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NEET MDS Synopsis - Lecture Notes
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📖 Anatomy

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The Layers of the Pharyngeal Wall
Anatomy

The Layers of the Pharyngeal Wall

  • The pharyngeal wall is composed of 5 layers. From internal to external, they are as follows.
  • Mucous membrane: this lines the pharynx and is continuous with all chambers with which it communicates.
  • Submucosa
  • Pharyngobasilar fascia: this is a fibrous layer that is attached to the skull.
  • Muscular layer: this is composed of inner longitudinal and outer circular parts.
  • Buccopharyngeal fascia: this is a loose connective tissue layer.
  • This fascia is continuous with the fascia covering the buccinator and pharyngeal muscle.
  • It contains the pharyngeal plexus of nerves and veins.
The Orbital Margin
Anatomy

The Orbital Margin

  • The frontal, maxillary and zygomatic bones contribute equally to the formation of the orbital margin.
  • The supraorbital margin is composed entirely of the frontal bone.
  • At the junction of its medial and middle thirds is the supraorbital foramen (sometimes a notch), which transmits the supraorbital nerves and vessels.
  • The lateral orbital margin is formed almost entirely of the frontal process of the zygomatic bone.
  • The infraorbital margin is formed by the zygomatic bone laterally and the maxilla medially.
  • The medial orbital margin is formed superiorly by the frontal bone and inferiorly by the lacrimal crest of the frontal process of the maxilla.
  • This margin is distinct in its inferior half only.
The Hard Palate
Anatomy

The Hard Palate

  • The anterior bony part of the palate is formed by the palatine process of the maxillae and the horizontal plates of the palatine bones.
  • Anteriorly and laterally, the hard palate is bounded by the alveolar processes and the gingivae.
  • Posteriorly, the hard palate is continuous with the soft palate.
  • The incisive foramen is the mouth of the incisive canal.
  • This foramen is located posterior to the maxillary central incisor teeth.
  • This foramen is the common opening for the right and left incisive canals.
  • The incisive canal and foramen transmit the nasopalatine nerve and the terminal branches of the sphenopalatine artery.
  • Medial to the third molar tooth, the greater palatine foramen pierces the lateral border of the bony palate.
  • The greater palatine vessels and nerve emerge from this foramen and run anteriorly into two grooves on the palate.
  • The lesser palatine foramen transmits the lesser palatine nerve and vessels.
  • This runs to the soft palate and adjacent structures.
The Masseter Muscle
Anatomy

The Masseter Muscle

  • This is a quadrangular muscle that covers the lateral aspect of the ramus and the coronoid process of the mandible.
  • Origin: inferior border and medial surface of zygomatic arch.
  • Insertion: lateral surface of ramus of mandible and its coronoid process.
  • Innervation: mandibular nerve via masseteric nerve that enters its deep surface.
  • It elevates and protrudes the mandible, closes the jaws and the deep fibres retrude it.