Neurologic System Structure and Function Flashcards

Flashcards covering the structure and function of the neurologic system, including dermatomes, developmental considerations, stroke risk factors, subjective data, and objective physical examination techniques.

What are the useful landmarks for dermatome segments?

The thumb, middle finger, and fifth finger are in the dermatomes of $C6$, $C7$, and $C8$; the axilla is at $T1$; the nipple is at $T4$; the umbilicus is at $T10$; the groin is in the region of $L1$; and the knee is at the level of $L4$.

What are the functional divisions of the peripheral nervous system fibers?

Somatic fibers, which innervate skeletal (voluntary) muscles, and autonomic fibers, which innervate smooth (involuntary) muscles, cardiac muscle, and glands.

What is the primary function of the autonomic system?

To maintain homeostasis of the body.

In what order does myelinization occur in infants?

A cephalocaudal and proximodistal order (head, then neck, trunk, and out to extremities).

What neurologic signs are considered normal in adults older than $65$ years?

General loss of muscle bulk; loss of muscle tone in the face, neck, and spine; decreased muscle strength; impaired fine coordination; loss of vibratory sense at the ankle; decreased or absent Achilles reflex; pupillary miosis; and decreased pupillary reflexes.

How does Alzheimer disease (AD) imaging differ from normal healthy aging?

Normal aging shows symmetric and generalized brain atrophy, while AD images show asymmetry and focal brain atrophy, most prominent in the temporal and parietal lobes, especially the hippocampus.

What effect does aging have on nerve conduction velocity?

The velocity of nerve conduction decreases between $5\%$ and $10\%$ with aging.

What are the four healthy lifestyle factors that can decrease stroke risk independent of genetic risk?

Nonsmoker, healthy diet, body mass index <$30\,kg/m^2$, and regular physical exercise.

What geographic regions are known as the 'stroke belt' and 'stroke buckle'?

The stroke belt refers to eight states with high stroke mortality in the U.S. southeast; the stroke buckle refers to the coastal plain of North Carolina, South Carolina, and Georgia.

What are the modifiable risk factors estimated to account for $91\%$ of stroke risk?

Hypertension, obesity, hyperglycemia, hyperlipidemia, and renal dysfunction.

What is the difference between syncope and vertigo?

Syncope is a sudden loss of strength and temporary loss of consciousness caused by lack of cerebral blood flow; vertigo is a rotational spinning sensation caused by neurologic disease in the vestibular apparatus or brainstem.

What term is used for a subjective sensation that precedes a seizure?

Aura, which could be auditory, visual, or motor.

What is the difference between paresis and paralysis?

Paresis is partial or incomplete paralysis, whereas paralysis is a total loss of motor function caused by a lesion in the neurologic or muscular system.

What is dysmetria?

The inability to control the distance, power, and speed of a muscular action.

Define dysarthria and dysphasia.

Dysarthria is difficulty forming words; dysphasia is difficulty with language comprehension or expression.

Why are teenagers more susceptible to concussions?

Because of thinner cranial bones, a larger head-to-body ratio, smaller brain size, and a larger subarachnoid space in which the brain can rattle.

What should be used to test Cranial Nerve I (Olfactory Nerve)?

Familiar, nonnoxious smells such as coffee, toothpaste, orange, vanilla, soap, or peppermint.

What is nystagmus and where does it occur?

A back-and-forth oscillation of the eyes; it occurs with disease of the vestibular system, cerebellum, or brainstem.

What are the three divisions of Cranial Nerve V (Trigeminal Nerve)?

(1) Ophthalmic, (2) maxillary, and (3) mandibular.

How is Cranial Nerve XII (Hypoglossal Nerve) tested?

By inspecting the tongue for wasting or tremors, noting if it protrudes in the midline, and checking if lingual speech (sounds of letters l, t, d, n) is clear and distinct.

What is dysdiadochokinesia?

A slow, clumsy, and sloppy response to rapid alternating movements (RAM), which occurs with cerebellar disease.

What does a positive Romberg sign indicate?

Loss of balance when closing the eyes, occurring with cerebellar ataxia (multiple sclerosis, alcohol intoxication), loss of proprioception, and loss of vestibular function.

What are the specific spinal levels for the deep tendon reflexes?

Biceps ($C5$ to $C6$), Triceps ($C7$ to $C8$), Brachioradialis ($C5$ to $C6$), Quadriceps ($L2$ to $L4$), and Achilles ($L5$ to $S2$).

How is the deep tendon reflex response graded?

On a $4$-point scale: $4+$ (very brisk/clonus/disease), $3+$ (brisker than average), $2+$ (average/normal), $1+$ (diminished/low normal), and $0$ (no response).

What is the Babinski sign in an adult?

The abnormal response to the plantar reflex where the big toe dorsiflexes and all toes fan; it indicates UMN disease of the corticospinal tract.

What are the four components of a neurologic recheck examination?

1. Level of consciousness, 2. Motor function, 3. Pupillary response, and 4. Vital signs.

What is the Cushing reflex?

A sign of increasing intracranial pressure characterized by a sudden elevation in BP with widening pulse pressure and a decreased, slow, and bounding pulse rate.

What are the three areas rated in the Glasgow Coma Scale (GCS)?

Eye opening, verbal response, and motor response.

What do GCS scores reflect?

A fully alert, healthy person has a score of $15$, whereas a score of $7$ or less reflects coma.