{"id":1515,"date":"2014-10-07T05:24:20","date_gmt":"2014-10-07T05:24:20","guid":{"rendered":"https:\/\/courses.candelalearning.com\/apvccs\/?post_type=chapter&#038;p=1515"},"modified":"2016-10-19T21:33:16","modified_gmt":"2016-10-19T21:33:16","slug":"anatomical-terminology","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/chapter\/anatomical-terminology\/","title":{"raw":"Anatomical Terminology","rendered":"Anatomical Terminology"},"content":{"raw":"<div title=\"1.6.\u00a0Anatomical Terminology\">\r\n<div>\r\n<div>\r\n<div class=\"bcc-box bcc-highlight\">\r\n<h3>Learning Objectives<\/h3>\r\n<ul>\r\n \t<li>Demonstrate the anatomical position<\/li>\r\n \t<li>Describe the human body using directional and regional terms<\/li>\r\n \t<li>Identify three planes most commonly used in the study of anatomy<\/li>\r\n \t<li>Distinguish between the posterior (dorsal) and the anterior (ventral) body cavities, identifying their subdivisions and representative organs found in each<\/li>\r\n \t<li>Describe serous membrane and explain its function<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<div>\r\n<ul>\r\n \t<li><a href=\"#m45990-fs-id1932675\">Anatomical Position<\/a><\/li>\r\n \t<li><a href=\"#m45990-fs-id2661204\">Regional Terms<\/a><\/li>\r\n \t<li><a href=\"#m45990-fs-id2138527\">Directional Terms<\/a><\/li>\r\n \t<li><a href=\"#m45990-fs-id2576027\">Body Planes<\/a><\/li>\r\n \t<li><a href=\"#m45990-fs-id2697376\">Body Cavities and Serous Membranes<\/a>\r\n<ul>\r\n \t<li><a href=\"#m45990-fs-id2384338\">Subdivisions of the Posterior (Dorsal) and Anterior (Ventral) Cavities<\/a><\/li>\r\n \t<li><a href=\"#m45990-fs-id1207231\">Abdominal Regions and Quadrants<\/a><\/li>\r\n \t<li><a href=\"#m45990-fs-id1364871\">Membranes of the Anterior (Ventral) Body Cavity<\/a><\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<\/div>\r\nAnatomists and health care providers use terminology that can be bewildering to the uninitiated. However, the purpose of this language is not to confuse, but rather to increase precision and reduce medical errors. For example, is a scar \u201cabove the wrist\u201d located on the forearm two or three inches away from the hand? Or is it at the base of the hand? Is it on the palm-side or back-side? By using precise anatomical terminology, we eliminate ambiguity. Anatomical terms derive from ancient Greek and Latin words. Because these languages are no longer used in everyday conversation, the meaning of their words does not change.\r\n\r\nAnatomical terms are made up of roots, prefixes, and suffixes. The root of a term often refers to an organ, tissue, or condition, whereas the prefix or suffix often describes the root. For example, in the disorder hypertension, the prefix \u201chyper-\u201d means \u201chigh\u201d or \u201cover,\u201d and the root word \u201ctension\u201d refers to pressure, so the word \u201chypertension\u201d refers to abnormally high blood pressure.\r\n<div title=\"Anatomical Position\">\r\n<div>\r\n<h2 id=\"m45990-fs-id1932675\">Anatomical Position<\/h2>\r\n<\/div>\r\nTo further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body \u201cmap,\u201d or\u00a0<em>anatomical position<\/em><a id=\"id510494\"><\/a>, is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in\u00a0Figure\u00a01.12. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the \u201canterior (front) carpal (wrist) region\u201d would be present on the palm side of the wrist. The term \u201canterior\u201d would be used even if the hand were palm down on a table.\r\n<div id=\"m45990-fig-ch01_06_01\" title=\"Figure\u00a01.12.\u00a0Regions of the Human Body\">\r\n<div><img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082356\/107_Regions_of_Human_Body_new.jpg\" alt=\"This illustration shows an anterior and posterior view of the human body. The cranial region encompasses the upper part of the head while the facial region encompasses the lower half of the head beginning below the ears. The eyes are referred to as the ocular region. The cheeks are referred to as the buccal region. The ears are referred to as the auricle or otic region. The nose is referred to as the nasal region. The chin is referred to as the mental region. The neck is referred to as the cervical region. The trunk of the body contains, from superior to inferior, the thoracic region encompassing the chest, the mammary region encompassing each breast, the abdominal region encompassing the stomach area, the coxal region encompassing the belt line, and the pubic region encompassing the area above the genitals. The umbilicus, or naval, is located at the center of the abdomen. The pelvis and legs contain, from superior to inferior, the inguinal or groin region between the legs and the genitals, the pubic region surrounding the genitals, the femoral region encompassing the thighs, the patellar region encompassing the knee, the crural region encompassing the lower leg, the tarsal region encompassing the ankle, the pedal region encompassing the foot and the digital\/phalangeal region encompassing the toes. The great toe is referred to as the hallux. The regions of the upper limbs, from superior to inferior, are the axillary region encompassing the armpit, the brachial region encompassing the upper arm, the antecubital region encompassing the front of the elbow, the antebrachial region encompassing the forearm, the carpal region encompassing the wrist, the palmar region encompassing the palm, and the digital\/phalangeal region encompassing the fingers. The thumb is referred to as the pollux. The posterior view contains, from superior to inferior, the cervical region encompassing the neck, the dorsal region encompassing the upper back and the lumbar region encompassing the lower back. The regions of the back of the arms, from superior to inferior, include the cervical region encompassing the neck, acromial region encompassing the shoulder, the brachial region encompassing the upper arm, the olecranal region encompassing the back of the elbow, the antebrachial region encompasses the back of the arm, and the manual region encompassing the palm of the hand. The posterior regions of the legs, from superior to inferior, include the gluteal region encompassing the buttocks, the femoral region encompassing the thigh, the popliteus region encompassing the back of the knee, the sural region encompassing the back of the lower leg, and the plantar region encompassing the sole of the foot. Some regions are combined into larger regions. These include the trunk, which is a combination of the thoracic, mammary, abdominal, naval, and coxal regions. The cephalic region is a combination of all of the head regions. The upper limb region is a combination of all of the arm regions. The lower limb region is a combination of all of the leg regions.