Anatomy of the ANS in the Head and Neck PDF

The Anatomy of the ANS in the Head and Neck John Martin, Ph.D. [email protected]  The Autonomic Nervous System: Four sessions: 1. ANS – Introduction 2. ANS – Thorax 3. ANS – Head and Neck 4. ANS – Abdomen and Pelvis  The Anatomy of the ANS...

The Anatomy of the ANS in the Head and Neck John Martin, Ph.D. [email protected]  The Autonomic Nervous System: Four sessions: 1. ANS – Introduction 2. ANS – Thorax 3. ANS – Head and Neck 4. ANS – Abdomen and Pelvis  The Anatomy of the ANS in the Head and Neck Objectives: 1. To review the functional types of neurons in the peripheral nervous system 2. To identify the origin and course of preganglionic and postganglionic sympathetic and parasympathetic fibers to the visceral tissues of the head and neck 3. To identify actions of the sympathetic and parasympathetic divisions to the visceral tissues of the head and neck 4. To describe Horner’s syndrome. Cranial & Spinal Nerves May Contain 4 Types of Fibers (axons) Somatic afferent – “Sensory” CNS PNS skin, joints, muscles Somatic efferent – “Motor” CNS PNS skeletal muscle Cranial & Spinal Nerves May Contain 4 Types of Fibers (axons) Visceral afferent CNS PNS visceral organs Visceral efferent CNS PNS glands ganglion smooth muscle cardiac preganglionic postganglionic axon axon muscle  ANS ANS - Head and Neck ANS - Head and Neck Will first describe the Will then describe the detailed organization of detailed organization of sympathetic neurons to the parasympathetic the visceral tissues of neurons to the visceral the head and neck. tissues of the head and neck.  Sympathetic Pathways To Head and Neck Preganglionic Sympathetic Neurons Originate in Spinal Cord Levels T1-T4 and Ascend Sympathetic Chain to Synapse in 3 pairs of Cervical Ganglia  Sympathetic Pathways SUP. To Head and Neck CERVICAL GANG. SPINAL NERVE MID. CERVICAL C1-C4 GANG. DORSAL RAMUS VENTRAL RAMUS C5-C6 INF. CERVICAL GREY GANG. COMMUNICATING RAMUS SYMPATHETIC CHAIN C7-C8 GREY COMMUNICATING RAMUS WHITE COMMUNICATING T1-T4 RAMUS  Sympathetic Pathways SUP. To Spinal Nerves CERVICAL GANG. SPINAL NERVE MID. CERVICAL C1-C4 GANG. DORSAL RAMUS VENTRAL RAMUS C5-C6 INF. SPINAL NERVES TO GREY CERVICAL GANG. SOMATIC TISSUES COMMUNICATING (Upper Body Wall, Neck, and Upper Limbs) RAMUS Arrector pili muscles Vascular smooth muscle Sweat glands of the skin SYMPATHETIC CHAIN C7-C8 GREY COMMUNICATING RAMUS WHITE COMMUNICATING T1-T4 RAMUS  Sympathetic Pathways SUP. To Thoracic Viscera CERVICAL GANG. SPINAL NERVE MID. CERVICAL C1-C4 GANG. DORSAL RAMUS VENTRAL RAMUS C5-C6 INF. SPINAL NERVES TO GREY CERVICAL GANG. SOMATIC TISSUES COMMUNICATING (Upper Body Wall, Neck, and Upper Limbs) RAMUS Arrector pili muscles Vascular smooth muscle Sweat glands of the skin SYMPATHETIC CHAIN C7-C8 GREY COMMUNICATING RAMUS CARDIOPULMONARY SPLANCHNIC NERVES “CARDIAC NERVES” WHITE T1-T4 Postganglionic fibers to cardiac, pulmonary, COMMUNICATING RAMUS and esophageal plexuses Thoracic viscera smooth and cardiac muscles  Sympathetic Pathways SUP. To Head and Neck CERVICAL GANG. SPINAL NERVE VISCERAL TISSUES OF HEAD via perivascular route Arrector pili muscles Vascular smooth muscle MID. Sweat glands of the skin CERVICAL C1-C4 GANG. DORSAL RAMUS VENTRAL RAMUS C5-C6 INF. SPINAL NERVES TO GREY CERVICAL GANG. SOMATIC TISSUES COMMUNICATING (Upper Body Wall, Neck, and Upper Limbs) RAMUS Arrector pili muscles Vascular smooth muscle Sweat glands of the skin SYMPATHETIC CHAIN C7-C8 GREY COMMUNICATING RAMUS CARDIOPULMONARY SPLANCHNIC NERVES “CARDIAC NERVES” WHITE T1-T4 Postganglionic fibers to cardiac, pulmonary, COMMUNICATING RAMUS and esophageal