The Laryngopharynx

• The laryngeal part of the pharynx lies posterior to the larynx.
• It extends from the superior border of the epiglottis to the inferior border of the cricoid cartilage, where it narrows to become continuous with the oesophagus.

• Posteriorly, the laryngopharynx is related to the bodies of C4 to C6 vertebrae.

• Its posterior and lateral walls are formed by the middle and inferior constrictor muscles, with the palatopharyngeus and stylopharyngeus internally.

• The laryngopharynx communicates with the larynx through the aditus or inlet of the larynx.
• The piriform recess is a small, pear-shaped depression of the laryngopharyngeal cavity on each side of the inlet of the larynx.

• This is the posterior curtain-like part, and has no bony support. It does, however, contain a membranous aponeurosis.
• The soft palate, or velum palatinum (L. velum, veil), is a movable, fibromuscular fold that is attached to the posterior edge of the hard palate.
• It extends posteroinferiorly to a curved free margin from which hangs a conical process, the uvula (L. uva, grape).

• The soft palate separates the nasopharynx superiorly and the oropharynx inferiorly.

• During swallowing the soft palate moves posteriorly against the wall of the pharynx, preventing the regurgitation of food into the nasal cavity.

• Laterally, the soft palate is continuous with the wall of the pharynx and is joined to the tongue and pharynx by the palatoglossal and palatopharyngeal folds.

• The soft palate is strengthened by the palatine aponeurosis, formed by the expanded tendon of the tensor veli palatini muscle.
• This aponeurosis attaches to the posterior margin of the hard palate.

The Submandibular Glands

• Each of these U-shaped salivary glands is about the size of a thumb and lies along the body of the mandible.
• It is partly superior and partly inferior to the posterior 1/2 of the base of the mandible.
• It is partly superficial and partly deep to the mylohyoid muscle.

• The submandibular duct arises from the portion of the gland that lies between the mylohyoid and hyoglossus muscle.

• The duct passes deep and then superficial to the lingual nerve.
• It opens by one to three orifices on a small sublingual papilla beside the lingual frenulum.

• The submandibular gland is supplied by parasympathetic, secretomotor fibres from the submandibular ganglion (preganglionic fibres from the chorda tympani via the lingual nerve).

Nerves of the Palate

• The sensory nerves of the palate, which are branches of the pterygopalatine ganglion, are the greater and lesser palatine nerves.
• They accompany the arteries through the greater and lesser palatine foramina, respectively.

• The greater palatine nerve supplies the gingivae, mucous membrane, and glands of the hard palate.

• The lesser palatine nerve supplies the soft palate.

• Another branch of the pterygopalatine ganglion, the nasopalatine nerve, emerges from the incisive foramen and supplies the mucous membrane of the anterior part of the hard palate.

Vessels of the Palate

• The palate has a rich blood supply from branches of the maxillary artery.

Internal Muscles of the Pharynx

• The internal, chiefly longitudinal muscular layer, consists of 3 muscles: stylopharyngeus, palatopharyngeus, and salpingopharyngeus.
• They all elevate the larynx and pharynx during swallowing and speaking.

The Stylopharyngeus Muscle

• This is a long, thin, conical muscles that descends inferiorly between the external and internal carotid arteries.
• It enters the wall of the pharynx between the superior and middle constrictor muscles.

• Origin: styloid process of temporal bone.
• Insertion: posterior and superior borders of thyroid cartilage with palatopharyngeus muscle.
• Innervation: glossopharyngeal nerve (CN IX).

• It elevates the pharynx and larynx and expands the sides of the pharynx, thereby aiding in pulling the pharyngeal wall over a bolus of food.

The Palatopharyngeus Muscle

• This is a thin muscle and the overlying mucosa form the palatopharyngeal arch.

The Salpingopharyngeus Muscle

• This is a slender muscle that descends in the lateral wall of the pharynx.
• The over lying mucous membrane forms the salpingopharyngeal fold.

• Origin: cartilaginous part of the auditory tube.
• Insertion: blends with palatopharyngeus muscle.
• Innervation: through the pharyngeal plexus.

• It elevates the pharynx and larynx and opens the pharyngeal orifice of the auditory tube during swallowing.

The Medial Wall of the Orbit 

• This wall is paper-thin and is formed by the orbital lamina or lamina papyracea of the ethmoid bone, along with contributions from the frontal, lacrimal, and sphenoid bones (L. papyraceus, "made of papyrus" or parchment paper).

• There is a vertical lacrimal groove in the medial wall, which is formed anteriorly by the maxilla and posteriorly by the lacrimal bone.
• It forms a fossa for the lacrimal sac and the adjacent part of the nasolacrimal duct.

• Along the suture between the ethmoid and frontal bones are two small foramina; the anterior and posterior ethmoidal foramina.
• These transmit nerves and vessels of the same name.