\" width=\"715\" height=\"629\" \/><\/div>\r\n<address><strong>Figure\u00a01.12.\u00a0Regions of the Human Body<\/strong><\/address><address>The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface.<\/address><address>\u00a0<\/address><\/div>\r\nA body that is lying down is described as either prone or supine.\u00a0<em>Prone<\/em><a id=\"id510587\"><\/a>\u00a0describes a face-down orientation, and\u00a0<em>supine<\/em><a id=\"id510600\"><\/a>\u00a0describes a face up orientation. These terms are sometimes used in describing the position of the body during specific physical examinations or surgical procedures.\r\n\r\n<\/div>\r\n<div title=\"Regional Terms\">\r\n<div>\r\n<h2 id=\"m45990-fs-id2661204\">Regional Terms<\/h2>\r\n<\/div>\r\nThe human body\u2019s numerous regions have specific terms to help increase precision (see\u00a0Figure\u00a01.12). Notice that the term \u201cbrachium\u201d or \u201carm\u201d is reserved for the \u201cupper arm\u201d and \u201cantebrachium\u201d or \u201cforearm\u201d is used rather than \u201clower arm.\u201d Similarly, \u201cfemur\u201d or \u201cthigh\u201d is correct, and \u201cleg\u201d or \u201ccrus\u201d is reserved for the portion of the lower limb between the knee and the ankle. You will be able to describe the body\u2019s regions using the terms from the figure.\r\n\r\n<\/div>\r\n<div title=\"Directional Terms\">\r\n<div>\r\n<h2 id=\"m45990-fs-id2138527\">Directional Terms<\/h2>\r\n<\/div>\r\nCertain directional anatomical terms appear throughout this and any other anatomy textbook (Figure\u00a01.13). These terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as \u201cinferior to\u201d another or a physician might describe a tumor as \u201csuperficial to\u201d a deeper body structure. Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts.\r\n<div>\r\n<ul>\r\n \t<li><em>\u00a0<strong>Anterior<\/strong><\/em><a id=\"id510695\"><\/a>\u00a0(or\u00a0<em>ventral<\/em><a id=\"id510708\"><\/a>) Describes the front or direction toward the front of the body. The toes are anterior to the foot.<\/li>\r\n \t<li><em>\u00a0<strong>Posterior<\/strong><\/em><a id=\"id510726\"><\/a>\u00a0(or\u00a0<em>dorsal<\/em><a id=\"id510739\"><\/a>) Describes the back or direction toward the back of the body. The popliteus is posterior to the patella.<\/li>\r\n \t<li><em>\u00a0<strong>Superior<\/strong><\/em><a id=\"id510757\"><\/a>\u00a0(or\u00a0<em>cranial<\/em><a id=\"id510770\"><\/a>) describes a position above or higher than another part of the body proper. The orbits are superior to the oris.<\/li>\r\n \t<li><em>\u00a0<strong>Inferior<\/strong><\/em><a id=\"id510788\"><\/a>\u00a0(or\u00a0<em>caudal<\/em><a id=\"id510801\"><\/a>) describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column). The pelvis is inferior to the abdomen.<\/li>\r\n \t<li><em>\u00a0<strong>Lateral<\/strong><\/em><a id=\"id510819\"><\/a>\u00a0describes the side or direction toward the side of the body. The thumb (pollex) is lateral to the digits.<\/li>\r\n \t<li><em>\u00a0<strong>Medial<\/strong><\/em><a id=\"id510837\"><\/a>\u00a0describes the middle or direction toward the middle of the body. The hallux is the medial toe.<\/li>\r\n \t<li><em>\u00a0<strong>Proximal<\/strong><\/em><a id=\"id510854\"><\/a>\u00a0describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium.<\/li>\r\n \t<li><em>\u00a0<strong>Distal<\/strong><\/em><a id=\"id510872\"><\/a>\u00a0describes a position in a limb that is farther from the point of attachment or the trunk of the body. The crus is distal to the femur.<\/li>\r\n \t<li><em>\u00a0<strong>Superficial<\/strong><\/em><a id=\"id510889\"><\/a>\u00a0describes a position closer to the surface of the body. The skin is superficial to the bones.<\/li>\r\n \t<li><em>\u00a0<strong>Deep<\/strong><\/em><a id=\"id510907\"><\/a>\u00a0describes a position farther from the surface of the body. The brain is deep to the skull.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<div id=\"m45990-fig-ch01_06_02\" title=\"Figure\u00a01.13.\u00a0Directional Terms Applied to the Human Body\">\r\n<div><img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082358\/108_Directional_Terms.jpg\" alt=\"This illustration shows two diagrams: one of a side view of a female and the other of an anterior view of a female. Each diagram shows directional terms using double-sided arrows. The cranial-distal arrow runs vertically behind the torso and lower abdomen. The cranial arrow is pointing toward the head while the caudal arrow is pointing toward the tail bone. The posterior\/anterior arrow is running horizontally through the back and chest. The posterior or dorsal arrow is pointing toward the back while the anterior, or ventral arrow, is pointing toward the abdomen. On the anterior view, the proximal\/distal arrow is on the right arm. The proximal arrow is pointing up toward the shoulder while the distal arrow is pointing down toward the hand. The lateral-medial arrow is a horizontal arrow on the abdomen. The medial arrow is pointing toward the navel while the lateral arrow is pointing away from the body to the right. Right refers to the right side of the woman\u2019s body from her perspective while left refers to the left side of the woman\u2019s body from her perspective.\" width=\"450\" \/><\/div>\r\n<address><strong>Figure\u00a01.13.\u00a0Directional Terms Applied to the Human Body<\/strong><\/address><address>Paired directional terms are shown as applied to the human body.<\/address><address>\u00a0<\/address><\/div>\r\n<\/div>\r\n<div title=\"Body Planes\">\r\n<div>\r\n<h2 id=\"m45990-fs-id2576027\">Body Planes<\/h2>\r\n<\/div>\r\nA\u00a0<strong><em>section<\/em><\/strong><a id=\"id510985\"><\/a>\u00a0is a two-dimensional surface of a three-dimensional structure that has been cut. Modern medical imaging devices enable clinicians to obtain \u201cvirtual sections\u201d of living bodies. We call these scans. Body sections and scans can be correctly interpreted, however, only if the viewer understands the plane along which the section was made. A\u00a0<strong><em>plane<\/em><\/strong><a id=\"id511006\"><\/a>\u00a0is an imaginary two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine, as illustrated in\u00a0Figure\u00a01.14.\r\n<div>\r\n<ul>\r\n \t<li>The\u00a0<strong><em>sagittal plane<\/em><\/strong><a id=\"id511043\"><\/a>\u00a0is the plane that divides the body or an organ vertically into right and left sides. If this vertical plane runs directly down the middle of the body, it is called the midsagittal or median plane. If it divides the body into unequal right and left sides, it is called a parasagittal plane or less commonly a longitudinal section.