plexuses Thoracic viscera smooth and cardiac muscles  Sympathetic Pathways To Head and Neck Axons of postganglionic neurons originate in: Superior cervical ganglion The chief source of postganglionic sympathetic innervation to the visceral tissues of the head and neck Is the origin of the superior cardiac nerve Middle cervical ganglion Is the origin of the middle cardiac nerve Inferior cervical ganglion May be fused with the first thoracic ganglion and is thus referred to as the stellate ganglion Is the origin of the inferior cardiac nerve  Sympathetic Pathways To Head and Neck Axons of postganglionic neurons travel as: Internal and external carotid nerves Hitch-hike along the internal and external carotid arteries, forming a network of nerves, referred to as the internal and external carotid plexuses By following blood vessels and entering branches of the trigeminal nerve, the internal and external carotid plexuses innervate: Smooth muscle in the eye Dilator muscle of iris Smooth muscle of upper eyelid Arrector pili muscles of face and scalp Vascular smooth muscle Sweat glands of the face and scalp  Superior Cervical The Sympathetic Ganglion (Thoracolumbar) Division visceral tissues (organs) Middle Cervical Internal and External Carotid Nerves: Ganglion postganglionic fibers to head and neck Inferior Cervical Cardiopulmonary T1 Ganglion Splanchnic Nerves “Cardiac Nerves”: somatic tissues postganglionic fibers to thoracic viscera Postganglionic sympathetic axons travel in spinal Greater, Lesser and Least nerves C1-C8 to: L2/L3 Splanchnic Nerves: 1. arrector pili muscles, preganglionic fibers to prevertebral 2. vascular smooth ganglia, postganglionic fibers to muscle, and abdominopelvic viscera 3. sweat glands of the skin prevertebral ganglia  ANS ANS - Head and Neck ANS - Head and Neck Will first describe the Will then describe the detailed organization of detailed organization of sympathetic neurons to the parasympathetic the visceral tissues of neurons to the visceral the head and neck. tissues of the head and neck. Parasympathetic Pathways  Parasympathetic Pathways MIDBRAIN To Thoracic Viscera CN III PONS CN VII CN IX MEDULLA Dorsal Vagal THORACIC & Nucleus ABDOMINAL CN X SMALL GANGLIA VISCERA WITHIN WALLS OF VISCERA S2, S3, S4  Parasympathetic Pathways MIDBRAIN Edinger-Westphal To Head and Neck Nucleus CN III CILIARY EYE GANGLION (IRIS, CILIARY MUSLCES) PONS Superior Salivatory LACRIMAL, NASAL, Nucleus PALATINE & CN VII PTERYGOPALATINE & PHARYNGEAL SUBMANDIBULAR GLANDS GANGLIA SALIVARY GLANDS Inferior Salivatory (SUBMANDIBULAR, Nucleus SUBLINGUAL) CN IX OTIC MEDULLA GANGLION PAROTID GLAND  The Parasympathetic (Craniosacral) Division Cranial outflow CN III, VII, IX, X Four ganglia in head  Ciliary Ganglion Associated with the Oculomotor Nerve (CN III) Parasympathetics Preganglionic parasympathetic fibers/axons travel in the oculomotor nerve to synapse in ciliary ganglion located in the orbit Postganglionic parasympathetic fibers/axons from the ciliary ganglion innervate the ciliary and sphincter muscles of the eye Sympathetics Preganglionic sympathetic fibers/axons travel in the sympathetic chain to synapse in the superior cervical ganglion Postganglionic sympathetic fibers/axons travel from the superior cervical ganglion via internal carotid nerve/plexus and the majority pass through the ciliary ganglion to innervate the dilator muscle of the pupil.  