Editing Neck (section)

== '''Nerves''' ==

=== '''Glossopharyngeal     nerve (CN IX)''' ===

** Leaves skull through jugular      foramen
** Superior to hypoglossal
** Passes between IJV and ICA
** Curves forward, lying upon      stylopharyngeus and middle pharyngeal constrictor
** Deep to hyoglossus

=== '''Spinal     accessory nerve'''     (CN XI) - Both cranial and spinal roots. Jugular foramen. Descends along     ICA, then into SCM. Emerges from posterior edge of SCM at junction of     upper and middle thirds, travels across the posterior triangle, then     enters anterior border of trapezius at the junction of lower and middle     thirds ===

=== '''Hypoglossal     nerve (CN XII)''' ===

** Motor nerve to all the      muscles of the tongue, except palatoglossus
** Emerges from hypoglossal      canal, and crosses behind IVJ but in front of ECA/ICA, 1-2cm above the      carotid bifurcation (gives off hitching C1 fibres to ansa cervicales)
** Curves forward at the level      of the angle of the mandible
** Emerges from behind      posterior belly of digastric and over occipital branch of ECA
** Crosses over the loop of the      lingual artery
** Passes up in between      hyoglossus and mylohyoid, inferior to deep part of submandibular gland
** Continues forward deep to      floor of mouth and reaches tip of tongue

=== '''Ansa     cervicales''' - the     nerve loop supplying the strap muscles, with parts from both C1     (hypoglossal) and C2-C3 (cervical plexus). ===

** Carries fibres from C1 which      curve off from the hypoglossal nerve as it passes
** C2-3 fibres come down on the      lateral surface of IJV before curving forwards to join the upper root
** The union between upper and      lower fibres occurs at the point where omohyoid crosses carotid.
** Passes down along medial      side of CCA

=== Cervical plexus ===

** Superior root of ansa      cervicales (C1)
** Branches to SCM (C2 and C3)
** Branches to trapezius (C3      and C4)
** Inferior root of ansa      cervicales (C2 and C3)
** Phrenic nerve
** '''Cervical      cutaneous nerves'''      - arise from C2-C4 spinal nerves. Emerge from posterior surface of SCM.      Note 'Erb's point' where these nerves emerge from SCM is the target for a      regional block.
*** '''Lesser       occipital nerve'''       (C2) passes upwards and backwards along the posterior border of SCM and       supplies skin from auricle back to occipit
*** '''Great       auricular nerve'''       (C2, 3) passes upwards immediately behind EJV to supply skin of the       auricle and pre-auricular region, lying deep to platysma. Anterior       division supplies skin over parotid and ear lobe, and posterior division       supplies retro-auricular skin.
*** '''Transverse       cervical nerve'''       (C2, 3) passes horizontally across SCM to supply skin of anterior neck
*** '''Supraclavicular       nerve''' (C3, 4)       passes downwards and divides into branches which pass over the clavicle       supplying the more lateral reaches of the neck