<\/li>\r\n \t<li>The\u00a0<strong><em>frontal plane<\/em><\/strong><a id=\"id511064\"><\/a>\u00a0is the plane that divides the body or an organ into an anterior (front) portion and a posterior (rear) portion. The frontal plane is often referred to as a coronal plane. (\u201cCorona\u201d is Latin for \u201ccrown.\u201d)<\/li>\r\n \t<li>The\u00a0<strong><em>transverse plane<\/em><\/strong><a id=\"id511085\"><\/a>\u00a0is the plane that divides the body or organ horizontally into upper and lower portions. Transverse planes produce images referred to as cross sections.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<div id=\"m45990-fig-ch01_06_03\" title=\"Figure\u00a01.14.\u00a0Planes of the Body\">\r\n<div><img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082359\/109_Planes_of_Body.jpg\" alt=\"This illustration shows a female viewed from her right, front side. The anatomical planes are depicted as blue rectangles passing through the woman\u2019s body. The frontal or coronal plane enters through the right side of the body, passes through the body, and exits from the left side. It divides the body into front (anterior) and back (posterior) halves. The sagittal plane enters through the back and emerges through the front of the body. It divides the body into right and left halves. The transverse plane passes through the body perpendicular to the frontal and sagittal planes. This plane is a cross section which divides the body into upper and lower halves.\" width=\"350\" \/><\/div>\r\n<address><strong>Figure\u00a01.14.\u00a0Planes of the Body<\/strong><\/address><address>The three planes most commonly used in anatomical and medical imaging are the sagittal, frontal (or coronal), and transverse plane.<\/address><address>\u00a0<\/address><\/div>\r\n<\/div>\r\n<div title=\"Body Cavities and Serous Membranes\">\r\n<div>\r\n<h2 id=\"m45990-fs-id2697376\">Body Cavities and Serous Membranes<\/h2>\r\n<\/div>\r\nThe body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments. The\u00a0<em>dorsal (posterior) cavity<\/em><a id=\"id511162\"><\/a>\u00a0and the\u00a0<em>ventral (anterior) cavity<\/em><a id=\"id511176\"><\/a>\u00a0are the largest body compartments (Figure\u00a01.15). These cavities contain and protect delicate internal organs, and the ventral cavity allows for significant changes in the size and shape of the organs as they perform their functions. The lungs, heart, stomach, and intestines, for example, can expand and contract without distorting other tissues or disrupting the activity of nearby organs.\r\n<div id=\"m45990-fig-ch01_06_04\" title=\"Figure\u00a01.15.\u00a0Dorsal and Ventral Body Cavities\">\r\n<div><img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082400\/110_Dorsal_Ventral_Body_Cavities.jpg\" alt=\"This illustration shows a lateral and anterior view of the body and highlights the body cavities with different colors. The cranial cavity is a large, bean-shaped cavity filling most of the upper skull where the brain is located. The vertebral cavity is a very narrow, thread-like cavity running from the cranial cavity down the entire length of the spinal cord. Together the cranial cavity and vertebral cavity can be referred to as the dorsal body cavity. The thoracic cavity consists of three cavities that fill the interior area of the chest. The two pleural cavities are situated on both sides of the body, anterior to the spine and lateral to the breastbone. The superior mediastinum is a wedge-shaped cavity located between the superior regions of the two thoracic cavities. The pericardial cavity within the mediastinum is located at the center of the chest below the superior mediastinum. The pericardial cavity roughly outlines the shape of the heart. The diaphragm divides the thoracic and the abdominal cavities. The abdominal cavity occupies the entire lower half of the trunk, anterior to the spine. Just under the abdominal cavity, anterior to the buttocks, is the pelvic cavity. The pelvic cavity is funnel shaped and is located inferior and anterior to the abdominal cavity. Together the abdominal and pelvic cavity can be referred to as the abdominopelvic cavity while the thoracic, abdominal, and pelvic cavities together can be referred to as the ventral body cavity.\" width=\"550\" \/><\/div>\r\n<address><strong>Figure\u00a01.15.\u00a0Dorsal and Ventral Body Cavities<\/strong><\/address><address>The ventral cavity includes the thoracic and abdominopelvic cavities and their subdivisions. The dorsal cavity includes the cranial and spinal cavities.<\/address><address>\u00a0<\/address><\/div>\r\n<div title=\"Subdivisions of the Posterior (Dorsal) and Anterior (Ventral) Cavities\">\r\n<div>\r\n<h2 id=\"m45990-fs-id2384338\">Subdivisions of the Posterior (Dorsal) and Anterior (Ventral) Cavities<\/h2>\r\n<\/div>\r\nThe posterior (dorsal) and anterior (ventral) cavities are each subdivided into smaller cavities. In the posterior (dorsal) cavity, the\u00a0<em><strong>cranial<\/strong> <strong>cavity<\/strong><\/em><a id=\"id511264\"><\/a>\u00a0houses the brain, and the\u00a0<strong><em>spinal cavity<\/em><\/strong><a id=\"id511278\"><\/a>\u00a0(or vertebral cavity) encloses the spinal cord. Just as the brain and spinal cord make up a continuous, uninterrupted structure, the cranial and spinal cavities that house them are also continuous. The brain and spinal cord are protected by the bones of the skull and vertebral column and by cerebrospinal fluid, a colorless fluid produced by the brain, which cushions the brain and spinal cord within the posterior (dorsal) cavity.\r\n\r\nThe anterior (ventral) cavity has two main subdivisions: the thoracic cavity and the abdominopelvic cavity (see\u00a0Figure\u00a01.15). The\u00a0<strong><em>thoracic cavity<\/em><\/strong><a id=\"id511312\"><\/a>\u00a0is the more superior subdivision of the anterior cavity, and it is enclosed by the rib cage. The thoracic cavity contains the lungs and the heart, which is located in the mediastinum. The diaphragm forms the floor of the thoracic cavity and separates it from the more inferior abdominopelvic cavity. The\u00a0<strong><em>abdominopelvic cavity<\/em><\/strong><a id=\"id511328\"><\/a>\u00a0is the largest cavity in the body. Although no membrane physically divides the abdominopelvic cavity, it can be useful to distinguish between the abdominal cavity, the division that houses the digestive organs, and the pelvic cavity, the division that houses the organs of reproduction.\r\n\r\n<\/div>\r\n<div title=\"Abdominal Regions and Quadrants\">\r\n<div>\r\n<h2 id=\"m45990-fs-id1207231\">Abdominal Regions and Quadrants<\/h2>\r\n<\/div>\r\nTo promote clear communication, for instance about the location of a patient\u2019s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure\u00a01.16).\r\n<div id=\"m45990-fig-ch01_06_05\" title=\"Figure\u00a01.16.