Nerves of the Thoracic Region Nerve Source Branches Motor Sensory Notes cardiac plexus cardiac brs. of the vagus n. and cervical ; thoracic l nn. the heart and lungs cardiac, cervical cardiac, vagal vagus n. (X) dorsal primary ramus first branch off of the dorsal side of the spinal nerve numerous moderates heart muscle (para: decreases rate contraction; : increases rate contraction); heart & lungs (); smooth muscle & mucous glands of bronchial tree (para ) heart (: increases rate contraction, para: decreases rate contraction); bronchial tree & lungs via plexus heart (para: decreases rate contraction; : increases rate contraction); bronchial tree and lungs via plexus to the deep back mm.; innervation to the heart, bronchial tree and lungs heart, bronchial tree and lungs general sense cardiac plexus is continuous with the coronary and plexuses; thoracic l nn. carry the heart to the upper thoracic spinal cord segments resulting in pain left upper limb in the T1 and T2 dermatomes cervical usually gives 3 cervical cardiac brs. l (superior, middle and inferior) to the cardiac plexus vagus n. has 2 cervical cardiac brs. (superior and inferior) and 1 or more thoracic cardiac brs. a mixed nerve containing both motor and sensory fibers 1
dorsal root dorsal root ganglion plexus ganglia, chain dorsal horn of the spinal cord to the spinal nerve skin to the skin of the back general sense dorsal root is entirely sensory in function; it is located dorsal to the denticulate ligament dorsal rootlets dorsal rootlets one dermatome a sensory ganglion; located in the intervertebral foramen of the vertebral column on the dorsal root - one per spinal nerve; location of the cell bodies of somatic afferent (sensory) neurons right and left vagus (X) nn.; thoracic l brs. of the fibers arrive via white rami of ventral primary rami of spinal nerves T1- anterior and posterior vagal s fibers depart via gray rami communicante s to all spinal nn.; internal & external carotid para axons vagus n. supply smooth muscle and glands of the thoracic esophagus and abdominal gut and its derivatives proximal to the left colic flexure; axons thoracic l brs. supply muscle in the vessels dilator pupillae, muscle, arrector pili muscles, sweat glands, medulla, heart, lungs and gut vagus: GVA esophagus and abdominal gut proximal to the left colic flexure; thoracic l brs.carry pain esophagus during development of the gut, the stomach and esophagus rotate 90 to the right with the result that the left and right vagus nerves mix in the plexus and emerge as anterior and posterior vagal s located lateral to the vertebral bodies in the neck, thorax & abdominopelvic cavity; the ganglia plus their interconnecting 2
ganglion, dorsal root gray ramus communicans L2 nn.; cervical cardiac brs.; thoracic direct l brs.; greater, lesser & least thoracic splanchnic nn.; lumbar splanchnic nn.; sacral splanchnic nn. fibers are also known as the ; cell bodies are gray matter of T1-L2 dorsal rootlets dorsal rootlets one dermatome a sensory ganglion; located in the intervertebral foramen of the vertebral column on the dorsal root - one per spinal nerve; location of the cell bodies of somatic afferent (sensory) neurons cell bodies chain ganglia T5-T9; the splanchnic nerve appears to arise by multiple contributions carries axons to the spinal nerve; spinal nerve will carry those axons peripherally to the skin, blood vessels, etc. celiac ganglion; fibers supply the adrenal medulla which releases epinephrine and norepinephrine into the blood the abdominal gray rami connect the chain to spinal nerves at all vertebral levels passes through the crus of the diaphragm; processes from the celiac ganglion spread down the aorta and distribute with its ; they innervate the vascular smooth of these 3
