Body Cavities PDF

# INTRODUCTION - The organs that make up the systems of the body are contained in four cavities: cranial, thoracic, abdominal, and pelvic. # CRANIAL CAVITY - The cranial cavity contains the brain and its boundaries are formed by the bones of the skull. - Anteriorly - 1 frontal bone - Late...

# INTRODUCTION - The organs that make up the systems of the body are contained in four cavities: cranial, thoracic, abdominal, and pelvic. # CRANIAL CAVITY - The cranial cavity contains the brain and its boundaries are formed by the bones of the skull. - Anteriorly - 1 frontal bone - Laterally - 2 temporal bones - Posteriorly - 1 occipital bone - Superiorly - 2 parietal bones - Inferiorly - 1 sphenoid and 1 ethmoid bone and parts of the frontal, temporal and occipital bones # THORACIC CAVITY - This cavity is situated in the upper part of the trunk. Its boundaries are formed by a bony framework and supporting muscles. - Anteriorly - the sternum and costal cartilages of the ribs - Laterally - 12 pairs of ribs and the intercostal muscles - Posteriorly - the thoracic vertebrae - Superiorly - The structures forming the root of the neck - Inferiorly - the diaphragm, a dome-shaped muscles - The main organs and structures contained in the thoracic cavity are: - the trachea, 2 bronchi, 2 lungs - the heart, aorta, superior and inferior vena cava, numerous other blood vessels, the esophagus - lymph vessels and lymph nodes, some important nerves - The mediastinum is the space between the lungs, including the structures found there, such as the heart, esophagus, and blood vessels. # ABDOMINAL CAVITY - This is the largest cavity in the body and is oval in shape. It is situated in the main part of the trunk and its boundaries are: - Superiorly - the diaphragm, which separates it from the thoracic cavity. - Anteriorly - the muscles forming the anterior abdominal wall. - Posteriorly - the lumbar vertebrae and muscles forming the posterior abdominal wall. - Laterally - the lower ribs and parts of the muscles of the abdominal wall. - Inferiorly - it is continuous with the pelvic cavity - Most of the abdominal cavity is occupied by the organs and glands of the digestive system such as the stomach, small intestine, and most of the large intestine, the liver, gall bladder, bile ducts and pancreas. - Other structures include: - the spleen, 2 kidneys, and the upper part of the ureters, 2 adrenal (suprarenal) glands, numerous blood vessels, lymph vessels, nerves lymph nodes # PELVIC CAVITY - The pelvic cavity is roughly funnel-shaped and extends from the lower end of the abdominal cavity. - The boundaries are: - Superiorly - it is continuous with the abdominal cavity. - Anteriorly - the pubic bones. - Posteriorly - the sacrum and coccyx. - Laterally - the innominate bones. - Inferiorly - the muscles of the pelvic floor. - The pelvic cavity contains the following structures: - sigmoid colon, rectum and anus - some loops of the small intestine - urinary bladder, lower parts of the ureters, and the urethra. - In female, the organs of the reproductive system: the uterus, uterine tubes, ovaries and vagina. - In male, some of the organs of the reproductive system: the prostate gland, seminal vesicles, spermatic cords, deferent ducts (vas deferens), ejaculatory ducts, and the urethra (common to the reproductive and urinary systems).