\u00a0Regions and Quadrants of the Peritoneal Cavity\">\r\n<div><img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082402\/111_Abdominal_Quadrant_Regions.jpg\" alt=\"This illustration has two parts. Part A shows the abdominopelvic regions. These regions divide the abdomen into nine squares. The upper right square is the right hypochondriac region and contains the base of the right ribs. The upper left square is the left hypochondriac region and contains the base of the left ribs. The epigastric region is the upper central square and contains the bottom edge of the liver as well as the upper areas of the stomach. The diaphragm curves like an upside down U over these three regions. The central right region is called the right lumbar region and contains the ascending colon and the right edge of the small intestines. The central square contains the transverse colon and the upper regions of the small intestines. The left lumbar region contains the left edge of the transverse colon and the left edge of the small intestine. The lower right square is the right iliac region and contains the right pelvic bones and the ascending colon. The lower left square is the left iliac region and contains the left pelvic bone and the lower left regions of the small intestine. The lower central square contains the bottom of the pubic bones, upper regions of the bladder and the lower region of the small intestine. Part B shows four abdominopelvic quadrants. The right upper quadrant (RUQ) includes the lower right ribs, right side of the liver, and right side of the transverse colon. The left upper quadrant (LUQ) includes the lower left ribs, stomach, and upper left area of the transverse colon. The right lower quadrant (RLQ) includes the right half of the small intestines, ascending colon, right pelvic bone and upper right area of the bladder. The left lower quadrant (LLQ) contains the left half of the small intestine and left pelvic bone.\" width=\"550\" \/><\/div>\r\n<address><strong>Figure\u00a01.16.\u00a0Regions and Quadrants of the Peritoneal Cavity<\/strong><\/address><address>There are (a) nine abdominal regions and (b) four abdominal quadrants in the peritoneal cavity.<\/address><address>\u00a0<\/address><\/div>\r\nThe more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). There are nine resulting regions. The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersect at the patient\u2019s umbilicus (navel).\r\n\r\n<\/div>\r\n<div title=\"Membranes of the Anterior (Ventral) Body Cavity\">\r\n<div>\r\n<h2 id=\"m45990-fs-id1364871\">Membranes of the Anterior (Ventral) Body Cavity<\/h2>\r\n<\/div>\r\nA\u00a0<em>s<strong>erous membrane<\/strong><\/em><a id=\"id511468\"><\/a>\u00a0(also referred to a serosa) is one of the thin membranes that cover the walls and organs in the thoracic and abdominopelvic cavities. The parietal layers of the membranes line the walls of the body cavity (pariet- refers to a cavity wall). The visceral layer of the membrane covers the organs (the viscera). Between the parietal and visceral layers is a very thin, fluid-filled serous space, or cavity (Figure\u00a01.17).\r\n<div id=\"m45990-fig-ch01_06_06\" title=\"Figure\u00a01.17.\u00a0Serous Membrane\">\r\n<div><img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082404\/112_Serous_Membrane_new.jpg\" alt=\"This diagram shows the pericardium on the left next to an analogy of a hand punching a balloon on the right. The pericardium is a two-layered sac that surrounds the entire heart except where the blood vessels emerge on the heart\u2019s superior side. The pericardium has two layers because it folds over itself in the shape of the letter U. The inner layer that borders the heart is the visceral pericardium while the outer layer is the parietal pericardium. The space between the two layers is called the pericardial cavity. The heart sits in the cavity much like a fist punching into a balloon. The balloon surrounds the lower part of the fist with a two-layered sac, with the top of the balloon, where it contacts the fist, being analogous to the visceral pericardium. The bottom of the balloon, where it is tied off, is analogous to the parietal pericardium. The air within the balloon is analogous to the pericardial cavity.\" width=\"420\" \/><\/div>\r\n<address><strong>Figure\u00a01.17.\u00a0Serous Membrane<\/strong><\/address><address>Serous membrane lines the pericardial cavity and reflects back to cover the heart\u2014much the same way that an underinflated balloon would form two layers surrounding a fist.<\/address><address>\u00a0<\/address><\/div>\r\nThere are three serous cavities and their associated membranes. The\u00a0<strong><em>pleura<\/em><\/strong><a id=\"id511556\"><\/a>\u00a0is the serous membrane that surrounds the lungs in the pleural cavity; the\u00a0<strong><em>pericardium<\/em><\/strong><a id=\"id511570\"><\/a>\u00a0is the serous membrane that surrounds the heart in the pericardial cavity; and the\u00a0<strong><em>peritoneum<\/em><\/strong><a id=\"id511584\"><\/a>\u00a0is the serous membrane that surrounds several organs in the abdominopelvic cavity. The serous fluid produced by the serous membranes reduces friction between the walls of the cavities and the internal organs when they move, such as when the lungs inflate or the heart beats. Both the parietal and visceral serosa secrete the thin, slippery serous fluid that prevents friction when an organ slides past the walls of a cavity. In the pleural cavities, pleural fluid prevents friction between the lungs and the walls of the cavity. In the pericardial sac, pericardial fluid prevents friction between the heart and the walls of the pericardial sac. And in the peritoneal cavity, peritoneal fluid prevents friction between abdominal and pelvic organs and the wall of the cavity. The serous membranes therefore provide additional protection to the viscera they enclose by reducing friction that could lead to inflammation of the organs.\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<div title=\"1.7.\u00a0Medical Imaging\"><\/div>","rendered":"<div title=\"1.6.