5 topics with brief reviews: definitions, key facts, and class questions.
This chapter is dedicated to the foundation of the neurological clinic — somatic sensation. Here, we analyze in detail how the nervous system perceives external stimuli, classify types of sensation, and trace the anatomy of sensory pathways from receptors to the cerebral cortex.
You will learn the clinical manifestations of sensory disorders (from routine hypesthesia to agonizing hyperpathia) and master the classical examination technique using a neurological pin, tuning fork, and cotton wisp.
Pay special attention to topical diagnosis. During rounds and examinations, this will be your primary focus: you must be able to accurately determine the level of the nervous system lesion based on the distribution pattern of sensory deficits (peripheral, segmental, or tract type).
Where are the cell bodies of the first-order neurons of the deep sensory pathways located?
The cell bodies of the first-order neurons are located in the dorsal root ganglia (spinal ganglia).
Where does the decussation of the spinothalamic tract occur?
The axons of the second-order neurons decussate to the contralateral side via the anterior gray commissure of the spinal cord 1–2 segments above the level of their entry.
What is the "gate control theory of pain"?
This is a mechanism whereby impulses traveling along thick myelinated fibers inhibit pain transmission at the level of the posterior horns of the spinal cord. It creates a sort of "gate control" for pain signals.
What is secondary astereognosis (stereoanesthesia)?
This is the inability to recognize an object by touch, primarily caused by impairment of elementary modalities of sensation (tactile and proprioceptive).
Why is temperature sensation lost on the healthy side in Brown-Séquard syndrome?
Because the fibers of the spinothalamic tract, which carry pain and temperature information, decussate within the spinal cord. Damage to one half of the spinal cord interrupts pathways that have already crossed over from the opposite side of the body.
Master the entire topic in the "Neurology" course
This is a summary. The course covers everything tested in classes and exams.
907 pages of study guides on all topics
Assignments and quizzes after every topic — just like in a colloquium