Spinal Cord

Spinal Cord Anatomy
  - Interneuron
  - Central Canal
  - Afferent Sensory Information
  - Dorsal Root
  - Synapse
  - Dorsal Root Ganglion
      - Cell Body of Sensory Neuron: Contains the neuron's nucleus and other organelles essential for cell function.
  - Receptor
  - Ventral Root
  - Vertebral Body
  - Spinal Nerve
      - Components:
          - Pedicle
  - Regions of Spinal Cord:
      - Dorsal Horn
      - Lateral Horn
      - Ventral Horn
  - White Matter: Composed of myelinated axons; responsible for communication between different parts of the spinal cord and brain.
  - Grey Matter: Contains neuronal cell bodies; involved in processing sensory and motor information.
  - Gray Commissure
  - Cell Body of Motor Neuron
  - Efferent Signals to Muscles and Glands
  - Synaptic Knobs
  - Effector Muscle
  - Spinal Cord Structure
  - Spinous Process

Anterior vs. Posterior Regions:
- Anterior (Ventral) Region: Primarily contains motor pathways (efferent signals).
- Posterior (Dorsal) Region: Primarily contains sensory pathways (afferent signals).

Herniated Disc:
    - Structures Involved:
        - Disk
        - Spinal Nerve
        - Spinal Cord
        - Vertebra

Location: At the L1 vertebra, the spinal cord ends in a tapered structure called the conus medullaris.
Cauda Equina: Below the conus medullaris, the spinal nerves form a bundle known as the cauda equina, resembling a horse's tail.

Function: Protects the spinal cord and brain; facilitates nutrient circulation.
Lumbar Puncture: A spinal needle is usually inserted between the 3rd and 4th lumbar vertebrae to collect cerebrospinal fluid.

Three Layers:
  - Dura Mater: The tough outer layer.
  - Arachnoid Mater: The middle layer; web-like structure.
  - Pia Mater: The delicate inner layer directly covering the spinal cord.
Denticulate Ligaments: Extensions from the pia mater that anchor the spinal cord to the arachnoid and dura mater, providing stability.

Filum Terminale: An extension of the pia mater that anchors the spinal cord to the coccyx.
Shingles:
- Caused by Varicella Zoster Virus (VZV); virus can reside dormant in the dorsal root ganglion.
Poliovirus:
- Attacks cells in the anterior horn of the spinal cord, which may lead to paralysis and respiratory failure if it affects the medulla oblongata.
- Bulbar Polio: Specifically attacks the medulla oblongata, causing breathing difficulties and often necessitating the use of an iron lung.

Functionality:
  - Maintains breathing via artificial means.
  - Components:
      - Bellows: Moves in and out, creating air pressure changes.
      - Handle for manual operation.
      - Window: For patient visibility.
      - Access port for medical attention.
      - Electric components to automate functions.
Mechanics: When bellows expand and contract, it aids the patient’s lungs in inhaling/exhaling air.

Spina Bifida Occulta:
- Malfusion of sacrum without damage to the cauda equina; can result in low back instability.
Spina Bifida:
  - Condition where the vertebral column does not close properly, allowing the spinal cord to protrude in varying degrees.
  - Types:
    - Normal
    - Spina Bifida Occulta
    - Meningocele
    - Myelomeningocele

Surgical Procedure:
  - A neurosurgeon consults for myelomeningoceles; if large, a plastic surgeon is also involved for skin closure.
  - Process:
    1. Open the herniated sac.
    2. Carefully dissect spinal cord elements from the surrounding skin.
    3. Repair the dura layer to encase the exposed spinal cord.
    4. Dissect muscle flaps (from erector spinae and/or gluteus maximus) to cover the defect.
    5. Perform a tension-free closure of the skin over the site.