Spinal cord anatomy

Anatomy, Organ-Based and Clinical Sciences

Anatomical Points

Conus medullaris terminates at L1 in the adult (L3 in the newborn), after which the SC is referred to as the cauda equina (L2 – sacral)

Tracts

Ascending

Dorsal Column/Medial Lemniscus

Tactile, vibration, proprioception. Located dorsally. First order neurons located in DRG. Travel on same side as DRG and cross over in the brainstem

Spinothalamic Tracts

Ventral and Lateral STh Tracts. Lateral STh Tract carries pain and temperature. Crosses over through the ventral white commissure and ascends on the opposite side as the DRG

Descending

Corticospinal Tracts

Ventral and Lateral. Cross over in the medulla (pyramidal decussation). Voluntary motor movement.

Hypothalamospinal Tracts

Overlaps with the lateral corticospinal tract. Projects from the hypothalamus to the IML

Autonomic Nervous System

White rami communicans contain myelinated preganglionic SNS fibers and exist from T1 to L3. Gray rami communicans contain unmyelinated postganglionic SNS fibers and exist at all levels

Blood Supply

Anterior spinal artery supplies anterior 2/3 of spinal cord (does not supply dorsal columns) as well as part of the medulla. Posterior spinal arteries supply the remainder. Great radicular artery (GRA, Artery of Adamkiewicz) is generally located between T9-12 but can be anywhere from T5-L5. Major blood supply to lower spinal cord.

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2018

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