Corpus: Soft palate

The soft palate or velum is a mobile soft tissue fold consisting of muscels, connective tissue, and mucous membrane that adjoins the hard palate posteriorly. It forms the cranial edge of the isthmus faucium.

The basis of the soft palate is formed by a fiber-rich connective tissue plate called the palatal aponeurosis, into which the palatal muscles radiate.

The posterior edge of the soft palate forms a symmetrical double arch reminiscent of the McDonald's symbol. In its center, the uvula is attached to the free posterior edge. The boundary line between the hard and soft palate is known as the Ah-line, as it appears when this vowel is articulated. In dentistry, it serves as the maximum rear limit of full dentures, as longer dentures would be lifted off by the movements of the soft palate. Two double folds, known as the palatopharyngeal and palatoglossal arches, extend from the lateral edge of the soft palate.

The soft palate is mainly moved by the palatal muscles:

• Levator veli palatini muscle
• Tensor veli palatini muscle
• Uvular muscle
• Palatopharyngeal muscle
• Palatoglossus muscle

2.1. Innervation

The soft palate is innervated by the pharyngeal plexus, which is formed by fibers of the glossopharyngeal nerve (IX nerve) and vagus nerve (X nerve).

2.2. Vascular supply

The descending palatine artery and the ascending palatine artery supply the soft palate with blood.

Together with the base of the tongue, the soft palate separates the oral cavity from the pharynx. During swallowing, the soft palate is pressed against the posterior wall of the pharynx by the constrictor pharyngis muscle, thereby sealing the oral cavity against the epipharynx and the adjoining nasal cavity. This prevents the unintentional entry of liquids or chyme into the nasal cavity.

The soft palate also plays an important role in sound formation (articulation).

• Oral sounds are produced by raising the soft palate. This separates the nasal cavity from the oral cavity and the phonation stream coming from the lungs glides through the pharynx and mouth.
• For purely nasal sounds (consonants), the oral cavity is closed by the soft palate and the tongue and the phonation stream is channelled through the nasal cavity.
• For nasalised vowels, the soft palate assumes a central position. The phonation stream then flows through both the oral and nasal cavities.

In cleft lip and palate, the soft palate may be split. This impedes the act of swallowing. The soft palate also plays a role in the pathogenesis of snoring.