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The Perineum. The perineum refers to the diamond-shaped region roughly extending between the coccyx and pubic symphysis Boundaries of the perineum Pubic symphysis ( anteriorly ) Inferior pubic rami and ischial rami ( anterolaterally ) Ischial tuberosities (laterally on each side)
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The Perineum • The perineum refers to the diamond-shaped region roughly extending between the coccyx and pubic symphysis • Boundaries of the perineum • Pubic symphysis(anteriorly) • Inferior pubic rami and ischialrami(anterolaterally) • Ischialtuberosities(laterally on each side) • Sacrotuberous ligaments (posterolaterally) • Tip of coccyx (posteriorly)
The Perineum • It is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. • is the region of the body inferior to the pelvic diaphragm and between the legs. • It is a diamond-shaped area on the inferior surface of the trunk that includes the anus and, in females, the vagina. • Its definition varies: it can refer to only the superficial structures in this region, or it can be used to include both superficial and deep structures. • The perineum corresponds to the outlet of the pelvis.
The Perineum • It is an erogenous zone for both males and females. • Perineal tears and episiotomy often occur in childbirth with first-time deliveries. • The anogenital distance is a measure of the distance between the anus and the base of the penisor vagina. • The human perineum is twice as long in males as in females. • Measuring the anogenital distance in neonatal humans has been suggested as a noninvasive method to determine male feminisation and thereby predict neonatal and adult reproductive disorders.
The Perineum • A line connecting the two ischial tuberosities divides the perineum in two triangular regions. • Urogenital region (triangle) • Pierced by: • Urethra • The vagina (female) • Serves as attachment site: • For the external genitalia • Contains: • The external genitalia • Anal region (triangle) • Contans: • Anal canal • Ischiorectal fossae
The Perineum • The perineum lies inferior to the pelvic floor between the lower limbs. Its margin is formed by the pelvic outlet. • An imaginary line between the ischialtuberosities divides the perineum into two triangular regions: • Anteriorly, the urogenital triangle • contains : • The roots of the external genitalia and, in women, the openings of the urethra and the vagina . • In men, the distal part of the urethra is enclosed by erectile tissues and opens at the end of the penis. • Posteriorly, the anal triangle contains the anal aperture.
The Perineum- Urogenital Region (Triangle) • Urogenital diaphragm • Formed by muscular shelf that stretches between the conjoint ischiopubic rami of the two sides. • It is pierced by the urethra and, in the female, also by the vagina. • Serves as a foundation for the attachment of the external genitalia. • Fascias attached to the urogenital diaphragm define two spaces of considerable anatomic and clinical importance. • Superficial perineal space • Deep perineal space
The Perineum • Urogenital diaphragm • Fascias attached to the urogenital diaphragm define two spaces of considerable anatomic and clinical importance. • Superficial perineal space • Deep perineal space
The Perineum- Urogenital Triangle • Superficial perineal space • is between superficial perineal (Colles’) fascia (continuation of Scarpa) and perineal membrane (the inferior fascia of the urogenital diaphragm).
The Perineum- Urogenital Triangle • Contents of superficial • perinealspace-FEMALE • Thelabiamajora • Thelabiaminora • Thebulb of thevestibule • Theclitoris • Thefemaleurethra • Greatervestibular (Bartholin’s) gland • Superficialtransverseperinealmuscle • Bulbospongiosusmuscle • Ischiocavernosusmuscle • Notethatthesemusclesareinvestedbythedeepperineal (investingorGallaudet’s) facia
The Perineum- Urogenital Triangle • Contents of superficial perineal space-FEMALE
The Perineum- Urogenital Triangle • Contents of superficial • perinealspace-MALE • Bulb of penis • Crus of penis • Superficialtransverseperinealmuscle • Bulbospongiosusmuscle • Ischiocavernosusmuscle • Notethatthesemusclesareinvestedbythedeepperineal (investingorGallaudet’s) facia
The Perineum- Urogenital Triangle • Contents of superficial perineal space-MALE
The Perineum- Urogenital Triangle • Contents of superficial • perinealspace in bothsexes • The superficial perineal muscles • Superficial transverse perineal muscle • Ischiocavernosus muscle • Bulbospongiosus muscle • Deep perineal fascia(investing fascia – Gallaudet’s fascia) • Invests the superficial perineal muscles • Branches of the internal pudendal vessels and pudendal nerves
The Perineum- Urogenital Triangle • Contents of superficial • perineal space in both sexes
The Perineum- Urogenital Triangle • Deep perineal space • is the space between the inferior and superior fascias of the urogenital diaphragm.
The Perineum- Urogenital Triangle • Deep perineal space • Is surrounded by the inferior and superior facias of the pelvic diaphragm. • Is completely closed. • It does not communicate with other perineal or pelvic spaces. • Superior facia of pelvic diaphragm forms the anterior recess of the ischiorectal fossa. • It is completely filled with the deep perineal muscles.
