Pelvis and perineum Flashcards
How is the pelvic cavity defined?
Coloured red. Abdominal and pelvic cavity is divided by the pelvic inlet. Note that its axis (red dotted line) is angled about 45 degrees, contrary to the axis of the abdominal cavity.
What does the pelvic girdle describe?
Concerns the bones of the pelvis and sacrum.
What are the two main functions of the pelvic girdle?
Hold the bodies weight and join to the lower limbs.
Label the parts of the pelvic girdle
1: Ala of sacrum
2: Iliac Crest
3: Iliac Fossa
4: Pelvic inlet
5: Sacrum
6: Ischial spine
7: Acetabulum
8: Pubic tubercle
9: Inferior pubic ramus
10: Pubic Arch
11: Pubic Synthesis
12: -
13: -
14: Obturator Foramen
15: Coccyx
16: Anterior Inferior Ililac Spine
17: Anterior sacral foramina
18: Anterior superior iliac spine
19: Sacro iliac joint
20: Base of sacrum
What are the two joints of the pelvic girdle?
Sacroiliac and pubic symphysis.
What is the true and false pelvis
The false pelvis contains the absominal cavity.
False is called the greater pelvis; true is the lesser pelvis and is the most important part of the pelvis.
Where are the superior and inferior pubic ligments situated?
Above and below the pubic synthesis respectively
What is the pelvic inlet and outlet?
Pelvic inlet is the superior aperture of the pelvis; pelvic outlet is a diamond shaped area – its boundaries are the pubic symphysis, right and left rami of the pubic arch, the sacrotuberous ligaments and tip of the coccyx.
What is the pubic angle? Alternative name? Differences between males and females?
AKA the subpubic angle, formed by the convergence of the inferior rami of the ischium and pubis on either side.
FEMALES: wide (usually larger than 90 degrees); MALES: narrower (usually smaller than 90 degrees).
What type of joint is the sacro-iliac joint?
Synovial.
What is the pubic symphysis made from? What is it specifically?
Cartilage – it is a secondary cartilaginous joint.
What are the three major bony regions of the hip bone?
ILIUM is the uppermost and largest part of the hip bone; ischium in blue; pubis in pink. These are THREE SEPARATE FUSED bones.
Where do the ilium, ischium and pubis fuse in the pelvis?
In the acetabular fossa.
What is the anatomy of the pelvic-femoral joint?
Acetabulum is the ‘socket’. The articular surface is a surface that makes normal direct contact with another skeletal structure as part of a synovial joint.
Where is the obturatur membrane
Thin fibrous sheet which almost completely closes the obturator foramen.
What does the sacro spinous ligment connect
Attatches ischium of pelvis to coccyx.
What is the pubic arch and sub pubic angle
What is the ischio-pubic ramus
What is the anterior longitudinal ligament ligaments
What is the greater sciatic notch/foramen
Lesser sciatic notch/foramen
D is the lesser sciatic notch/foramen. Formed by the sacrotuberous and sacrospinous ligament (add photo).
What are the differences between male and female pelvises? (x6)
[Note about photo – X = difference between symphysis pubis and anterior margin of acetabulum; Y = diameter of the acetabulum.]
Differences are based around the fact that female pelvises are designed for childbirth.
What does the lumbosacral ligament connect?
The lumbar and sacrum
Surface markings of the Kidney
What does the iliolumbar ligament connect
The iliac crest and lumbar 1
What does the anterior and posterior sacroiliac ligament connect
Sacrum and iliac crest
What does the sacrotuberous ligament connect
The sacrotuberous ligament is attached by its broad base to the posterior superior iliac spine, the posterior sacroiliac ligaments (with which it is partly blended), to the lower transverse sacral tubercles and the lateral margins of the lower sacrum and upper coccyx.
Where is the location of the transpyloric plane
Midway down the midclavicular line between clavicle and AIIS
or
Midway between pubic symphesis and sternal angle
runs at L1 level. T12 is halfway between scapula and highest point of iliac crest, then L1 is one vertebrae lower
How is palpation of Kidneys carried out?
“The subject should lie flat on a couch with knees and hips semi flexed, if necessary, to relax the abdominal wall muscles. The entire abdomen should be exposed. Only the lower poles of the kidneys can be palpated through the anterior abdominal wall just below the costal margins.
”
Bimanual palpation, using both hands, keep left hand under patients flank palm up-facing. Use right hand to palpate kidney anteriorally, and use index and third finger to ballott the kidney.
Shouldnt be able to feel in a healthy patient
Label the parts of the pelvic girdle
1: Ala of sacrum
2: Iliac Crest
3: Iliac Fossa
4: Pelvic inlet
5: Sacrum
6: Ischial spine
7: Acetabulum
8: Pubic tubercle
9: Inferior pubic ramus
10: Pubic Arch
11: Pubic Synthesis
12: -
13: -
14: Obturator Foramen
15: Coccyx
16: Anterior Inferior Ililac Spine
17: Anterior sacral foramina
18: Anterior superior iliac spine
19: Sacro iliac joint
20: Base of sacrum
What is the true and false pelvis
The false pelvis contains the absominal cavity
Where are the superior and inferior pubic ligments situated?
Above and below the pubic synthesis respectively
What is the pelvic inlet and what are its borders?
