What Are Body Planes?
Body planes are hypothetical geometric planes that divide the human body into sections. Mainly these body planes are used in human anatomy to describe the direction and location of body structures.
A human body in the anatomical position is described with the help of a coordinate system, which includes three-axis (X, Y, and Z). The X-axis is going from left to right, Z-axis from front to back, and Y-axis from up to down. In anatomical terminology, three references plane are considered standard planes; these planes differentiate the body anterior and posterior, ventral and dorsal, dexter, and sinister portions.
Let me tell you about these standard planes in detail. We will also see the body regions and quadrants and anatomical terminology for body cavities
The Transverse Plane
This plane is known as the X-Z plane or axial plane; it divides the head (superior) and tail (inferior) portions of the human body. The transverse plane is parallel in an upright human and perpendicular to the median and coronal plane. Concerning the ground, it runs parallel, that’s why it is called a horizontal plane.
Horizontal is used as a key term for this plane, and the horizontal axis runs from side to side and divides the body into top and bottom instead of left and right halves.
A longitudinal plane will be perpendicular to the transverse plane. It divides the body into two halves and cut the person straight into left and right halves from the head through the belly button and down to the toes. The sagittal plane, coronal plane, and parasagittal plane are categorized as longitudinal planes.
The Sagittal Plane
A vertical plane that runs parallel to the median plane is called a Sagittal plane. This Y-Z or lateral plane separates the body right (dexter) and left (sinister) halves. The midsagittal plane (median plane) passes through the center of the body while all other sagittal planes are parallel to this midsagittal planes. It is sometimes called paramedian planes, as the ‘para’ refers to parallel to something else.
The Coronal Plane (Frontal Plane)
It is also known as Y-X plane or Frontal planes; the coronal plane divides the body into ventral (front) and dorsal (back) portions. This plane also gives a clear image of the posterior and anterior portions of the body. The coronal planes intersect the median plane at a 90-degree angle and show the anatomical body parts into front and back halves.
- These three are significant references plane, and all other planes are shown with these planes, such as Parasagittal planes are parallel to the sagittal (Y-Z) plane.
Anatomical Terminology for body cavities
All vertebrates have fluid-filled spaces, which are called body cavities, and these cavities contain organs. The human also gave several body cavities, which are named anatomically according to the body organ and location where this cavity is found, such as a thoracic cavity, cranial cavity, and pelvic cavity.
These cavities also protect body organs. Here we will see the anatomical terms and anatomical planes of these body cavities.
The dorsal cavity is situated at the dorsal side of the body, and it occupies the upper central nervous system, such as the brain and spinal cord. The meninges membrane within the dorsal cavity protects the brain and spinal cord.
This cavity is located anteriorly to the dorsal cavity and houses the space inside the skull. This cranial cavity is occupied with the brain, meninges, and cerebrospinal fluid.
This cavity is located interiorly in front of the body and a house of many different organ systems. Besides, this cavity is divided by the diaphragm into anterior and posterior portions. It looks like a sheet of skeletal muscles underneath the lungs and organs within this ventral cavity is known as viscera.
The posterior portion of the dorsal cavity within the vertebral column is known as the vertebral cavity. Among all body cavities, it is the narrower body cavity and seems like a thread. It is filled with the spinal cord, meninges of the spinal cord, and left space filled with fluid.
The thoracic cavity is part of the anterior ventral body cavity situated in the torso within the rib cage. This cavity mainly includes the organs of the respiratory and cardiovascular system but also consists of the other system organs such as the thymus gland and esophagus.
A membrane lines the thoracic cavity called mesothelium; it has two types the pericardium lining of the heart and pleural lining of the lungs.
A cavity which is located posteriorly to the ventral body cavity and found beneath the diaphragm and thoracic cavity. This cavity is divided into the pelvic and abdominal cavity, and it contains the organs of many systems such as renal and digestive systems.
