In the form of a funnel, it is composed at the bone level of the sacrum (and coccyx), a true base of the spine, which itself is articulated with the two iliac bones, which operate in a "toothed wheel" (external rotation/antiversion/ascent of the EIPS of one or both iliums, and conversely internal rotation/retroversion/decirional).

Needless to say, the importance of this region in biomechanics, due to its location. It is through him that the lines of downward forces linked to gravity and ascending associated with the reaction on the ground pass. Indeed, it makes the link with the lower limbs at the hips.

A veritable pelvic floor, it contains the perineum, which is shaped like a hammock.

Between the hamstrings in the back (the bone on which one sits), and the pubis in front, are the shutter holes, where passes a part of the so-called pelvic-trochanter muscles, numbering 6.

It is narrow in men, flared in women, it is the area of reproduction.

In humans, it contains the prostate, which is located under the bladder, in front of the rectum, and behind the pubic symphysis. It is a sex gland that makes sperm (20%) with the seminal vesicles (80%), and joins the urethra through the ejaculating channels.

Unlike women, the urethra has a dual function in men, eliminating urine and expelling sperm.

In women, the pelvis contains:

1) The ovaries, which have a particular situation, as they are considered to be enteritone, located in the peritoneal cavity between the 2 visceral and parietal sheets but are not covered with peritoneum except on their ventral and upper edge, via the mesovarium.

They are the size of an olive, and have the main role of synthesizing the eggs.

The ovary is located behind the uterus and is held by 3 ligaments:

a) forward to the uterus, by the uterus-ovarian ligament or clean ligament of the ovary.

b) backwards to the lumbar spine, by the lumbar-ovarian ligament or suspensive ligament of the ovary, which allows it almost entirely its vascularization by the ovarian artery (96%), which is born from the abdominal aorta at the level of the intervetebral disc L2/L3.

c) laterally, to the tube by the infundibulo-ovarian ligament.

They are suspended from the tubes, which are sub-peritoneal, covered with peritoneum, wrapped by their mesosalpinx (upper part of the broad ligaments).

They are located high, in front of the ureters in the nullipare woman (who has never given birth), and are located lower, para-rectal in the woman who has already given birth (primipare, if a birth or multipare, if several deliveries)

2) The uterus, and more precisely its body, rests on the bladder at the vesico-uterine cul-de-sac, when it is positioned in an earlier than 75% of women, and can lead to urination disorders, such as urinary incontinence.

It can be found in backversion in 25% of women, the uterus then rests on the rectum at the level of Douglas' cul-de-sac, and can eventually lead to constipation-type transit disorders. This backversion can also cause pain during sex (dyspareunia).

Remember that the antiversion is the angle that forms the uterus with the axis of the vagina, it is on average 90 degrees, while the aneflexion is the angle that forms the uterus with the cervix, it is on average 170 degrees.

It consists of:

1) a mucous membrane, the endometrium that crumbles and causes bleeding during menstruation.

This mucous membrane can abnormally migrate to the ovaries, bladder, rectum, peritoneum, even the kidneys, and cause what is called external endometriosis, or migrate to the uterine muscle, and cause internal endometriosis, still called adenimiosis). In biomechanics, it is thought that these tissue migrations are due to adhesions between tissues, which, in the long run, create ectopic tissues, with cells that differ in those of the tissue on which it is attached.

2)of a muscle, the myometer.

3) means of fixity, the uterus is sub-peritoneal and attached to the bone pelvis by:

a) forward pubo-vesico-uterine ligaments and round ligaments

b) back the utero-sacred ligaments

c) sideways the SacroRecto Genociti-Bryo-Pubian blades (LSRGVP) from back to front

(d)cross ligaments, stretched from the lateral edges of the uterus to the lateral pelvic peritoneum. They contain all the vessels, nerves for the uterus, as well as the ureter.

The large ligaments are made up of two parts:

• upper is the mesometer, and its 3 peritoneal folds, called fins. It consists of the mesosalpinx between the uterus and the tube (upper fin), below, we have back the mesovarium between the uterus and the ovary (posterior fin), and forward the funicular meso that contains the round ligament (anterior fin).

• lower is the parameter, also called Mackenrodt ligament, which is traversed by the uterine artery coming from the internal iliac artery and then below by the paracervix that connects the cervix to the lateral parietal wall. Between the parameter and the paracervix at the neck, passes the ureter.

It also contains part of the urinary tract, the bladder, sub-peritoneal, which receives the ureters and is the origin of the urethra, and which is able to store between 300 ml and 600 ml of urine in adults.

The passage of a nerve particularly catches our attention, since it is often the cause of pains that affect men more, it is the pudendal nerve, or internal shameful nerve, which passes through the Alcock canal between the sacro-tuberal ligament (formerly large sacrosciatic ligament) and the internal shutter muscle.

Its compression of pain radiating in the anus, testicles in men or large lips in women, with sensations of electric shocks, tingling, tingling.

Osteopath will be able to relieve patients suffering from pudendalgia, including the mobility of the pelvis (sacrum, ilium) and hip (coxo-femoral joint), generating a reflex perineal muscle relaxation resulting in nerve decompression.

At the muscular level, note the presence of the Psoas muscles.

There are 2, right and left, and located behind the anterior abdominal muscle wall.

The psoas muscle consists of 2 beams, a deep one affixed in front of the spine, and a superficial, to join the iliac muscle and form the iliac psoas muscles on the small trochanter of the femur.

Even if they do not fit into the bony pelvis, since they connect the lumbar to the hips, they are given a considerable biomechanical role, without which walking would be impossible.

Indeed, they alone must thwart the action of the antagonistic muscles that are the spine erectizers, the Dove Squares, the Ilio-costals, and the Great Dorsals mainly (not to mention the deep spinal, interpinal, transverse-thorny muscles…). Note that they do not have the same open chain action as closed chain action.

They are also called "garbage muscles" because they store all metabolic waste from the lower limbs through the femoral veins to join the iliac veins and end up in the lower cave veins towards the right cardiac atrium (atrium).

At the nerve level, it contains the sacred plexus, which is composed of several contingents, the sciatic nerve being the known and the largest of the organism. It is located in the buttocks and corresponds to the meeting of outgoing nerves of the last 2 lumbar vertebrae and sacred holes. Mixed, that is, conveying both the sensitivity of the lower limbs by bringing tactile information to the brain (cold, hot…), it is also motor, bringing to the muscles of the lower limbs (hamstrings behind the thighs, calves, anterior, posterior leggings) the energy necessary for their contraction.

At the vegetative level, we note the presence of parasympathetic splanchnic nerves, which are de^rived ^from the 2nd, 3rd and 4th sacred nerves, to join the lower hypogastric plexus, destined for the pelvic viscera.