| Organ/Part of Organ | Location/Description | Notes |
|---|---|---|
| apex | tip of the left ventricle of the heart | apex of the heart is located 3" to the left of the midline at the level of the 5th intercostal space |
| 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 |
| atrium, right | chamber of the heart that receives deoxygenated blood from the systemic circulation (body) | right atrium forms the right margin of the heart; it receives blood from the superior vena cava, inferior vena cava and coronary sinus |
| atrium, left | chamber of the heart that receives oxygenated blood from the pulmonic circulation (lungs) | left atrium is located on the posterior aspect of the heart; it receives blood from the pulmonary vv. |
| auricle | small appendage that projects anteriorly from the atrium | paired, one on each atrium; right auricle lies beside the aorta and covers the right coronary artery; left auricle lies beside the pulmonary trunk |
| base | the superior aspect of heart | base of the heart is where the aorta, pulmonary trunk and superior vena cava exit/enter the heart |
| bronchi | the air conducting passages of the lungs | bronchi may be classified as primary, secondary (lobar), and tertiary (segmental) |
| bronchus, primary | first branch of the air conducting system arising from the bifurcation of the trachea at T4/T5 intervertebral disc | paired, right and left; one primary bronchus enters the hilus of each lung; the right primary bronchus is shorter, larger in diameter and more vertically oriented than the left so that aspirated foreign bodies tend to lodge in the right primary bronchus |
| bronchus, secondary | a branch of the air conducting system arising from the primary bronchus | there are 3 secondary bronchi in the right lung: upper, middle, lower; there are 2 secondary bronchi in the left lung: upper, lower; also known as: lobar bronchi |
| bronchus, tertiary | a branch of the air conducting system arising from the secondary (lobar) bronchus | there are 10 tertiary bronchi in the right lung: branching from the right superior lobar bronchus - apical, anterior, posterior; branching from the right middle lobar bronchus - medial, lateral; branching from the right inferior lobar bronchus - superior, anterior basal, posterior basal, medial basal, lateral basal; there are 8 tertiary bronchi in the left lung: branching from the left superior lobar bronchus - apicoposterior, anterior; branching from the lingular bronchus (off of the superior lobar bronchus) - superior lingular, inferior lingular; branching from the inferior lobar bronchus - superior, anteromedial basal, posterior basal, lateral basal; also known as: segmental bronchi |
| bronchus, segmental | a branch of the air conducting system arising from the secondary (lobar) bronchus | there are 10 tertiary bronchi in the right lung: branching from the right superior lobar bronchus - apical, anterior, posterior; branching from the right middle lobar bronchus - medial, lateral; branching from the right inferior lobar bronchus - superior, anterior basal, posterior basal, medial basal, lateral basal; there are 8 tertiary bronchi in the left lung: branching from the left superior lobar bronchus - apicoposterior, anterior; branching from the lingular bronchus (off of the superior lobar bronchus) - superior lingular, inferior lingular; branching from the inferior lobar bronchus - superior, anteromedial basal, posterior basal, lateral basal; also known as: segmental bronchi |
| carina | keel-shaped cartilage lying within the tracheal bifurcation | carina trachealis is an important landmark during endoscopy of the bronchial tree |
| 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 |
| coronary sulcus | groove on the surface of the heart that separates the atria from the ventricles | coronary sulcus contains the coronary sinus, circumflex a., and right coronary a. |
| 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 |
| cupula | serous membrane lining the pleural cavity which extends above the level of the 1st rib into the root of the neck | cupular pleura is continuous inferiorly with the costal and mediastinal parietal pleurae; it is reinforced by a specialization of scalene fascia (called Sibson's fascia or suprapleural membrane); also known as: cervical parietal pleura or cervical dome of pleura |
| esophagus | the portion of the gastrointestinal tract between the pharynx and the stomach | connects: superiorly with laryngopharynx at lower border of cricoid cartilage; inferiorly it passes through diaphragm at the T10 vertebral level to reach the stomach; the upper 1/3 is skeletal muscle innervated by the recurrent laryngeal, the lower 2/3rds is smooth muscle innervated by the vagus nn. via the esophageal plexus |
| fissure, oblique | deep groove in the surface of the lung that separates the upper lobe from the lower lobe (both lungs), and the middle lobe from the lower lobe (right lung) | oblique fissure extends from the level of the T3 vertebra posteriorly to the 6th costochondral junction anteriorly |
| fissure, horizontal | deep groove in the surface of the lung that separates the middle lobe from the upper lobe (right lung only) | horizontal fissure extends from the 5th rib at the mid-axillary line along the 4th rib to the sternum anteriorly |
| 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 |
| heart | muscular pump for blood located within middle mediastinum of the thorax | heart is nearly surrounded by the pericardial sac and pericardial cavity |
| interventricular sulcus, anterior | groove between the ventricles on the anterior surface of the heart | anterior interventricular sulcus contains the anterior interventricular a. and the great cardiac v.; it marks the location of the interventricular septum |
| interventricular sulcus, posterior | groove between the ventricles on the diaphragmatic surface of the heart | posterior interventricular sulcus contains the posterior interventricular a. and the middle cardiac v.; it marks the location of the interventricular septum |
| 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 |
