Cavities of the Body and Their Subdivisions
Body cavities are confined (limited) space within the
body that contains internal organs or viscera.
A body cavity is a fluid-filled space inside the body that
houses organs, holds the organs, and protects internal organs.
The cavities refer to any
space or compartment or “hollow space”. The cavity of the body is differentiated or separated by membranes and other structures bones,
muscles, or ligaments.
Know here the anatomical
position of the body and directional terms.
Human Body Cavities
The two main body cavities are –
1. Ventral or anterior cavity, and
2. Dorsal cavities or posterior
cavity
1. Dorsal Body Cavity
It is located near the dorsal surface (back) of the
body. The dorsal body cavity includes; the brain and vertebral cord (spinal
cord).
Subdivision of dorsal cavity are-
A. Cranial Body Cavity
B. Vertebral Body Cavity
A. Cranial Body Cavity
The cranial body cavity is formed by skull bone that contains
the brain.
The cranial cavity is enclosed by the skull and contains the brain.
B. Vertebral Body Cavity
The vertebral body cavity is formed by vertebrae of the
backbone, contains the vertebral cord (spinal cord) and spinal nerves.
The spinal cavity is enclosed by the spine and contains the spinal
cord.
2. Ventral Body Cavity
It is located on the ventral (front), anterior
surface of the body. A lined by thin, slippery tissue called serous
membrane lines the wall of the ventral body cavity and organs within
it.
The ventral cavity allows for significant changes in the
size and shape of the internal organs within, perform their functions.
The organs inside is called viscera. Double-walled
sacs of serous membrane surround these cavities.
The two walls (membrane) that make up these sacs are
separated by a thin film of serous fluids, which act as a lubricant
and facilitate the nearly frictionless movements of an organ such as the heart,
lungs, and stomach.
Subdivisions of a ventral body cavity are-
A. Thoracic Body Cavity
B. Abdominopelvic Body Cavity
A. Thoracic Body Cavity
The thoracic cavity is protected by the thoracic cage (rib
cage) and its associated musculature (arrangement of muscle) and sternum
anteriorly and 12 thoracic vertebrae posteriorly.
The thoracic cavity is separated from the abdominal cavity by
the diaphragm.
Thoracic cavity contains three compartments-
1. Pleural Cavity
There are two pleural cavities present; right and left. Each
of two pleural cavities surrounds the lungs.
Each pleural cavity is a small, fluid-filled space between
the parts of the serous membrane that covers the lung (visceral pleura) and the
part that lines the walls of the thoracic cavity (parietal pleura).
The pleural cavity or pleural space is bounded by a
double-layered serous membrane called “pleura”.
The serous membrane associated with the lungs is called “pleura”.
2. Pericardial Cavity
The pericardial cavity is a fluid-filled space between the
parts of the serous membrane that covers the heart (visceral pericardium) and
the part that lines the thoracic cavity (parietal pericardium).
The serous membrane that surrounds the heart is called the “pericardium”.
Pericardial fluid (serous fluid) acts to reduce surface tension, lubricates the
cavity, and facilitates the free movement of the heart.
3. Mediastinum
The mediastinum is the region between the lungs extending from
the sternum to the vertebral column or backbone.
Space between both lungs inside the chest cavity between
right and left lung. It is a central compartment of the thoracic cavity,
located between the two pleural sacs.
The mediastinum contains all the contents of the thoracic
cavity except for the lung themselves.
It contains a heart and its attached blood vessels,
pericardial cavity, esophagus, trachea, thymus gland, lymph nodes, thoracic
duct, phrenic nerves, and vagus nerves.
B. Abdominopelvic Body Cavity
The abdominopelvic body cavity is the largest cavity in the
body, consists of the abdominal cavity and the pelvic cavity. It extends from
the diaphragm inferiorly to the floor of the pelvis. It is bounded primarily by
abdominal muscles.
It is divided by an imaginary line at the superior margin of
the pelvis into the superior abdominal cavity and inferior pelvis cavity.
A serous membrane that
lines the abdominopelvic cavity and covers the organs within it, called the “Peritoneum”.
Check out here what are quadrants
and regions of abdomen?
The abdominopelvic body cavity contains two compartments-
1. Abdominal Cavity
The abdominal cavity contains; the stomach, liver, kidney,
spleen, gall bladder, pancreas, small intestine, and most of the large
intestine.
2. Pelvic Cavity
The pelvic cavity is directly continuous with the rest of
the abdomen but is situated in the space bounded by the sacrum bone behind, the
ischium bone on each side, and the pubic bone (pubis) in front.
The pelvic cavity contains; the urinary bladder, sigmoid colon
(pelvic colon), rectum, lower parts of ureters, internal portions of the male
and female reproductive system, inferior portion of the peritoneal cavity, and
some loops of the small intestine.
What organs are found in the abdominopelvic
regions? Check out
here abdominopelvic
regions and quadrants organs.
Functions of Body Cavity
1. The cavities
help to protect, separate, and support the internal organ.
2. Cavities permit
the internal organs to a significant change in size and shape of an organ
without disrupting the activities of nearby organs.
3. They act as cushions
or shock absorbers while walking, jumping, or running.
4. Cavities of the body house
and protect the internal organs.
Check out here what are anatomical
planes and sections of the Body?
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