Neurological Assessment

• Nervous System


  Divided into 2 regions: Central Nervous System (CNS) - brain and spinal cord, Peripheral Nervous System (PNS) - cranial nerves, spinal nerves and autonomic nervous system

  
• Central Nervous System (CNS)


  • Brain and spinal cord

  
• Peripheral Nervous System (PNS)


  • Cranial nerves, spinal nerves and autonomic nervous system

  
• Functions of the Nervous System


  1. Carries sensory (afferent) messages TO the CNS from sensory receptors

  2. Carries motor (efferent) messages FROM the CNS out to the muscles and glands

  3. Carries autonomic messages that govern the internal organs and blood vessels

  
• CNS Components


  • Brain: Cerebrum, Diencephalon, Brain stem, Cerebellum
  • Spinal cord
  • Meninges
• Thalamus


  • Largest part, influences mood and registers an unlocalized, uncomfortable perception of pain
• Epithalamus


  • Small area superior and posterior to the thalamus, involved in the emotional and visceral response to odors, pineal body (onset of puberty)
• Hypothalamus


  • Most inferior part, important in maintaining homeostasis, plays a central role in the control of body temperature, hunger and thirst, plays a major role in controlling the secretion of hormones from the pituitary gland
• Three major units of the Brain


  • Cerebrum
  • Cerebellum
  • Brainstem (Medulla, Pons, Midbrain)

  
• Cerebrum


  • Largest part of the brain, divided into left and right hemisphere by a longitudinal fissures, surface is wrinkled by presence of eminences known as Gyri and furrows called Sulci or Fissures

  
• Frontal Lobe


  • Principal motor area, important in the control of voluntary motor functions, motivation, aggression, mood, and olfactory (smell) reception, Broca's area

  
• Parietal Lobe


  • Principal center for the reception and conscious perception of most sensory information, such as touch, pain, temperature, balance and taste, Principal sensory area
• Occipital Lobe


  • Functions in the reception and perception of visual input, Principal visual cortex

  
• Temporal Lobe


  • Involved in olfactory (smell) and auditory (hearing) sensations and plays an important role in memory, They associated in abstract thought and judgement, Primary auditory cortex, Wernicke's area

  
• Wernicke's area


  In temporal lobe associated with language comprehension, when damaged in the person's dominant hemisphere, receptive aphasia results; person hears sound, but it has no meaning, like hearing a foreign language

  
• Broca's area


  In frontal lobe mediates motor speech, when injured in dominant hemisphere, expressive aphasia results; person cannot talk; person can understand language and knows what they want to say, but can produce only garbled sound

  
• Cerebellum


  • Composed of gray matters, Posterior and inferior to the cerebrum, Involved in balance, maintenance of muscle tone and coordination of fine motor movements, Major function is that of comparator, Also involves learning motor skills
• Brainstem Components


  • Midbrain
  • Pons
  • Medulla

  
• Medulla Oblongata


  • Most inferior portion of the brainstem, Continuous with the spinal cord, Extends from the level of the foramen magnum to the pons, Contains cranial nerves 9, 10, 11, 12, Specific functions: regulation of HR and BV diameter, breathing, swallowing, vomiting, coughing, sneezing, balance and coordination
• Pons


  • Immediately superior to the medulla oblongata, Means "bridge", Contains cranial nerves 5, 6, 7, 8, Lower part controls breathing, swallowing and balance, Other nuclei control functions such as chewing and salivation
• Midbrain


  • Superior to the pons, Smallest region of the brainstem, Contains cranial nerves 3 and 4, Found superior and inferior colliculus, Superior colliculi involved in visual reflexes, turning the head, a sudden loud noise, bright flash of light, Inferior colliculi major relay centers for the auditory nerve pathways in the CNS

  
• Spinal Cord


  • Long cylindrical structure of nervous tissue that occupies upper two thirds of vertebral canal from medulla to lumbar vertebrae L1 to L2, Main highway for ascending and descending fiber tracts that connect the brain to spinal nerves, and it mediates reflexes, Nerve cell bodies, or gray matter, arranged in butterfly shape with anterior and posterior "horns"

  
• Crossed representation is notable feature of nerve tracts, Left cerebral cortex receives sensory information from and controls motor function to right side of the body, Right cerebral cortex likewise interacts with left side of body

  
• Cranial Nerves


  • 12 pairs

  
• Spinal Nerves


  • 31 pairs, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal

  
• Spinal Nerves


  "Mixed" nerves, they contain both sensory and motor fibers, Each innervates particular segment of body, Dermal segmentation is cutaneous distribution of various spinal nerves

  
• Peripheral Nervous System


  Composed of cranial nerves and spinal nerves, Divided functionally into somatic fibers that innervate skeletal (voluntary) muscles, and autonomic fibers that innervate smooth (involuntary) muscles, cardiac muscle, and glands

  
• Autonomic Nervous System


  Mediates unconscious activity, Composed of Sympathetic and Parasympathetic divisions
• Sympathetic Nervous System


  • ADRENERGIC system, Originates from the T1-L2/L3 segments of the spinal cord (thoracolumbar), Utilized by the body for FLIGHT and FIGHT response, Neurotransmitter agents are Epinephrine and Norepinephrine (coming from the adrenal gland)
• Sympathetic Responses


  • Increased: HR, RR, BP, Visual Acuity (Pupillary Dilation)
  • Smooth Muscle tones sphincters are contracted
  • Vasoconstriction - peripheral
  • Metabolism: ↑ glucose, ↑ fatty acids
  • Decreased: Peristalsis, Salivary secretions, Ejaculation
• Parasympathetic Nervous System


  • CHOLINERGIC system, The vegetative system, Feed and Breed responses (Rest and Digest), Cranio-sacral location, Cranial nerves- 3, 7, 9, 10 and S2-S4, Neurotransmitter is Acetylcholine
• Parasympathetic Responses


  • Decreased: HR, RR, BP, Visual Acuity (Pupillary constriction), Smooth Muscle tone
• Reflexes


  Basic defense mechanisms of nervous system, Involuntary - below level of conscious control permitting quick reaction to potentially painful or damaging situations
• Types of Reflexes


  • Deep tendon reflexes (myotatic), e.g., knee jerk
  • Superficial - e.g., corneal reflex, abdominal reflex
  • Visceral - e.g., pupillary response to light
  • Pathologic (abnormal) - e.g., Babinski's reflex or extensor plantar reflex
• Glasgow Coma Scale


  Used to objectively describe the extent of impaired consciousness in all types of acute medical and trauma patients, Assesses patients according to three aspects of responsiveness: eye-opening, motor, and verbal responses