Pelvic fascia скачать в хорошем качестве

Pelvic fascia

Pelvic Fascia The pelvic fascia is connective tissue that occupies the space between the membranous peritoneum and the muscular pelvic walls and floor not occupied by the pelvic viscera. This layer is a continuation of the comparatively thin (except around kidneys) endoabdominal fascia that lies between the muscular abdominal walls and the peritoneum superiorly. The pelvic fascia has been described as having parietal and visceral components. Membranous Pelvic Fascia: Parietal and Visceral The parietal pelvic fascia is a membranous layer of variable thickness that lines the inner (deep or pelvic) aspect of the muscles forming the walls and floor of the pelvis. The parietal pelvic fascia therefore covers the pelvic surfaces of the obturator internus, piriformis, coccygeus, levator ani, and part of the urethral sphincter muscles. Specific parts of the parietal fascia are named for the muscle they cover (e.g., obturator fascia). This layer is continuous superiorly with the transversalis and iliopsoas fascias. The visceral pelvic fascia includes the membranous fascia that directly ensheathes the pelvic organs, forming the adventitial layer of each. The membranous parietal and visceral layers become continuous where the organs penetrate the pelvic floor. Here the parietal fascia thickens, forming the tendinous arch of pelvic fascia, a continuous bilateral band running from the pubis to the sacrum along the pelvic floor adjacent to the viscera. The anteriormost part of this tendinous arch (puboprostatic ligament in males; pubovesical ligament in females) connects the prostate to the pubis in the male or the fundus (base) of the bladder to the pubis in the female. The posteriormost part of the band runs as the sacrogenital ligaments from the sacrum around the side of the rectum to attach to the prostate in the male or the vagina in the female. Endopelvic Fascia: Loose and Condensed Usually, the abundant connective tissue remaining between the parietal and the visceral membranous layers is considered part of the visceral fascia, but various authors label parts of it as parietal. It is probably more realistic to consider this remaining fascia simply as extraperitoneal or subperitoneal endopelvic fascia, which is continuous with both the parietal and the visceral membranous fascias. This fascia forms a connective tissue matrix or packing material for the pelvic viscera. It varies markedly in density and content. Some of it is extremely loose areolar (fatty) tissue, relatively devoid of all but minor lymphatics and nutrient vessels. In dissection or surgery, the fingers can be pushed into this loose tissue with ease, creating actual spaces by blunt dissection; for example, between the pubis and the bladder anteriorly and between the sacrum and the rectum posteriorly. These potential spaces, normally consisting only of a layer of loose fatty tissue, are the retropubic (or prevesical, extended posterolaterally as paravesical) and retrorectal (or presacral) spaces, respectively. The presence of loose connective tissue here accommodates the expansion of the urinary bladder and rectal ampulla as they fill. Although these types of endopelvic fascia do not differ much in their gross appearance, other parts of the endopelvic fascia have a much more fibrous consistency, containing an abundance of collagen and elastic fibers and, according to some authors, a scattering of smooth muscle fibers. These parts are often described as fascial condensations or pelvic ligaments. For example, during dissection, if you insert the fingers of one hand into the retropubic space and the fingers of the other hand into the presacral space and attempt to bring them together along the lateral pelvic wall, you will find that they do not meet or pass from one space to the other. They encounter the so-called hypogastric sheath, a thick band of condensed pelvic fascia. This fascial condensation is not merely a barrier separating the two potential spaces; it gives passage to essentially all the vessels and nerves passing from the lateral wall of the pelvis to the pelvic viscera, along with the ureters and, in the male, the ductus deferens. As it extends medially from the lateral wall, the hypogastric sheath divides into three laminae (leaflets or wings) that pass to or between the pelvic organs, conveying neurovascular structures and providing support. Because of the latter function, they are also referred to as ligaments. The anteriormost lamina, the lateral ligament of the bladder, passes to the bladder, conveying the superior vesical arteries and veins. The posteriormost lamina passes to the rectum, conveying the middle rectal artery and vein. In the male, the middle lamina forms a relatively thin fascial partition, the rectovesical septum, between the posterior surface of the bladder and the prostate anteriorly and the rectum posteriorly. In the female, the middle lamina is