| lobe, inferior | the portion of the lung supplied by the inferior lobar bronchus | inferior lobe of the right lung: possesses 5 bronchopulmonary segments - superior, anterior basal, posterior basal, medial basal, lateral basal; inferior lobe of the left lung: possesses 4 bronchopulmonary segments - superior, anteromedial basal, posterior basal, lateral basal |
| lobe, middle | the portion of the right lung supplied by the middle lobar bronchus | middle lobe is found in the right lung only; it possesses 2 bronchopulmonary segments: medial and lateral; lingula of the inferior lobe of the left lung is equivalent to the middle lobe of the right lung |
| lobe, superior | the portion of the lung supplied by the superior lobar bronchus | superior lobe of the right lung: possesses three bronchopulmonary segments - apical, anterior and posterior; superior lobe of the left lung: possesses four bronchopulmonary segments - apicoposterior, anterior, superior lingular, inferior lingular |
| lung | the portion of the respiratory system where exchange of gasses occurs between the air and the blood; located in the thoracic cavity | paired; right lung is divided into three lobes: superior, middle and inferior; left lung has two lobes: superior and inferior |
| 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 atrium: anterior, posterior, septal; there are two in the left atrium: 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 |
| pericardial sinus, oblique | an area of the pericardial cavity located behind the left atrium of heart | serous pericardium reflects onto the inferior vena cava and pulmonary vv. to define this space |
| pericardial sinus, transverse | an area of the pericardial cavity located behind the aorta and pulmonary trunk and anterior to the superior vena cava | transverse pericardial sinus was a simple structure when the heart tube began to form during development; it separates the outflow vessels from the inflow vessels of the heart |
| pericardium, fibrous | a fibrous sac that attaches to the central tendon of the diaphragm and fuses with the adventitia of the great vessels superiorly | fibrous pericardium contains the pericardial cavity and heart; it is lined on its inner surface by the parietal layer of serous pericardium; it defines the outermost boundary of the middle mediastinum |
| pericardium, parietal serous | serous membrane lining the pericardial cavity; it is located on the inner surface of the fibrous pericardium | parietal serous pericardium reflects onto the heart at the origins of the great vessels to become continuous with the visceral serous pericardium |
| pericardium, visceral serous | serous membrane covering the surface of the heart | visceral serous pericardium reflects onto the inner surface of the fibrous pericardium at the origins of the great vessels to become continuous with the parietal serous pericardium; also known as: epicardium |
| pleura | serous membrane lining the pleural cavity | there are two types of pleura: visceral pleura covers the lungs, parietal pleura lines the inner surfaces of the walls of pleural cavity; parietal pleura is sensitive to pain but visceral pleura is not sensitive to pain |
| pleura, cervical parietal | serous membrane lining the pleural cavity which extends above the level of the 1st rib into the root of the neck | cervical parietal pleura is continuous inferiorly with the costal and mediastinal parietal pleurae; it is reinforced by a specialization of scalene fascia (called Sibson's fascia or suprapleural membrane); also known as: cupula or cervical dome of pleura |
| pleura, costal parietal | serous membrane lining the pleural cavity on the inner surfaces of the ribs, costal cartilages, and intercostal mm. | costal parietal pleura is continuous anteriorly with the mediastinal parietal pleura at the costomediastinal reflection; it is continuous posteriorly with the mediastinal parietal pleural at the vertebral bodies; it is continuous inferiorly with the diaphragmatic parietal pleura at the costodiaphragmatic reflection; it is continuous superiorly with the cervical parietal pleura at the level of the 1st rib |
| pleura, diaphragmatic parietal | serous membrane lining the pleural cavity on the superior surface of the diaphragm | diaphragmatic parietal pleura is continuous superiorly with the costal parietal pleura at the costodiaphragmatic reflection; it is continuous superiorly with the mediastinal pleura at the inferomedial borders of the pleural cavities |
| pleura, mediastinal parietal | serous membrane lining the pleural cavity on the lateral surface of the mediastinum | mediastinal parietal pleura is continuous anteriorly with the costal parietal pleura at the costomediastinal reflection; it is continuous inferiorly with the diaphragmatic pleura at the inferomedial borders of the pleural cavities; it is continuous posteriorly with the costal parietal pleura lateral to the vertebral bodies; it is continuous superiorly with the cervical pleura at the level of the 1st rib |
| pleura, visceral | serous membrane lining the surfaces of the lungs | visceral pleura extends into the oblique and horizontal fissures of the lungs; it does not have pain fibers |
| 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 |
| pulmonary ligament | fold of pleura located below the root of the lung | pulmonary ligament is where the visceral pleura and the mediastinal parietal pleura are continuous with each other |
| 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 |
| sulcus terminalis | groove on the external surface of the right atrium marking the location of the crista terminalis | the sinuatrial node is located at the superior end of the crista terminalis |
| 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 |
| trachea | main airway that lies anterior to the esophagus | trachea extends from vertebral level C6 to the level of the T4/5 intervertebral disc; superiorly it is connected to the cricoid cartilage via the cricotracheal ligament; it bifurcates into two primary bronchi |
| 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 |
| ventricle, right | heart chamber that pumps blood to the pulmonary circulation | right ventricle has a septomarginal trabecula and 3 papillary mm.; it pumps blood into the pulmonary trunk |
| ventricle, left | heart chamber that pumps blood to the systemic circulation | left ventricle has 2 papillary mm.; it pumps blood into the ascending aorta |