Cranial Nerves IX, X, XI, XII in the Neck 2024 PDF

CRANIAL NERVES IX, X, XI, XII IN THE NECK Key: 1.Glossopharynge al nerve 2. Vagus nerve...

CRANIAL NERVES IX, X, XI, XII IN THE NECK Key: 1.Glossopharynge al nerve 2. Vagus nerve 3. Hypoglossal nerve 4. Accessory nerve 5.First cervical spinal nerve 6. Spinal root of accessory nerve Cranial Nerves IX, X, XI, XII in the neck… 1  GLOSSOPHARYNGEAL (IX) Somatic motor: stylopharyngeus Somatic sensory: pharynx, palatine tonsil, & posterior part of tongue. Parasympathetic secretomotor: parotid gland (inferior salivatory nucleus – lesser petrosal nerve – otic ganglia & hitchhike on auriculotemporal nerve Special sensation: taste posterior 1/3 of tongue Attached by 3 or 4 filaments to upper part of medulla oblongata, in groove between olive & inferior peduncle. Cranial Nerves IX, X, XI, XII in the neck… 1  GLOSSOPHARYNGEAL (IX) On emerging in neck, IX lies between ICA & IJV Descends in front of carotid artery Passes medial to styloid process & styloid muscles Runs laterally & forwards around stylopharyngeus Pierces wall of pharynx between superior & middle constrictors Passes deep to stylohyoid ligament & to posterior free edge of hyoglossus muscle Cranial Nerves IX, X, XI, XII in the neck… 1  GLOSSOPHARYNGEAL (IX) Cranial Nerves IX, X, XI, XII in the neck…  VAGUS (X) Motor & sensory to larynx & pharynx Parasympathetic fibers to thoracic cavity & GIT Contributions to: pharyngeal, osophageal & cardiac plexus. Exits jugular foramen- accompanied by XI In neck, vagus descends vertically in carotid sheath Lies between IJV & ICA At level of upper border of thyroid cartilage – lies between IJV & CCA Cranial Nerves IX, X, XI, XII in the neck… 1  VAGUS (X) Cranial Nerves IX, X, XI, XII in the neck… 1 VAGUS (X) Branches PHARYNGEAL Descend to middle constrictor where it forms pharyngeal plexus Supply muscles of pharynx & soft palate (except tensor veli palatini [supplied by mandibular nerve via otic ganglion] CAROTID SINUS SUPERIOR LARYNGEAL NERVE Arises from caudal ganglion of vagus Descends on wall of pharynx to middle constrictor where it divides into internal & external branches INTERNAL BRANCH Sensory to supravocal half of larynx, pharynx, epiglottis, adjacent part of tongue Runs in gap between middle & inferior constrictors Enters larynx by piercing thyrohyoid membrane EXTERNAL BRANCH Supplies cricothyroid Supplies inferior constrictor Cranial Nerves IX, X, XI, XII in the neck… 1 VAGUS (X) Branches RECURRENT LARYNGEAL NERVE RIGHT Arises in front of right subclavian- hooks below it to ascend behind it & CCA Crosses superficial or deep to inferior thyroid artery; ascends posterior to lobe of thyroid gland LEFT Arises on left side of arch of aorta- winds below arch immediately behind attachment of ligamentum arteriosum to the concavity of the arch & ascends to the side of trachea. The nerve ascends in the tracheo-oesophageal groove Each recurrent laryngeal nerve passes deep to lower border of inferior constrictor to enter larynx behind cricorthyoid joint Each is sensory to infravocal half of larynx & motor to all intrinsic muscles of larynx except cricothyroid Supplies mucosa & muscles of oesophagus, trachea, inferior constrictor Cranial Nerves IX, X, XI, XII in the neck… 1  ACCESSORY (XI) Motor to sternocleidomastoid, trapezius muscles EXTERNAL BRANCH (SPINAL ACCESSORY NERVE) Leaves internal branch Lies between IJV & ICA Runs towards apex of carotid triangle Branches Communicates with C2,3,4 C2,3 provide proprioceptive fibers to sternocleidomastoid C3,4 provide proprioceptive fibers to trapezius Lesser occipital nerve hooks around external branch at posterior border of Cranial Nerves IX, X, XI, XII in the neck… sternocleidomastoid 1  HYPOGLOSSAL (XII) Motor nerve of tongue Exits via hypoglossal canal Lies medial to Ix, X, XI & IJV & ICA Inclines laterally & downwards, behind ICA & IX & X to lie in front of IJV Crosses anterior aspect of vagus, ICA, ECA, lingual artery Passes over hyoglossus, deep to digastric, stylohyoid, mylohyoid Enters genioglossus & supplies all intrinsic muscles of tongue except palatoglossus Cranial Nerves IX, X, XI, XII in the neck… 1  HYPOGLOSSAL (XII) BRANCHES Cranial Nerves IX, X, XI, XII in the neck… 1  HYPOGLOSSAL (XII) BRANCHES BRANCHES SUPERIOR ROOT OF ANSA CERVICALIS Derived from C1 Joins inferior root of ansa Ansa gives branches to both bellies of omohyoid, sternohyoid, sternothyroid NERVE TO THYROHYOID Crosses greater cornu of hyoid bone to reach muscle MUSCULAR BRANCHES To styloglossus, hyoglossus, genioglossus, geniohyoid, intrinsic muscles of tongue Cranial Nerves IX, X, XI, XII in the neck… 1  Dr OS Aladeyelu Email: [email protected] WhatsApp: 065 697 5373