PG Medical entrance|USMLE preparation|Cavernous sinus Anatomy and thrombosis

How to solve question based on cavernous sinus:

This is one of the important topic from anatomy asked in various PG medical Entrance and USMLE exams. So the question can be framed like this

Which of the following structure is seen in Cavernous sinus?

  1. Internal Carotid artery
  2. First Cranial nerve
  3. 5th cranial nerve
  4. Optic nerve

So the correct answer here is 1. Internal carotid artery.

Cavernous sinus anatomy important points:

 

Cavernous sinus is Situated in middle cranial fossa on the sides of body of sphenoid

It is 2 cms long 1 cm wide

 

Relations of Anterior   – sup. Orbital fissure

Posterior –  Apex of petrous temp. bone

Floor & medial wall – endosteal layer of dura

Roof & lateral Wall  –  meningeal layer of dura

Structure passing through cavernous sinus include

  1. Int. carotid surrounded by venous and

    sympathetic plexuses

  1. Abducent N. (Inf. lat. to carotid art.)

Structures in lateral wall of Cavernous sinus include

1.Oculomotor N.

2.Trcochlear N.

3.Ophthalmic N.

4.Maxillary N.

Cavernous sinus thrombosis:

Cause: Sepsis from dangerous area of face, paranasal sinuses, nasal cavities can spread to Cavernous sinus and can lead to Cavernous sinus thrombsosis

It is characterized by

  1. severe pain eye and forehead

2. Paralysis of ocular muscles supplied by–

– 3rd , 4th and 6th n.

3. Venous block – oedema of eye lids, cornea, nose

exophthalmos

4. Injury causing communication between cavernous sinus and carotid leads to pulsating exophthalmos

 

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