intercostal n. intercostobrachia l n. intermediate supraclavicular n. lateral supraclavicular n. least thoracic lesser thoracic ventral primary rami of spinal nerves T1-T11 also known as the lateral cutaneous br. of the ventral primary ramus of T2 spinal cord level T12 T10-T11; the lesser thoracic splanchnic nerve appears to arise by multiple contributions lateral & anterior cutaneous brs. intercostal muscles; abdominal wall muscles (via T7- T11); muscles of the forearm and hand (via T1) motor innervation to skin renal plexus aorticorenal ganglion; skin of the chest and abdomen anterolaterally; skin of the medial side of the upper limb (via T1-T2) skin of the medial side of the arm upper chest, near the midclavicle upper the gland the gland vessels and organs supplied intercostal n.travels below the posterior intercostal a. in the costal groove intercostobrachia l n. communicates with the medial brachial cutaneous nerve least thoracic pass through the crus of the diaphragm; it synapses in minute ganglia renal plexus lesser thoracic passes through the crus of the diaphragm; processes from the ganglion supply vascular smooth muscle of of the renal a. and aa.; 4
medial supraclavicular n. phrenic n. plexus, cardiac plexus, ventral primary rami of spinal nerves C3-C5 () cardiac brs. of the vagus n. and cervical ; thoracic l nn. right and left vagus (X) nn.; thoracic l brs. of the anterior and posterior vagal s skeletal muscle of the diaphragm moderates heart muscle (para: decreases rate contraction; : increases rate contraction); heart & lungs (); smooth muscle & mucous glands of bronchial tree (para ) para axons vagus n. supply smooth muscle and glands of the thoracic esophagus and abdominal gut and its derivatives proximal to the left colic flexure; axons thoracic l brs. supply upper chest, anteriorly diaphragmatic pleura; some fibers contributed to the pericardium and to the adjacent mediastinal and costal pleurae the heart and lungs vagus: GVA esophagus and abdominal gut proximal to the left colic flexure; thoracic l brs.carry pain esophagus gland phrenic n. crosses the anterior surface of the anterior scalene m. cardiac plexus is continuous with the coronary and plexuses; thoracic l nn. carry the heart to the upper thoracic spinal cord segments resulting in pain left upper limb in the T1 and T2 dermatomes during development of the gut, the stomach and esophagus rotate 90 to the right with the result that the left and right vagus nerves mix in the plexus and emerge as anterior and posterior vagal s 5
plexus, continuous with the cardiac plexus; thoracic l nn.; brs. of vagus preaortic ganglia splanchnic nn. plexuses to abdominal and pelvic ramus communicans, gray ramus communicans, white cell bodies chain ganglia cell bodies lateral horn gray matter of spinal cord levels T1- L2; muscle in the vessels para: smooth muscle & glands of the bronchial tree; : lungs muscle of vessels that supply abdominopelvic carries axons to the spinal nerve; spinal nerve will carry those axons peripherally to the skin, blood vessels, etc. axons contained within white rami will synapse on cell bodies that will ultimately innervate the skin,, abdominopelvi c is carried back to the spinal cord through the white ramus communicans plexus is located along the vessels and primary bronchi in the root of the lung also known as: collateral ganglia which include the celiac ganglion, aorticorenal ganglion, superior mesenteric ganglion and inferior mesenteric ganglion; para axons of vagal origin pass through the preaortic ganglia but do not synapse there gray rami connect the chain to spinal nerves at all vertebral levels white rami connect the chain to spinal nerves at vertebral levels T1-L2; carries 6
ramus, dorsal primary ramus, ventral primary root, dorsal root, ventral splanchnic, first branch off of the dorsal side of the spinal nerve first branch off of the ventral side of the spinal nerve dorsal horn of the spinal cord to the spinal nerve ventral horn of the spinal cord to the spinal nerve numerous numerous glands, blood vessels, etc. to the deep back mm.; innervation to the skin to skeletal mm. of the neck, and extremities; innervation to the skin general sense to the skin of the back general sense to the skin of the (except the back) and extremities; l pain via the white rami of the nervous system (T1-L2) general sense to skeletal mm.; (T1- L2) celiac ganglion; fibers supply the adrenal medulla the abdominal axons a mixed nerve containing both motor and sensory fibers a mixed nerve containing both motor and sensory fibers dorsal root is entirely sensory in function; it is located dorsal to the denticulate ligament entirely motor in function; located ventral to the denticulate ligament; at all spinal core levels it contains GSE for skeletal mm.; at levels T1-L2 it contains GVE ( ) for blood vessels, sweat glands, thoracic, abdominal, pelvic passes through the crus of the 7
