Heart, Superior Mediastinum

Gross Anatomy


Internal Features of the Heart, Superior Mediastinum


Anatomy Tables for Today's Topic

Nerves of the Thoracic Cavity
Great Vessels
Internal Features of the Heart

Nerves of the Thoracic Cavity

Nerve Source Branches Motor Sensory Notes
cardiac plexus cardiac brs. of the vagus n. and cervical sympathetic trunk; thoracic visceral nn. no named branches moderates heart muscle (parasympathetic: decreases rate and force of contraction; sympathetic: increases rate and force of contraction); vascular smooth muscle of the heart & lungs (sympathetic); smooth muscle & mucous glands of bronchial tree (parasympathetic) pain from the heart and lungs cardiac plexus is continuous with the coronary and pulmonary plexuses; thoracic visceral nn. carry pain from the heart to the upper thoracic spinal cord segments resulting in pain referred to the left upper limb in the T1 and T2 dermatomes
cardiac, sympathetic cervical sympathetic trunk no named branches heart (sympathetic: increases rate and force of contraction, parasympathetic: decreases rate and force of contraction); bronchial tree & lungs via pulmonary plexus heart, bronchial tree and lungs cervical sympathetic trunk usually gives 3 cervical cardiac brs. l (superior, middle and inferior) to the cardiac plexus
cardiac, vagal vagus n. (X) no named branches heart (parasympathetic: decreases rate and force of contraction; sympathetic: increases rate and force of contraction); bronchial tree and lungs via pulmonary plexus heart, bronchial tree and lungs vagus n. has 2 cervical cardiac brs. (superior and inferior) and 1 or more thoracic cardiac brs.
pulmonary plexus continuous with the cardiac plexus; thoracic visceral nn.; pulmonary brs. of vagus no named branches parasympathetic: smooth muscle & glands of the bronchial tree; sympathetic: vascular smooth muscle of the lungs none pulmonary plexus is located along the pulmonary vessels and primary bronchi in the root of the lung
vagus n. medulla: dorsal motor nucleus (GVE preganglionic parasympathetic); inferior ganglion (GVA); nucleus ambiguus (SVE); superior ganglion (GSA); inferior ganglion(SVA) auricular br., pharyngeal br., superior laryngeal, superior and inferior cervical cardiac brs., recurrent laryngeal n., thoracic cardiac brs., brs. to the pulmonary plexus, brs. to the esophageal plexus, anterior and posterior vagal trunks SVE: intrinsic muscles of the larynx, pharynx (except stylopharyngeus), and palate (except tensor veli palatini); GVE: smooth muscle of the respiratory tree & gut (proximal to the left colic flexure), heart; secretomotor: mucous glands of the larynx, respiratory tree, pharynx and gut; secretomotor to digestive glands GSA: skin of the external auditory meatus; GVA: viscera of head, neck, thorax & abdomen proximal to the left colic flexure; SVA: taste from the epiglottis 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

Great Vessels

ArterySourceBranchesSupplyNotes
aorta, ascending left ventricle of the heart left and right coronary aa. heart, entire body ascending aorta is the shortest part of the aorta; it continues as the aortic arch
arch, aortic the continuation of the ascending aorta brachiocephalic trunk, left common carotid a., left subclavian a. the entire body except the heart aortic arch continues as the descending thoracic aorta; the fibrous ligamentum arteriosum connects to the inferior surface of the aortic arch and it marks the location of the fetal ductus arteriosus aortic arch continues as the descending thoracic aorta
brachiocephalic trunk aortic arch right common carotid a., right subclavian a. right side of the head and neck; right upper limb and right side of the chest wall there is only one brachiocephalic trunk
carotid, common brachiocephalic trunk (right), aortic arch (left) external carotid a., internal carotid a. most of the head and upper neck common carotid a. bifurcates at the level of the superior border of the thyroid cartilage; the internal carotid a. and the external carotid a. are its terminal brs.; the carotid sinus and carotid body are located at the bifurcation
subclavian brachiocephalic a. (right), aortic arch (left) 1st part: vertebral a., thyrocervical trunk, internal thoracic a.; 2nd part: costocervical trunk; 3rd part: dorsal scapular a. (70%) neck, brain, spinal cord, thyroid gland, larynx, shoulder, chest muscles, upper limb subclavian a. is continuous with the axillary a., the name change occurs at the lateral border of the first rib; anterior scalene muscle passes anterior to the subclavian a., dividing it into 3 parts

