Renal anatomy 3 Flashcards
(32 cards)
What are the functions of the bony pelvis?
Supporting the spine, torso and upper body
Locomotion
Housing and protecting the pelvic viscera
What are the bones that make up the bony pelvis?
The sacrum and the left and right innominate/hip bones
What is the innominate/hip bone made up of?
The ilium, ischium and pubis (more medial- yellow)
What are the 5 articulations of the bony pelvis?
Hip joint- between the head of the femur and the acetabulum of the pelvis
Sacroiliac joint- Between the sacrum and ilium of the hip bone. (stable and strong and supported by many ligaments)
Pubic symphysis- between 2 pubic bones (almost no movement permitted)
Lumbosacral joint- Between the 5th lumbar vertebrae and the sacrum
Sacrococcygeal joint- Between the sacrum and coccyx
What is the acetabulum?
It is the socket where the head of the femur articulates with the bony pelvis
It is also the point where the ilium, ischium and pubis of the hip bone fuse.
What is the surface landmark for the iliac crest? What is its clinical significance?
The intercristal line (highest point of iliac crests) marks the level of L4/L5 disc space – useful for lumbar puncture or epidural injection.
What is the surface landmark for the anterior superior iliac spine?
It is the most anterior point of the ilium
What is the surface landmark for the iliac tubercles?
The intertubercular line marks the division of the lower third of the abdomen from the middle third, thus delineating the suprapubic region from the umbilical region.
What are the surface landmarks for the pubic tubercle and inguinal ligament?
Pubic tubercle- the most medial point of the pubic bone (palpable in most people)
Inguinal ligament- running from the anterior superior iliac spine to the pubic tubercle
What are the surface landmarks for the mid-inguinal point and mcburney’s point?
Mid inguinal point- Midpoint of a line drawn from the ASIS to the pubic symphysis. (femoral artery is palpable here)
Mcburney’s point- ⅔ the way on a line drawn from the umbilicus to the ASIS. - approximate location of base of appendix.
What are the pelvic organs in both males and females?
Males
Rectum, bladder, prostate and seminal vesicles
Females
Rectum, bladder, uterus, ovaries and vagina
What is the arterial supply to the pelvis? What are some of its branches?
Arterial supply is from the left and right internal iliac arteries
Key branches include:
Vesical arteries- supply the bladder in both sexes and the prostate and seminal vesicles in males
Uterine and vaginal arteries in females
Middle rectal artery- supplying the rectum
Internal pudendal artery- exits the pelvis to supply the perineum (protecting the pelvic floor muscle and blood vessels that supply the genitals and urinary tract.
Superior and inferior gluteal arteries- exit pelvis to supply the gluteal region
Take note that the pelvis has several venous plexuses which drain the pelvic organs. They unite and mostly drain into the internal iliac vein.
What are the key nerves of the sacral plexus?
Sciatic nerve- L4-S3. It exits the pelvis to supply the lower limb
Pudendal nerve- S2-S4 (somatic nerve- sensory and motor) - Major nerve of the perineum
Superior and inferior gluteal nerves- innervate the gluteal region
Pelvic splanchnic nerve- carrying parasympathetic fibres from S2-S4 to the pelvic viscera
Sympathetic fibres innervating the pelvic viscera arise from the lumbar splanchnic nerves and so are not included.
What are the functions of the pelvic floor?
They prevent herniation of the pelvic organs inferiorly (and out of the pelvis)
They control the continence of urine and faeces (continence means you can control when you want to pee basically) by providing a sphincter action on the urethra and rectum respectively.
They increase intraabdominal pressure
What is the pelvic floor made up of?
2 muscles: the levator ani and coccygeus.
What is the levator ani composed of? (all muscles)
Puborectalis- most anterior muscle of levator ani. U shaped muscle attaching to the pubic bones anteriorly and forms a sling around the rectum. It pulls on the rectum so that a sharp angle is formed between the rectum and anal canal, preventing defecation. (when it relaxes, the path between the rectum and anal canal straightens allowing faeces to pass through). It also contributes to control of micturition.
Pubococcygeus- Lies posterior and lateral to puborectalis. It attaches to the pubic bone (pubis) anteriorly and the coccyx and sacrum posteriorly
Iliococcygeus- Lies lateral to the pubococcygeus. It attaches to the spines of the ischium and coccyx
What is the levator ani innervated by?
A branch of the S4 nerve and branches of the pudendal nerve (S2-S4)
What is the perineum and where is it located?
The perineum protects the pelvic floor muscles and the blood vessels that supply the genitals and urinary tract.
It is located (in a diamond shape) immediately superficial and inferior to the pelvic floor. Between the pubic symphysis and the coccyx, and in between the medial surfaces of the thighs.
What is the perineum split into and where is it split?
The anterior urogenital and posterior anal triangles. A horizontal line is drawn between the ischial tuberosities
Where and what is the perineal body?
Where exactly is it situated in both male and female bodies?
It is located in the middle of the two triangles of perineum.
It is a dense mass of fibrous tissue and muscles that sits in the centre of the perineum to act as an attachment for almost all the perineal and pelvic floor muscles (levator ani, external anal sphincter, external urethral sphincter, superficial and deep transverse perineal muscles and bulbospongiosus.
Males- between the bulb of penis and the anus
Females- between vagina and external anal sphincter
What do the corpora cavernosa do in the superficial perineal pouch?
The corpora cavernosa are symmetrical and run along the ischial rami to converge in the midline, to form a strong foundation for the clitoris or penis.
The crura of the clitoris/penis refers to the parts of the corpora cavernosa that are attached to the ischial rami.
What is the difference between corpus spongiosum in males and females?
In males, the corpus spongiosum sits in the midline, it expands proximally and rests on the perineal membrane. This is the bulb of the penis.
In females, the corpus spongiosum sits in the midline, splits into 2 parts that flank the vaginal opening and rests on the perineal membrane (either side of the vaginal opening). This is the bulb of the vestibule/clitoris
What are the corpora cavernosa and corpus spongiosum covered by and what are the functions of that?
Corpora cavernosa is covered by ischiocavernosus muscles and the corpus spongiosum is covered by the bulbospongiosus muscle.
The ischiocavernosus helps to stabilise the erect penis and clitoris
In males, the bulbospongiosus assists in maintaining erection by compressing the veins that drain erectile tissues and it contracts to squeeze any remaining urine or semen from the urethra
In females, it helps maintain clitorial erection and constricts around the vaginal orifice which can help expression of fluid from the greater vestibular glands.
What is the arterial supply and innervation of the perineum?
The internal pudendal artery, a branch of the internal iliac artery.
The main nerve of the perineum is the pudendal nerve (S2-S4) also by autonomic nerves
