Pelvic diaphragm - anatomic information for physiotherapeutic treatment
Muscular pelvic floor (diaphragm pelvis) is the biggest part of the muscle group musculi perinei and therefore it is, in terms of anatomy as well as physiology, closely related to the surrounding urogenital organs.
It consists of (Fig. 1, 2):
- m. levator ani, which closes a major part of the pelvic aperture and in the anal area forms m. sphincter ani externus
- m. coccygeus, accompanying ligamentum sacrospinale
Ventrally, under the sharebone lower shoulders, a hiatus urogenitalis crevice is formed in m. levator ani, closed by the muscular diaphragma urogenitale (made up of m. transversus perinei and m. sphincter urethrae), through which pass the urethra and vagina. This diaphragm is complemented with surface muscles m. bulbospongiosus and m. ischiocavernosus.
In the course of evolution the mentioned muscles developed from tail backbone muscles and cloaca.
Innervation: direct branches from plexus sacralis and n. pudendus ( S2, S3 ).
Due to the close relation between the pelvic floor and the womb and tubes, m. levator ani and coccygeus may be under increased tension and may reflexively influence tubes and cervix uteri in an adverse manner, by creating spasms and subsequent lumina narrowing . Somatic - visceral reflexes (and their influencing) have been known in the abdominal and pelvic organs and they have been successfully used in medical treatment and physiotherapy. Apart from m. levator ani, the other so-called "stress muscles" include m. gluteus, m. piriformis and others.
From the anatomic - physiologic perspective, physiotherapeutic effects on the pelvic floor (particularly its increased tension) are possible through vertebrogenic mobilization and massage (reflexive excitation of spinal nerves) and mobilization of sacroiliacal joints (i.e. reflexive stimulation of direct branches from plexus sacralis ) or using exercises of the pelvic floor and its massage, which represent major physiotherapeutic effects on somatic - visceral reflexes: innervation of the womb and tube is from z plexus hypogastricus from the segments Th12 - L1 ( sympaticus ) and S2 - S4 ( parasympaticus ).
Assoc. prof. MUDr. Pavel Matonoha, CSc.
Department of Anatomy, Faculty of Medicine, Masaryk University , Brno, Czech Republic
Texts to the Figures:
Fig. l : Pelvic diaphragm seen on the inferior aspect.
Fig. 2 : Pelvic diaphragm, coronal section.