Facial nerve—a clinical and anatomical review

Facial Nerve Palsy and the Eye: Etiology, Diagnosis, and Management

“…The classic textbook example of facial paralysis is Bell’s palsy so it will be the main focus of this review. Bell’s palsy is an acute peripheral facial mononeuropathy without a confirmed cause and is the most common cause associated with facial nerve weakness 1–10 . Although recent evidence increasingly supports the long-held view that a viral etiology is the underlying cause, the exact mechanism of Bell’s palsy is currently unknown 8,9 .…”

“…An all-inclusive enumeration of the etiological factors causing FNP is beyond the scope of this review article as more than 100 different causes have been identified so far, 1–13 but briefly speaking they can be categorized as central or peripheral causes 6 . Central causes include stroke, brain tumor, or trauma, while peripheral causes include congenital and hereditary causes, infections, Bell’s palsy, Ramsay-Hunt syndrome, or compression of the facial nerve by a tumor mass 6,10,13 .…”

“…In the periocular region, the ophthalmic consequences occur secondary to loss of orbicularis muscle function resulting in an inability to close the eyelids, which if left untreated could lead to serious vision-threatening complications such as corneal ulceration, scarring, and loss of vision 1 . Furthermore, facial animation, smiling, and the ability to blink in a normal manner are essential parts of human communication, so that patients with FNP often suffer significant social torment and may not be able to communicate properly both at a personal and professional level 2,3 …”

“…Of the many possible etiologies, idiopathic facial nerve palsy, referred to as Bell’s palsy, is the most common cranial nerve palsy encountered in clinical practice, 1–13 and refers to the spontaneous onset of FNP with no identifiable cause. The terms “Bell’s palsy” and “facial palsy” are sometimes used interchangeably, 13 and consequently, a few patients may be mistakenly presumed to have Bell’s palsy although they may have an organic or treatable lesion 1–4 …”

“…1 Furthermore, facial animation, smiling, and the ability to blink in a normal manner are essential parts of human communication, so that patients with FNP often suffer significant social torment and may not be able to communicate properly both at a personal and professional level. 2,3 Of the many possible etiologies, idiopathic facial nerve palsy, referred to as Bell's palsy, is the most common cranial nerve palsy encountered in clinical practice, [1][2][3][4][5][6][7][8][9][10][11][12][13] and refers to the spontaneous onset of FNP with no identifiable cause. The terms "Bell's palsy" and "facial palsy" are sometimes used interchangeably, 13 and consequently, a few patients may be mistakenly presumed to have Bell's palsy although they may have an organic or treatable lesion.…”