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Introduction
1. Cardiopulmonary system
2. Pulmonary system
3. Neuromuscular system
3.1 Central nervous system
3.2 Anatomy and function of spinal cord
3.3 Peripheral nervous system
3.4 Compare and contrast central nervous systems pathologies part 1
3.5 Compare and contrast central nervous systems pathologies part 2
3.6 Peripheral nervous system conditions
3.7 Other neurological conditions
3.8 Interventions for neurological conditions
3.9 Vestibular system
4. Pediatrics
5. Musculoskeletal system
6. Other system
7. Non systems
Wrapping up
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3.2 Anatomy and function of spinal cord
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3. Neuromuscular system
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Anatomy and function of spinal cord

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Primary function of the spinal cord

  • Acts as a relay pathway between the peripheral system and the brain
    • Provides sensory information regarding the environment to the brain
    • Manages motor commands to the peripheral system in reaction to the environment
    • Coordinates simple reflexes that do not need to go to the brain, such as withdrawal from pain, patellar reflex, etc.

Anatomy of the spinal cord

  • Cervical spine
    • Eight (8) nerves that provide innervation to the neck and upper extremity
  • Thoracic spine
    • Twelve (12) nerves that provide innervation to the upper chest, chest, abdomen, and upper back
  • Lumbar spine
    • Five (5) nerves that provide innervation to the legs and feet
  • Sacral spine
    • Five (5) nerves that provide innervation to the sacrum and pelvis
  • Coccygeal spine
    • One (1) nerve that provides innervation to the perineal area
Spinal cord sections
Spinal cord sections

Protective layers of the spinal cord

  • Dura mater
    • Outermost protective layer
    • Space between dura and bony vertebral body referred to as epidural space, which contains adipose tissue and blood vessels
  • Arachnoid mater
    • Middle layer with a web-like appearance
    • Space between arachnoid and pia referred to as subarachnoid space and contains cerebrospinal fluid
  • Pia mater
    • Innermost layer that is in direct contact with the spinal cord
Spinal cord anatomy
Spinal cord anatomy
Definitions
Dorsal root
Sensory nerve that carries information from the spinal cord to the brain.
Ventral root
Motor nerve that carries information from the brain to the spinal cord.
Spinal nerve
Pathway for sensory and motor information to move between the peripheral system and the spinal cord.
Denticulate ligament
Ligament that provides stabilization of the spinal cord.
Posterior (dorsal) gray horn
Nerve fibers containing sensory information from the body.
Lateral gray horn
Nerve fibers containing sympathetic nervous system information are only found in the thoracic, upper lumbar, and sacral regions of the spinal cord.
Anterior (ventral) gray horn
Nerve fibers containing motor neurons that control skeletal muscles.
Posterior (dorsal) white column
Nerve fibers containing sensory information from the body, such as two-point discrimination, fine touch, vibration, and proprioception.
Lateral white column
Nerve fibers that contain sensory information such as pain, temperature, and crude touch.
Anterior (ventral) white column
Nerve fibers containing sensory and motor nerve fibers that provide motor commands from the brain to the same side of the body (ipsilateral), but also transmit sensory signals (like crude touch and pressure) to the opposite side of the brain (contralateral).
Sympathetic nervous system
A division of the autonomic nervous system that prepares the body to respond to physical activity, psychological stress, or perceived danger by initiating the “fight-or-flight” response.
Parasympathetic nervous system
A division of the autonomic nervous system that promotes recovery, conservation of energy, and homeostasis after stress or exertion — often called the “rest-and-digest” system.

The sympathetic nervous system increases heart rate, blood pressure, and respiratory rate to deliver oxygen to working muscles and vital organs, while dilating the pupils and bronchioles, redirecting blood away from nonessential processes such as digestion, and releasing glucose and fatty acids for immediate energy. The parasympathetic nervous system reverses these effects — slowing heart rate and blood pressure, constricting the pupils and bronchioles, and stimulating gastrointestinal activity, nutrient absorption, and waste elimination.

Cross section of spinal column
Cross section of spinal column

Spinal tracts

Pathways of spinal cord
Pathways of spinal cord
  • Ascending tracts
    • Carry sensory information such as touch, pain, and temperature from the peripheral system to the brain
      • Dorsal column-medial lemniscal: transmits light touch, deep pressure, two-point discrimination, and vibratory information to the cerebrum via the thalamus; crosses in the medulla to the contralateral side
      • Anterior and lateral spinothalamic: transmit pain, crude touch, and temperature information to the cerebrum via the thalamus; crosses in the medulla to the contralateral side
      • Spinocerebellar: transmits proprioceptive information to the cerebellum; does not cross, stays on the same side
  • Descending tracts
    • Carry motor information from the brain to the peripheral system to give voluntary commands of movement of axial and skeletal muscles
    • Anterior and lateral corticospinal: transmit commands to move axial and/or skeletal muscles
      • Anterior corticospinal: motor system that descends uncrossed in the front of the spinal cord, controlling trunk/axial muscles for posture
      • Lateral corticospinal: motor system where fibers cross over (decussate) in the lower medulla, forming the lateral tract, which controls movement of the extremities — particularly fine, coordinated movements — on the opposite (contralateral) side of the body

