Each taste bud consists of up to 100 polarized neuroepithelial cells that form “islands” of columnar pseudostratified cells embedded in the epithelium. Each bud has a central taste pore through…

The direct motor component of the pyramidal tract runs from the precentral gyrus through the posterior limb of the internal capsule and into the midbrain, where it gives slips to…

DISORDERS OF THE VESTIBULOCOCHLEAR NERVE AND SYSTEM Vestibular Ménière disease is an idiopathic process characterized by bouts of episodic vertigo, fluctuating but eventually progressive sensorineural hearing loss, tinnitus, and a…

The mandibular nerve (V3) is the largest branch of the trigeminal nerve and consists of a large sensory root and a small trigeminal motor root. The sensory portion innervates the…

Segments C5 to T1 innervate the arm and hand, with the anterolateral aspect of the shoulder supplied by C5. The thumb and index finger are good markers for C6, the…

OLFACTORY NERVE DISORDERS Anosmia is not always apparent to the patient, and due to the close association of flavor perception and olfaction, may be reported as altered taste rather than…

CHIASMAL AND POSTCHIASMAL NEUROLOGIC DEFICITS Lesions at the optic chiasm will result in bitemporal hemianopsia, caused by damage to the fibers from the nasal segment of both retinas. Interruption of…

The vestibular labyrinth receives dual innervation. The distal axonal processes of the bipolar vestibular afferent neurons have cell bodies housed in the vestibular ganglion of the internal acoustic meatus. The…

Meninges. The cord is surrounded by dura, arachnoid, and pia mater, which are continuous with the corresponding layers of the cerebral meninges at the foramen magnum. The spinal dura mater,…