NEET MDS Lessons
Anatomy
Muscles of the Soft Palate
The Levator Veli Palatini (Levator Palati)
- Superior attachment: cartilage of the auditory tube and petrous part of temporal bone.
- Inferior attachment: palatine aponeurosis.
- Innervation: pharyngeal branch of vagus via pharyngeal plexus.
- This cylindrical muscle runs inferoanteriorly, spreading out in the soft palate, where it attaches to the superior surface of the palatine aponeurosis.
- It elevates the soft palate, drawing it superiorly and posteriorly.
- It also opens the auditory tube to equalise air pressure in the middle ear and pharynx.
The Tensor Veli Palatini (Tensor Palati)
- Superior attachment: scaphoid fossa of medial pterygoid plate, spine of sphenoid bone, and cartilage of auditory tube.
- Inferior attachment: palatine aponeurosis.
- Innervation: medial pterygoid nerve (a branch of the mandibular nerve).
- This thin, triangular muscle passes inferiorly, and hooks around the hamulus of the medial pterygoid plate.
- It then inserts into the palatine aponeurosis.
- This muscle tenses the soft palate by using the hamulus as a pulley.
- It also pulls the membranous portion of the auditory tube open to equalise air pressure of the middle ear and pharynx.
The Palatoglossus Muscle
- Superior attachment: palatine aponeurosis.
- Inferior attachment: side of tongue.
- Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
- This muscle, covered by mucous membrane, forms the palatoglossal arch.
- The palatoglossus elevates the posterior part of the tongue and draws the soft palate inferiorly onto the tongue.
- Superior attachment: hard palatThe Palatopharyngeus Musclee and palatine aponeurosis.
- Inferior attachment: lateral wall of pharynx.
- Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
- This thin, flat muscle is covered with mucous membrane to form the palatopharyngeal arch.
- It passes posteroinferiorly in this arch.
- This muscle tenses the soft palate and pulls the walls of the pharynx superiorly, anteriorly and medially during swallowing.
The Musculus Uvulae
- Superior attachment: posterior nasal spine and palatine aponeurosis.
- Inferior attachment: mucosa of uvula.
- Innervation: cranial part of accessory through the pharyngeal branch of vagus, via the pharyngeal plexus.
- It passes posteriorly on each side of the median plane and inserts into the mucosa of the uvula.
- When the muscle contracts, it shortens the uvula and pulls it superiorly.
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Muscle
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Emotion
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Epicranius
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Surprise
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Orbicularisoculi
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Squinting
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Orbicularisoris |
Pouting |
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Nasalis
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Smelling
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Zygomaticus
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Smiling
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Buccinator
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Chewing
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Mentalis
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Doubt
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Triangularis
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Sadness
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Platysma
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Sadness
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Masseter
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Chewing
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Temporalis
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Sternness
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Pterygoid
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Conternation
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Genioglossus and Styloglossus
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Swallowing, Speaking, Chewing
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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.
The Lips
- These are mobile muscular folds that surround the mouth, the entrance of the oral cavity.
- The lips (L. labia) are covered externally by skin and internally by mucous membrane.
- In between these are layers of muscles, especially the orbicularis oris muscle.
- The upper and lower lips are attached to the gingivae in the median plane by raised folds of mucous membrane, called the labial frenula.
Sensory Nerves of the Lips
- The sensory nerves of the upper and lower lips are from the infraorbital and mental nerves, which are branches of the maxillary (CN V2) and mandibular (CN V3) nerves.
The Salivary Glands
- There are three large, paired salivary glands: the parotid, submandibular, and sublingual glands.
- In addition to the main salivary glands, there are numerous small accessory salivary glands scattered over the palate, lips, cheeks, tonsils, and tongue.
Innervation of the Pharynx
- The motor and most of the sensory supply of the pharynx is derived from the pharyngeal plexus of nerves on the surface of the pharynx.
- The plexus is formed by pharyngeal branches of the vagus (CN X) and glossopharyngeal (CN IX) nerves, and by sympathetic branches for the superior cervical ganglion.
- The motor fibres in the pharyngeal plexus are derived from the cranial root of accessory nerve (CN XI), and are carried by the vagus nerve to all muscles of the pharynx and soft palate.
- The exceptions are stylopharyngeus (supplied by CN IX) and the tensor veli palatini (supplied by CN V3).
Mylohyoid Muscle
- Origin: Mylohyoid line of the mandible.
- Insertion: Median raphe and body of the hyoid bone.
- Nerve Supply: Nerve to mylohyoid (branch of the trigeminal nerve, CN V3).
- Arterial Supply: Sublingual branch of the lingual artery and submental branch of the facial artery.
- Action: Elevates the hyoid bone, base of the tongue, and floor of the mouth; depresses the mandible.