Soft palate

SOFT PALATE

Definition External Features Folds Structure Muscles Blood Supply Nerve Supply Movements & Functions Clinical Anatomy
01

Definition

  • Soft palate is a movable, muscular fold suspended from the posterior border of the hard palate.
  • It separates the nasopharynx from the oropharynx, which is the crossroads between the food and air passages.
02

External Features

A. Surfaces

The soft palate has two surfaces:

1. Anterior (Oral) Surface

  • Concave.
  • Marked by a median raphe.

2. Posterior Surface

  • Convex.
  • Continuous superiorly with the floor of the nasal cavity.

B. Borders

The soft palate has two borders:

1. Superior Border

  • Attached to the posterior border of the hard palate.
  • Blends on each side with the pharynx.

2. Inferior Border

  • Free.
  • Bounds the pharyngeal isthmus.
  • From its middle hangs a conical projection called the uvula.
  • Uvula → Latin for small grape.
03

Folds from the Base of Uvula

From each side of the base of the uvula, two curved folds of mucous membrane extend laterally and downwards.

A. Palatoglossal Arch

  • Also called the anterior pillar of fauces.
  • Contains the palatoglossus muscle.
  • Reaches the side of the tongue at the junction of its:
    • Oral part
    • Pharyngeal part
  • Forms the lateral boundary of the oropharyngeal isthmus / isthmus of fauces.

B. Palatopharyngeal Arch

  • Also called the posterior pillar of fauces.
  • Contains the palatopharyngeus muscle.
  • Forms the posterior boundary of the tonsillar fossa.
  • Merges inferiorly with the lateral wall of the pharynx.
04

Structure

The soft palate is a fold of mucous membrane containing the following parts:

A. Palatine Aponeurosis

  • It is the flattened tendon of tensor veli palatini.
  • It forms the fibrous basis of the soft palate.
  • Near the median plane, the aponeurosis splits to enclose the musculus uvulae.

B. Muscles

  • Levator veli palatini
  • Palatopharyngeus
  • Lie on the superior surface of the palatine aponeurosis.
  • Palatoglossus
  • Lies on the inferior or anterior surface of the palatine aponeurosis.

C. Glands and Taste Buds

  • Numerous mucous glands are present.
  • Some taste buds are present.

D. Tissue Components

Soft palate comprises:

  1. Epithelium
  2. Connective tissue
  3. Muscles
  • Epithelium is from the ectoderm of the maxillary process.
  • Muscles are derived from the 1st, 4th and 6th branchial arches.
  • Accordingly, they are innervated by the mandibular and vagoaccessory complex.
05

Muscles of the Soft Palate

They are:

  1. Tensor palati (tensor veli palatini)
  2. Levator palati (levator veli palatini)
  3. Musculus uvulae
  4. Palatoglossus
  5. Palatopharyngeus

Their origin, insertion and actions are given below from the source table.

Origin, Insertion and Actions of Muscles of Soft Palate

Muscle Origin Insertion Actions
1. Tensor veli palatini
  1. Lateral side of auditory tube
  2. Adjoining part of base of skull (greater wing and scaphoid fossa of sphenoid bone)
 Muscle descends and converges to form a delicate tendon which winds round the pterygoid hamulus, passes through the origin of the buccinator and flattens out to form the palatine aponeurosis.

Aponeurosis is attached to:
  1. Posterior border of hard palate
  2. Inferior surface of palate behind the palatine crest
  1. Tightens the soft palate, chiefly the anterior part.
  2. Opens the auditory tube to equalize air pressure between the middle ear and the nasopharynx.
2. Levator veli palatini
  1. Inferior aspect of auditory tube
  2. Adjoining part of inferior surface of petrous temporal bone
 Muscle enters the pharynx by passing over the upper concave margin of the superior constrictor, runs downwards and medially and spreads out in the soft palate.

It is inserted into the upper surface of the palatine aponeurosis.
  1. Elevates soft palate and closes the pharyngeal isthmus.
  2. Opens the auditory tube like the tensor veli palatini.
3. Musculus uvulae
  1. Posterior nasal spine
  2. Palatine aponeurosis
 Mucous membrane of uvula Pulls up the uvula.
4. Palatoglossus Oral surface of palatine aponeurosis Descends in the palatoglossal arch to the side of the tongue at the junction of its oral and pharyngeal parts Pulls up the root of the tongue, approximates the palatoglossal arches and thus closes the oropharyngeal isthmus.
5. Palatopharyngeus
  1. Anterior fasciculus from posterior border of hard palate
  2. Posterior fasciculus from palatine aponeurosis
 Descends in the palatopharyngeal arch and spreads out to form the greater part of the longitudinal muscle coat of the pharynx.

Inserted into:
  1. Posterior border of the lamina of thyroid cartilage
  2. Wall of pharynx and its median raphe
 Pulls up the wall of the pharynx and shortens it during swallowing.
06

Blood Supply

A. Arteries

  1. Greater palatine branch of maxillary artery
  2. Ascending palatine branch of facial artery
  3. Palatine branch of ascending pharyngeal artery

B. Veins

  • Pass to the pterygoid and tonsillar plexuses of veins.

C. Lymphatics

  • Drain into the upper deep cervical and retropharyngeal lymph nodes.
07

Nerve Supply

A. Motor Nerves

  • All muscles of the soft palate except tensor veli palatini are supplied by the pharyngeal plexus.
  • Fibres of this plexus are derived from the cranial part of the accessory nerve through the vagus.
  • Tensor veli palatini is supplied by the mandibular nerve.

B. General Sensory Nerves

Derived from:

  1. Middle and posterior lesser palatine nerves
    • Branches of the maxillary nerve through the pterygopalatine ganglion.
  2. Glossopharyngeal nerve.

C. Special Sensory / Gustatory Nerves

  • Carry taste sensations from the oral surface.
  • They are contained in the lesser palatine nerves.
  • Fibres travel through the greater petrosal nerve to the geniculate ganglion of the facial nerve.
  • From there, they pass to the nucleus of the tractus solitarius.

D. Secretomotor Nerves

  • Also contained in the lesser palatine nerves.
  • Derived from the superior salivatory nucleus.
  • Travel through the greater petrosal nerve.
08

Movements and Functions of the Soft Palate

1. During Swallowing

Soft palate separates the oropharynx from the nasopharynx during swallowing to prevent entry of food into the nose.

2. During Chewing and Breathing

Separates the oral cavity from the oropharynx to facilitate chewing and breathing simultaneously.

3. Voice

Voice modulation.

4. Protection of Nasal Mucosa

By diverting airflow through the mouth during sneezing.

5. During Coughing

Prevents entry of mucous into the nose during coughing.

09

Clinical Anatomy

1. Paralysis of Soft Palate

Paralysis of the soft palate in lesions of the vagus nerve produces:

  1. Nasal regurgitation of liquids
  2. Nasal twang in voice
  3. Flattening of the palatal arch
  4. Deviation of uvula to the normal side.

2. Choking

  • Choking by food/fluid causes:
    • Laryngeal obstruction
    • Asphyxia
  • Heimlich manoeuvre can remove the obstruction.

Heimlich Manoeuvre

  1. Stand behind the patient.
  2. Pass your arm under his arm.
  3. Put hand in his epigastrium.
  4. One hand is made into a fist.
Soft Palate — Study Notes