Clinical Case Study: Mysterious Episodes of Mary: Neuroanatomy
What is hypoesthesia? How does it differ from paresthesia?
Hypoesthesia refers to a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli; in layman's terms, it's numbness. Paresthesia is a sensation of tingling, tickling, pricking, or burning of a person's skin with no apparent and obvious long-term physical effect. The difference is "numbness" is common to hypoesthesia, whereas the sensation of "pins and needles" or of a limb "falling asleep" is common to paresthesia.
Related to Episode 1: Which of Mary's cranial nerves is affected in this episode?
In Episode 1, Mary's Trigemial (V) nerve was affected because this particular nerve's sensory root detects facial sensation, including stimuli from the oral and nasal cavities.
Mary has experienced symptoms and effects associated with many parts of the human nervous system. Which of the following parts of her nervous system DOES NOT appear to show any effects?
The autonomic nervous system (ANS) within the motor division. It doesn't appear to show any effects because the ANS is a division of the nervous system that influences the function of internal organs (to say the least).
In which region of the brain do cranial nerves III-X originate?
The brain stem
Identify the part of the human nervous system that is usually associated with symptoms of hypoesthesia and paresthesia.
The part of the human nervous system that is usually associated with symptoms of hypoesthesia (numbness) and paresthesia (tingling-"pins and needles") is the Peripheral Nervous System (PNS); specifically, the sensory division. The PNS consists of nerves that carry signals from the senses (skin, ears, eyes, etc.) to the Central Nervous System (CNS: Brain and spinal cord). In other words, the PNS connects the body to the brain.
All of Mary's symptoms were related to cranial nerve functions associated with the head and neck region. Which is the only cranial nerve that extends beyond the head and neck to the thorax and abdomen?
X (vagus) nerve because it's the main parasympathetic nerve, and the most widely distributed nerve in the body. It innervates both the throat and anterior neck, and nearly all of the abdominal viscera. (FYI innervates means to supply with nerves).
As part of the neurological exam, the physician placed her hands on the side of Mary's head and asked her to rotate her head against resistance. The neurologist then pressed down on Mary's shoulders while Mary was asked to shrug. Which of Mary's cranial nerves is being evaluated with this exam?
XI (accessory) nerve because the spinal component turns inferiorly and exits the cranial cavity to innervate the trapezius and sternocleidomastoid muscles of the neck and shoulders. (FYI innervates means to supply with nerves).
