HODGE BLUEPRINTS: IDENTIFICATION, FUNCTIONS, IMPORTANCE - MEDICINE - 2025

The Hodge planes are four imaginary anatomical divisions, which project onto the pelvis of the pregnant woman and serve as a guide to determine the position of the fetus in the birth canal.

The pelvis is an anatomical cavity made up of the bones below the trunk. This cavity contains the internal reproductive organs. To divide the pelvis according to Hodge's planes, its anatomy must be well known.

Henry Vandyke Carter and one more author - Henry Gray (1918) Anatomy of the Human Body

The four planes are parallel imaginary lines and are drawn from specific points on the bones that make up the pelvis.

During labor, the fetus descends from the pelvis to its exit through the vagina. Knowing the anatomical points of the pelvis to calculate the Hodge planes, it is possible to know how high the fetus is in the pelvis, in relation to the vaginal opening.

By calculating the Hodge planes during a woman's labor, the doctor can tell if the labor is progressing normally or if, on the contrary, the labor is not being effective and other measures should be used to help expulsion of the fetus.

The four planes of Hodge

Anatomy of the pelvis during pregnancy

During pregnancy, the female pelvis undergoes various modifications, especially at the end of gestation. These changes become more important at the time of birth, when the fetus passes through the birth canal to be finally expelled.

The distance between the head of the fetus and the vaginal opening is known as the fetal height. A quick and efficient way to know this measurement is through the Hodge blueprints.

The pelvis is the bony structure under the spine, resting on the proximal bones of the legs (femur). These bones form a cavity where some abdominal organs and internal reproductive organs are located.

It is funnel-shaped, presenting a wide upper circumference known as the upper narrow and a lower circumference with a smaller diameter known as the lower narrow.

There are three bones that make up the pelvis: behind is the sacral bone, which is the terminal portion of the vertebral column, and in front the two iliac bones united in the pubis.

Hodge Blueprint Identification

Hodge's planes are 4 parallel, imaginary lines that are numbered from top to bottom and that locate the height of the fetus relative to the vagina at the time of delivery.

Planes are identified from anatomical points in the pelvis as follows:

- Foreground: is the line that is drawn from the symphysis pubis to the junction of the fifth lumbar vertebra with the sacrum. This junction is also known as a promontory. Hodge's close-up coincides with the upper pelvis.

- Second Plane: its identification is carried out by means of the union of the second sacral vertebra to the lower edge of the pubic symphysis.

- Third Plane: in this case, the line is drawn at the height of the ischial spines, parallel to the previous one. The ischial spines are two prominences of the lateral bones of the pelvis.

- Fourth Plane: for the last of the parallels, the union of the sacrum with the coccyx, known as the sacral vertex, is taken as a reference. From there a line is drawn parallel to all the previous ones.

When the fetus reaches this plane, it is about to be expelled.

Features

Hodge planes are used in obstetric medical history. That is, the measurement is done exclusively in pregnant women.

When the doctor refers to the fetus based on the Hodge planes, he is giving a specific measurement of the fetal height.

Since the identification of the planes is known and used worldwide, these terms are universally understood without the need to provide more detailed data regarding the height at which the fetus is in the birth canal.

Importance of Hodge planes in patients in labor

The identification of the Hodge planes is especially important during the passage of the fetus through the birth canal.

William Smellie - Plate 14, from A Set of Anatomical Tables with Explanations

When taking the medical history of a woman in labor, the height at which the fetus is located is established through vaginal examination thanks to the Hodge planes. That way it's easy to keep track as the hours go by.

Normal labor

Once the anatomical points for the calculation of Hodge's imaginary parallels are known, through physical examination, the doctor can know how high the fetus is.

In a normal pregnancy, the fetus descends through the different pelvic planes. By means of vaginal examination, which is a test performed by the doctor introducing two fingers through the vagina, the head of the fetus can be touched when it reaches the last two planes of Hodge.

Hodge's third and fourth planes correspond to the so-called fetal nesting. This means that the fetal head is fully insinuated into the birth canal and the fetus is about to be delivered.

Pathological labor

When a fetus does not progress beyond one of the planes, the patient must be studied in order to make an adequate diagnosis and try to solve it by continuing the delivery.

In some cases, the diameter of the woman's pelvis is smaller than the head or shoulders of the fetus. For this reason, there can be a good progression between Hodge's first two shots, which are wider, and stop at the third, when the pelvis narrows.

If the fetus cannot progress further through the pelvis, it is vitally important to attend the delivery to avoid fetal distress.

The fetus manages to be born once the doctor manages its passage through the last bony area of ​​the birth canal, corresponding to the fourth plane of Hodge. After exceeding this diameter, a vaginal delivery is achieved.

References

1. Bottle J; Clavero, J. (1993). Obstetric examination. Treaty of Gynecology.

2. Bonilla-Musoles, F; Pellicer, A. (2007). The canal and the object of childbirth. Basic Obstetrics, Reproduction and Gynecology.

3. Sicuranza, BJ; Tisdall, H; They read WM; Palmeri T. (1970). The planes of Hodge as an index of the progress of labor. The Journal of Reproductive Medicine. Taken from: ncbi.com

4. Steer, P; Flint, C. (1999). ABC of labor care: Physiology and management of normal labor. BMJ. Taken from: ncbi.com

5. Carvajal, H; Chambi, G. (2012). Anatomical description of the obstetric pelvis and pelvimetric examination in pregnant women. Bolivian Archives of Medicine. Taken from: scielo.isciii.es