Pelvis and Pelvic floor Flashcards
What is the pelvic inlet?
Rostral opening of the pelvis
What are the borders of the pelvic inlet?
Posterior: sacral promontory (the superior portion of the sacrum) and sacral wings
Lateral: arcuate line on the inner surface of the ilium, and the pectineal line of the superior pubic ramus.
Anterior: pubic symphysis.
What does the sacrotuberous ligament attach?
Sacrum to ischial tuberosities
What does the sacrospinous ligament attach?
Sacrum and coccyx to ischial spine
What spaces to the sacrotuberous and sacrospinous ligaments form?
The greater and lesser sciatic foramina
How does the pudenal nerve pass through the pelvis?
Passes through the greater sciatic foramen and gains access to the perineal muscles inferior to the pelvic floor by passing through the lesser sciatic foramen.
Which nerve passes through both the lesser and greater sciatic foramen?
Pudenal
What is the pelvic outlet?
Caudal opening of the pelvis
What are the borders of the pelvic outlet?
Posterior: The tip of the coccyx
Lateral: The ischial tuberosities and the inferior margin of the sacrotuberous ligament
Anterior: The pubic arch
What is the angle between the pubic arch known as and how does it vary between men and women?
Sub-pubic angle
Greater in women
The female sub-pubic angle is greater than __ degrees?
80
Where do the muscles of the pelvic floor all partly attach?
The fascia covering the obturator internus
Where does the perineum lie in relation to the pelvic floor?
Beneath
What two features make up the perineum?
The perineal body and the perineal membrane
What is the perineal body?
The perineal body is a ‘node’ or ‘knot’ of fibrous tissue
Where does the perineal body lie in relation to the pelvis bones?
Midline between the two ischial tuberosities
What is the perineal body and important site of attachment for?
Levator ani muscles and muscles of the perineum
What muscle forms the muscular pelvic floor?
Skeletal muscle (somatic)
What is the role of the pelvic floor?
Supports and maintains the position of pelvic viscera and has an important role in anal continence and defecation.
What muscles make up the pelvic floor?
Left and right levator ani (composed of pubococcygeus, puborectalis and iliococcygeus)
Right and left coccygeus muscles
What does the levator ani attach to?
The posterior surface of the body of the pubis
The fascia covering obturator internus
The spine of the ischium.
What are the three fibres of the levator ani?
Anterior fibres Intermediate fibres (puborectalis and pubococcygeus) Posterior fibres (iliococcygeus)
What do the anterior fibres attach to/form a sling around?
Form a sling around the prostate/vagina and are attached to the perineal body.
What does the puborectalis of the intermediate fibres form a sling around and where does the pubococcygeus attach?
Puborectalis fibres form a sling around the junction between the rectum and anal canal.
Pubococcygeus passes to the coccyx
Where does the posterior fibres/iliococcygeus attach?
Coccyx
What are the attachments of the coccygeus muscle?
Attached from the ischial spine to the junction of the sacrum and the coccyx.
What is the role of coccygeus muscle
Coccygeus assists levator ani in supporting the pelvic viscera.
Muscles and ligaments provide support, normally preventing the pelvic viscera from passing through the pelvic outlet (prolapse).
What is the perineum divided into?
A urogenital triangle and an anal triangle
What divides the anal and urogenital triangles?
The line joining the two ishcial tuberosities
What does the peritoneal membrane consist of?
Strong connective tissue
In the urogenital triangle what lies deep to the peritoneal membrane?
Striated muscle, the sphincter urethrae, external urethral sphincter
What perforates the tissues of the urogenital triangle in both males and females?
Urethra
What perforates the tissues of the urogenital triangle in females only?
Urethra and vagina
What is the superficial perineal pouch?
Anatomical space that lies below the perineal membrane and above the perineal fascia
What are the perineum pouches in the anal triangle called and where are they located?
Ischioanal fossae, one each side of the anal canal
Where is the perineal body located in males?
Lies in the midline between the deep and superficial perineal spaces anteriorly and the anal canal posteriorly.
Where is the perineal body located in the female?
Lies in the midline, between the lower end of the vagina and the anal canal.
In females where is the deep perineal pouch?
Deep perineal space lies inferior to the pelvic floor but superior to the muscles of the deep pouch and the perineal membrane
What does the deep perineal pouch contain in women?
External urethral sphincter / sphincter urethrae muscle
Compressor urethrae muscle (CU)
Deep transverse perineal muscles
In women, what lies in the superficial perineal space?
Lower end of the vagina, and on either side, the bulb of vestibule (erectile tissue)
What muscles make up the superficial perineum in women?
Small superficial transverse perineal muscle, the ischiocavernosus muscle and the bulbospongiosus muscle.
In males where is the deep perineal pouch?
Lies inferior to the pelvic floor but superior to the muscles of the deep pouch and the perineal membrane.
What muscles does the male deep perineal pouch contain?
External urethral sphincter and the deep transverse perineal muscles.
In males what muscles make up the superficial perineum?
Ischiocavernosus
Bulbospongiosus
Superficial transverse perineal muscles
What shape is the female and male obturator foramen?
Male, oval
Female, triangular
What forms the posterior part of the floor?
Coccygeus
What lies anterior to the sacrospinous ligament?
Coccygeus
What is the anococcygeal raphe?
A musculotendinous structure passing between the anterior coccyx and the posterior anus
What are the key arteries of the pelvis/ branches of the internal iliac?
Internal iliac, superior gluteal, inferior gluteal, obturator, internal pudendal
Internal iliac supplies?
Pelvic walls viscera, external genitalia, perineum, buttock, medial thigh
Superior gluteal supplies?
Gluteus medius, gluteus minimus, tensor fasciae latae
Inferior gluteal supplies?
Gluteus maximus, piriformis, quadrator femoris
Obturator artery supplies?
Obturator externus, adductor compartment, femur
Internal pudendal artery supplies?
External genitalia, perineum
How does the pudendal nerve travel?
Exit pelvis through greater sciatic foramen and enters perineum via lesser sciatic foramen
Innervates perineum
Coccygeal plexus roots
S4-S5
What are the pelvic plexuses (inferior hypogastric plexuses)?
Autonomic and give both sympathetic and parasympathetic
What contributes to the pelvic plexi?
Superior hypogastric (symp) sacral splanchnic (symp) and pelvic splanchnic (para)
