Geniculate Ganglion

LOCATION & RELATIONS:
  • The geniculate ganglion (from Latin genu, for "knee") is an L-shaped collection of fibers and sensory neurons of the facial nerve located in the facial canal of the head.
FIBERS:
  • It receives fibers from the motor, sensory, and parasympathetic components of the facial nerve and sends fibers that will innervate the lacrimal glands, submandibular glands, sublingual glands, tongue, palate, pharynx, external auditory meatus, stapedius, posterior belly of the digastric muscle, stylohyoid muscle, and muscles of facial expression.
  • The geniculate ganglion contains special sensory neuronal cell bodies for taste, from fibers coming up from the tongue through the chorda tympani and from fibers coming up from the roof of the palate through the greater petrosal nerve.
  • Sensory and parasympathetic inputs are carried into the geniculate ganglion via the nervus intermedius.
  • Motor fibers are carried via the facial nerve proper. 
  • The greater petrosal nerve, which carries preganglionic parasympathetic fibers, emerges from the anterior aspect of the ganglion. 
  • The motor fibers of the facial nerve proper and parasympathetic fibers to the submandibular and pterygopalatine ganglia do not synapse in the geniculate ganglion. 
  • The afferent fibers carrying pain, temperature, and touch from the posterior auricular nerve do synapse in the geniculate ganglion, as do special sensory (taste) fibers from the tongue.
  • The geniculate ganglion is one of several ganglia of the head and neck. Like the others, it is a bilaterally distributed structure, with each side of the face having a geniculate ganglion.
APPLIED ANATOMY:
  • Lesion occurring at the level of geniculate ganglion will injure greater petrosal branch and will lead to dryness of eyes
  • The Ramsay Hunt Syndrome is caused by reactivation of Herpes Zoster in the geniculate ganglion and consists of a severe facial nerve palsy associated with a vesicular eruption in the external auditory canal and sometimes in the pharynx and other parts of the cranial integument
Exam Question
  • Lesion occurring at the level of geniculate ganglion will injure greater petrosal branch and will lead to dryness of eyes
  • The Ramsay Hunt Syndrome is caused by reactivation of Herpes Zoster in the geniculate ganglion

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