Main cavities: Cranial, thoracic, abdominal, and pelvic

Body Cavities

Body cavities are spaces within the body that serve to divide the numerous body cavities from one another as well as to help protect, separate, and support internal organs, muscles, ligaments, and other structures. In our body, there are four cavities.

Cranial Cavity

It houses the brain, which is enclosed by the cranium.

• Anteriorly
  • Frontal bone one
• Laterally
  • Temporal bone two
• Posteriorly
  • Occipital bone one
• Superiorly
  • Parietal bones two
• Inferiorly
  • Sections of the frontal, temporal, and occipital bones, as well as 1 sphenoid, 1 ethmoid bone, and                                                      

Thoracic Cavity

Space for the heart and lungs is provided by the thoracic cavity. The mediastinum divides it into the right, left, and median sections. The lungs are located on the right and left sides. It is shielded anteriorly by the sternum and the ribcage's accompanying muscles.

• Anteriorly
  • The sternum and ribs' costal cartilages.
• Laterally
  • The intercostal muscles and the 12 pairs of ribs.
• Posteriorly
  • The thoracic spine

The main organs and structures contained in the thoracic cavity are:

• Trachea, two bronchi, and two lungs
• The vena cava, the aorta, the heart, and several other blood arteries.
• An oesophagus
• Lymph nodes and lymphatic vessels

The area between the lungs known as the mediastinum contains the heart, oesophagus, and blood vessels, among other structures.

The Abdominal Cavity

This oval-shaped cavity is the largest one in the body. It is located in the trunk and is surrounded by the kidney, gallbladder, liver, spleen, stomach, and intestine.

• Superiorly
  • It is separated from the thoracic cavity by the diaphragm.
• Anteriorly
  • The abdominal muscles that make up the anterior wall
• Laterally
  • The lower ribs and a portion of the abdominal muscles
• Posteriorly
  • The muscles and lumbar vertebrae making up the posterior abdominal wall
• Interiorly
  • Along with the pelvic cavity, it is continuous.

Clinically, the abdomen is divided into 9 regions along two horizontal and two vertical axes.

The Horizontal Planes are

• Transpyloric Plane
  • At the level of the L1 vertebra, a line is drawn at the lower edge of the patient's hand, just below the xiphisternum, in the middle of the superior borders of the sternum's manubrium and the pubic symphysis.
• Transtubercular Plane
  • There is a horizontal line that connects the two spots. After the anterior superior iliac spine, 5 cm (ASIS).

 The vertical Planes Are

• Mid-Clavicular Lines
  • Vertical line connecting the inguinal ligaments' midpoints.

Organs of four Quadrants of Abdomin

Organs of the Nine Regions

• Right Hypochondriac                                                    
  • Gallbladder and liver
  • Biliary system
  • Colon's hepatic flexure
• Right Lumbar
  • Correct kidney
  • Appropriate suprarenal gland
  • Raising colon
• Right Iliac Fossa
  • Caecum
  • Vermiform appendix
• Epigastric
  • Stomach
  • Left lobe of liver
  • First part of duodenum
• Umbilical
  • Small Intestine
  • Pancreas
• Hypogastrium
  • Urinary Bladder
  • Uterus
• Left Hypochondriac
  • Spleen
  • Splenic flexure colon
  • Part of pancreas
• Left Lumbar
  • Lateral kidney
  • Suprarenal gland on the left
  • Dropping colon
• Left Iliac Fossa
  • Sigmoid colon

The lower end of the abdominal cavity extends into the roughly funnel-shaped pelvic cavity. The distal portion of the large intestine, the urine bladder, the urethra, and the reproductive organs are all located in the pelvic cavity. The restrictions are:

• Superiorly
  • Along with the abdominal cavity, it is continuous.
• Anteriorly
  • The genital bones
• Posteriorly
  • The coccyx and sacrum
• Laterally
  • Bones of the innominate
• Inferiorly
  • The pelvic floor muscles

The following structures are located in the pelvic cavity:

• Rectum, sigmoid colon, and anus
• A few tiny intestinal loops
• Urinary bladder, ureters' lower segments, and urethra
• The reproductive system's female components, including the uterus, uterine tubes, ovaries, and vagina