Male Pelvic Anatomy
Top Contributors - Stacy Schiurring, Kim Jackson, Lucinda hampton and Jess Bell
Introduction[edit | edit source]
Knowing the theory of the anatomy and the physiology of the male pelvis is the first step in becoming clinically competent. -Pierre Roscher PT
It is essential to have some sort of pelvis model when treating men’s health patients to aid in understanding and comfort with treatment concepts and interventions. It is a powerful teaching aid. A 2018 study by Meyer et al. found that the use of a virtual 3D pelvis model during the training of medical professions was effective and valid in learning needed anatomy. These findings suggest that a virtual 3D pelvis model, such as on a smart phone or computer app, could be used in the clinic as part of patient education when a physical model is not available.
Follow this link to PhysioSkills for a free printable model of the pelvic floor muscles.
Pelvis Musculoskeletal Overview[edit | edit source]
The pelvis does not function alone. It is highly interconnected with the musculoskeletal features of the hips and the gluteal musculature. Together, these areas support the internal organs and core muscles. The physiology of the male pelvic floor involves pelvic organ support, bowel and bladder control and sexual functioning. This article will focus on the male pelvis as associated with the pelvic floor. For more information on the greater pelvic girdle, please read here.
Osteology[edit | edit source]
The human pelvis is a bony ring formed by two bilateral innominate bones, made from the ilium, ischium, and pubis, and the sacrum. The innominates articulate with each other anteriorly at the pubic symphysis and posteriorly with the sacrum at the sacroiliac joints. The coccyx extends from the distal sacrum and functions as an attachment to ligaments and tendons.
The stability of the pelvis comes from two mechanisms: force closure and form closure. Form closure stability comes from the anatomy of the pelvis, through the interconnections of the bony surfaces themselves. Force closure comes from the compressive forces of the muscles, ligaments, and fascia.
Ligaments of the Male Pelvis[edit | edit source]
- composed of thick and strong fibrous bands of connective tissue originating from the L5 transverse process to the posterior part of the inner lip of the iliac crest
- functions to stabilise and strengthen the lumbosacral joint, and limit the rotational movement at the lumbosacral joint
- dysfunction can lead to back pain
- composed of a triangular band of connective tissue that attaches to the ischial spine of the ischial bone and the lateral side of the sacrum and coccyx
- the sacrospinous ligament divides the greater sciatic notch to the greater sciatic foramen and the lesser sciatic foramen
- composed of a fan-shaped fibrous band of connective tissue that attaches to the sacrum and the upper coccyx to the tuberosity of the ischial tuberosity
- location of possible pudendal nerve entrapment
Muscles of the Male Pelvic Floor[edit | edit source]
The male pelvic floor muscles make up a dome-shaped structure in the pelvis, similar to a hammock. The male pelvic floor is made up of three layers: deep, middle, and superficial, and has a complex relationship with the surrounding bony pelvis, fascia, ligaments and nerves.
Superficial Layer of the Male Pelvic Floor[edit | edit source]
The muscles of the superficial layer include the bulbospongiosus, ischiocavernosus, and superficial transverse perineal. The external anal sphincter is also found in this layer. The superficial muscles are particularly involved in ejaculation as well as urinary and faecal continence.
Middle Layer of the Male Pelvic Floor[edit | edit source]
The middle layer is comprised of the perineal membrane, the deep transverse perineals, the sphincter urethrae and the compressor urethrae. This layer is particularly responsible for urinary continence when there is increased intraabdominal pressure (eg coughing or sneezing).
Deep Layer of the Male Pelvic Floor[edit | edit source]
The muscles of the deep layer include: the levator ani, iliococcygeus, pubourethralis, and ischiococcygeus. These muscles are particularly responsible for the support of pelvic organs and maintenance of continence. The deep layer is also known as the pelvic diaphragm.
The levator ani is composed of three muscles: puborectalis, pubococcygeus, and iliococcygeus. The puborectalis forms a U-shaped sling around the rectum and, through a sphincter-like action on the anorectal junction, contributes to faecal continence. Of clinical relevance for activities of daily living: sitting with a forward lean and legs supported in a squat-like position is the ideal positioning for defecation due to this anatomical sling.
Not technically part of the pelvic floor, the piriformis is also present in the deep layer originating on the anterior sacrum. The piriformis can influence movement control around the pelvis: with a fixed sacrum, the piriformis laterally rotates an extended thigh, or abducts a flexed thigh. If the legs are fixed, it retroverts the pelvis. It is a possible source of pelvic pain.
The following short video shows a basic overview of the male pelvic floor muscles and a demonstration of their muscle contractions to control continence.
Innervation of the Male Pelvic Floor[edit | edit source]
The pelvic floor has parasympathetic, sympathetic and somatic nerve supply. This means there is both voluntary and involuntary control of the area.
Arising from S2-4 of the sacral plexus, the pudendal nerve passes between the piriformis and coccygeal muscles which can be a source of entrapment. There are 3 main branches of the pudendal nerve: the inferior rectal nerve, the perineal nerve, and the dorsal nerve of the penis. The pudendal nerve controls a wide variety of functions and sensory input. It innervates the penis, the bulbospongiosus and ischiocavernosus muscles, the perineum, the anus and the external anal sphincter, and the urethral sphincter. The pudendal nerve is involved in external genital sensation, bowel and bladder continence, orgasm, and ejaculation.
