ONE 1 WK1

Session 1 Outline

• Topics covered include course introduction, nervous system review, blood supply, arterial occlusions, venous drainage, cerebrospinal fluid, and a lab on vertebrobasilar insufficiency tests.

Course Introduction

• Orthopedics focuses on correcting or preventing skeletal and associated structure issues (tendons and ligaments).
• Neurology concerns the structure, function, and diseases of the nervous system.
• Biomechanics studies the mechanics of muscular activity.
• Reasons for studying these disciplines, their practical applications, and their relationships to Traditional Chinese Medicine (TCM) are discussed.

Nervous System Review

• The central nervous system (CNS) and peripheral nervous system (PNS) structures related to neurology are reviewed.
• Basal ganglia (CNS)
• Diencephalon (CNS)
• Brain stem (CNS)
• Cerebellum (CNS)
• Spinal cord (CNS)
• Cranial nerves (PNS)
• Peripheral nerves (PNS)
• Spinal cord, cranial, and peripheral nerves will be covered later.

Basal Nuclei (Basal Ganglia)

• Structures: caudate nucleus, putamen, globus pallidus, and substantia nigra.
• Primary function is motor control.
• Crucial for starting, stopping, and regulating movement intensity.
• Also plays a role in cognition and emotion.
• Acts as a filter to screen for inappropriate responses.

Diencephalon

• Structures include thalamus, hypothalamus, and epithalamus.

Thalamus

• Gateway for information entering the cerebral cortex.
• Acts as a sensory relay center, sorting and sending information to appropriate areas.
• Related to emotions, visceral functions, and memory.

Brain Stem

• Structures: midbrain, pons, and medulla oblongata
• Conducts sensory and motor signals between the body and brain.
• Contains 9 of the 12 cranial nerve nuclei (CN I and II originate in the cerebrum, CN XI in the cervical spine).
• Integral to cardiovascular and respiratory control, pain sensitivity, awareness, and consciousness.

Cerebellum

• Cerebellar peduncles are three paired neuronal pathways connecting cerebellum to the brain stem.
• Superior peduncles connect with the midbrain, communicating with the cerebral motor cortex.
• Middle peduncles connect with the pons.
• Inferior peduncles connect with the medulla.
• Refines motor activity, influencing thinking, language, and emotion.
• Coordinates and smooths movements.
• Maintains posture and muscle tone.

Blood Supply – Circle of Willis

• A key arterial structure supplying the brain.
• Located at the base of the brain.
• An anastomotic system of arteries.
• Three arteries enter from the neck (Vertebral Basilar Artery (VBA), Internal Carotid Artery (ICA)).
• Six arteries exit to supply the brain (e.g., Anterior Cerebral Arteries (ACAs), Middle Cerebral Arteries (MCAs), Posterior Cerebral Arteries (PCAs)).
• Three arteries connect the others, completing the circle.
• Three small communicating arteries (Anterior Communicating Artery (ACOM), Posterior Communicating Arteries (PCOM)) connect the other arteries.
• The paired vertebral arteries originate from the subclavian arteries, travel up the cervical spine through the transverse foramina, and combine to form the basilar artery at the foramen magnum.
• The VBA continues to the base of the brain where it becomes part of the circle of Willis, and also forms the posterior cerebral arteries (PCAs). These exit the circle.
  • The VBA and the PCAs supply blood to the brain stem, parts of the thalamus, the occipital lobe, the cerebellum, and temporal lobe.
• The ICAs are major suppliers of arterial blood to the brain, forming a large portion of the Circle of Willis; they form anterior and middle cerebral arteries (ACAs and MCAs).
  • The ICA supplies brain regions that the VBA does not.
• Anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) are branches that supply specific regions of the brain to the lower body, upper body, and the occipital lobe, and parts of the thalamus and temporal lobe, respectively.

Arterial Occlusion

• Strokes (cerebrovascular accidents, CVAs) are the most common cause of neurological disability in adults and a leading cause of death.
• CVA affecting the ICA could result in unilateral blindness, severe contralateral hemiplegia and hemianesthesia, and profound aphasia.
• CVA affecting the MCA could result in alterations in communication, cognition, mobility, and sensation, as well as contralateral homonymous, hemianopia or hemiparesis; motor and sensory loss, greater in face and arm than leg.
• CVA affecting the ACA could result in emotional lability, confusion, amnesia, personality changes, urinary incontinence, contralateral hemiplegia or hemiparesis, more pronounced in the lower than upper extremities.
• CVA affecting the PCA could result in hemiparesis (greater in the face, and upper extremities), cerebellar ataxia and tremor, visual loss(homonymous hemianopia, cortical blindness), receptive aphasia, and memory deficits.
• VBA occlusion can result in transient ischemic attacks (TIAs), weakness in extremities, motor deficits involving the face, tongue, and throat; sensory loss.
• VBA complete blockages could result in coma, miotic pupils, decerebrate rigidity, respiratory and circulatory issues, and death.

Venous Drainage

• Blood drains from the brain via dural venous sinuses.
• These sinuses lie between the layers of the dura mater.
• Specific sinuses include the superior sagittal sinus (draining blood from the top of the brain), inferior sagittal sinus (draining blood from the inside of the brain), cavernous sinus (draining blood from the face and eyes), and transverse sinus (connecting with all other sinuses and draining into the internal jugular vein).

Cerebrospinal Fluid (CSF)

• CSF cushions and supports the brain and spinal cord.
• CSF is created by choroid plexuses in the brain ventricles.
• CSF is reabsorbed by arachnoid villi within the dural venous sinuses.
• CSF is a clear, colorless fluid similar in composition to blood plasma. (contains slight amounts of protein, glucose, and ions like Na+ and Cl−.)
• Normally contains very few, or zero, white and red blood cells.
• Approximately 150 ml of CSF in adults.
  • About 500 ml produced per day.
• If there is a blockage (e.g., tumor, infection, hemorrhage), CSF builds up resulting in hydrocephalus.
• Hydrocephalus symptoms in children include skull enlargement due to the lack of fully closed cranial sutures in infants.
• Symptoms of increased intracranial pressure in adults include exploding headaches, projectile vomiting, ataxia, loss of vision, and seizures.
• Death can be the result of brain stem and cerebellum displacement through the foramen magnum.

Lab: Vertebrobasilar Insufficiency Tests

• George's Test and Hautant's Test are used to evaluate blood flow in the vertebral arteries.
  • George's Test: patient seated with extended and rotated neck looking at a stationary object. Measures lateral vision, and checks for dizziness, vision disturbance, nausea, or headache to check for nystagmus. Positive result = vascular impairment. Repeat on opposite side.
  • Hautant's Test: Involves the patient's arms being extended to shoulder level, and palms facing upward.
  • Part 1 is to assess potential neurological issues. Patient closes eyes with extended arms. Positive results indicate neuro issues, test should not continue to Part 2.
  • Part 2 (only if Part 1 was normal) involves extended neck rotation with eyes closed, checking for loss of arm position. Positive result = vascular impairment. Repeat on opposite side.

Session 2 Outline

• The second session will cover a quiz, spinal cord review, spinal columns and tracts, upper and lower motor neurons, and a lab on pathological reflexes.
• Students need to start collecting tools such as reflex hammers.

This quiz covers the fundamental concepts of neurology, biomechanics, and orthopedics, including a review of the nervous system and blood supply. It explores the interconnections between these disciplines and their relevance to Traditional Chinese Medicine. Prepare to test your understanding of the nervous system structures and associated clinical applications.