The anatomy and histology of the sacrouterine ligaments.

Abstract To determine the gross and microscopic anatomy of the sacrouterine ligaments as well as their physiology and clinical significance, a review of the literature and an anatomical study were undertaken. Many articles refer to these ligaments, but little specific work has been done on them. Mainly they are mentioned secondarily as uterine supports or pertaining to the correction of uterine malposition. The studies which have previously been done leave the nature of these ligaments in a confused and controversial status. However, from the literature it may be concluded that the main supportive structures of the uterus are the parametrial and paravaginal musculofascial tissues, and that the sacrouterine ligaments are secondary in supportive action. Functionally the sacrouterine ligaments act to hold the cervix upward and posteriorly. Clinically these ligaments may be helpful in a differential diagnostic respect as well as being involved in certain pathological processes. Various surgical procedures have been directed toward these structures, some primary and others secondary to other procedures in the pelvis. An attempt was made to determine the actual anatomical configuration and histological components of the sacrouterine ligaments. To do this the pelves of thirty-three cadavers were studied. Ten of these were partially preserved dissecting laboratory specimens while the remainder were autopsy material. Thorough dissections of the ligaments and their contained structures were carried out in five cases. Drawings were made of each case: first, before the pelvic organs were disturbed, and second, after the sacrouterine ligaments were placed under tension. The entire ligaments or blocks thereof were removed for microscopic examination in twelve cases, and various staining techniques were utilized to demonstrate the tissue components. To summarize the gross and microscopic anatomy of the sacrouterine ligaments it may be said that they are bands of tissue coursing from the cervix around the inlet of the pouch of Douglas to become attached to the sacrum. Grossly they are often merely potential ligamentous structures. Histologically they may be divided into thirds. The anterior or cervical third contains in order of prominence (Table III) smooth muscle, fibroelastic connective tissue, blood vessels, nerves, and lymphatics. The intermediate third is made up of III . Histological components of the sacrouterine ligaments in order of thier prominence Histological Components by Regions Cervical (Anterior third) Smooth muscle Connective tissue Blood vessels Nerves (Sympathetics and parasympathetics) Lymphatics Intermediate (Middle third) Dense connective tissue (stratum fibrosum) Loose connective tissue and fat Nerves and ganglia (parasympathetic) Blood vessels Smooth muscle Lymphatics Sacral (Posterior third) Loose connective tissue and fat Blood vessels Nerves and lymphatics connective tissue concentrated in a subserosal stratum fibrosum and scattered in the deeper zone as a less dense meshwork. Nerve elements are numerous and blood vessels are moderately prominent. There are also a few scattered strands of smooth muscle in this region, and lymphatics may be present to a variable extent. The posterior or sacral third is composed almost entirely of loose strands of connective tissue and intermingling fat. There are a few vessels, nerves, and lymphatics located here. There is no reason why, if the sacrouterine ligaments are well developed, they should not be utilized in such operations as vaginal hysterectomy, enterocele correction, uterine retroversion, and prolapse; but they should not be credited with undue supportive value. The anterior or uterine end of the ligament may be, and often is, well developed. This has led to the opinion that these ligaments have more supportive action than this study would appear to justify, due to the weak and insignificant development of the posterior aspect. The old addage that a chain is no stronger than its weakest link can aptly be applied here, for the supportive action of the posterior third of the ligament is certainly questionable.