Introduction
The pelvic floor represents the connective tissue-muscular floor of the pelvic cavity in humans. It has various functions and is divided into three layers: It is used to close the pelvic outlet and to secure the position of the organs in the pelvis. – The anterior part of the pelvic floor (urogenital diaphragm),
- The posterior part of the pelvic floor (pelvis diaphragm) and
- The erectile tissue and sphincter layer.
Structure of the pelvic floor
1. anterior pelvic floor part: diaphragm urogenital It is formed by the musculus transversus perinei profundus and superficialis and represents a horizontal muscle plate. The deeper lying muscle transversus perinei profundus originates from the ischium (ramus ossi ischii) and the lower part of the pubic bone (ramus inferior ossis pubis). It has a trapezoidal structure when viewed from below and forms the supporting plate of the pelvic floor.
From the inside it lies on the superficial muscle transversus perinei superficialis. It originates from a bony protrusion of the ischium (tuber ischiadicum) and is formed from split fibres of the deep lying M. transversus perinei profundus. Together with the deep-lying muscle, the two muscles close the levator gate and thus support each other’s action.
Both muscles are innervated by the pudendal nerve which runs through the pelvis. 2. posterior part of the pelvic floor: pelvis diaphragm This forms a funnel-shaped muscle loop in the pelvis and is called the musculus levator ani. On closer examination, however, it becomes clear that this muscle is made up of several muscles.
The individual muscles usually get their name from their respective bone origin (M. puborectalis, M. pubococcygeus and M. iliococcygeus). The individual fibres then radiate into a common muscle plate and thus form the M. levator ani (innervated by branches of the sacral plexus). The central fibers of the large muscle form the so-called levator gate.
The urethra and, in women, the vagina, pass through this gate. Some fibres of the puborectalis muscle wrap around the rectum and connect to the fibres of the opposite side behind the rectum. This forms a muscle loop which is particularly important for maintaining continence.
During defecation, this muscle slackens. Another muscle of the pelvis diaphragm is the coccygeal muscle. It originates from a bony projection of the pelvic bone (spina ischiadica), attaches to the coccyx (Os coccygis) and strengthens the function of the muscle levator ani.
In some cases, however, this muscle may be missing. However, this does not lead to any symptoms or other abnormalities if the muscle levator ani functions without problems. 3. cavernous and sphincter layer It is formed by the ischiocavernosus muscle, the bulbospongiosus muscle and the sphincter ani externus muscle.
The perineal centre is located between the urogenital diaphragm and the rectum. It consists of taut connective tissue, tendons and fascia of the pelvic floor muscles and forms the mechanical centre of the muscular pelvic floor. – The musculus ischiocavernosus is also innervated by the nervus pudendus and serves to strengthen the erection.
In addition, it inhibits the backflow of blood from the penis or clitoris in men and women. This compression can be random and reflective. – The musculus bulbospongiosus causes rhythmic contractions during orgasm and thus triggers a pulsating pressure wave in the man’s urethral cavernous body and thus the ejaculation of semen during ejaculation.
This muscle can also be contracted reflectorically or arbitrarily. – The muscle sphincter ani externus is the external anal and sphincter muscle and can be contracted and relaxed at will. It is used for continence preservation or defecation.
With its muscular and connective tissue components, the pelvic floor forms the closure of the pelvic outlet and ensures that the organs lying in the pelvis are secured in position. The pelvic floor also has three main functions: Tension is important for maintaining continence in both men and women. The muscles of the pelvic floor provide significant support for the lower part of the urethra, the sphincters of the bladder and rectum.
When urinating or defecating, the pelvic floor must relax to allow emptying. In men, the pelvic floor also relaxes during an erection. During an orgasm, tension and relaxation alternate.
Reflective counterholding is necessary when coughing, sneezing, laughing, jumping or carrying heavy loads. This prevents reflective incontinence. – Tension
- Relaxation
- Reflective counterholding.