\u00a0Anatomical Terminology\">\n<div>\n<div>\n<div class=\"bcc-box bcc-highlight\">\n<h3>Learning Objectives<\/h3>\n<ul>\n<li>Demonstrate the anatomical position<\/li>\n<li>Describe the human body using directional and regional terms<\/li>\n<li>Identify three planes most commonly used in the study of anatomy<\/li>\n<li>Distinguish between the posterior (dorsal) and the anterior (ventral) body cavities, identifying their subdivisions and representative organs found in each<\/li>\n<li>Describe serous membrane and explain its function<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n<div>\n<ul>\n<li><a href=\"#m45990-fs-id1932675\">Anatomical Position<\/a><\/li>\n<li><a href=\"#m45990-fs-id2661204\">Regional Terms<\/a><\/li>\n<li><a href=\"#m45990-fs-id2138527\">Directional Terms<\/a><\/li>\n<li><a href=\"#m45990-fs-id2576027\">Body Planes<\/a><\/li>\n<li><a href=\"#m45990-fs-id2697376\">Body Cavities and Serous Membranes<\/a>\n<ul>\n<li><a href=\"#m45990-fs-id2384338\">Subdivisions of the Posterior (Dorsal) and Anterior (Ventral) Cavities<\/a><\/li>\n<li><a href=\"#m45990-fs-id1207231\">Abdominal Regions and Quadrants<\/a><\/li>\n<li><a href=\"#m45990-fs-id1364871\">Membranes of the Anterior (Ventral) Body Cavity<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/div>\n<p>Anatomists and health care providers use terminology that can be bewildering to the uninitiated. However, the purpose of this language is not to confuse, but rather to increase precision and reduce medical errors. For example, is a scar \u201cabove the wrist\u201d located on the forearm two or three inches away from the hand? Or is it at the base of the hand? Is it on the palm-side or back-side? By using precise anatomical terminology, we eliminate ambiguity. Anatomical terms derive from ancient Greek and Latin words. Because these languages are no longer used in everyday conversation, the meaning of their words does not change.<\/p>\n<p>Anatomical terms are made up of roots, prefixes, and suffixes. The root of a term often refers to an organ, tissue, or condition, whereas the prefix or suffix often describes the root. For example, in the disorder hypertension, the prefix \u201chyper-\u201d means \u201chigh\u201d or \u201cover,\u201d and the root word \u201ctension\u201d refers to pressure, so the word \u201chypertension\u201d refers to abnormally high blood pressure.<\/p>\n<div title=\"Anatomical Position\">\n<div>\n<h2 id=\"m45990-fs-id1932675\">Anatomical Position<\/h2>\n<\/div>\n<p>To further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body \u201cmap,\u201d or\u00a0<em>anatomical position<\/em><a id=\"id510494\"><\/a>, is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in\u00a0Figure\u00a01.12. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the \u201canterior (front) carpal (wrist) region\u201d would be present on the palm side of the wrist. The term \u201canterior\u201d would be used even if the hand were palm down on a table.<\/p>\n<div id=\"m45990-fig-ch01_06_01\" title=\"Figure\u00a01.12.\u00a0Regions of the Human Body\">\n<div><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082356\/107_Regions_of_Human_Body_new.jpg\" alt=\"This illustration shows an anterior and posterior view of the human body. The cranial region encompasses the upper part of the head while the facial region encompasses the lower half of the head beginning below the ears. The eyes are referred to as the ocular region. The cheeks are referred to as the buccal region. The ears are referred to as the auricle or otic region. The nose is referred to as the nasal region. The chin is referred to as the mental region. The neck is referred to as the cervical region. The trunk of the body contains, from superior to inferior, the thoracic region encompassing the chest, the mammary region encompassing each breast, the abdominal region encompassing the stomach area, the coxal region encompassing the belt line, and the pubic region encompassing the area above the genitals. The umbilicus, or naval, is located at the center of the abdomen. The pelvis and legs contain, from superior to inferior, the inguinal or groin region between the legs and the genitals, the pubic region surrounding the genitals, the femoral region encompassing the thighs, the patellar region encompassing the knee, the crural region encompassing the lower leg, the tarsal region encompassing the ankle, the pedal region encompassing the foot and the digital\/phalangeal region encompassing the toes. The great toe is referred to as the hallux. The regions of the upper limbs, from superior to inferior, are the axillary region encompassing the armpit, the brachial region encompassing the upper arm, the antecubital region encompassing the front of the elbow, the antebrachial region encompassing the forearm, the carpal region encompassing the wrist, the palmar region encompassing the palm, and the digital\/phalangeal region encompassing the fingers. The thumb is referred to as the pollux. The posterior view contains, from superior to inferior, the cervical region encompassing the neck, the dorsal region encompassing the upper back and the lumbar region encompassing the lower back. The regions of the back of the arms, from superior to inferior, include the cervical region encompassing the neck, acromial region encompassing the shoulder, the brachial region encompassing the upper arm, the olecranal region encompassing the back of the elbow, the antebrachial region encompasses the back of the arm, and the manual region encompassing the palm of the hand. The posterior regions of the legs, from superior to inferior, include the gluteal region encompassing the buttocks, the femoral region encompassing the thigh, the popliteus region encompassing the back of the knee, the sural region encompassing the back of the lower leg, and the plantar region encompassing the sole of the foot. Some regions are combined into larger regions. These include the trunk, which is a combination of the thoracic, mammary, abdominal, naval, and coxal regions. The cephalic region is a combination of all of the head regions. The upper limb region is a combination of all of the arm regions. The lower limb region is a combination of all of the leg regions.\" width=\"715\" height=\"629\" \/><\/div>\n<address><strong>Figure\u00a01.12.\u00a0Regions of the Human Body<\/strong><\/address>\n<address>The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface.<\/address>\n<address>\u00a0<\/address>\n<\/div>\n<p>A body that is lying down is described as either prone or supine.\u00a0<em>Prone<\/em><a id=\"id510587\"><\/a>\u00a0describes a face-down orientation, and\u00a0<em>supine<\/em><a id=\"id510600\"><\/a>\u00a0describes a face up orientation. These terms are sometimes used in describing the position of the body during specific physical examinations or surgical procedures.<\/p>\n<\/div>\n<div title=\"Regional Terms\">\n<div>\n<h2 id=\"m45990-fs-id2661204\">Regional Terms<\/h2>\n<\/div>\n<p>The human body\u2019s numerous regions have specific terms to help increase precision (see\u00a0Figure\u00a01.12). Notice that the term \u201cbrachium\u201d or \u201carm\u201d is reserved for the \u201cupper arm\u201d and \u201cantebrachium\u201d or \u201cforearm\u201d is used rather than \u201clower arm.\u201d Similarly, \u201cfemur\u201d or \u201cthigh\u201d is correct, and \u201cleg\u201d or \u201ccrus\u201d is reserved for the portion of the lower limb between the knee and the ankle. You will be able to describe the body\u2019s regions using the terms from the figure.