A patient with a basal skull fracture through the petrous temporal bone may develop a CSF otorrhea with Battle's sign. The CSF leaks via which anatomical route?
- A Via the Eustachian tube to the nasopharynx or through a torn tympanic membrane to the external auditory meatus ✓
- B Through the cribriform plate into the nasal cavity
- C Through the foramen ovale into the infratemporal fossa
- D Via the jugular foramen along CN IX
Correct answer: A. Via the Eustachian tube to the nasopharynx or through a torn tympanic membrane to the external auditory meatus
Explanation
A fracture of the petrous part of the temporal bone can tear the dura along the superior surface of the petrous bone where it is closely adherent. CSF can then enter the middle ear (via rupture of the tympanic membrane, exiting the external auditory meatus as otorrhea) or travel via the Eustachian tube to present as CSF rhinorrhea from the nasopharynx. Battle's sign (post-auricular ecchymosis over the mastoid) and hemotympanum are classic signs. CSF from the cribriform plate fracture causes anterior cranial fossa rhinorrhea. The beta-2 transferrin test confirms CSF.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.