The temporal lobe takes up most of the space of the middle fossa and extends to the inferior portion of the anterior fossa. The GSPN branches from the geniculate ganglion and passes through a small hiatus into the middle fossa before coursing parallel to the petrous ridge of the temporal bone and entering the foramen lacerum. The GSPN, which is composed of parasympathetic fibers from the facial nerve to the lacrimal gland, is an important surgical landmark. It is easily identified and can be followed back medially to the foramen lacerum and the petrous ICA.
Hearing loss occurs either due to lack of function in the inner ear, or when sound has a problem reaching the nerve cells of the inner ear. With the latter, conventional hearing aids are not effective solutions to increase a patients hearing. Instead, the best solution is a hearing aid based on bone conduction. The bone-anchored hearing aid uses a surgically implanted abutment to transmit sound by direct conduction through bone to the inner ear, thereby passing the middle ear and external auditory canal. The surgery itself involves a small incision to place a titanium prosthesis in the skull, with the small abutment exposed to the outside skin. A sound processor sits on the abutment and sends sound vibrations to the titanium implant, thereby vibrating the skull and inner ear, stimulating the nerve fibers of the inner ear and allowing hearing.
A thorough medical history and physical examination , including a neurological examination , are the first steps in making a diagnosis. This alone may be sufficient to diagnose Bell's Palsy, in the absence of other findings.  Additional investigations may be pursued, including blood tests such as ESR for inflammation, and blood sugar levels for diabetes. If other specific causes, such as sarcoidosis or Lyme disease are suspected, specific tests such as angiotensin converting enzyme levels, chest x-ray or Lyme titer may be pursued.  If there is a history of trauma, or a tumour is suspected, a CT scan may be used.