Anatomy and Physiology of the Speech, Language, and Hearing Systems
Core structures to know
A candidate must be able to trace the pathway from respiration through phonation, resonance, and articulation. Key landmarks: the larynx (thyroid, cricoid, arytenoid cartilages; true vs. false vocal folds; cricothyroid for pitch elevation, thyroarytenoid for shortening and lowering pitch), the vocal tract (pharynx, oral and nasal cavities), and the articulators (tongue, lips, velum, jaw). For hearing, know the outer, middle (tympanic membrane, ossicles: malleus, incus, stapes), and inner ear (cochlea, organ of Corti, hair cells), plus the auditory pathway to the temporal lobe. For language, know the left-hemisphere dominance for most speakers, Broca's area (inferior frontal gyrus) and Wernicke's area (posterior superior temporal gyrus), and the arcuate fasciculus connecting them. Cranial nerves V, VII, IX, X, XI, and XII are essential for speech and swallowing.
Traps in questions
Questions often confuse the cricothyroid (lengthens folds, raises pitch) with the thyroarytenoid (shortens folds, lowers pitch). Another trap is mixing conductive versus sensorineural sites: middle-ear problems cause conductive loss; cochlear hair-cell damage causes sensorineural loss. Do not confuse Broca's (production) with Wernicke's (comprehension). Remember that the velum elevates to close the nasal port during most oral sounds; failure to do so produces hypernasality.
Rule of thumb
Map each symptom to its anatomical level: hoarseness → larynx; hypernasality → velopharyngeal; distorted /r/ → tongue shape; word-finding difficulty → cortical language network.
Worked example: A child with a cleft palate shows nasal emission on pressure consonants. Localize to velopharyngeal incompetence, not to the articulators themselves.