

2) Anterior spinothalamic tract: crude touch, pressure.

3) Lateral spinothalamic tract: pain/temperature

Function: general sensation.

Pathway: Posterior root (right side) --> Posterior funiculus --> Medulla Oblongata (CROSSES OVER to LEFT SIDE) --> Medial lemniscus --> Thalamus --> Postcentral gyrus (Primary somatosensory cortex; left side)

• Significance:
• 1) Damage to T5 = no sensation from there and ABOVE.
• 2) Damage on right side of T6 = no sensation from there and BELOW.

Function: pain/temperature to the brain.

• Pathway:
• 1) axons travel in anterior and lateral funiculi on the right side of body through the posterior horn
• 2) Second-order neurons CROSS IMMEDIATELY after synapse to the left side.
• 3) Ascends through the PONS (secondary neuron) and MESENCEPHALON to the THALAMUS to the CEREBRUM.
• 4) Tertiary neuron culminates at the Postcentral gyrus (primary somatosensory cortex) on the LEFT SIDE of cerebrum.

*Crosses over IMMEDIATELY through the Posterior Horn of the Spinal Cord.

Function: conduct proprioception to cerebellum.

Significance: departs (diverges) to the RIGHT and LEFT side of the CEREBELLUM.

Mnemonic: Spino "splits" (SS)

Function: motor communication.

• Pathway:
• 1) Axons DESCEND from the cerebral cortex (precentral gyrus) & form PYRAMIDS on the ANTERIOR MEDULLA OBLONGATA.

2) 85% of the axons form the LATERAL CORTICOSPINAL TRACT, which crosses to the OPPOSITE side of the MEDULLA OBLONGATA at the "decussation of the pyramids."

3) Descends into the SPINAL CORD through the LATERAL FUNICULI.

Significance: 85% of axons cross to opposite side (left to right thru lateral finiculus) while 15% of axons stays in anterior finuculus.