Peter Dornan PT published a map of the pudendal nerve which outlines different dysfunctions of each of the three branches and how it influences pelvic pain. This can be very useful in differential diagnosis for pelvic pain.
The Pelvic Pain Foundation of Australia shares information on pudendal neuralgia (PN) as well as a useful diagram adapted from Peter Dornan's work.
Urogenital System[edit | edit source]
The urogenital system in males has a common passage for both the urinary and reproductive systems. The urinary system includes: the kidneys, ureters, bladder and urethra. This system is responsible for removing waste from the body in the form of urine.
Bladder[edit | edit source]
The bladder is a storage organ for urine. The average bladder capacity for an adult is 800-1000mL. The need for bladder voiding is controlled by a stretch reflex of the detrusor muscle which is located in the walls of the bladder.
Normal continence is maintained when the closure pressure of the urethra is greater than the pressure from the bladder above it. It requires the complex interaction between the autonomic nervous system that controls the more proximal smooth muscles in the urethra (internal sphincters) as well as the somatic nervous system that controls the striated muscles surrounding the urethra (external sphincter).
Urethra[edit | edit source]
The average urethra is 15 to 17 cm long, measured from the base of the bladder to the exit of the penis. The urethra can be divided into three sections: prostatic, membranous, and penile urethra. Urethral length dictates full penile length possibilities in many men.
Prostate[edit | edit source]
The prostate is a gland which produces seminal fluid. This fluid nourishes and transports sperm. The prostate is directly inferior to the bladder and anterior to the rectum. It is surrounded by a capsule that contains the cavernous nerves, which play a direct role in erection production.
Sphincters[edit | edit source]
A sphincter is a cylindrical muscles that closes around a structure. The two sphincters of the male pelvic floor which control urinary continence are made up of the pelvic floor muscles where they encircle the urethra as it travels through the prostate.
Between the bladder and the prostate is the internal urethral sphincter, which is made of smooth muscle and is under autonomic control. Below the prostate is the external urethral sphincter which is made of skeletal striated muscle and is under voluntary control.
Micturition occurs when the bladder detrusor contracts and the internal sphincter relaxes through involuntary autonomic nervous control. The muscles of the pelvic floor voluntarily relax to open the external sphincter and allow urine to flow out of the body. The coordination of these muscular actions for sphincter control is essential for urinary continence.
External Genitalia[edit | edit source]
Penis[edit | edit source]
The penis is the external organ of the male reproductive system and has two functions:
- Sexual intercourse
The average penis length is 9-10 cm at rest and 12 to 16 cm when erect. The average girth is 9-10 cm at rest and 12 centimetres erect. The average urethra is 15 to 17 cm long.
The penis can be divided into three anatomical sections:
- Root – contains 3 erectile tissues and two muscles, the bulbospongiosis and the ischiocavernosus, which play an important role to play in the stability of an erection as well as the trapping of blood into the penile tissues. The root of the penis is supported by the suspensory ligament and the fundiform ligament.
- Body – suspended from the pubic symphysis and contains 3 cylinders of the erectile tissue. The three cylinders include: the corpus spongiosum, which contains the urethra, and two corpus cavernosum. These three chambers work together in different pressure scenarios to maintain an erection by trapping venous blood in the erectile tissues.
- Glans – contains the opening of the urethra.
The penis itself is surrounded by connective tissue layers, some of which extend into the abdominal wall. The most superficial fascial layer is called Colles Fascia or the External Fascia of Colles. The deeper fascia is known as Buck’s Fascia or the Deeper Fascia of the Penis. This deep layer contains the corpora cavernosa and a corpus spongiosum of the penis.
The penis innervation is supplied by the S2-S4 spinal cord segments and has sensory and sympathetic innervation supplied to it by the dorsal nerve of the penis a branch of the pudendal nerve. Parasympathetic innervation is carried by cavernous nerves from the peri-prostatic nerve plexus, and is responsible for the vascular changes which causes penile erection.
Normal sexual function is a coordinated effort of the pelvic floor muscles, genitalia, and autonomic nervous system. The male sexual response is controlled by the autonomic nervous system, with the parasympathetic division responsible for the excitement phase and the sympathetic division responsible for the orgasm phase. Penile erection is under parasympathetic control, allowing the smooth muscle of the corpus cavernosa to relax and fill with blood, while the perineal striated pelvic floor muscles contract to promote rigidity. Seminal emission is under sympathetic control. Ejaculation is primarily a spinal cord reflex.
Scrotum[edit | edit source]
The scrotum is a fibro-muscular cutaneous sack located between the penis and the anus. It is a dual chambered structure forming an expansion of the perineum and has a midline separation of connective tissue called the scrotal raphe. The scrotum contain a set of testes which produce sperm. Located on the head of each testicle is the epididymis which stores sperm. The testicles are suspended from the abdomen by the spermatic cord. During ejaculation, sperm travel along two tubes called the vas deferens and the seminal vesicles. The seminal vesicles are attached to the prostate. Where the vas deferens meet the seminal vesicles is called the ejaculatory duct.
