dental gross anatomy case 1 cavernous sinus thrombosis

DENTAL GROSS ANATOMY

CASE 1

CAVERNOUS SINUS THROMBOSIS

HISTORY Patient develops a boil on his upper lip after cutting himself shaving on a hunting trip He presents to his physician with a high fever and severe headaches Patient does not improve with penicillin injections and is admitted to a hospital

EXAMINATION Rigidity of neck muscles Upper lip swollen and oozing pus Cheek, side of nose and eyelids swollen Exophthalmos Edema of optic nerve at papilla Inability to move eye Paresthesia of forehead, side of nose and upper cheek Blood culture positive for Staphylococcus aureus

DIAGNOSIS Staphylococcic infection of upper lip and infectious cavernous sinus thrombosis

THERAPY AND FURTHER COURSE Patient is put on intravenous antibiotics Warm, moist dressings applied to face Narcotics given for pain Patient responds slowly to antibiotics and ocular functions improve only gradually After three weeks patient has made a complete recovery and is discharged

PATIENT WITH CAVERNOUS SINUS THROMBOSIS

1. Where is the cavernous sinus located?

Cavernous sinus

2. What anatomical features does the cavernous sinus share with other venous sinuses and in what respects does it differ?

Cavernous sinus Optic chiasm

Hypophysis

Sphenoid sinuseswithin body of sphenoid bone

Similarities withother sinuses

Within dura

Differences fromother sinuses

Lined by endotheliumLacks muscular coat

Lacks valves

IIIIV

V1V2

VI

Int. carotid a.(w/sympathetic plexus)

Containstrabeculae

3a. What are the tributaries to the cavernous sinus?

b. What veins directly drain the cavernous sinus?

Cavernous sinusSup. ophthalmic v.

Inf. ophthalmic v.(not shown)

Central v. of retina(inside optic n.)

Sphenoparietal sinus

Superficial middle cerebral v.

Drainage

Tributaries

Sup. petrosalsinus

Inf. petrosalsinus

Intercavernous sinus

3c. Into what vein does the blood in the cavernous sinus ultimately drain?

Sup. petrosal sinus

Inf. petrosal sinus

Sigmoid sinus

To int. jugular v.

4a. What is the definition of an emissary vein? Can the ophthalmic veins be regarded as emissary veins?

b. What is the direction of blood flow in emissary veins?

c. In view of your answer (to b) above, what is the clinical significance of emissary veins?

Sup. ophthalmic v.

Inf. ophthalmic v.

Cavernous sinus

Angular v.

Facial v.

5. Describe the venous pathway by which infectious material reached the cavernous sinus in this patient.

Sup. labial v.

Facial v.

Angular v.

Sup. ophthalmic v.

6. How do you explain the swelling of the eyelids and conjunctivae, the exophthalmos, the dilation of the retinal veins and the edema of the optic nerve in this patient?

Retinal v.

Central v. of retina

Optic n.

Optic disc(papilla)

7. What cranial nerves have been affected by this infectious thrombosis? (Give reasons for your answers). Through what openings do these nerves leave the cranial cavity?

III

IV

VI

Sup. oblique m.

Inf. oblique m.

Levator palpebrae superioris m.

Sup. rectus m.

Inf. rectus m.Med. rectus m. Lat. rectus m.

SO4, LR6, R3

Ophthalmic n. (V1)

Maxillary n. (V2)

Mandibular n. (V3)

Optic canal (II)

Sup. orbital fissure(III, IV, VI, V1)

F. rotundum (V2)

8. What might be the consequence if the infectious material invaded the internal carotid artery within the sinus?

Cavernous sinuscontaining ICA

Ant. cerebral a.

Mid. cerebral a.

ICA

Ant. cerebral a.

Mid. cerebral a.

Ant. communicating a.

Vertebral a.

Basilar a.

Post. cerebral a.

Post. communicating a.

Superficial middlecerebral v.

9. Explain how osteomyelitis (inflamation of the bone and marrow) of the upper or lower jaw following tooth extraction could lead to infectious cavernous sinus thrombosis. (Hint: What important venous structure lies in the infratemporal fossa?)

Inf. alveolar v.

Post. sup. alveolar v.

Pterygoid plexus of vv.

Emissary v. connectingw/ cavernous sinus viaf. ovale

Additional Note

Infectious cavernous sinus thrombosis was almost invariably fatalprior to the advent of antibiotics. In this era of intensive antibiotictreatment the condition is not as common as it used to be but the prognosis, should one contract it, is grim —80% mortality and in the survivors 75% after effects, mainly involving eye muscles and changes in visual acuity.

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