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Equine Nervous System - Horse Anatomy (view source)
Revision as of 16:16, 21 November 2012
, 16:16, 21 November 2012→Facial nerve (VII)
====Facial nerve (VII)====
====Facial nerve (VII)====
The facial nerve is part of the cranial nerve group responsible for the innervation of structures originating from the branchial arches. It originates from the '''medulla oblongata''' and from the second branchial arch. It has a common dura sheet with the opthalmic (V1) branch of the trigeminal nerve. The facial nerve is of a mixed composite, made up of a number of different fibre types. It has a '''general somatic efferent fibre''' within the ear canal, a '''general visceral efferent fibre''' acting under parasympathetic control to some salivary glands, lacrimal glands, nasal cavity and palate, a '''special visceral afferent fibre''' providing taste to the rostral 2/3 of the tongue and finally it has a '''general somatic efferent fibre''' supplying motor function to the muscles of facial expression and ''caudal digastricus''.
The facial nerve enters the petrosal bone via the [[Skull and Facial Muscles - Anatomy & Physiology#Temporal Bone (os_temporale)|'''internal acoustic meatus''']] along with the vestibulocochlear nerve. The facial nerve also runs inside the '''facial canal'''. There are a number of intermediate branches which separate from the main facial nerve inside the facial canal including the '''greater petrosal nerve''', '''stapedial nerve''' (motor) and the '''chorda tympani'''. These then emerge via the [[Skull and Facial Muscles - Anatomy & Physiology#Major Foramen and Canals|'''stylomastoid foramen''']] at the caudoventral aspect of the skull. The chorda tympani of the facial nerve represents the '''special visceral afferent fibre''' supplying taste to the rostral 2/3 of the tongue.
There are also numerous external branches of the facial nerve once the facial nerve has left the facial canal. These include the '''internal auricular nerve''', the '''auriculopalpebral nerve''', the '''rostral auricular nerve''', the '''palpebral nerve''', the '''dorsal buccolabial nerve''', the '''ventral buccolabial nerve''', the '''ramus colli''', the '''digastric nerve''', the '''stylohoid nerve''' and the '''caudal auricular nerve'''.
The facial nerve supplies motor innervation to the muscles of facial expression. These are superficial flat, thin muscles that originate from bony areas of fascia and then radiate out around the skin. They may also often from sphincters such as around the mouth and eye.
During a clinical examination any facial paralysis, drooling or abscence of blinking may indicate a problem with the facial nerve.
====Vestibulocochlear nerve (VIII)====
====Vestibulocochlear nerve (VIII)====
====Glossopharyngeal nerve (IX)====
====Glossopharyngeal nerve (IX)====