Smooth muscle fibres of the dartos muscle located within the scrotum help regulate testes temperature by wrinkling of the skin of the scrotum to manage heat exchange.
The blood supply and the lymphatic drainage of the scrotum and the testes differ due to their locations during embryonic development. The testes are originally located on the posterior abdominal wall but during embryonic development they descend down the abdomen through the inguinal canal to reach the scrotum. Therefore, they keep their neuro-vascular and lymphatic supply from the abdomen.
Rectum[edit | edit source]
The rectum is the most distal segment of the large intestine and it has an important role in temporary faecal storage. It is a continuation of the sigmoid and it terminates distally in the anal canal. The rectum should normally be empty, and it is a sign of constipation if there is any faecal matter present during a rectal exam. 
The rectum is highly innervated. It receives sympathetic innervation as well as parasympathetic innervation from visceral afferent fibres.
Defecation occurs when the anal sphincter and puborectalis muscles relax simultaneously to open the rectoanal angle and allow faeces to pass. Abdominal muscles contract during a Valsalva action to increase abdominal pressure to assist with bowel movements. Anal sphincter relaxation is an autonomic nervous system reflex, mainly under parasympathetic control. The muscles of the pelvic floor and abdomen are under voluntary control to allow defecation to occur in a socially acceptable time and place.
Resources[edit | edit source]
Virtual anatomy apps[edit | edit source]
- Visible Body: computer based; free trial
- 3D Anatomy Learning: apple, google; free
- ANATOMY 3D ATLAS: macOS, Windows, iPhone, iPad, Android; free to download with in-app purchases
- Complete Anatomy 2022: macOS, Windows, iPhone, iPad, Android; free trial
Printable 3D paper pelvic floor model[edit | edit source]
References[edit | edit source]
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 Roscher, P, Men's Health. Male Pelvic Anatomy. Plus. February 2022.
- ↑ Meyer ER, James AM, Cui D. Hips Don't Lie: Expert Opinions Guide the Validation of a Virtual 3D Pelvis Model for Use in Anatomy Education and Medical Training. HAPS Educator. 2018 Aug;22(2):105-18.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 Eickmeyer SM. Anatomy and physiology of the pelvic floor. Physical Medicine and Rehabilitation Clinics. 2017 Aug 1;28(3):455-60.
- ↑ 4.0 4.1 4.2 4.3 4.4 Chaudhry SR, Imonugo O, Chaudhry K. Anatomy, Abdomen and Pelvis, Ligaments. InStatPearls [Internet] 2021 Jan 21. StatPearls Publishing.
- ↑ Knol‐de Vries PhD GE. Exploring pelvic floor muscle function in men with and without pelvic floor symptoms: A population‐based study. 2022.
- ↑ 6.0 6.1 6.2 Cohen D, Gonzalez J, Goldstein I. The role of pelvic floor muscles in male sexual dysfunction and pelvic pain. Sexual medicine reviews. 2016 Jan 1;4(1):53-62.
- ↑ George SE, Borello-France DF. Perspective on physical therapist management of functional constipation. Physical therapy. 2017 Apr 1;97(4):478-93.
- ↑ Youtube. Male Pelvic Floor Muscle - 3D animation. Available from: https://www.physio-pedia.com/index.php?title=Male_Pelvic_Anatomy&action=edit [last accessed 27/02/2022]
- ↑ Wyndaele JJ. Sensation and Pelvic Floor. InSensation in the Pelvic Region 2022 Nov 19 (pp. 117-126). Cham: Springer International Publishing.
- ↑ 10.0 10.1 10.2 Shermadou ES, Rahman S, Leslie SW. Anatomy, Abdomen and Pelvis, Bladder. In: StatPearls. StatPearls Publishing, Treasure Island (FL); 2020. PMID: 30285360.
- ↑ Hodges PW, Stafford RE, Hall L, Neumann P, Morrison S, Frawley H, Doorbar-Baptist S, Nahon I, Crow J, Thompson J, Cameron AP. Reconsideration of pelvic floor muscle training to prevent and treat incontinence after radical prostatectomy. InUrologic Oncology: Seminars and Original Investigations 2019 Dec 25. Elsevier.
- ↑ Capogrosso P, Ventimiglia E, Cazzaniga W, Stabile A, Pederzoli F, Boeri L, Gandaglia G, Dehò F, Briganti A, Montorsi F, Salonia A. Long‐term penile morphometric alterations in patients treated with robot‐assisted versus open radical prostatectomy. Andrology. 2018 Jan;6(1):136-41.
- ↑ Campbell J, Gillis J. A review of penile elongation surgery. Translational Andrology and Urology. 2017 Feb;6(1):69.
- ↑ 14.0 14.1 Serra J, Pohl D, Azpiroz F, et al. European society of neurogastroenterology and motility guidelines on functional constipation in adults. Neurogastroenterol Motil. 2020;32(2):e13762.