ENT Surgery and Cranial Nerves Overview

ENT Surgery

• An ENT surgeon operates on ear ossicles in the middle ear cavity.
• Access is through the suprameatal triangle, tympanic bone, or mastoid process.

Extra Cranial Facial Nerve Injury

• Diagnosis of extracranial facial nerve injury affects structures such as lacrimal glands and anterior 2/3rds of the tongue.
• Stapedius muscle and posterior belly of the digastrics are not affected.

Superior Orbital Fissure

• Structures passing through the superior orbital fissure within the tendonous ring include oculomotor, trochlear, and abducent nerves.
• The optic nerve does not pass through the superior orbital fissure.

Maxillary Nerve Branch

• The lacrimal gland is supplied by the lacrimal nerve branch of the maxillary nerve.
• Infraorbital, zygomatic, and posterior superior alveolar nerves are other branches of the maxillary nerve.

Cranial Nerves in Temporal Bone

• Mandibular, facial, and maxillary nerves pass through the temporal bone.
• The olfactory nerve does not pass through the temporal bone.

Kasselbach's Anastomoses

• The superior labial artery participates in Kasselbach's anastomoses.
• Greater palatine, sphenopalatine, and anterior ethmoidal arteries are other vessels involved in the anastomosis.

Pharyngeal Plexus and Tongue Muscles

• Muscles supplied by the pharyngeal plexus include the palatoglossus muscle.
• Genioglossus, hyoglossus, and styloglossus muscles are also tongue muscles, but are not supplied by the pharyngeal plexus.

Rotation of Head

• Head rotation (e.g., "no" movement) occurs primarily at the atlanto-axial joints.

Deep Cervical Fascia

• The investing layer of deep cervical fascia surrounds the thyroid gland, larynx, and trachea.
• Prevertebral, pretracheal, and pharyngobasilar fascia and buccopharyngeal fascia don't invest these structures.

Internal Jugular Vein Tributaries

• Posterior auricular, inferior thyroid, and superior thyroid veins are tributaries of the internal jugular vein.
• External jugular veins are not internal jugular vein tributaries.

External Carotid Artery Branches

• Facial artery is a branch of the external carotid artery arising within the carotid triangle.
• Superficial temporal artery, maxillary artery, and posterior auricular artery are branches arising within the carotid triangle.

Carotid and Digastric Triangles

• Common carotid artery, facial artery, and vagus nerve—and inferior pharyngeal constrictor muscle are found within both triangles.

Neck Movement and Nerve Injury

• Damage to the accessory spinal nerve in the posterior triangle of the neck can hinder neck movements.
• Transverse cervical nerve, suprascapular vein, and suprascapular artery are not in the posterior triangle of the neck.

Oropharyngeal Isthmus

• The palatoglossal muscle forms part of the oropharyngeal isthmus.
• Palatopharyngeus, tensor palati, and levator palati muscles are not part of the isthmus.

TMJ Dislocation Causes

• TMJ dislocation is most commonly caused by the head of the condyle moving too far anteriorly, beyond the articular eminence, causing injury to the auriculotemporal nerve.
• Medial/lateral displacement, condyle movement too far posteriorly (causing temporal bone fracture) are other possible causes.

Venous Drainage from the Face

• The spread of facial infection during meningitis frequently involves the inferior ophthalmic vein's venous drainage.

Parotid Gland Nerve Involvement

• The absence of the nasolabial fold post-parotidectomy (removal of the parotid gland) typically indicates a branch of the facial nerve was damaged during surgery. The zygomatic and buccal branches are most likely to be affected.

Submandibular Duct Incision Nerve Injury

• During submandibular duct incision, the clinician must take care not to injure the lingual nerve.
• Facial, submental, and chorda tympani nerves are not typically at risk during this procedure.

Vocal Cord Abduction Deficiency

• Damage to the posterior cricoarytenoid muscle can reduce the vocal cords' ability to abduct, which is critical for quiet breathing. Transverse arytenoid and vocal cords muscles are not directly involved.

Cranial Nerve Locations

• The optic nerve is not located throughout the carotid sheath.
• The glossopharyngeal and vagus nerves are located in the carotid sheath.
• The spinal accessory and hypoglossal are not centrally located in the carotid sheath.
• Glossopharyngeal is not located throughout the carotid sheath.

Microscopic Structure in Bladder

• The lining of the human bladder shows transitional epithelium, not squamous epithelium, pseudostratified epithelium, or simple cuboidal epithelium.

Bone Matrix Components

• Bone matrix is composed primarily of collagen fibers, rather than elastic fibers, reticular fibers, or dense regular connective tissue.

Lymphoid Follicles in Palatine Tonsils

• Palatine tonsils contain lymphoid follicles arranged primarily within the cortical region of the tonsil.
• Lymphoid follicles in paracortical areas and those directly beneath the covering are less common in tonsils.

Acidophilic Cell Structures

• Acidophilic structures typically seen inside cells are mitochondria, which are crucial for energy production. A cell is typically not a structure in itself.

CSF in Lumber Puncture

• Before reaching the subarachnoid space, the needle penetrates the dura mater, arachnoid mater, and pia mater, sequentially in that order.
• Ligamentum flavum is not penetrated during lumber puncture procedures.

Serous Glands in Tongue

• Serous Von-Ebnar's glands are located in the fungiform papillae of the tongue—not in circumvallate, foliate, or filiform papillae.

Abundant Collagen Fibers

• Type I collagen fibers are the most abundant collagen fiber types.

Blood-Thymic Barrier Cells

• Epithelial reticular cells form parts of the blood-thymic barrier.

Trigeminal Neuralgia Symptoms

• Trigeminal neuralgia involves excruciating, stabbing pain on one side of the face.
• Such pain often manifests in areas between the mouth, orbit, and nose.

Surgical Nerve Damage

• If a patient experiences postoperative facial paralysis after a major salivary gland removal, it's highly likely that a postoperative facial nerve injury is responsible.

This quiz covers essential topics related to ENT surgery, including operations on ear ossicles and the anatomy of cranial nerves. It explores the implications of facial nerve injuries and the structures involved in the superior orbital fissure. Test your knowledge on the relevant nerve branches and their functions.