Written Examination Part IV. (36 pts) - Essay: Head and Neck (October 27, 2006)

Note: This is an outline of topics to be covered. It is not the "answer key." It is an answer guide.

The Pterygopalatine Fossa

Dr. Bollard explained that patients with trigeminal neuralgia need to decide for themselves what is worse; the pain of neuralgia or the numbness that results from nerve block. A treatment for trigeminal neuralgia is to inject nerve blocking agents into the pterygopalatine fossa. Discuss the Pterygopalatine Fossa. Include contents, relationships, foramina, nerve distributions, and the expected consequences of blocking each nerve and functional component within the pterygopalatine fossa. (12 pts).

• General Comments - The pterygopalatine fossa contains the maxillary nerve and branches. These branches widely disperse to the regions of the face, nasal cavity, nasopharynx, maxillary sinus, orbit, and oral cavity.
• Contents
  • Maxillary nerve and branches (GSA)
  • Pterygopalatine ganglion - site of postganglionic parasympathetic cell bodies (GVE)
  • Nerve of the pterygoid canal - conveys GVA, preganglionic parasympathetic GVE, and SVA from the facial nerve and postganglionic GVE sympathetics from the internal carotid plexus
    • Greater superficial petrosal nerve combines with deep petrosal nerve to form nerve of the pterygoid canal
  • Arteries/veins named for the foramina that they pass through
• Boundaries, relationships, bones and foramina
  • Anterior
    • inferior orbital fissure - between lesser wing of sphenoid and maxilla
      • Maxillary nerve continues as infraorbital nerve
      • Zygomatic nerve (GSA, postganglionic GVE)
  • Posterior
    • Greater wing of the sphenoid
    • Foramen rotundum: PPF to MCF
      • Maxillary nerve (GSA)
      • Artery of foramen rotundum (the maxillary nerve)
    • Body of the sphenoid bone
      • pterygoid canal: PPF to MCF (lacerate foramen)
    • Anterior wall of the sphenoid sinus - pterygoid canal along floor
  • Superior: body of sphenoid bone
    • Sphenoid sinus
    • Sphenoethmoidal recess
  • Inferior
    • inferior and posterior wall - palatovaginal canal: PPF to nasopharynx
    • Inferior and posterior - lesser palatine canal: PPF to soft palate
    • Inferior and anterior - greater palatine canal: PPF to hard palate
    • The greater and lesser palatine may share common superior opening
  • Medial
    • sphenopalatine foramen
    • perpendicular plate of palatine bone
    • medial pterygoid plate
  • Lateral
    • pterygomaxillary fissure - posterior aspect of maxilla and anterior border of lateral pterygoid plate
• Foramina and contents
  • Foramen rotundum
    • maxillary nerve
      • GSA - cell bodies in trigeminal ganglion, distribute to face, orbit, nasopharynx, oral cavity, nasal cavity, nasopharynx, sphenoid and maxillary air sinuses
  • Pterygoid canal
    • Vidian nerve (nerve of the pterygoid canal)
      • Formed within lacerate foramen by union of the greater superficial petrosal nerve and the deep petrosal nerve
      • GVE - Postganglionic sympathetic from internal carotid plexus (cell bodies in superior cervical sympathetic trunk ganglion)
      • GVE - Preganglionic parasympathetic cell bodies in lacrimal nucleus and native to greater superficial petrosal nerve (CNVII)
      • SVA - Taste to the hard and soft palate cell bodies in geniculate ganglion and native to greater superficial petrosal nerve (CNVII)
      • GVA - Touch to the soft palate, cell bodies in geniculate ganglion and native to greater superficial petrosal nerve (CNVII)
  • Inferior orbital fissure
    • Infraorbital nerve GSA - Touch to maxillary sinus and face, cell bodies in trigeminal ganglion
    • Zygomatic nerve GSA GVE - Touch to face, motor to mucosa, postganglionic parasympathetic cell bodies in the pterygopalatine ganglion
      • Zygomatic nerve to zygomaticotemporal nerve to lacrimal nerve to lacrimal gland
  • Pterygomaxillary fissure
    • Posterior superior alveolar nerve GSA GVE - enters posterior wall of maxillary sinus within the infratemporal fossa
  • Sphenopalatine foramen
    • Lateral posterior nasal nerves (superior middle and inferior) GSA GVE - distributes to turbinates of lateral posterior nasal wall
    • Nasopalatine nerve GSA GVE SVA - distributes to nasal septum and anterior hard palate
  • Greater palatine canal
    • Greater palatine nerve GSA GVE SVA - distributes to the hard palate
  • Lesser palatine canal
    • Lesser palatine nerve GSA GVE SVA GVA - distributes to the soft palate
  • Palatovaginal canal (pharyngeal canal)
    • Pharyngeal nerve GSA GVE - distributes to the the nasopharynx

