DENTAL GROSS ANATOMY

CASE 2.1

History

A 36yo woman slept near an open window on a cold drafty night. Upon awakening she noticed that her face was distorted. She was not able to close her right eye and she had difficulty speaking, eating (but not swallowing) and drinking. Additionally, her sense of taste was impaired. She consulted her physician.

Examination

Examination reveals that the patient’s face is immobile and without expression on the right side. Right forehead is without wrinkles and right eyebrow droops. Right lower eyelid sags and tears flow down her face. Right corner of her mouth sags, and she cannot purse her lips. Nose and mouth are deviated toward the unaffected side. When attempting to laugh, the facial distortion becomes more noticeable.

Diagnosis, Therapy and Further Course

A diagnosis was made. Therapy included electrical stimulation, massage and active exercises of the facial muscles. After five weeks the patient was almost completely recovered and only traces of the paralysis could be seen.

1a. What is the diagnosis?

b. What major structure was affected?

PEOPLE AFFLICTED WITH BELL’S PALSY (DAMAGE TO FACIAL NERVE)

2. What is (are) the underlying cause(s) of this condition?

VII. FACIAL N.

VII in facial canalof temporal bone

VII entering internal auditory meatus

Posterior auricular a.( supplies VII)VII

3a. What is the name of the foramen by which this major structure leaves the base of the skull?

b. Name the five terminal branches of this structure.

Stylomastoid foramen(exit of VII)

Temporal branchesZygomatic branches

Buccal branches

Marginal mandibular branch

Cervical branch

Main trunk of VII

TO ZANZIBAR BY MOTOR CAR

Posteriorauricular n.(to occipitalis m.)

4a. Why were wrinkles absent from the patient’s forehead and why did the right eyebrow droop?

b. Why was the patient unable to purse her lips and why did liquids run out of the corner of her mouth when she tried to drink?

Frontalis m.

Orbicularis oris m.

4c. Paralysis of which muscle resulted in food collecting in the vestibule of the patient’s mouth? What is the anatomical origin of this muscle? What is its embryological origin? Is it a true muscle of mastication?

Buccinator m.

Superior pharyngeal constrictor m.

Pterygoid hamulus

Buccinator m.

Pterygomandibular raphe

Mandible

Buccinator also originates fromalveolar processes of maxilla and mandible

PHARYNGEAL ARCH MUSCLES

V3VII

IXXX

Muscles of mastication: Arch 1

Muscles of facial expression: Arch 2(INCLUDING BUCCINATOR)

4d. Why couldn’t the patient close her right eye? What serious complication might be the result?

Orbicularis oculi m.(orbital part)

Orbicularis oculi m.(palpebral part)

5. In this patient there was sagging of the lower eyelid and spilling of tears down the side of her face. What is the pathway by which tears normally drain from the conjunctival sac?

Lacrimal gland(orbital part)

Lacrimal gland(palpebral part)

Ducts of lacrimal gland(open into superolateralpart of conjunctival sac)

Superior lacrimal papilla and punctum

Inferior lacrimal papilla and punctum

Lacrimal canaliculi

Lacrimal sac

Nasolacrimal duct

Opening of nasolacrimal duct (into inferior meatusof nasal cavity)

6a. Why did this patient experience impairment of taste?

b. Where, precisely, was the loss of taste sensation?

COURSE OF VII IN FACIAL CANAL

VII in facial canalof temporal bone

Int. auditory meatus

Stylomastoid for.

Greater petrosal n. (autonomic to lacrimal gland)

Chorda tympani n. (autonomic to submandibular & sublingual glands, taste from ant. 2/3 of tongue)

Nerve to stapedius m.(paralysis > hyperacusis)

Branches to muscles of facial expression

Geniculate ganglion (sensory)

Pterygopalatine ganglion(autonomic)

Submandibular ganglion (autonomic)

Additional note:

According to Moore & Agur(Essential Clinical Anatomy),VII is the most frequently paralyzed cranial nerve.

END OF CASE 2.1

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