Submandibular Ganglion Associated with the Facial Nerve (CN VII) Parasympathetics Preganglionic parasympathetic fibers/axons travel in the chorda tympani nerve (a branch of the facial nerve), then in the lingual nerve (a branch of the mandibular nerve) to synapse in the submandibular ganglion Postganglionic parasympathetic fibers/axons from the submandibular ganglion innervate the submandibular and sublingual salivary glands Sympathetics Preganglionic sympathetic fibers/axons travel in sympathetic chain to synapse in the superior cervical ganglion Postganglionic sympathetic fibers/axons travel from the superior cervical ganglion via external carotid nerve/plexus to the submandibular and sublingual salivary glands.  Pterygopalatine Ganglion Associated with the Facial Nerve (CN VII) Parasympathetics Preganglionic parasympathetic fibers/axons travel in the greater petrosal nerve (a branch of the facial nerve), then in the nerve of the pterygoid canal to synapse in the pterygopalatine ganglion Postganglionic parasympathetic fibers/axons from the pterygopalatine ganglion innervate the lacrimal gland and glands in the nasal cavity, pharynx, and palate Sympathetics Preganglionic sympathetic fibers/axons travel in sympathetic chain to synapse in the superior cervical ganglion Postganglionic sympathetic fibers/axons travel from the superior cervical ganglion via the internal and external carotid nerves/plexuses and pass through the pterygopalatine ganglion to the lacrimal gland and glands in the nasal cavity, pharynx, and palate.  Otic ganglion Associated with the Glossopharyngeal Nerve (CN IX) Parasympathetics Preganglionic parasympathetic fibers/axons travel in the lessor petrosal nerve (a branch of the glossopharyngeal nerve) to synapse in the otic ganglion Postganglionic parasympathetic fibers/axons travel from the otic ganglion via the auriculotemporal nerve to innervate the parotid gland. Sympathetics Preganglionic sympathetic fibers/axons travel in sympathetic chain to synapse in the superior cervical ganglion Postganglionic sympathetic fibers/axons travel from the superior cervical ganglion via external carotid nerve/plexus to the parotid gland. Summary of Autonomic Distribution to the Head and Neck  Some Actions of Sympathetic System to Head and Neck “Fight or flight” Catabolic (energy-expending) Stimulates sweat secretion and goose bumps  Some Actions of Sympathetic System to Head and Neck “Fight or flight” Catabolic (energy-expending) Dilates pupil Mydriasis  Some Actions of Sympathetic System to Head and Neck “Fight or flight” Catabolic (energy-expending) Inhibits lacrimal, nasal, palatine, pharyngeal and salivary gland secretions.  Some Actions of Parasympathetic System to Head and Neck “Feed & breed”, “rest & digest” Anabolic (energy-conserving) Constricts pupil Miosis  Some Actions of Parasympathetic System to Head and Neck “Feed & breed”, “rest & digest” Anabolic (energy-conserving) Stimulates lacrimal, nasal, palatine, pharyngeal and salivary gland secretions.  Horner’s Syndrome Sympathetic Denervation of the Face Results in: Ptosis (slight drooping of the eyelid) due denervation of the superior tarsal muscle Anhidrosis (absence of sweating) and flushing of affected side of face Miosis (pupil constriction)  Horner’s Syndrome Sympathetic Denervation of the Face Associated with lesions of: Spinal cord at T1-T4 Sympathetic chain Cervical ganglia – typically due to lung tumor Aneurysm of internal carotid artery  Questions? Objectives: 1. To review the functional types of neurons in the peripheral nervous system 2. To identify the origin and course of preganglionic and postganglionic sympathetic and parasympathetic fibers to the visceral tissues of the head and neck 3. To identify actions of the sympathetic and parasympathetic divisions to the visceral tissues of the head and neck 4. To describe Horner’s syndrome.