The Perineum- Urogenital Triangle • Contents of the deep perineal • pouch • In males • Membranous part of the urethra • Bulbourethral glands • In females • Proximal part of the urethra • Part of vagina
The Perineum- Urogenital Triangle • Deepperinealspace (pouch) • External urethral sphincter muscle • Deep transverse perineal muscles • Two muscles form the urogenital diaphragm • Thereforethedeepperinealpouchcontainstheurogenitaldiaphragmin bothsexes • Urogenitaldiaphragmis used to refer to a layer of the pelvis that separates the deep perinealpouchfrom the upper pelvis, such a discrete border of the sac probably does not exist
The Perineum- Urogenital Diaphragm • External urethral sphincter muscle • Deep transverse perineal muscles
The perineal membrane is related above to a thin space called the deep perineal pouch (deep perineal space), which contains a layer of skeletal muscle and various neurovascular elements. ThePerineum- DeepPerinealSpace (Pouch) FEMALE MALE
The Perineum- Anal Region (Triangle) • Pelvic diaphragm • Formed by levator ani and coccygeus mucles. • Contains: • Ischiorectal (ischioanal) fossa • Pudendal canal • Anal canal • External anal sphincter
The Perineum- Anal Region (Triangle) • Levator ani muscle • Puborectalis • Pubococcygeus • Iliococcygeus
The Perineum- Anal Region (Triangle) • Levator ani muscle • Originatesalong a semicircularlinethatskirtsthepelvicwallsfromthepelvicsurface of the body of thepubistotheischialspine. • Attachesto a bandlikereinforcement in theobturator facia , arcustendineus (tendinousarch of thelevator ani) andperinealstructures. • Thefibers of themusclesweepbackward as well as downwardwithvaryingdegrees of obliquity.
ThePelvicDiaphragmandItsComponents Levator Prostatae or Sphincter Vaginae Sphincter Vaginae (or Levator Prostatae) Pubic Symphysis Urethra Vagina Puborectalis Rectum Pubococcygeus Puborectalis Perineal Body Pubococcygeus Obturator Internus Coccyx Iliococcygeus Coccygeus Iliococcygeus Coccygeus Coccyx Sacrum Superior View Inferior View
The Perineum • Perineal body (central tendon of perineum-centrum tendineum): • The midpoint of the line joining the ischial tuberosities. • Located in the median plane anterior to the anal canal and inferior to the inferior fascia of the urogenital diaphragm (perineal membrane) • Lies deep to the subcutaneous tissue.
The Perineum • Perineal body • Contains collagenous and elastic fibers, as well as smooth and skeletal muscle fibers. • The attachment point of several perineal muscles: • Bulbospongiosus • External anal sphincter muscle • Superficial and deep transverse perineal muscles
The Perineum • Perineal body(central tendon of perineum-centrum tendineum): • The midpoint of the line joining the ischial tuberosities. • Located in the median plane anterior to the anal canal and inferior to the inferior fascia of the urogenital diaphragm (perineal membrane) • Lies deep to the subcutaneous tissue. • Contains collagenous and elastic fibers, as well as smooth and skeletal muscle fibers. • The attachment point of several perineal muscles: • Bulbospongiosus • External anal sphincter muscle • Superficial and deep transverse perineal muscles
Sphincter of urethra (male) or urethrovaginal sphincter (female) Bulbocavernousus Deep transverse muscles of perineum Superficial transverse muscle of perineum Levator ani Sphincter ani externus The Perineum
The Episiotomy • is an incision of the perineum to enlarge the vagina for childbirth. • This incision can be midline, from vagina to the anus or be a midlateral incision, from vagina to the thigh. • The importance of this incision is described in degrees. A first degree means that only the skin and mucous membranes are affected. • In the case of a second or a third degree perineal muscles are cut too. It is not uncommon that the cut extends to reach and even tear the anal sphincter (fourth degree). • Episiotomies are practice with a pair of scissors, just before the release of the baby's head.
The Perineum- Anal Region (Triangle) • Ischiorectal (ischioanal) fossa • Roughlywedgeshapedspaces on eachside of the anal canal. • The anal canalandperineal body separatethefossae of thetwosides. • Theonlycommunicationbetweenthem is posteriorlythrough a narrowpotentialspacelocateddeeptothefibers of thesphincter ani externus.
The Perineum- Anal Region (Triangle) • Ischiorectal (ischioanal) fossa • Lateralwall: • Moreorlessvertical, formedbytheobturatorinternusmuscle. • Base: • Perineal skin • Superomedialwall: • Is slopingandformedbythelevator ani muscle. • is sealedoffabovebythefusion of theinferior facia of thepelvicdiaphragmtotheobturator facia.
ThePerineum- Ischiorectal Fossa • Laterallyboundedbytheobturatorinternusmusclesandfasciacovering it • Pudendalcanallies on thiswall • Mediallyboundedbythe external anal sphincter • Posteriorlyboundedbythegluteusmaximusmuscle • Anteriorlyboundedbythebodies of thepubicbones
The Perineum- Anal Region (Triangle) • Pudendalcanal • Formation: • Thefacialsheath of thenerveandvessels is fusedtotheobturatorfasciaand is calledthepudendalcanal. • Contents: • Pudendalnerve • Internalpudendalartery • Internalpudendalvein
The Perineum- Anal Region (Triangle) • Pudendalcanal • Formation: • Thefacialsheath of thenerveandvessels is fusedtotheobturatorfasciaand is calledthepudendalcanal. • Contents: • Pudendalnerve • Internalpudendalartery • Internalpudendalvein
ThePerineum- PudandalBlock • The pudendal nerve is within the pudendal canal as the nerve wraps itself around the ischial spine and before it sends out its branches. • The palpating finger is used to locate the ischial spine and sacrospinous ligament per vaginam. • The needle is inserted through the vaginal wall, is directed towards the spine and then passed through the sacrospinous ligament. • As soon as the needle has passed through the ligament, a loss of resistance is felt. At this point anaesthetic solution is injected.
