Non-reproductive features of the Pelvis and Perineum Flashcards
What type of joint in the sacroiliac joint?
Synovial Joint
What type of joint is the pubic symphysis?
Secondary cartilaginous joint
What are the three main parts of the pelvis?
Ischium, pubic, ilium
What is the name of the surface that articulates with the head of the femur?
Acetabular fossa
What is considered the ‘true pelvis’?
Within the pelvic inlet.
What constitutes the pelvic wall?
Sacrum, coccyx and pelvic bones
What are the two main ligaments in the true pelvis?
Sacrospinous (sacrum to the ischial spine)
Sacrotuberous (sacrum to the ischial tuberosity)
Describe the orientation of the pelvic cavity.
The axis of the pelvic cavity is at a 45 degree angle to the axis of the abdominal cavity
Which muscle lines most of the pelvic bone facing the pelvic cavity?
Obturator internus
Where does the obturator internus insert and what other muscle inserts here?
Medial surface of the greater trochanter of the femur - the piriformis also inserts here
What muscle overlays the sacrospinous ligament?
Coccygeus muscle
What are the three main muscles of the pelvic floor and what are they called collectively?
Iliococcygeus muscle
Pubococcygeus muscle
Puborectalis muscle
These muscles make up Levator Ani
What forms the border between the obturator internus and the levator ani?
Tendinous arch of obturator internus fascia
What other ligament is found in these group of muscles?
Anococcygeal ligament
What is the nerve supply to the levator ani?
Pudendal nerve (S2-S4) and directly from S4
What are the openings in the levator ani?
Urethra, vagina and anus
What is the structure that is formed by the levator ani?
Pelvic diaphragm
What is the name of the fat-filled space between the levator ani and the obturator internus in a male?
Ischio-anal fossa
What are the two sphincters in the urethra of a male?
Internal urethral sphincter
External urethral sphincter
What are the four parts of the male urethra? How long is it?
Preprostatic, prostatic, membranous and spongy
20 cm
Describe the arrangement of the uterus and the bladder in women.
The uterus sits on top of the bladder
What is different about the urethral sphincters in women?
Women have a poorly organised internal sphincter.
External urethral sphincter is skeletal muscle surrounding the urethra in the deep perineal pouch.
Where is the external urethral sphincter of women found?
In the deep perineal pouch
What are two additional groups of muscle found in females?
Sphinter urethrovaginalis
Compressor urethrae
Describe the shape of an empty bladder.
Tetrahedral
What are the structures are each corner of the tetrahedron?
The posterior vertices have the ureters coming from them. The anterior vertex has the median umbilical ligament. The posterior inferior vertex has the urethra coming from it.
Describe the structure of the rectum.
It has a double S bend. There are three transverse rectal folds (superior, middle and inferior). Keeps the load off the sphincter.
What vessels supply the rectum?
Superior, middle and inferior rectal arteries
Which nerves supply the rectum and which nerves supply the anal canal?
Rectum - autonomic nerves
Anal canal - somatic nerves
Which muscle is most important for faecal continence and what does it do?
Puborectalis muscle - it puts a sharp angle into the recto-anal junction.
What could badly injure this muscle?
Episiotomy
What main blood vessels supply all the pelvic organs?
Internal iliac artery
What is the auricular surface? What type of joint forms between the two?
The surfaces of the ilium and sacrum that articulate with each other - a synovial joint forms between the two
