GI Anatomy 6 Flashcards
What is the perineum and what are its superior and inferior boundaries?
Space superficial to the pelvic floor, most made up of fat but has some important nerves and vessels running through it
Bounded superiorly by the pelvic floor and inferiorly by the skin
What is the difference between the pelvic cavity and the greater pelvis?
Pelvic cavity is bounded superiorly by the pelvic inlet
Greater pelvis is the area superior to the pelvic inlet but inferior to a line joining the 2 ASIS
What is the ischial spine?
Bony prominence of the pelvic bone between the greater and lesser sciatic notches
Where is the ischial tuberoscity?
Bony prominence on the internal surface of the ischium
The sacrospinous ligament runs from where to where and creates which foramen?
From the sacrum to the ischial spine, creates the greater sciatic foramen
The sacrotuberous ligament runs from where to where and creates which foramen?
From the sacrum to the ischial tuberoscity and forms the lesser sciatic foramen
What is the difference between the obtruator foramen and the obtruator canal?
Obturator foramen is the entire hole in between the ischial and the pubic rami of the pelvic bone, the obtruator foramen has a membrane lining it called the obtruator membrane which leaves a small opening in the obtruator foramen called the obtruator canal
On what does the obtruator muscle lie?
Deep to the obtruator membrane
What lies deep to the obtruator muscle?
The obtruator fascia
What are the 3 functions of the pelvis?
1) Provide a surface for muscle attachments: muscles of the trunk and lower limb
2) Transfers the weight of the trunk to the lower limbs when standing and the ischial tuberosity when sitting
3) Protect pelvic organs and the developing embryo/foetus
What 2 parts of the pelvis lie in the same vertical plane in anatomical position?
ASIS and the pubic tubercles
What forms the lateral walls of the pelvis?
Obtruator muscle
Levator ani muscle
Piriformis muscle
What forms the posterior (posterior-superior) wall of the pelvis?
Sacrum
What nerves make up the sacral plexus?
nerves to the lower limb, pelvic splanchnics (autonomic) and pudendal nerve (somatic)
What 3 muscles make up the levator ani muscle and which lies most medial/laterla?
1) Puborectalis muscle most medially
2) Pubococcygeas muscle in between
3) Ischiococcygeas muscle most laterally
When deficating which of the levator ani muscles relaxes in particular and why does this occur?
Puborectalis muscle - relaxes to allow the recto-anal angle to straighten to faeces can pass out (normally the puborectalis muscle creates a sling around the anus creating an angle to prevent involuntary defecation)
Where does the coccygeas muscle run from and to?
From the coccyx and sacrum to the ischial spine
What is the perineal body?
Formed where the levator ani muscle converge in the midline. Fibromuscular mass at the junction between urogenital hiatus and anus
Its essential for the integrity of the pelvic floor and when this is ruptured during pregnancy (there is not a good blood supply as fibrous tissue so doesnt heal well) there is a tendency to prolapse
What is the anococcygeal body?
Formed in the midline where the levator ani and coccygeas muscles converge
How does the piriformis muscle exit the pelvic cavity?
Through the greater sciatic foramen
Which way did blood flow in the umbilical artery? How many did you have and what is the remnant of this?
From the fetus to the mother
Have 2
Remnant is the median umbilical ligament
Which way did the blood flow in the umbilical vein? What is the remnant of this?
From the mother to the fetus - remnant is the ligamentum terres in the falciform ligament
