Lecture on the Spinal Cord

Introduction

• Presenter: Dr. Gonzalez
• Main Topic: Spinal cord anatomy and function
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Structure and Function of the Spinal Cord

• Composed of neurons and neuroglia.
• Functions:
  • Operates independently from the brain.
  • Controls voluntary and involuntary movements.
  • Processes reflexes.
  • Integrates excitatory (EPSPs) and inhibitory (IPSPs) signals.
  • Conducts sensory impulses to the brain and motor impulses to effectors.

Anatomy of the Spinal Cord

• Starts as an extension of the medulla oblongata; ends at L2.
• Protected by:
  • Vertebrae (bone)
  • Meninges (connective tissues)
  • Cerebrospinal fluid (CSF)
• Segmentation:
  • Cervical, Thoracic, Lumbar, Sacral, Coccygeal regions.
  • Cervical and lumbar enlargements.

Spinal Nerves

• Cervical spinal nerves: 8
• Thoracic spinal nerves: 12
• Lumbar spinal nerves: 5
• Sacral spinal nerves: 5
• Coccygeal spinal nerve: 1
• Total pairs: 31

Internal Anatomy of the Spinal Cord

• Gray Matter:
  • Composed of neuron cell bodies.
  • Organized into horns (posterior, lateral, anterior).
  • Functions as integration and reflex processing center.
• White Matter:
  • Composed of myelinated and unmyelinated axons.
  • Organized into columns (posterior, lateral, anterior).
  • Facilitates information transfer along the spinal cord.
• Spinal nerves are formed from roots (ventral and dorsal) merging.

Branching and Plexuses

• Spinal Nerve Rami:
  • Dorsal (posterior) ramus
  • Anterior (ventral) ramus
• Nerve Plexuses:
  • Cervical Plexus (C1-C4):
    • Nerves: Transverse cervical, great auricular, lesser occipital, supraclavicular, phrenic.
    • Innervates neck muscles and diaphragm.
  • Brachial Plexus (C5-T1):
    • Divided into roots, trunks, divisions, cords, branches.
    • Mnemonic: "Robert Taylor drinks cold beer."
    • Nerves: Dorsal scapular, suprascapular, thoracodorsal, axillary, medial & lateral pectoral, etc.
  • Lumbar Plexus (T12-L4):
    • Nerves: Iliohypogastric, ilioinguinal, genitofemoral, femoral, obturator.
    • Innervates anterior lower extremity.
  • Sacral Plexus (L4-S4):
    • Nerves: Sciatic, gluteal, pudendal, posterior femoral cutaneous, tibial, fibular.

Dermatomes

• Areas of skin supplied by spinal nerves.
• Each spinal nerve (C2-S5) innervates specific skin segments.
• Facial region innervated by the trigeminal nerve (cranial nerve).

Conclusion

• Encouragement to subscribe, like, and share for more educational content.
• Reference to additional resources for further learning.