The human body contains several cavities, but the term "four major body cavities" isn't precisely defined in the provided reference. However, based on typical anatomical usage, and the reference information we can identify and describe the main cavities, which can be categorized into four.
The reference lists the following cavities: cranial, vertebral, thoracic (containing pericardial and pleural cavities), abdominal, and pelvic. By grouping related cavities and considering their prominence, we can present a list that can be considered as the major four.
Here's a table summarizing these cavities:
| Body Cavity | Description | Major Organs Housed |
|---|---|---|
| Cranial Cavity | Enclosed by the bones of the skull. | Brain |
| Thoracic Cavity | Enclosed by the ribs, sternum, and vertebral column. Contains the pericardial and pleural cavities. | Heart, lungs, esophagus, trachea, thymus gland |
| Abdominal Cavity | Enclosed by the abdominal muscles, vertebral column, and diaphragm. | Stomach, intestines, liver, gallbladder, pancreas, spleen, kidneys, ureters |
| Pelvic Cavity | Enclosed by the pelvic bones. | Urinary bladder, reproductive organs, rectum |
These four cavities (cranial, thoracic, abdominal, and pelvic) are typically considered the major body cavities due to their size and the number of important organs they contain. The vertebral cavity, while important, is often discussed in conjunction with the cranial cavity as part of the dorsal cavity. The thoracic cavity, as the reference specifies, contains the pericardial and pleural cavities, highlighting its complex internal organization.