splanchnic, least thoracic splanchnic, lesser thoracic stellate ganglion T5-T9; the splanchnic nerve appears to arise by multiple contributions spinal cord level T12 T10-T11; the lesser thoracic splanchnic nerve appears to arise by multiple contributions spinal cord level T1 gray rami communicans to spinal nerves C8 and T1 ( ); thoracic l br. which releases epinephrine and norepinephrine into the blood renal plexus aorticorenal ganglion; muscle, arrector pili muscle, sweat glands of the C8 & T1 cutaneous distribution on chest & upper limb (C8 and T1 dermatomes); the gland the gland lungs diaphragm; processes from the celiac ganglion spread down the aorta and distribute with its ; they innervate the vascular smooth of these vessels and organs supplied least thoracic pass through the crus of the diaphragm; it synapses in minute ganglia renal plexus lesser thoracic passes through the crus of the diaphragm; processes from the ganglion supply vascular smooth muscle of of the renal a. and aa.; gland stellate ganglion is formed by the fusion of the inferior cervical ganglion and the T1 ganglion of the 8
supraclavicular, intermediate supraclavicular, lateral supraclavicular, medial chain ganglia vagus n. fibers arrive via white rami of ventral primary rami of spinal nerves T1- L2 medulla: dorsal motor nucleus (GVE para) ; inferior ganglion (GVA); nucleus ambiguus (SVE); superior ganglion (GSA); inferior ganglion(sva) fibers depart via gray rami communicante s to all spinal nn.; internal & external carotid nn.; cervical cardiac brs.; thoracic direct l brs.; greater, lesser & least thoracic splanchnic nn.; lumbar splanchnic nn.; sacral splanchnic nn. auricular br., pharyngeal br., superior laryngeal, superior and inferior cervical cardiac brs., recurrent laryngeal n., thoracic cardiac brs., brs. to the plexus, brs. to the plexus, anterior and posterior lungs dilator pupillae, muscle, arrector pili muscles, sweat glands, medulla, heart, lungs and gut SVE: intrinsic muscles of the larynx, pharynx (except stylopharyngeus), and palate (except tensor veli palatini); GVE: smooth tree & gut (proximal to the left colic flexure), heart; secretomotor: mucous glands of upper chest, near the midclavicle upper upper chest, anteriorly GSA: skin of the external auditory meatus; GVA: of head, neck, thorax & abdomen proximal to the left colic flexure; SVA: taste epiglottis located lateral to the vertebral bodies in the neck, thorax & abdominopelvic cavity; the ganglia plus their interconnecting fibers are also known as the ; cell bodies are gray matter of T1-L2 also known as: CN X, 10th cranial nerve; the vagus n. passes through the jugular foramen to exit the posterior cranial fossa; vagus means "wanderer" in reference to its extensive distribution to the body cavities 9
ventral primary ramus ventral root white ramus communicans first branch off of the ventral side of the spinal nerve ventral horn of the spinal cord to the spinal nerve cell bodies lateral horn gray matter of spinal cord levels T1- L2; vagal s numerous the larynx, tree, pharynx and gut; secretomotor to digestive glands to skeletal mm. of the neck, and extremities; innervation to the skin to skeletal mm.; (T1- L2) axons contained within white rami will synapse on cell bodies that will ultimately innervate the skin,, glands, blood vessels, etc. general sense to the skin of the (except the back) and extremities; l pain via the white rami of the nervous system (T1-L2) is carried back to the spinal cord through the white ramus communicans a mixed nerve containing both motor and sensory fibers entirely motor in function; located ventral to the denticulate ligament; at all spinal core levels it contains GSE for skeletal mm.; at levels T1-L2 it contains GVE ( ) for blood vessels, sweat glands, thoracic, abdominal, pelvic white rami connect the chain to spinal nerves at vertebral levels T1-L2; carries axons 10