Arterial circulation of the spinal cord

  • Two (2) primary arteries of the spinal cord
    • Anterior spinal artery
      • Supplies blood to the anterior two-thirds of the spinal cord, except the dorsal column
    • Posterior spinal artery
      • Provides blood supply to the posterior spinal cord via two (2) branches that supply the dorsal sensory column, dorsal gray matter, and posterior columns

Primary function of the spinal cord

  • Relay pathway between peripheral system and brain
  • Manages sensory input and motor output
  • Coordinates simple reflexes (e.g., withdrawal, patellar reflex)

Anatomy of the spinal cord

  • Cervical spine: 8 nerves, neck and upper extremity innervation
  • Thoracic spine: 12 nerves, upper chest, chest, abdomen, upper back innervation
  • Lumbar spine: 5 nerves, legs and feet innervation
  • Sacral spine: 5 nerves, sacrum and pelvis innervation
  • Coccygeal spine: 1 nerve, perineal area innervation

Protective layers of the spinal cord

  • Dura mater: outermost layer, epidural space with fat and blood vessels
  • Arachnoid: middle, web-like, subarachnoid space with cerebrospinal fluid
  • Pia mater: innermost, direct contact with spinal cord

Key spinal cord structures and definitions

  • Dorsal root: sensory nerve to brain
  • Ventral root: motor nerve from brain
  • Spinal nerve: pathway for sensory and motor info
  • Denticulate ligament: stabilizes spinal cord
  • Gray horns:
    • Posterior (dorsal): sensory fibers
    • Lateral: sympathetic fibers (thoracic, upper lumbar, sacral)
    • Anterior (ventral): motor neurons for skeletal muscles
  • White columns:
    • Posterior (dorsal): sensory (touch, vibration, proprioception)
    • Lateral: sensory (pain, temperature, crude touch)
    • Anterior (ventral): sensory and motor to contralateral brain
  • Sympathetic nervous system: “fight-or-flight” response
  • Parasympathetic nervous system: “rest-and-digest” functions

Spinal tracts

  • Ascending tracts: carry sensory info to brain
    • Dorsal column-medial lemniscal: light touch, pressure, vibration (crosses in medulla)
    • Anterior/lateral spinothalamic: pain, crude touch, temperature (crosses in medulla)
    • Spinocerebellar: proprioception (does not cross)
  • Descending tracts: carry motor commands from brain
    • Anterior corticospinal: controls trunk/axial muscles (uncrossed)
    • Lateral corticospinal: controls extremities, fine movements (crosses in medulla)

Arterial circulation of the spinal cord

  • Anterior spinal artery: supplies anterior two-thirds (except dorsal column)
  • Posterior spinal artery: supplies posterior cord, dorsal sensory column, dorsal gray matter

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Anatomy and function of spinal cord

Primary function of the spinal cord

  • Acts as a relay pathway between the peripheral system and the brain
    • Provides sensory information regarding the environment to the brain
    • Manages motor commands to the peripheral system in reaction to the environment
    • Coordinates simple reflexes that do not need to go to the brain, such as withdrawal from pain, patellar reflex, etc.

Anatomy of the spinal cord

  • Cervical spine
    • Eight (8) nerves that provide innervation to the neck and upper extremity
  • Thoracic spine
    • Twelve (12) nerves that provide innervation to the upper chest, chest, abdomen, and upper back
  • Lumbar spine
    • Five (5) nerves that provide innervation to the legs and feet
  • Sacral spine
    • Five (5) nerves that provide innervation to the sacrum and pelvis
  • Coccygeal spine
    • One (1) nerve that provides innervation to the perineal area

Protective layers of the spinal cord

  • Dura mater
    • Outermost protective layer
    • Space between dura and bony vertebral body referred to as epidural space, which contains adipose tissue and blood vessels
  • Arachnoid mater
    • Middle layer with a web-like appearance
    • Space between arachnoid and pia referred to as subarachnoid space and contains cerebrospinal fluid
  • Pia mater
    • Innermost layer that is in direct contact with the spinal cord
Definitions
Dorsal root
Sensory nerve that carries information from the spinal cord to the brain.
Ventral root
Motor nerve that carries information from the brain to the spinal cord.
Spinal nerve
Pathway for sensory and motor information to move between the peripheral system and the spinal cord.
Denticulate ligament
Ligament that provides stabilization of the spinal cord.
Posterior (dorsal) gray horn
Nerve fibers containing sensory information from the body.
Lateral gray horn
Nerve fibers containing sympathetic nervous system information are only found in the thoracic, upper lumbar, and sacral regions of the spinal cord.
Anterior (ventral) gray horn
Nerve fibers containing motor neurons that control skeletal muscles.
Posterior (dorsal) white column
Nerve fibers containing sensory information from the body, such as two-point discrimination, fine touch, vibration, and proprioception.
Lateral white column
Nerve fibers that contain sensory information such as pain, temperature, and crude touch.
Anterior (ventral) white column
Nerve fibers containing sensory and motor nerve fibers that provide motor commands from the brain to the same side of the body (ipsilateral), but also transmit sensory signals (like crude touch and pressure) to the opposite side of the brain (contralateral).
Sympathetic nervous system
A division of the autonomic nervous system that prepares the body to respond to physical activity, psychological stress, or perceived danger by initiating the “fight-or-flight” response.
Parasympathetic nervous system
A division of the autonomic nervous system that promotes recovery, conservation of energy, and homeostasis after stress or exertion — often called the “rest-and-digest” system.