<\/p>\n<\/div>\n<div title=\"Directional Terms\">\n<div>\n<h2 id=\"m45990-fs-id2138527\">Directional Terms<\/h2>\n<\/div>\n<p>Certain directional anatomical terms appear throughout this and any other anatomy textbook (Figure\u00a01.13). These terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as \u201cinferior to\u201d another or a physician might describe a tumor as \u201csuperficial to\u201d a deeper body structure. Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts.<\/p>\n<div>\n<ul>\n<li><em>\u00a0<strong>Anterior<\/strong><\/em><a id=\"id510695\"><\/a>\u00a0(or\u00a0<em>ventral<\/em><a id=\"id510708\"><\/a>) Describes the front or direction toward the front of the body. The toes are anterior to the foot.<\/li>\n<li><em>\u00a0<strong>Posterior<\/strong><\/em><a id=\"id510726\"><\/a>\u00a0(or\u00a0<em>dorsal<\/em><a id=\"id510739\"><\/a>) Describes the back or direction toward the back of the body. The popliteus is posterior to the patella.<\/li>\n<li><em>\u00a0<strong>Superior<\/strong><\/em><a id=\"id510757\"><\/a>\u00a0(or\u00a0<em>cranial<\/em><a id=\"id510770\"><\/a>) describes a position above or higher than another part of the body proper. The orbits are superior to the oris.<\/li>\n<li><em>\u00a0<strong>Inferior<\/strong><\/em><a id=\"id510788\"><\/a>\u00a0(or\u00a0<em>caudal<\/em><a id=\"id510801\"><\/a>) describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column). The pelvis is inferior to the abdomen.<\/li>\n<li><em>\u00a0<strong>Lateral<\/strong><\/em><a id=\"id510819\"><\/a>\u00a0describes the side or direction toward the side of the body. The thumb (pollex) is lateral to the digits.<\/li>\n<li><em>\u00a0<strong>Medial<\/strong><\/em><a id=\"id510837\"><\/a>\u00a0describes the middle or direction toward the middle of the body. The hallux is the medial toe.<\/li>\n<li><em>\u00a0<strong>Proximal<\/strong><\/em><a id=\"id510854\"><\/a>\u00a0describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium.<\/li>\n<li><em>\u00a0<strong>Distal<\/strong><\/em><a id=\"id510872\"><\/a>\u00a0describes a position in a limb that is farther from the point of attachment or the trunk of the body. The crus is distal to the femur.<\/li>\n<li><em>\u00a0<strong>Superficial<\/strong><\/em><a id=\"id510889\"><\/a>\u00a0describes a position closer to the surface of the body. The skin is superficial to the bones.<\/li>\n<li><em>\u00a0<strong>Deep<\/strong><\/em><a id=\"id510907\"><\/a>\u00a0describes a position farther from the surface of the body. The brain is deep to the skull.<\/li>\n<\/ul>\n<\/div>\n<div id=\"m45990-fig-ch01_06_02\" title=\"Figure\u00a01.13.\u00a0Directional Terms Applied to the Human Body\">\n<div><img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082358\/108_Directional_Terms.jpg\" alt=\"This illustration shows two diagrams: one of a side view of a female and the other of an anterior view of a female. Each diagram shows directional terms using double-sided arrows. The cranial-distal arrow runs vertically behind the torso and lower abdomen. The cranial arrow is pointing toward the head while the caudal arrow is pointing toward the tail bone. The posterior\/anterior arrow is running horizontally through the back and chest. The posterior or dorsal arrow is pointing toward the back while the anterior, or ventral arrow, is pointing toward the abdomen. On the anterior view, the proximal\/distal arrow is on the right arm. The proximal arrow is pointing up toward the shoulder while the distal arrow is pointing down toward the hand. The lateral-medial arrow is a horizontal arrow on the abdomen. The medial arrow is pointing toward the navel while the lateral arrow is pointing away from the body to the right. Right refers to the right side of the woman\u2019s body from her perspective while left refers to the left side of the woman\u2019s body from her perspective.\" width=\"450\" \/><\/div>\n<address><strong>Figure\u00a01.13.\u00a0Directional Terms Applied to the Human Body<\/strong><\/address>\n<address>Paired directional terms are shown as applied to the human body.<\/address>\n<address>\u00a0<\/address>\n<\/div>\n<\/div>\n<div title=\"Body Planes\">\n<div>\n<h2 id=\"m45990-fs-id2576027\">Body Planes<\/h2>\n<\/div>\n<p>A\u00a0<strong><em>section<\/em><\/strong><a id=\"id510985\"><\/a>\u00a0is a two-dimensional surface of a three-dimensional structure that has been cut. Modern medical imaging devices enable clinicians to obtain \u201cvirtual sections\u201d of living bodies. We call these scans. Body sections and scans can be correctly interpreted, however, only if the viewer understands the plane along which the section was made. A\u00a0<strong><em>plane<\/em><\/strong><a id=\"id511006\"><\/a>\u00a0is an imaginary two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine, as illustrated in\u00a0Figure\u00a01.14.<\/p>\n<div>\n<ul>\n<li>The\u00a0<strong><em>sagittal plane<\/em><\/strong><a id=\"id511043\"><\/a>\u00a0is the plane that divides the body or an organ vertically into right and left sides. If this vertical plane runs directly down the middle of the body, it is called the midsagittal or median plane. If it divides the body into unequal right and left sides, it is called a parasagittal plane or less commonly a longitudinal section.<\/li>\n<li>The\u00a0<strong><em>frontal plane<\/em><\/strong><a id=\"id511064\"><\/a>\u00a0is the plane that divides the body or an organ into an anterior (front) portion and a posterior (rear) portion. The frontal plane is often referred to as a coronal plane. (\u201cCorona\u201d is Latin for \u201ccrown.\u201d)<\/li>\n<li>The\u00a0<strong><em>transverse plane<\/em><\/strong><a id=\"id511085\"><\/a>\u00a0is the plane that divides the body or organ horizontally into upper and lower portions. Transverse planes produce images referred to as cross sections.<\/li>\n<\/ul>\n<\/div>\n<div id=\"m45990-fig-ch01_06_03\" title=\"Figure\u00a01.14.\u00a0Planes of the Body\">\n<div><img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082359\/109_Planes_of_Body.jpg\" alt=\"This illustration shows a female viewed from her right, front side. The anatomical planes are depicted as blue rectangles passing through the woman\u2019s body. The frontal or coronal plane enters through the right side of the body, passes through the body, and exits from the left side. It divides the body into front (anterior) and back (posterior) halves. The sagittal plane enters through the back and emerges through the front of the body. It divides the body into right and left halves. The transverse plane passes through the body perpendicular to the frontal and sagittal planes. This plane is a cross section which divides the body into upper and lower halves.\" width=\"350\" \/><\/div>\n<address><strong>Figure\u00a01.14.