Midsagittal Plane Definition

The body is divided into two pieces by the midsagittal plane, also known as the middle plane. It divides each item or creature vertically into two roughly equal halves—left and right. In humans, half of the head, thorax, abdomen, and genitals, as well as one arm and one leg, are divided into two bisected divisions.

The Route of the Human Midsagittal Plane

The most common use of the midsagittal plane is to depict a person in an anatomical posture, with arms and legs slightly apart, as seen above.

The two mirrored portions are known as left or right midsagittal sections, where left and right relate to the subject’s left and right, not the point of view of the person looking at, say, a computed tomography scan. While sagittal planes (also known as parasagittal planes) might split an organism into unequal vertical portions along its longitudinal axis, the midsagittal plane focuses on a middle division that divides the organism into two equal-sized halves. The term “medial” refers to an organ or point of reference that is near to the mid-line. Lateral points are those that are further away from the mid-line.

Head

The midsagittal or median plane goes from the top of the skull to the maxilla and mandible, passing through the frontal, parietal, occipital, and nasal bones, as well as the maxilla and mandible. The middle portion of the human skull is seen in the figure below.

The median plane divides the brain into its two hemispheres in the soft tissues of the skull, as well as the nasal cavity, tongue, throat, and larynx, the last of which may be seen below.

Through the spinal cord, the whole vertebral column — cervical, thoracic, and lumbar — is separated vertically into two parts. The graphic depicts the thoracic and lumbar vertebral median division.

Thorax

The soft and hard tissues of the thorax are separated vertically into two portions, each containing one lung and a pair of ribs. The contents of each midsagittal segment are never precisely the same due to the non-symmetrical divisions inside the human body. For example, the aortic arch is more visible in the left portion than in the right, and the trachea, which is somewhat to the right, will be most evident in the right section.

The anterior (front) X-ray clearly reveals the heart in its asymmetrical position in the image below, while the 3D photo next to it illustrates this in more detail. The ventricles are predominantly located in the left midsagittal part, and the atria are mostly located in the right midsagittal section, keeping in mind that the left and right sides correlate to the subject’s orientation and are opposed to viewer perception.

Abdomen

The location of “symmetrical” organs like the kidneys does not necessarily offer a mirror image, as seen in the above illustration. This is especially true in the abdominal area. The pancreas, stomach, appendix, liver, and gall bladder are also found in the abdomen, all of which are unique and are contained entirely or partly inside a single midsagittal region.

The huge liver is located inside the right half of the body, and the left kidney is much higher than the right kidney. On both sides of a midsagittal picture, the bladder and pelvic bones are centrally located and feature in relative symmetry.

On the whole, the male and female urogenital systems are symmetrical. One ovary is found in a single midsagittal segment of the female reproductive system, whereas one testis is found in the male reproductive system. The urethra, bladder, uterus, and penis are all separated in the centre.

Abnormal Midsagittal Sections in Humans

Many anatomical anomalies might provide odd medical outcomes. Scoliosis, for example, prevents a midsagittal segment from running smoothly through the centre of each vertebra.

The absence of an organ due to genetic abnormalities, such as renal agenesis or the absence of one or both kidneys during foetal development, can result in aberrant imaging. The location of the heart may be affected by situs inversus, a condition in which key organs seem to be inverted from normal human anatomy (dextrocardia).

Situs inversus totalis is an uncommon disease in which all the thoracic and abdominal organs are mirrored. Except when pre-surgery imaging is ignored, this does not result in medical issues. The heart of a person with situs inversus is shown in the figure below in a reversed posture.

Irregularities between the left and right midsagittal portions may also be caused by craniomaxillofacial (CMF) abnormalities. Facial dissymmetry, which is usually caused by facial injuries or hereditary anomalies, may lead to further issues such as breathing and vision problems. In reconstructive craniomaxillofacial surgery, professionals aim to restore trauma sufferers to their premorbid (pre-trauma) midsagittal plane, or to a normal anatomical structure in the event of hereditary defects.

A condition in which the body has an additional portion, organ, or part of an organ is referred to as supernumerary anatomy. These additions might be symmetrical or asymmetrical, as in the case of Myrtle Corbin (seen below). Supernumerary anatomy is usually the consequence of genetic abnormalities disrupting embryonic development. When a medicine like thalidomide is used by the mother during pregnancy, it might induce mutations in the baby.