This lesson introduces the spinal cord’s basic organization and explains how clinicians examine conscious somatic sensation. Understanding where sensory information enters and travels helps an examiner test systematically and interpret differences between body regions.
The spinal cord connects the body with the central nervous system (CNS). Cranial nerves connect the head and neck directly with the brain, while spinal nerves carry sensory information toward the CNS and motor commands toward the body.
All flashcards
How are gray and white matter arranged in a spinal cord cross-section?
Gray matter surrounds the central canal, while white matter lies outside it in dorsal, lateral, and anterior columns.
How do somatic and visceral senses differ?
Somatic senses arise mainly from skin, muscle, and tendon receptors and are usually consciously perceived. Visceral senses arise from internal organs and often support homeostasis without conscious awareness.
What does a dermatome represent?
A dermatome is a region of skin supplied predominantly by sensory fibers associated with a particular spinal nerve.
How can an examiner test proprioception?
Move a finger or toe and ask the patient to identify the movement. If it is not detected distally, repeat at progressively more proximal joints.
What does tactile-movement testing ask the patient to identify?
The direction in which a light stimulus is drawn across the skin.
Quiz questions
Which finding is commonly associated with an upper motor neuron lesion?Answer: Increased deep tendon reflexes and spasticity.
Which pattern is most characteristic of a lower motor neuron lesion?Answer: Weakness with reduced tone and reflexes.
How is muscle tone assessed during a neurological examination?Answer: By moving a relaxed limb passively through its range of motion.
During a pronator-drift test, what position should the patient assume?Answer: Extend both arms forward, turn the palms upward, and close the eyes.
What is the typical plantar response in an adult?Answer: Flexion of the toes.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.