\u00a0Planes of the Body<\/strong><\/address>\n<address>The three planes most commonly used in anatomical and medical imaging are the sagittal, frontal (or coronal), and transverse plane.<\/address>\n<address>\u00a0<\/address>\n<\/div>\n<\/div>\n<div title=\"Body Cavities and Serous Membranes\">\n<div>\n<h2 id=\"m45990-fs-id2697376\">Body Cavities and Serous Membranes<\/h2>\n<\/div>\n<p>The body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments. The\u00a0<em>dorsal (posterior) cavity<\/em><a id=\"id511162\"><\/a>\u00a0and the\u00a0<em>ventral (anterior) cavity<\/em><a id=\"id511176\"><\/a>\u00a0are the largest body compartments (Figure\u00a01.15). These cavities contain and protect delicate internal organs, and the ventral cavity allows for significant changes in the size and shape of the organs as they perform their functions. The lungs, heart, stomach, and intestines, for example, can expand and contract without distorting other tissues or disrupting the activity of nearby organs.<\/p>\n<div id=\"m45990-fig-ch01_06_04\" title=\"Figure\u00a01.15.\u00a0Dorsal and Ventral Body Cavities\">\n<div><img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082400\/110_Dorsal_Ventral_Body_Cavities.jpg\" alt=\"This illustration shows a lateral and anterior view of the body and highlights the body cavities with different colors. The cranial cavity is a large, bean-shaped cavity filling most of the upper skull where the brain is located. The vertebral cavity is a very narrow, thread-like cavity running from the cranial cavity down the entire length of the spinal cord. Together the cranial cavity and vertebral cavity can be referred to as the dorsal body cavity. The thoracic cavity consists of three cavities that fill the interior area of the chest. The two pleural cavities are situated on both sides of the body, anterior to the spine and lateral to the breastbone. The superior mediastinum is a wedge-shaped cavity located between the superior regions of the two thoracic cavities. The pericardial cavity within the mediastinum is located at the center of the chest below the superior mediastinum. The pericardial cavity roughly outlines the shape of the heart. The diaphragm divides the thoracic and the abdominal cavities. The abdominal cavity occupies the entire lower half of the trunk, anterior to the spine. Just under the abdominal cavity, anterior to the buttocks, is the pelvic cavity. The pelvic cavity is funnel shaped and is located inferior and anterior to the abdominal cavity. Together the abdominal and pelvic cavity can be referred to as the abdominopelvic cavity while the thoracic, abdominal, and pelvic cavities together can be referred to as the ventral body cavity.\" width=\"550\" \/><\/div>\n<address><strong>Figure\u00a01.15.\u00a0Dorsal and Ventral Body Cavities<\/strong><\/address>\n<address>The ventral cavity includes the thoracic and abdominopelvic cavities and their subdivisions. The dorsal cavity includes the cranial and spinal cavities.<\/address>\n<address>\u00a0<\/address>\n<\/div>\n<div title=\"Subdivisions of the Posterior (Dorsal) and Anterior (Ventral) Cavities\">\n<div>\n<h2 id=\"m45990-fs-id2384338\">Subdivisions of the Posterior (Dorsal) and Anterior (Ventral) Cavities<\/h2>\n<\/div>\n<p>The posterior (dorsal) and anterior (ventral) cavities are each subdivided into smaller cavities. In the posterior (dorsal) cavity, the\u00a0<em><strong>cranial<\/strong> <strong>cavity<\/strong><\/em><a id=\"id511264\"><\/a>\u00a0houses the brain, and the\u00a0<strong><em>spinal cavity<\/em><\/strong><a id=\"id511278\"><\/a>\u00a0(or vertebral cavity) encloses the spinal cord. Just as the brain and spinal cord make up a continuous, uninterrupted structure, the cranial and spinal cavities that house them are also continuous. The brain and spinal cord are protected by the bones of the skull and vertebral column and by cerebrospinal fluid, a colorless fluid produced by the brain, which cushions the brain and spinal cord within the posterior (dorsal) cavity.<\/p>\n<p>The anterior (ventral) cavity has two main subdivisions: the thoracic cavity and the abdominopelvic cavity (see\u00a0Figure\u00a01.15). The\u00a0<strong><em>thoracic cavity<\/em><\/strong><a id=\"id511312\"><\/a>\u00a0is the more superior subdivision of the anterior cavity, and it is enclosed by the rib cage. The thoracic cavity contains the lungs and the heart, which is located in the mediastinum. The diaphragm forms the floor of the thoracic cavity and separates it from the more inferior abdominopelvic cavity. The\u00a0<strong><em>abdominopelvic cavity<\/em><\/strong><a id=\"id511328\"><\/a>\u00a0is the largest cavity in the body. Although no membrane physically divides the abdominopelvic cavity, it can be useful to distinguish between the abdominal cavity, the division that houses the digestive organs, and the pelvic cavity, the division that houses the organs of reproduction.<\/p>\n<\/div>\n<div title=\"Abdominal Regions and Quadrants\">\n<div>\n<h2 id=\"m45990-fs-id1207231\">Abdominal Regions and Quadrants<\/h2>\n<\/div>\n<p>To promote clear communication, for instance about the location of a patient\u2019s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure\u00a01.16).<\/p>\n<div id=\"m45990-fig-ch01_06_05\" title=\"Figure\u00a01.16.\u00a0Regions and Quadrants of the Peritoneal Cavity\">\n<div><img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082402\/111_Abdominal_Quadrant_Regions.jpg\" alt=\"This illustration has two parts. Part A shows the abdominopelvic regions. These regions divide the abdomen into nine squares. The upper right square is the right hypochondriac region and contains the base of the right ribs. The upper left square is the left hypochondriac region and contains the base of the left ribs. The epigastric region is the upper central square and contains the bottom edge of the liver as well as the upper areas of the stomach. The diaphragm curves like an upside down U over these three regions. The central right region is called the right lumbar region and contains the ascending colon and the right edge of the small intestines. The central square contains the transverse colon and the upper regions of the small intestines. The left lumbar region contains the left edge of the transverse colon and the left edge of the small intestine. The lower right square is the right iliac region and contains the right pelvic bones and the ascending colon. The lower left square is the left iliac region and contains the left pelvic bone and the lower left regions of the small intestine. The lower central square contains the bottom of the pubic bones, upper regions of the bladder and the lower region of the small intestine. Part B shows four abdominopelvic quadrants. The right upper quadrant (RUQ) includes the lower right ribs, right side of the liver, and right side of the transverse colon. The left upper quadrant (LUQ) includes the lower left ribs, stomach, and upper left area of the transverse colon. The right lower quadrant (RLQ) includes the right half of the small intestines, ascending colon, right pelvic bone and upper right area of the bladder. The left lower quadrant (LLQ) contains the left half of the small intestine and left pelvic bone.