Dysphagia Anatomy, Swallowing Phases & Cranial Nerves

Intrinsic vs. extrinsic tongue muscles?

Intrinsic change tongue shape; extrinsic change tongue position.

What can reduced tongue-base retraction cause?

Reduced pharyngeal pressure and vallecular residue.

What is the laryngeal vestibule?

Space from the laryngeal inlet to the false vocal folds.

What distinguishes penetration from aspiration?

Penetration stays above the true vocal folds; aspiration passes below.

What prevents bolus entry into the nasopharynx?

Velopharyngeal closure through soft palate elevation.

What is the function of the hypopharynx?

Directs the bolus around the larynx toward the UES.

What do arytenoids do during swallowing?

Approximate and move anteriorly to help close the laryngeal inlet.

Tensor vs. levator veli palatini: function and nerve?

Tensor: tenses, CN V3. Levator: elevates, CN X.

What is the primary function of CN XI?

Motor control of sternocleidomastoid and trapezius.

Which muscle primarily protrudes the tongue?

Genioglossus, innervated by CN XII.

Which muscle primarily depresses the tongue?

Hyoglossus, innervated by CN XII.

Which muscle retracts and elevates the tongue?

Styloglossus, innervated by CN XII.

What does palatoglossus do?

Elevates posterior tongue and narrows the oropharyngeal isthmus; CN X.

What does the transverse intrinsic tongue muscle do?

Narrows and elongates the tongue; CN XII.

What does the vertical intrinsic tongue muscle do?

Flattens and broadens the tongue; CN XII.

Which phase includes mastication and bolus formation?

Oral preparatory phase.

Which phase propels the bolus posteriorly using the tongue?

Oral transit phase.

Which swallowing phase includes laryngeal vestibule closure?

Pharyngeal phase.

Where is the nasopharynx located?

Posterior to the nasal cavity, superior to the soft palate.

Where is the oropharynx located?

Posterior to the oral cavity, below the soft palate.

What are the pyriform sinuses?

Paired hypopharyngeal channels directing bolus toward the UES.

What is distinctive about cricoid cartilage?

It is the only complete ring of laryngeal cartilage.

What do aryepiglottic folds form?

The lateral boundaries of the laryngeal inlet.

What are the inferior boundaries of the laryngeal vestibule?

The vestibular (false vocal) folds.

Which folds define the aspiration threshold?

True vocal folds: material below them is aspiration.

Which nerve supplies tensor veli palatini?

CN V3, the mandibular division of trigeminal nerve.

Which nerve supplies levator veli palatini?

CN X via the pharyngeal plexus.

What may impaired velopharyngeal closure cause?

Nasal regurgitation during swallowing.

What is the key role of hyolaryngeal anterior excursion?

Helps open the UES by traction.

What else is required for UES opening besides traction?

Cricopharyngeal relaxation and bolus-driven distension.

What may reduced UES opening cause?

Pyriform sinus residue and impaired bolus passage.

What may reduced pharyngeal constriction cause?

Diffuse pharyngeal residue after the swallow.

What may delayed laryngeal vestibule closure cause?

Airway invasion during the swallow.

What may incomplete laryngeal vestibule closure cause?

Laryngeal penetration or aspiration.

What can vallecular residue suggest?

Reduced tongue-base retraction or impaired epiglottic movement.

Which cranial nerve carries key laryngeal motor fibers?

CN X (vagus), via its laryngeal branches.

What is the recurrent laryngeal nerve responsible for?

Motor supply to most intrinsic laryngeal muscles; branch of CN X.

Which intrinsic laryngeal muscle is NOT supplied by recurrent laryngeal nerve?

Cricothyroid; supplied by external branch of superior laryngeal nerve.

How can CN XI weakness affect dysphagia management?

Impaired head rotation or postural control may limit compensatory positioning.