Spinal Cord / Clinical Correlations

Spinal cord is…..

a cylindrical structure about 18in long is adults and extends from the foramen magnum to L1-L2 vertebral level in adults L3-L4 in children

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal make up the…..

31 pairs of spinal nerves

C1 spinal nerve exits:

above the C1 vertebra 

C8 spinal nerve exits:

Below C7 vertebra 

Spinal cord Meninges in order from outer to most inner:

Epidural space→ Dura Mater→ Subdural space→ Arachnoid Mater→ Subarachnoid Space→ Pia Mater

Lumbar puncture is located where

L3-L4 in adults
L4-L5 in children

Spinal Cord Development Problems: Myelocele 

failure of the neural groove to close 

Spinal Cord Development Problems: Spina Bifida

Failure of the vertebral laminae to enclose the spinal cord

Spinal Cord Development Problems: Spina Bifida Oculta 

Most mild form or Spina Bifida and Characterized from a small patch of hair on the back where there is a small hole 

Spinal Cord Development Problems: Meningomyelocele (Spina Bifida Cystica)

Sever form where meninges and spinal cord protrude through the defect- Deadly causes stillbirth 

Grey Matter

Neuron cell bodies, dendrites, and synapse; they process information

White matter 

myelinated axons forming ascending (sensory) and descending (motor) tracks 

Dorsal Primary Ramus

Sensory of intrinsic back muscles, and skin of the back

Ventral Primary Ramus

Becomes thoracic nerves/ roots of cervical plexus

Differential Growth between Vertebral Column and Spinal Cord 

The vertebral clumn grows faster than the spinal cord (ends at L1-L2 in adults) the rest of the nerve roots extend downwards forming the cauda equina 

Filum Terminale

anchors the cord of the coccyx

Spino Thalamic Tract-

crude touch ,pain, and temp (cross at the spinal cord level)

Fasciculus Gracilis 

Lower ½ of the body : goes straight up and cross at the medullary level 

Fasciculus Cuneatus

Upper ½ of the body: goes straight up and cross at the medullary level

Spino Cerebellar Tract 

unconscious proprioception to the cerebellum

Lateral Corticospinal Tract-

80% crosses in medulla: precise voluntary movement

Anterior Corticospinal Tract 

20% crosses at spinal cord level

Upper Motor Neuron Syndrome (stroke)

• Between brain and spinal cord- reflexes are intact 

• Weakness or paralysis of specific movements (extension of arms and flexion of legs)

• NO wasting of muscles

• Hypertonia- an abnormal increase in muscle tone, causing stiffness and making movement difficult

• Hyperreflexia- a neurological condition characterized by exaggerated or overactive muscle reflexes, such as a limb kicking out farther or faster than normal

Lower Motor Neuron Syndrome (poliomyelitis)

• Weakness (paresis) or paralysis (plegia) of individual muscles 

• Hypotonia- an abnormally low level of muscle tone and wasting of muscles 

• Hyporelexia- a condition where reflexes are reduced in intensity, often caused by damage to the nervous system

• Areflexia- the complete absence of reflexes, such as the knee-jerk reaction

Ischemic stroke

is a type of stroke caused by a blockage in a blood vessel to the brain, cutting off oxygen and nutrients to brain tissue

Hemorrhagic Stroke

is a stroke that occurs when a blood vessel in or around the brain bursts, causing bleeding into brain tissue

Brocas Area 

is in the frontal lobe and is primarily involved in language production

Wernicke's area

in the temporal lobe and is primarily involved in language comprehension

Broca's aphasia

where a person can understand language but struggles to speak fluently

Wernicke's aphasia

where a person can speak fluently but their speech lacks meaning and they have difficulty understanding others

Upper cervical cord lesions

Quadriplegia (loss of movement in all 4 limbs), diaphragm weakness( problems breathing)

Lower cervical Cord Lesion

Affected: Arms + legs, but diaphragm is OK.

• Quadriparesis → weakness in both arms AND legs
  (arms especially affected because brachial plexus = C5–T1)

• Sensory loss below the lesion

• Reflex changes below lesion

Thoracic cord lesion

Affects: trunks and legs but arms are normal

• Paraplegia (Loss of movement in both legs)

• Normal arm strength and sensation

• May lose trunk control depending on the level

• Loss of abdominal reflexes

• Autonomic problems (Bladder/Bowel)

Lumbar Cord Lesion

Affected: Leg muscles supplied by lumbar nerves.

Main effects:

• Leg weakness (pattern depends on level)

  • L2–L4: hip flexion, knee extension issues

  • L5: foot drop, toe extension loss

• Sensory loss over anterior or lateral leg

• Reflex changes:

  • ↓ knee jerk (L3–L4)

  • ↓ medial hamstring or medial malleolus sensation (L4–L5)

• No arm involvement

Horners Syndrome

Lesions/compression of one side of the cervical or thoracic sympathetic chain, which generates symptoms on the ipsilateral side of the body