spinal cord

Examples of spinal cord in the following topics:

• Overview of the Spinal Cord

  • A lumbar puncture (spinal tap) is an example of a medical procedure that directly targets the spinal cord.
  • The brain and spinal cord together make up the central nervous system (CNS).
  • The spinal cord is divided into cervical, thoracic, and lumbar regions.
  • The nerves of the lumbosacral spinal cord supply the pelvic region, legs, and feet.
  • Thirty-one pairs of spinal nerves (sensory and motor) branch from the human spinal cord.

• Spinal Cord Trauma

  • A spinal cord injury (SCI) refers to any injury to the spinal cord that is caused by trauma and not disease.
  • A spinal cord injury (SCI) refers to any injury to the spinal cord that is caused by trauma instead of disease.
  • The American Spinal Injury Association (ASIA) first published an international classification of spinal cord injury in 1982, called the International Standards for Neurological and Functional Classification of Spinal Cord Injury.
  • An incomplete spinal cord injury involves preservation of motor or sensory function below the level of injury in the spinal cord.
  • Autonomic dysreflexia (AD) occurs most often in spinal cord-injured individuals with spinal lesions above the T6 spinal cord level, although, it has been known to occur in patients with a lesion as low as T10.

• Spinal Cord Compression

  • Spinal cord compression occurs when the spinal cord is compressed by bone fragments.
  • Spinal cord compression develops when the spinal cord is compressed by bone fragments from a vertebral fracture, a tumor, abscess, ruptured intervertebral disc, or other lesion .
  • It is regarded as a medical emergency independent of its cause, and requires swift diagnosis and treatment to prevent long-term disability due to irreversible spinal cord injury.
  • The median survival of patients with metastatic spinal cord compression is about 12 weeks, reflecting the generally advanced nature of the underlying malignant disease.
  • In spinal cord compression, the spinal cord (shown here) may be compressed by bone fragments from a vertebral fracture, a tumor, abscess, ruptured intervertebral disc, or other lesion.

• Spina Bifida

  • Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open.
  • The protruded portion of the spinal cord and the nerves that originate at that level of the cord are damaged or not properly developed .
  • As a result, there is usually some degree of paralysis and loss of sensation below the level of the spinal cord defect.
  • The spinal cord lesion or the scarring due to surgery may result in a tethered spinal cord.
  • In some individuals, this causes significant traction and stress on the spinal cord.

• Spinal Cord Grey Matter and Spinal Roots

  • The length of the spinal cord is much shorter than the length of the bony spinal column.
  • The spinal cord is compressed dorsoventrally, giving it an elliptical shape .
  • Each segment of the spinal cord is associated with a pair of ganglia, called dorsal root ganglia, which are situated just outside of the spinal cord.
  • Hence, the spinal ganglia can be regarded as grey matter of the spinal cord that became translocated to the periphery.
  • Describe the grey matter and spinal roots of the spinal cord

• Subdivisions of the Nervous System

  • The CNS includes the brain and spinal cord, while the PNS is a network of nerves linking the body to the brain and spinal cord.
  • White matter includes all of the nerves of the PNS and much of the interior of the brain and spinal cord.
  • The PNS is a vast network of nerves consisting of bundles of axons that link the body to the brain and the spinal cord.
  • The central nervous system (2) is a combination of the brain (1) and the spinal cord (3).
  • The brain and the spinal cord are the central nervous system (CNS) (shown in yellow).

• Sensory and Motor Tracts

  • The spinothalamic tract is a sensory pathway originating in the spinal cord.
  • The pathway decussates at the level of the spinal cord.
  • In both pathways, primary sensory neuron cell bodies are found in the dorsal root ganglia, and their central axons project into the spinal cord.
  • The corticospinal tract conducts impulses from the brain to the spinal cord.
  • The brain sends impulses to the spinal cord relaying the message.

• Autonomic Dysreflexia

  • Autonomic dysreflexia is an acute reaction of the autonomic nervous system to overstimulation in patients with previous spinal cord injury.
  • AD occurs most often in spinal cord-injured individuals with spinal lesions above the T6 spinal cord level although it has been known to occur in patients with a lesion as low as T10 .
  • The sympathetic discharge that occurs is usually in association with spinal cord injury (SCI) or disease (e.g. multiple sclerosis).
  • AD is believed to be triggered by afferent stimuli (nerve signals that send messages back to the spinal cord and brain) which originate below the level of the spinal cord lesion.
  • Autonomic dysreflexia (AD) occurs most often in spinal cord-injured individuals with spinal lesions above the T6 spinal cord level, although, it has been known to occur in patients with a lesion as low as T10.

• Function and Physiology of the Spinal Nerves

  • Spinal nerves connect the brain and spinal cord to the limbs and organs of the body.
  • The peripheral nervous system (PNS) consists of the nerves and ganglia outside of the brain and spinal cord.
  • The term spinal nerve generally refers to a mixed spinal nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body.
  • Each pair of spinal nerves roughly correspond to a segment of the vertebral column: 8 cervical spinal nerve pairs (C1-C8), 12 thoracic pairs (T1-T12), 5 lumbar pairs (L1-L5), 5 sacral pairs (S1-S5), and 1 coccygeal pair.
  • If the spinal cord is transected above C3, then spontaneous breathing is not possible.

• Brachial Plexus

  • The brachial plexus is formed by the four lower cervical spinal nerves and the first thoracic spinal nerve.
  • The brachial plexus is divided into roots, trunks, divisions, cords, and branches.
  • Five roots: Te five anterior rami of the spinal nerves, after they have given off their segmental supply to the muscles of the neck.
  • These six divisions will regroup to become the three cords.
  • The cords are named by their position with respect to the axillary artery: The posterior cord is formed from the three posterior divisions of the trunks (C5-C8,T1), the lateral cord is the anterior divisions from the upper and middle trunks (C5-C7), and the medial cord is simply a continuation of the anterior division of the lower trunk (C8,T1)