Internal Features of the Heart

Organ/Part of Organ Location/Description Notes
atrioventricular bundle part of the conduction system of the heart atrioventricular bundle is a strand of specialized myocardium that passes through the right fibrous trigone into the muscular part of the interventricular septum; it divides into right and left branches to supply the ventricles; also known as: bundle of His
atrioventricular node part of the conduction system of the heart atrioventricular node is located in the wall of the right atrium above the opening of the coronary sinus and the septal cusp of the tricuspid valve
atrioventricular valve, left heart valve located between the left atrium and the left ventricle left atrioventricular valve has two valve cusps; also known as: mitral or bicuspid valve
atrioventricular valve, right atrioventricular node between the right atrium and the right ventricle right atrioventricular valve has three valve cusps; also known as: tricuspid valve
chordae tendineae thin connective tissue cords that attach the atrioventricular valve cusps to the papillary mm. chordae tendineae are found only in the ventricles, not in the atria
crista terminalis ridge of cardiac muscle separating the smooth sinus venarum posteriorly from the roughened wall of the primitive atrium anteriorly the sinuatrial node lies within the superior end of the crista terminalis
fossa ovalis shallow depression in the left wall of the right atrium fossa ovalis is the remnant of the foramen ovale which provided an open communication between the right atrium and left atrium in the fetus
ligamentum arteriosum fibrous cord of connective tissue that connects the left pulmonary a. near its origin with the undersurface of the aortic arch ligamentum arteriosum is a remnant of the ductus arteriosus; the left recurrent laryngeal n. passes beneath it
limbus fossa ovalis the ridge around the fossa ovalis in the left wall of the right atrium limbus fossa ovalis is the margin of the septum secundum
mitral valve heart valve located between the left atrium and the left ventricle mitral valve has two valve cusps; it is named for the similarity of its shape to that of a bishop's miter; also known as: left atrioventricular valve or bicuspid valve
moderator band ridge of cardiac muscle spanning from the interventricular septum to the anterior papillary m. in the right ventricle septomarginal trabecula contains part of the right branch of the atrioventricular bundle; also known as: septomarginal trabecula
papillary muscle a small, nipple-like projection of cardiac muscle located within the ventricles papillary muscles attach to the cusps of the atrioventricular valves via chordae tendineae and act to keep the valve cusps from prolapsing under systolic blood pressure; there are three in the right ventricle: anterior, posterior, septal; there are two in the left ventricle: anterior, posterior
pectinate muscles prominent ridges of myocardium located on the inner surface of the right atrium pectinate muscles are very pronounced in the right atrium and in both auricles
pulmonary conus smooth area of the right ventricle below the opening into the pulmonary trunk pulmonary conus is the pulmonary part of the conus cordis which divides during development to form the outflow portions of the right and left ventricles
semilunar valves valve with three pocket-shaped cusps located in the base of the pulmonary trunk and ascending aorta semilunar valve has a thin endothelial free margin on each cusp called a lunula; a dense nodule is located at the midpoint of the free margin of each valve cusp; the pulmonary semilunar valve has anterior, left and right cusps; the aortic semilunar valve has right, left and posterior cusps
septomarginal trabecula ridge of cardiac muscle spanning from the interventricular septum to the anterior papillary m. in the right ventricle septomarginal trabecula contains part of the right branch of the atrioventricular bundle; also known as: moderator band
sinuatrial node part of the conduction system of the heart sinuatrial node is located within the crista terminalis near the superior vena cava; it is the "pacemaker" of the heart
trabeculae carnae ridges of cardiac muscle located on the inner wall of both ventricles the word trabecula is derived from the Latin word trabs, which means a beam
tricuspid valve a three cusped valve located at the ostium between the right atrium and the right ventricle tricuspid valve possesses anterior, posterior and septal cusps; also known as: right atrioventricular valve


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Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of tables edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2005, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.