Parametrium

PARAMETRIUM. The term "parametrium" is understood in various ways: some authors call the parametrium the connective tissue located on the surface of the uterus beneath its serous covering (the so-called adventitial sheath of the uterus); others designate with this term the connective tissue of the broad uterine ligaments, either in its entirety or only those connective tissue bands that are located at the base of these ligaments (pars cardinalis, s. basalis); Martin accepts as the parametrium an anatomical formation to which he gave the name retinaculum uteri; finally, some authors (French) understand by the parametrium, in the broad sense of the word, the entire pelvic connective tissue. "Nowhere is there such an abundance of connective tissue as in the cavity of the small pelvis," notes Bichat. The pelvic connective tissue, of which the parametrium is a distinct part, performs various functions here. First of all, loose connective tissue fills the "empty places" (gaps, slits, spaces) between the various organs of the pelvis, ensuring them the mobility necessary for their physiological functions and the ability to both expand and collapse. The loose sections of connective tissue, in addition, serve as a place for the deposition of fat masses, which is important for the tone and resistance of the tissues. The denser sections of the pelvic connective tissue (the so-called "zones of condensation," or fasciae) are formations that hold the uterus and other organs of the small pelvis in a mobile-suspended state (the fixing and suspending apparatus of the indicated organs). Covering the pelvic organs further in the form of a mantle, including the uterus, the connective tissue is at the same time the anatomical substrate for the attachment of the peritoneum, a substrate ensuring the latter a certain mobility. Furthermore, the pelvic connective tissue contains blood vessels, an abundant network of lymphatic vessels and lymph nodes, a dense network of nerves, the ureters, etc. Finally, according to the latest data (Roessle), connective tissue is considered an organized apparatus of metabolism; the so-called reticulo-endothelial apparatus plays a particularly large role here. Corresponding to such a variety of functions, the connective tissue of the pelvis, or the parametrium, appears far from homogeneous in its character and structure. In it, one can distinguish the following differentiated elements: 1) loose, wide-meshed tissue with an abundant fat content; 2) the connective tissue of the pelvic organs (adventitial sheaths of the uterus and other organs); 3) fairly dense connective tissue sheaths for blood vessels, lymphatic vessels, and for the ureters; 4) the fasciae of the pelvic muscles;

5) the so-called "zones of condensation" (W. A. Freund)—denser sections of pelvic connective tissue located in the depths, which are in intimate connection with the visceral layer of the pelvic fascia and with the adventitial sheaths of the pelvic organs; in addition to connective tissue, these zones contain elastic fibers with an admixture of smooth muscle fibers. Several such "zones of condensation" are distinguished. First of all, the retinaculum uteri is formed at their expense, with its three sections: the anterior (pars anterior), representing dense connective tissue bands located in the vesicocervical ligaments (lig. vesico-cervicalia); the middle (pars media), the most powerful, which is part of the so-called lig. cardinalia of the broad ligaments; and the posterior (pars posterior), forming the connective tissue base of the uterosacral ligaments (lig. sacro-uterina). The retinaculum uteri in

Figure 1. Topography of the pelvic connective tissue: 1-spatium parauterinum; 2-spatium praecervicale; 3-spatium paravesicale; 4-spatium retrocervicale; 5-spatium pararectale.

its entirety is a solid apparatus supporting the normal situs of the uterus. In addition to the "zones of condensation" that are part of the retinaculum, there are other similar formations in the small pelvis that are usually treated as separate ligaments (lig. rotunda, vesico-umbilicalia lateralia, infundibulo-pelvica, s. suspensoria ovariorum, ovarii propria). In the case of parametritis, the listed condensations, together with the retinaculum, play a significant role, serving as the boundaries of the so-called subserous connective tissue spaces, in which products of inflammatory processes (serous exudate, pus, etc.) accumulate and from where these products spread in one direction or another. Three connective tissue spaces (spatia subserosa) are distinguished: 1) the paravesical (spatium paravesicale), 2) the parauterine (spatium parauterinum), and 3) the pararectal (spatium pararectale) (Figs. 1 and 2). All of them are in connection with each other, although not particularly closely; certain boundaries can be drawn between them. The paravesical space is bounded in front by the anterior abdominal wall and the posterior wall of the symphysis, behind by the urinary bladder (fascia propria Velpeau), on the sides by fibrous plates located in the mesenteries of the round uterine ligaments (mesodesma lig. rotundi), below by the pubovesical ligaments (lig. pubo-vesicalia), and finally above by the peritoneum, which passes from the anterior abdominal wall to the urinary bladder. The paravesical space anatomically coincides with the boundaries of the so-called cavum Retzii. This section of the pelvic connective tissue has no direct relation to the parametrium. In inflammatory processes in the region of the space of Retzius, the exudate as a rule spreads upward under the anterior abdominal wall, appearing in the form of a triangle with its apex directed toward the navel (the so-called plastron abdominal of French authors). The spread of phlegmon of the paravesical connective tissue into the region of the parauterine connective tissue is prevented by the mesenteries of the round ligaments. The parauterine space—right and left—is significantly larger in size than the paravesical. Its boundaries: in front—the urinary bladder and the fibrous framework of the round ligament (mesodesma), on the sides—the lateral walls

Figure 2. Horizontal section of the pelvis at the level of the lower third of the uterine body: 1-uterus; 2-posterior Douglas space; 3-spatium parauterinum sin.; 4-anterior Douglas space; 5-urinary bladder; 6-rectum.

of the pelvis, where the parauterine connective tissue merges at the boundary line (l. terminalis, s. innominata) with the subperitoneal connective tissue of the iliac wing, behind—the "zones of condensation" that are part of the infundibulopelvic ligament and the proper ligament of the ovary, above—the apex of the broad ligament, and below—the fascia endopelvina. The parauterine space is less well demarcated from neighboring parts compared to others. The exudates accumulating here have two paths for their spread: one along the round ligament, in the direction of the internal opening of the inguinal canal (above the Poupart ligament), the other—directly to the iliac fossa and further in the direction of the caecum, or the S-Romanum, up to the region of the kidneys. In practical terms, the parauterine space is divided into two sections: the upper—the mesosalpinx (ala vespertilionis) and the lower—the root of the broad ligament (pars cardinalis). Within the parauterine space, it is customary to distinguish two more small sections of connective tissue—one in front of the uterus, between the bladder and the cervix (spatium praecervicale), and the other behind, between the posterior surface of the uterine cervix and the rectum (spatium retrocervicale). The boundaries of the spatium praecervicale: in front—the posterior wall of the bladder, behind—the cervix of the uterus, above—the peritoneum of the anterior Douglas space, below—the vesicocervical ligaments; on the sides, the connective tissue of the praecervical space, embracing the neck of the bladder, communicates with the paravesical connective tissue, and behind it passes into the parauterine space. The boundaries of the spatium retrocervicalis: in front—the posterior wall of the uterine cervix, behind—the rectum, above—the peritoneum of the posterior Douglas space, below—the mucous membrane of the posterior fornix; this section of connective tissue has communication on one side with the pararectal connective tissue and on the other—with the parauterine. The pararectal space contains connective tissue located on both sides of the rectum and on the anterior surface of the sacrum. Its boundaries: in front—the "zones of condensation" that are part of the infundibulopelvic ligaments and the proper ligaments of the ovaries, behind—the sacrum, above—the promontory, below—the fascia of the m. levator ani. The pararectal connective tissue has no direct relation to the parametrium.