The Orbit

Drs. Quillen and Wilkinson explained that enlargement of the orbital contents causes exophthalmos. Discuss the anatomy of the orbit. Include contents, relationships, fascial specializations, vascularization, innervation, lymphatic drainage, muscles and movements, and nerve injury. What grave condition is indicated by pulsatile exophthalmos? (12 pts)

• General Comments
• Bones
  • Superior - orbital plate of frontal bone
  • Inferior - maxilla
  • lateral - zygoma
  • Medial - lacrimal bone, ethmoid bone, palatine bone
  • Posterior - greater wing of sphenoid bone, body of sphenoid bone,
• Contents
  • Periorbita
  • Bulbar fat
  • CN2,3,4,5,6,7
  • Sympathetic root of ciliary ganglion
  • Extraocular muscles
  • Globe
  • Ophthalmic artery and branches
  • Opthalmic vein and branches
  • Ciliary ganglion
  • Annulus tendineus
  • Lacrimal gland
• Relationships
  • Structures passing through annulus tendineus
  • Ciliary ganglion
  • Trochlea
• Fascial specializations
  • Annulus tendineus
  • Periorbita
  • Bulbar fat
  • Trochlear
  • Orbital septum
  • Conjuctiva
• Vascularization
  • Ophthalmic artery and branches
    • Lacrimal artery
    • Supraorbital artery
    • Supratrochlear artery
    • Infratrochlear artery
    • Anterior ethmoidal artery and clinical significance
    • Posterior ethmoidal artery
  • Ophthalmic vein and branches
    • Clinical significance of facial and orbital venous drainages
    • Clinical significance of inferior ophthalmic vein and pterygoid venous plexus
• Innervation
  • Optic nerve
  • Superior division oculomotor nerve
  • Inferior division oculomotor nerve
  • Motor root of ciliary ganglion
  • Sympathetic root of ciliary ganglion
  • Nasociliary nerve
  • Sensory root of ciliary ganglion
  • Long and short ciliary nerves
  • Anterior and posterior ethmoidal nerves
  • Infratrochlear nerve
  • Lacrimal nerve and non-native fibers
  • Frontal nerve and branches
  • Trochlear nerve
  • Aducens nerve
• Muscles and movements
  • Rectus muscles
  • Rotation by the obliques
  • Levator palprebrae superiorus and superior tarsal muscle
  • Obicularis oculi
• Nerve injury
  • Inferior root CN3 and ciliary ganglion
  • Abducens and cavernous sinus infection
  • Sympathetic root of ciliary ganglion and ptosis
  • Horner's syndrome
• Pulsating exophthalmos
  • Arteriovenous shunt within cavernous sinus

The Pharynx

Drs. Fornadley and Fedok explained how infections that erode the pharyngeal walls can become widely dispersed. Discuss the pharynx. Include fascial barriers, contents, relationships, nerve distributions, and nerve injury. Discuss the spread of infection from the pharynx into the spaces defined by the cervical fascias. (12 pts)

• General Comments
  • A defined region of the alimentary canal that shares common boundaries with the airways.
• Contents
• Relationships
  • Posterior nasal aperature
  • Auditory tube
  • Torus Tubarius
  • Palatine tonsilar bed
  • Epiglottus
  • Median and lateral glossoepiglottic folds
  • Vallecula
  • Piriform recesses
• Fascial barriers
  • Pharyngobasilar fascia
  • Bucopharyngeal fascia
  • Alar layer of prevertebral fascia
• Vascularization
  • Ascending pharyneal artery
  • Facial artery
  • Lingual artery
  • Superior thyroid artery
  • Inferior thyroid artery
• Innervation
  • Nasopharynx - CNV (GSA) CNX (SVE)
  • Oropharynx - CNIX (GVA), CNX (SVE)
  • Hypopharynx - CNX (GVA), CNX (SVE)
• Muscles and movements
  • Superior constrictor - pterygomandicular raphe and buccinator
    • Salpingopharyngeus
    • Palatopharyngeus
    • Levator palati
  • Middle constrictor - stylohyoid ligament and hyoid bone
    • Stylopharyngeus
  • Inferior constrictor - Thyroid and cricoid cartilage
    • Cricopharyngeus
• Nerve injury
  • Gag reflex
  • Cough reflex
• Spread of infection
  • Retropharyngeal space
  • Danger space

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-- LorenEvey - 03 Nov 2006