Neupsy Key

Dysfunction of either the brainstem or both cerebral hemispheres is necessary for loss of consciousness (LOC) to occur. Syncope, caused by global hypoperfusion of the brain due to a drop…

Urinary continence requires coordination of both the somatic and autonomic nervous systems, and also involves elements of volitional control and assessments of social appropriateness. Urinary storage is primarily mediated involuntarily…

Gait disorders can result from dysfunction of motor coordination systems, pyramidal or extrapyramidal motor pathways, or impairments in proprioceptive sensation. In addition, there are a number of nonneurologic causes of…

A. Initial evaluation should determine whether ataxia appears sensory or cerebellar. Profoundly decreased sensation and hyporeflexia in the absence of dysarthria or oculomotor findings make sensory ataxia more likely. Nystagmus,…

Aside from the olfactory cranial nerve (CN I) and the optic nerve (CN II), the remaining cranial nerves (CN III–XII) have nuclei in the brainstem. These then have axons extending…

The muscle stretch, or “deep tendon,” reflex is the product of a segmental reflex arc involving specific spinal cord or brainstem regions; this makes testing reflexes useful for anatomic localization….

Temperature and pain sensations are conveyed via small myelinated and unmyelinated nerve fibers. These enter the spinal cord via the dorsal spinal root and synapse in the dorsal horn at…

Fasciculations are caused by spontaneous depolarization of lower motor neurons, which results in contraction of the muscle fibers in the associated motor unit. Clinically this manifests as a visible twitch…

Unilateral foot drop is a common complaint. Careful examination of the anatomical pattern of the weakness helps identify the most likely location of the causative lesion. In some cases, clinical…

The quadriceps muscles in the anterior thigh extend the knee and are innervated by the femoral nerve, which arises from the lumbar plexus. The L2, L3, and L4 nerve roots…