Relevant Embryology
To fully understand the specific etiologies of velopharyngeal disorders and the numerous approaches to their assessment and treatment, the speech-language pathologist should have a working knowledge of the embryological development of the head, face, palate, and pharyngeal structures. To gain a better understanding of how these structures develop, click on the video below.
Key points:
-
Cleft palate and other craniofacial abnormalities can occur if tissues stemming from the embryological neural crest fail to migrate into specific structures.
-
The alveolus and lip begins development at approximately 6 weeks.
-
The palate begins development at approximately 8 weeks.
Source: Kummer, A. (2013). Cleft Palate and Craniofacial Anomalies: Effects of Speech and Resonance (3rd Ed.). Cengage Learning.
Relevant Anatomy
The anatomy of the velopharyngeal mechanism (soft palate) is composed of numerous muscular structures and innervated by multiple branches of cranial nerves. For an overview of the velopharyngeal landmarks, histology, musculature, and innervation, see the video below.
Key Points:
-
Anatomical Landmarks - uvula, anterior/posterior faucial pillars
-
Musculature - levator veli palatini, musculus uvulae, tensor veli palatini, palatoglossus, palatopharyngeus
-
Innervation - spinal accessory (CN #11), vagus (CN #10), trigeminal (CN #5) [tensor veli palatini only]
-
Physiological Mechanism - The velar structures of the soft palate elevate and close in a circular fashion
to mechanically separate the naso- and oro-pharyngeal cavities when swallowing producing non-nasal speech sounds. At rest, the velum remains in a depressed (or lowered) position, allowing for nasal breathing and the production of nasal consonants.
Source: Seikel, JA., King, DW., Drumwright, DG. (2010). Anatomy and Physiology for Speech, Language, and Hearing (4th Ed.). Delmar-Cengage Learning.
Relevant Etiologies
Velopharyngeal disorders are a result of both congenital and acquired abnormalities. In most congenital cases, a known syndromic or genetic event is clearly defined as the etiology, there are also congenital cases of non-specific origin. While most professionals are most familiar with velopharyngeal dysfunction related to cleft palate, however neurological insults such as strokes, trauma, or tumors are also known causes.
Congenital Etiologies:
-
There are over 100 syndromic causes of velopharyngeal dysfunction due to neurologic, neuromuscular, or clefting defects (e.g., velocardiofacial syndrome, Beckwith-Wiedemann syndrome, Turner syndrome).
-
Velopharyngeal clefts are also found to have no known specific etiology.
-
See the first video below to hear a sample of hypernasal speech resulting from cleft palate.
Acquired Etiologies:
-
Cerebrovascular accidents, tumors, trauma, are all possible causes of acquired velopharyngeal dysfunction (e.g. Paralysis to the neuromuscular units controlling velar elevation by a lower motor neuron lesion).
-
Hear an example of hypernasal speech resulting from flaccid dysarthria in the small second video clip below.
Sources: Bhatnagar, S. (2012). Neuroscience for the Study of Communicative Disorders (4th Ed.). Lippincott Williams & Wilkins.; Kummer, A. (2013). Cleft Palate and Craniofacial Anomalies: Effects of Speech and Resonance (3rd Ed.). Cengage Learning.; Seikel, JA., King, DW., Drumwright, DG. (2010). Anatomy and Physiology for Speech, Language, and Hearing (4th Ed.). Delmar-Cengage Learning.; Shprintzen, R. J. (2000). Syndrome identification for speech-language pathologists: An illustrated pocketguide. Singular Publishing Group.