Also, it has organs of endocrine systems such as adrenal glands. It lies within the reproductive system and bladder and lined by a mesothelium called “peritoneum.” It is one of the essential body cavity anatomically.
Abdominal Regions and Quadrants
Anatomists divide the abdominopelvic cavity into smaller regions to facilitate the study of body planes. This anatomical abdominal region division is used to recognize the location of the abdomen organs and to diagnose abdominal pain. The commonly abdominopelvic region is divided into four quadrants and nine regions.
These quadrants are arranged within the sagittal and umbilical plane. These abdominal quadrants are used by radiologists and anatomists to determine the tissues and organs that cause discomfort in that region.
Left Lower Quadrant
The left lower quadrant houses some of the large intestine portions, the majority of the small intestine, left ureter, and the left half of the female reproductive system.
Right Lower Quadrant
When dissecting the right lower quadrant, it appeared it includes an appendix, cecum, right half of the female reproductive system, right ureter, and parts of the small intestine. Pain in this region is associated with appendicitis.
Right Upper Quadrant
This quadrant contains the right side of body organs such as liver, right kidney, gallbladder, duodenum, pancreas, a small portion of the stomach, and parts of the small intestine.
Left Upper Quadrant
The left upper quadrant consists of the left kidney, spleen portion of descending and transverse colon, stomach part, and parts of the small intestine. Pain in the left upper quadrant is associated with malrotation of the intestine and colon.
The nine divisions are part of parasagittal and two transverse planes of body-centered around the navel. These divisions are important anatomically to determine the location of the organ within the abdomen and pelvic area.
This region houses the gallbladder, the right kidney, parts of the small intestine, and right portion of the liver.
The left hypochondriac region contains the left kidney, part of the stomach, colon, small intestine, and the pancreas.
The right iliac contains the lower body organs such as right iliac fossa, appendix, and cecum.
The left iliac region contains left iliac fossa, sigmoid colon, and sigmoid colon. It is also known as the left inguinal region.
The right lumbar region consists of the right kidney, ascending colon, gallbladder, and liver.
It gives space to the descending colon, spleen, and left kidney.
The umbilical region contains the umbilicus (navel), duodenum, jejunum, ileum, transverse colon, and the bottom portions of both the left and right kidney.
The hypogastric region contains organs around the pubic bone, such as the uterus and ovaries in females and the prostate in males.
The epigastric region contains the majority of the stomach, part of the liver, pancreas, duodenum, and the adrenal glands.
Applications of Body Planes
These anatomical planes have great significance in medical imaging techniques, for example, MRI scans, CT scans, Sonography, and PET scans. Sometimes for medical imaging, the orientation of these references plane is needed. Medical imaging techniques are the primary applications of body planes.
When a radiologist imaging a patient, firstly, it divides the patient body into X, Y, and Z-axis to get the body planes to the images. Z-axis shows the body image from toe to head while X-axis divides the body into the right to left, and Y-axis passes from front to back.
Besides, these planes show the patient-internal organs and help the radiologist to identify the small structure within that main organ.
These anatomical planes are used to describe the action axis performed by the body. An anatomist could model a limb’s range of motion by measuring these planes along which planes limb can move and how far it can move.
We understand this application with an example; when a person jumps up and down, then his body will run through the transverse plane in sagittal and coronal planes. So, an anatomist can understand and detect the body movement with the help of these anatomical planes.
These anatomical planes help to view any anatomical change during embryological development. These planes provide a basis in comparative embryology to see different types of organism’s development within the womb.
In the initial phase of human embryonic development, the coronal plane looks horizontal, while when the embryo develops into a fetus, it looks vertical in position.
- Kinetic Anatomy With Web Resource—3rd Edition. Human Kinetics. 2012. pp. 31–. ISBN 978-1-4504-3391-4.
- “How are the different head and MRI coordinate systems defined?”. FieldTrip. FieldTrip. 2019-08-26. Retrieved 2019-09-24.