Anatomical plane
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Anatomical terminology |
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An anatomical plane is a hypothetical
- The sagittal plane or lateral plane (longitudinal, anteroposterior) is a plane parallel to the sagittal suture. It divides the body into left and right.
- The coronal planeor frontal plane (vertical) divides the body into dorsal and ventral (back and front, or posterior and anterior) portions.
- The transverse plane or axial plane (horizontal) divides the body into cranial and caudal (head and tail) portions.
Terminology
There could be any number of sagittal planes, but only one cardinal sagittal plane exists. The term cardinal refers to the one plane that divides the body into equal segments, with exactly one half of the body on either side of the cardinal plane. The term cardinal plane appears in some texts as the principal plane. The terms are interchangeable.[1]
Human anatomy
In human anatomy, the anatomical planes are defined in reference to a body in the upright or standing orientation.
- A transverse plane (also known as axial or horizontal plane) is parallel to the ground; it separates the transumbilical (or umbilical) plane, the supracristal plane, the intertubercular plane, and the interspinous plane.
- A coronal plane (also known as frontal plane) is perpendicular to the ground; it separates the anterior from the posterior, the front from the back, and the ventral from the dorsal.
- A sagittal plane (also known as anteroposterior plane) is perpendicular to the ground, separating left from right. The median (or midsagittal) plane is the sagittal plane in the middle of the body; it passes through midline structures such as the navel and the spine. All other sagittal planes (also known as parasagittal planes) are parallel to it.
The axes and sagittal plane are the same for bipeds and quadrupeds, but the orientations of the coronal and transverse planes switch. The axes on particular pieces of equipment may or may not correspond to the axes of the body, especially since the body and the equipment may be in different relative orientations.
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Brain viewed from below. This is an example of a transverse plane.
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Brain cut in half through the midsection. This is an example of a sagittal plane.
Uses
Motion
When describing anatomical motion, these planes describe the axis along which an action is performed. So by moving through the transverse plane, movement travels from head to toe. For example, if a person jumped directly up and then down, their body would be moving through the transverse plane in the coronal and sagittal planes.
A longitudinal plane is any plane perpendicular to the transverse plane. The coronal plane and the sagittal plane are examples of longitudinal planes.
Medical imaging
Sometimes the orientation of certain planes needs to be distinguished, for instance in
Finding anatomical landmarks
In humans, reference may take origin from
- The midaxillary line, a line running vertically down the surface of the body passing through the apex of the axilla (armpit). Parallel are the anterior axillary line, which passes through the anterior axillary skinfold, and the posterior axillary line, which passes through the posterior axillary skinfold.
- The mid-clavicular line, a line running vertically down the surface of the body passing through the midpoint of the clavicle.
In addition, reference may be made to structures at specific levels of the
Occasionally, in medicine, abdominal organs may be described with reference to the trans-pyloric plane, which is a transverse plane passing through the pylorus.
Comparative embryology
In discussing the neuroanatomy of animals, particularly rodents used in neuroscience research, a simplistic convention has been to name the sections of the brain according to the homologous human sections. Hence, what is technically a transverse (orthogonal) section with respect to the body length axis of a rat (dividing anterior from posterior) may often be referred to in rat neuroanatomical coordinates as a coronal section, and likewise a coronal section with respect to the body (i.e. dividing ventral from dorsal) in a rat brain is referred to as transverse. This preserves the comparison with the human brain, whose length axis in rough approximation is rotated with respect to the body axis by 90 degrees in the ventral direction. It implies that the planes of the brain are not necessarily the same as those of the body.
However, the situation is more complex, since comparative embryology shows that the length axis of the neural tube (the primordium of the brain) has three internal bending points, namely two ventral bendings at the
History
Some of these terms come from Latin. Sagittal means "like an arrow", a reference to the position of the spine that naturally divides the body into right and left equal halves, the exact meaning of the term "midsagittal", or to the shape of the sagittal suture, which defines the sagittal plane and is shaped like an arrow.
See also
- Anatomical terms of location
- Horizontal plane
- Radial plane
References
- 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.