\" width=\"550\" \/><\/div>\n<address><strong>Figure\u00a01.16.\u00a0Regions and Quadrants of the Peritoneal Cavity<\/strong><\/address>\n<address>There are (a) nine abdominal regions and (b) four abdominal quadrants in the peritoneal cavity.<\/address>\n<address>\u00a0<\/address>\n<\/div>\n<p>The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). There are nine resulting regions. The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersect at the patient\u2019s umbilicus (navel).<\/p>\n<\/div>\n<div title=\"Membranes of the Anterior (Ventral) Body Cavity\">\n<div>\n<h2 id=\"m45990-fs-id1364871\">Membranes of the Anterior (Ventral) Body Cavity<\/h2>\n<\/div>\n<p>A\u00a0<em>s<strong>erous membrane<\/strong><\/em><a id=\"id511468\"><\/a>\u00a0(also referred to a serosa) is one of the thin membranes that cover the walls and organs in the thoracic and abdominopelvic cavities. The parietal layers of the membranes line the walls of the body cavity (pariet- refers to a cavity wall). The visceral layer of the membrane covers the organs (the viscera). Between the parietal and visceral layers is a very thin, fluid-filled serous space, or cavity (Figure\u00a01.17).<\/p>\n<div id=\"m45990-fig-ch01_06_06\" title=\"Figure\u00a01.17.\u00a0Serous Membrane\">\n<div><img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082404\/112_Serous_Membrane_new.jpg\" alt=\"This diagram shows the pericardium on the left next to an analogy of a hand punching a balloon on the right. The pericardium is a two-layered sac that surrounds the entire heart except where the blood vessels emerge on the heart\u2019s superior side. The pericardium has two layers because it folds over itself in the shape of the letter U. The inner layer that borders the heart is the visceral pericardium while the outer layer is the parietal pericardium. The space between the two layers is called the pericardial cavity. The heart sits in the cavity much like a fist punching into a balloon. The balloon surrounds the lower part of the fist with a two-layered sac, with the top of the balloon, where it contacts the fist, being analogous to the visceral pericardium. The bottom of the balloon, where it is tied off, is analogous to the parietal pericardium. The air within the balloon is analogous to the pericardial cavity.\" width=\"420\" \/><\/div>\n<address><strong>Figure\u00a01.17.\u00a0Serous Membrane<\/strong><\/address>\n<address>Serous membrane lines the pericardial cavity and reflects back to cover the heart\u2014much the same way that an underinflated balloon would form two layers surrounding a fist.<\/address>\n<address>\u00a0<\/address>\n<\/div>\n<p>There are three serous cavities and their associated membranes. The\u00a0<strong><em>pleura<\/em><\/strong><a id=\"id511556\"><\/a>\u00a0is the serous membrane that surrounds the lungs in the pleural cavity; the\u00a0<strong><em>pericardium<\/em><\/strong><a id=\"id511570\"><\/a>\u00a0is the serous membrane that surrounds the heart in the pericardial cavity; and the\u00a0<strong><em>peritoneum<\/em><\/strong><a id=\"id511584\"><\/a>\u00a0is the serous membrane that surrounds several organs in the abdominopelvic cavity. The serous fluid produced by the serous membranes reduces friction between the walls of the cavities and the internal organs when they move, such as when the lungs inflate or the heart beats. Both the parietal and visceral serosa secrete the thin, slippery serous fluid that prevents friction when an organ slides past the walls of a cavity. In the pleural cavities, pleural fluid prevents friction between the lungs and the walls of the cavity. In the pericardial sac, pericardial fluid prevents friction between the heart and the walls of the pericardial sac. And in the peritoneal cavity, peritoneal fluid prevents friction between abdominal and pelvic organs and the wall of the cavity. The serous membranes therefore provide additional protection to the viscera they enclose by reducing friction that could lead to inflammation of the organs.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div title=\"1.7.\u00a0Medical Imaging\"><\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-1515\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Chapter 1: An Introduction to the Human Body. <strong>Authored by<\/strong>: OpenStax College. <strong>Provided by<\/strong>: Rice University. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/openstaxcollege.org\/files\/textbook_version\/low_res_pdf\/13\/col11496-lr.pdf\">http:\/\/openstaxcollege.org\/files\/textbook_version\/low_res_pdf\/13\/col11496-lr.pdf<\/a>. <strong>Project<\/strong>: Anatomy &amp; Physiology. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: This content is available for free at http:\/\/cnx.org\/content\/col11496\/1.6<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":74,"menu_order":6,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Chapter 1: An Introduction to the Human Body\",\"author\":\"OpenStax College\",\"organization\":\"Rice University\",\"url\":\"http:\/\/openstaxcollege.org\/files\/textbook_version\/low_res_pdf\/13\/col11496-lr.pdf\",\"project\":\"Anatomy & Physiology\",\"license\":\"cc-by\",\"license_terms\":\"This content is available for free at http:\/\/cnx.org\/content\/col11496\/1.6\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-1515","chapter","type-chapter","status-publish","hentry"],"part":35,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/pressbooks\/v2\/chapters\/1515","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/wp\/v2\/users\/74"}],"version-history":[{"count":5,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/pressbooks\/v2\/chapters\/1515\/revisions"}],"predecessor-version":[{"id":2985,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/pressbooks\/v2\/chapters\/1515\/revisions\/2985"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/pressbooks\/v2\/parts\/35"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/pressbooks\/v2\/chapters\/1515\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/wp\/v2\/media?parent=1515"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/pressbooks\/v2\/chapter-type?post=1515"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/wp\/v2\/contributor?post=1515"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-ap1\/wp-json\/wp\/v2\/license?post=1515"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}