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Specimen Identification: Transverse Sections of the Spinal Cord

The specimen in the glass jar (labeled 17) consists of two transverse (cross-sectional) slices of the spinal cord, preserved in formalin and mounted on a supporting pin/thread for display.

Identification

Specimen: Transverse sections of the spinal cord (likely human or large mammal)
This matches the classic gross anatomy museum preparation used in medical teaching. The two slices are mounted side by side, allowing bilateral comparison.

What You Can See in the Specimen

StructureAppearanceSignificance
Gray matterCentral butterfly / "H"-shaped darker regionContains neuronal cell bodies
Anterior hornsBroader, rounded projections of gray matter (ventrally)House lower motor neuron (LMN) cell bodies - efferent
Posterior hornsNarrower projections of gray matter (dorsally)House sensory relay neuron cell bodies - afferent
White matterLighter surrounding ringMyelinated ascending and descending fiber tracts
Central canalTiny dot at the centerRemnant of neural tube lumen, contains CSF
Anterior median fissureDeep ventral grooveLandmark dividing left and right
Posterior median sulcusShallow dorsal grooveDivides posterior white columns
Here is the textbook diagram for comparison:
Spinal cord cross section showing gray matter, white matter, anterior horn, and posterior horn

Key Anatomical Points (for viva/exam)

  1. Gray matter is central; white matter is peripheral - opposite to the brain, where gray matter is the outer cortex.
  2. Functional arrangement:
    • Anterior horn = Motor (efferent) - lower motor neurons (alpha and gamma motor neurons)
    • Posterior horn = Sensory (afferent)
    • Lateral horn (present at T1-L2 and S2-S4) = Autonomic neurons
  3. White matter tracts are organized into three funiculi on each side:
    • Posterior funiculus: dorsal columns (fine touch, proprioception, vibration)
    • Lateral funiculus: corticospinal tract (motor, descending), spinothalamic tract (pain/temp, ascending)
    • Anterior funiculus: anterior corticospinal tract and other tracts
  4. The spinal cord has 31 segments: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal.
  5. The conus medullaris (tip of spinal cord) ends at L1-L2 in adults.
  6. Central canal is lined by ependymal cells and is continuous with the fourth ventricle superiorly.

Clinical Relevance

  • Brown-Sequard syndrome (hemisection): ipsilateral motor loss + contralateral pain/temp loss
  • Anterior cord syndrome: loss of motor + pain/temp bilaterally below lesion; dorsal columns preserved
  • Syringomyelia: cavity in central cord destroys anterior white commissure - "cape-like" bilateral loss of pain and temperature
  • Subacute combined degeneration (Vit B12 deficiency): degeneration of posterior and lateral funiculi
Source: General Anatomy and Musculoskeletal System, THIEME Atlas of Anatomy, p. 102
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