The Pelvic Floor and Its Relationship to the Psoas
By Evan Osar
The pelvic floor is an important myofascial structure in the stabilization of the thoracopelvic cylinder (TPC) as well in bowel, bladder, and sexual functions. Until recently not much attention had been paid to the pelvic floor, and millions of individuals suffered in silence with incontinence and sexual dysfunction, and with stabilization issues of the TPC and hips. The pelvic floor has now garnered the much-needed attention it deserves, and there has been an advent of pelvic floor specialists to address these pelvis- related issues. While it is beyond the scope of this book to discuss this topic in depth, it is worth noting how the pelvic floor functions in conjunction with the psoas in stabilization and posture.
￼￼￼￼￼￼Functional Anatomy of the Pelvic Floor
The pelvic floor is arranged in three layers:
(1) the endopelvic fascia,
(2) the pelvic diaphragm, and
(3) the urogenital diaphragm (Carrière 2002):
• The first layer, or endopelvic fascia, comprises smooth muscle, fascia, and ligaments that support the pelvic organs.
• The second layer is referred to as the pelvic diaphragm. The primary muscle of this layer, the levator ani, is considered by Carrière to be the most important in this region. The other muscles within this layer are: pubococcygeus, puborectalis, pubovaginalis (in females), levator prostatae (in males), iliococcygeus, coccygeus, and internal sphincter muscles of the bladder and rectum. This layer contains approximately 70% slow-twitch fibers and 30% fast-twitch fibers; it is primarily responsible for continence (control of urine and feces) and for supporting the anus, vagina, and prostate and the stability of the sacroiliac joint.
• The third layer, referred to as the urogenital diaphragm, consists of several muscles:
deep transverse perineal, superficial transverse perineal, bulbospongiosus, ischiocavernosus, and anal sphincter. These muscles support the levator ani, continence, and sexual function.
Role of the Pelvic Floor
There are three primary functions of the pelvic floor muscles:
1. Pelvic organ support. The pelvic floor supports the pelvic organs. The muscles of the pelvic floor must be strong enough to eccentrically contract to control the descent of the pelvic organs during inhalation, and then lift the organs back up during exhalation. When lifting, coughing, sneezing, and/or laughing, these muscles must quickly contract to maintain bowel and bladder continence.
2. Sphincter control. The pelvic floor muscles control the bladder and anal sphincters to ensure continence; when relaxed they allow urination and defecation. These muscles also support healthy function of the sexual organs.
3. Pelvic and hip stabilization. The pelvic floor muscles work with the respiratory diaphragm, psoas, and abdominal muscles to regulate internal pressure, which helps stabilize the pelvis and hips. In the breathing chapter (Chapter 2) it was discussed how the diaphragm and pelvic floor work in tandem—they lower during inspiration and rise during expiration. Additionally, in individuals with no evidence of pelvic floor muscle dysfunction, the pelvic floor and transversus abdominis co-activate to stabilize the lumbopelvic-hip complex (Sapsford et al. 2001).
As discussed in the functional anatomy chapter (Chapter 1), the psoas fascially blends into the pelvic floor. While there has been no research carried out to evaluate the combined roles of the psoas and pelvic floor, it is hypothesized that the psoas helps stabilize the lumbar spine and pelvis, so that contraction of the diaphragm and pelvic floor are coordinated and efficient (Osar 2015).
Signs of Non-optimal Use of the Pelvic Floor
There are three primary signs that indicate non-optimal function of the pelvic floor:
1. Urinary incontinence. Leakage of urine is the most common sign of pelvic floor dysfunction. It is often thought that incontinence is an issue that affects women only after childbirth and as they age. However, studies have shown incontinence to be common in elite nulliparous (never having given birth) female athletes, with a reported rate of occurrence of 28–45% (Poswiata et al. 2014, Thyssen et al. 2002, Nygaard et al. 1994). Pelvic floor training has been shown to improve pelvic floor function and continence in most populations that have been prescribed specific exercises to target these particular muscles.
2. Hip gripping and posterior pelvic tilt. As discussed in Appendix VI (Sitting), a slumped posture—posterior pelvic tilt and lumbar spine flexion—is extremely common in many people when sitting. Posterior hip gripping (superficial gluteus maximus, hip rotators, and/or hamstrings) and superficial abdominal gripping (external/internal obliques
and rectus abdominis) respectively pull the pelvis into a posterior pelvic tilt and flex the lumbar spine. Either of these conditions makes it impossible to assume an upright sitting posture without compensating by overextending in the thoracic spine. This undesirable sitting strategy perpetuates muscle imbalances, including inhibition of the psoas and pelvic floor, which subsequently lead to non-optimal TPC stabilization and breathing dysfunction.
Interestingly, individuals standing in a hypolordotic posture (generally associated with a posterior pelvic tilt) demonstrated a higher resting tone of the pelvic floor, suggesting overactivity of these muscles, than when standing in either a neutral or hyperlordotic posture (Capson et al. 2011).
Retraining control of neutral alignment in a variety of positions can improve the function of not only the pelvic floor but also the psoas. As reported by Sapsford et al. (2008), both continent and incontinent women who sat more upright (i.e. assumed a position approximating neutral lumbar spine and pelvic alignment) tended to have greater pelvic floor activation than those who sat in a slumped posture. In this book several strategies have been discussed for improving alignment and control of the lumbar spine, pelvis, and hips, as well as for restoring function of the deep myofascial system (DMS) (e.g. psoas, transversus abdominis, and pelvic floor).
3. Pelvic pain syndrome. Pelvic pain syndrome (PPS) includes pain that originates from the joints, myofascia, or organs within the pelvis. PPS affects the ability to optimally recruit the pelvic floor, and can also impact breathing and activation of the DMS. Most individuals experiencing PPS require the services of a pelvic floor specialist to address the pain component as well as identify the cause. Specific retraining of the pelvic floor muscles (the entire DMS), restoring three-dimensional breathing, and incorporating the corresponding strategies into the activities of daily living and exercise can help those individuals improve function and reduce symptoms.
Improving activation of the pelvic floor as part of an overall core stabilization strategy was discussed in the breathing chapter (Chapter 2). For more detailed information on this topic, readers are encouraged to consult the works of Lee (2012), Hodges et al. (2013), Richardson et al. (2004), Sapsford et al. (2008, 2001), and Carrière (2002).
Taken from, The Psoas Solution: The Practitioner’s Guide to Rehabilitation, Corrective Exercise, and Training for Improved Function, Evan Osar, published by Lotus Publishing, 2017. Order from amazon. co.uk, price £14.99, 978 1 905367 78 8