The sympathetic nervous system increases heart rate, blood pressure, and respiratory rate to deliver oxygen to working muscles and vital organs, while dilating the pupils and bronchioles, redirecting blood away from nonessential processes such as digestion, and releasing glucose and fatty acids for immediate energy. The parasympathetic nervous system reverses these effects — slowing heart rate and blood pressure, constricting the pupils and bronchioles, and stimulating gastrointestinal activity, nutrient absorption, and waste elimination.

Spinal tracts

  • Ascending tracts
    • Carry sensory information such as touch, pain, and temperature from the peripheral system to the brain
      • Dorsal column-medial lemniscal: transmits light touch, deep pressure, two-point discrimination, and vibratory information to the cerebrum via the thalamus; crosses in the medulla to the contralateral side
      • Anterior and lateral spinothalamic: transmit pain, crude touch, and temperature information to the cerebrum via the thalamus; crosses in the medulla to the contralateral side
      • Spinocerebellar: transmits proprioceptive information to the cerebellum; does not cross, stays on the same side
  • Descending tracts
    • Carry motor information from the brain to the peripheral system to give voluntary commands of movement of axial and skeletal muscles
    • Anterior and lateral corticospinal: transmit commands to move axial and/or skeletal muscles
      • Anterior corticospinal: motor system that descends uncrossed in the front of the spinal cord, controlling trunk/axial muscles for posture
      • Lateral corticospinal: motor system where fibers cross over (decussate) in the lower medulla, forming the lateral tract, which controls movement of the extremities — particularly fine, coordinated movements — on the opposite (contralateral) side of the body

Arterial circulation of the spinal cord

  • Two (2) primary arteries of the spinal cord
    • Anterior spinal artery
      • Supplies blood to the anterior two-thirds of the spinal cord, except the dorsal column
    • Posterior spinal artery
      • Provides blood supply to the posterior spinal cord via two (2) branches that supply the dorsal sensory column, dorsal gray matter, and posterior columns
Key points

Primary function of the spinal cord

  • Relay pathway between peripheral system and brain
  • Manages sensory input and motor output
  • Coordinates simple reflexes (e.g., withdrawal, patellar reflex)

Anatomy of the spinal cord

  • Cervical spine: 8 nerves, neck and upper extremity innervation
  • Thoracic spine: 12 nerves, upper chest, chest, abdomen, upper back innervation
  • Lumbar spine: 5 nerves, legs and feet innervation
  • Sacral spine: 5 nerves, sacrum and pelvis innervation
  • Coccygeal spine: 1 nerve, perineal area innervation

Protective layers of the spinal cord

  • Dura mater: outermost layer, epidural space with fat and blood vessels
  • Arachnoid: middle, web-like, subarachnoid space with cerebrospinal fluid
  • Pia mater: innermost, direct contact with spinal cord

Key spinal cord structures and definitions

  • Dorsal root: sensory nerve to brain
  • Ventral root: motor nerve from brain
  • Spinal nerve: pathway for sensory and motor info
  • Denticulate ligament: stabilizes spinal cord
  • Gray horns:
    • Posterior (dorsal): sensory fibers
    • Lateral: sympathetic fibers (thoracic, upper lumbar, sacral)
    • Anterior (ventral): motor neurons for skeletal muscles
  • White columns:
    • Posterior (dorsal): sensory (touch, vibration, proprioception)
    • Lateral: sensory (pain, temperature, crude touch)
    • Anterior (ventral): sensory and motor to contralateral brain
  • Sympathetic nervous system: “fight-or-flight” response
  • Parasympathetic nervous system: “rest-and-digest” functions

Spinal tracts

  • Ascending tracts: carry sensory info to brain
    • Dorsal column-medial lemniscal: light touch, pressure, vibration (crosses in medulla)
    • Anterior/lateral spinothalamic: pain, crude touch, temperature (crosses in medulla)
    • Spinocerebellar: proprioception (does not cross)
  • Descending tracts: carry motor commands from brain
    • Anterior corticospinal: controls trunk/axial muscles (uncrossed)
    • Lateral corticospinal: controls extremities, fine movements (crosses in medulla)

Arterial circulation of the spinal cord

  • Anterior spinal artery: supplies anterior two-thirds (except dorsal column)
  • Posterior spinal artery: supplies posterior cord, dorsal sensory column, dorsal gray matter

More from Neuromuscular system

  • Central nervous system
  • Peripheral nervous system
  • Compare and contrast central nervous systems pathologies part 1
  • Compare and contrast central nervous systems pathologies part 2
  • Peripheral nervous system conditions