Where is the obturatur membrane
What does the sacro spinous ligment connect
Attatches ischium of pelvis to coccyx
What is the pubic arch and sub pubic angle
What is the ischio-pubic ramus
What is the anterior longitudinal ligament ligaments
What is the greater sciatic notch/foramen
Lesser sciatic notch/foramen
D is the lesser sciatic notch/foramen
What separates the greater and lesser sciatic notch/foramen?
Sacrospinous ligament.
What is the difference between male and female pelvis
What does the lumbosacral ligament connect?
The lumbar and sacrum
What does the iliolumbar ligament connect
The iliac crest and lumbar 1
What are the superior and inferior pubic ligaments?
.
What does the anterior and posterior sacroiliac ligament connect
Sacrum and iliac crest
What does the sacrotuberous ligament connect
The sacrotuberous ligament is attached by its broad base to the posterior superior iliac spine, the posterior sacroiliac ligaments (with which it is partly blended), to the lower transverse sacral tubercles and the lateral margins of the lower sacrum and upper coccyx.
What is the obturator internus muscle?
Most of the pelvic bone facing the pelvic cavity is covered by the obturator internus muscle and its fascia. Found at the anterior (internal) region of the lesser pelvis and arises from the obturator membrane, and the medial surface of the greater trochanter of femur. LINES THE PELVIC WALL.
What are the nerves associated with the pelvic wall?
Lumbar sacral plexus (seen in image) are the nerves that supply the lower limb, perineum and buttocks.
What is the Piriformis muscle and its attachments?
Attached to the anterior part of the sacrum and across the superior sciatic foramen where it attaches to the medial surface of the greater trochanter of femur.
What are the components of the pelvic diaphragm and purpose?
They form the floor of the pelvic cavity, support pelvic viscera, and elevate the anus.
Iliococcygeus, pubococcygeus and puborectalis collectively form the Levator ani muscle (they are three divisions of the same muscle). Coccygeus muscle is located posterior to this muscle. There’s also the obturator internus.
What are the attachments of the Levator ani muscle?
Tendinous arch (of obturator internus fascia – an area of thickened arch) and interdigitate medially and form the anococcygeal ligament from both Levator ani muscles (from each side).
Surface markings of the Kidney
How is the pelvic diaphragm – the Levator ani muscle innervated? Origin?
The pair of Levator ani muscles are skeletal, so are under voluntary control! They are supplied by a somatic nerve – the pubendal nerve (from S2, S3 and directly from S4 (derived from same place as the PNS S2,3,4 nerves, but are separate!)).
How does the pelvic diaphragm look inferiorly? Two divisions of the pelvic diaphragm in inferior view?
Anterior half of the pelvic diaphragm is covered in perineal membrane (from which the genitals are also attached).
Anterior region is called the UROGENITAL TRIANGLE.
Posterior half has no perineal membrane. Posterior region is called the ANAL TRIANGLE.
How is the pelvic girdle orientated – landmarks that we should be familiar with?
- In the anatomical position, ASIS and pubic tubercles are in the SAME PLANE.
- Greater and lesser pelvises are continuous.
- Axis of the pelvic cavity is approximately 45 degrees.
What are the anatomical relations of the anal and urogenital triangles to the pelvic girdle?
Photo.
What happens to the peritoneum in the pelvic cavity?
- Parietal peritoneum continues into the pelvic cavity but does not reach the pelvic floor.
- Pelvic viscera are therefore only PARTIALLY covered by peritoneum (except the uterine tubes which are completely covered).
- Several folds and pouches are formed.
[NOTE that peritoneum in the photo is indicated in blue].
Where is pelvic fascia found?
Pelvic fascia is found in the spaces between the peritoneum and the pelvic wall not occupied by viscera. Pelvic fascia is indicated by yellow in the photo and has parietal (green line) and visceral (orange line) components.
What are the contents of the male pelvic cavity?
- Ureter, bladder, urethra;
- prostate, ductus deferens, seminal vesicles, bulbourethral glands;
- rectum;
- some of the abdominal GI tract spills into the greater pelvis (caecum, appendix, parts of the sigmoid colon and ileum);
- vessels, nerves and lymphatics.
NOTE the two bends of the urethra (1 and 2) in the photo – only number 2 can be straightened.
What is the ductus deferens?
AKA the vas deferens: Small muscular tube in the male reproductive system that carries sperm from the epididymis (emerging tube of the testicle) to the ejaculatory duct (created when the seminal vesicle’s duct merges with the ductus deferens).
What are seminal vesicles?
AKA vesicular glands: a pair of simple tubular glands posteroinferior to the urinary bladder that secrete fluid that partly composes the semen.
What are bulbourethral glands?
Located beneath the prostate that add fluids to semen during ejaculation.
What structures in the male pelvis can be felt by a digital rectal examination (DRE) of a healthy man?
Feel enlarged rectum, diagnosis of appendicitis, you can also feel the bladder.
What is the anatomical position of the prostate gland?
Surrounds the 1st (prostatic) part of the urethra.
What is the anatomical position of the ductus deferens?
From the testes, passes through the inguinal canal, then over and behind the URETER to enter the URETHRA through the prostate.
What is the anatomical position of the seminal vesicles?
Posteroinferior to the bladder and opens into the ductus deferens between the AMPULLA of VAS DEFERENS and EJACUALTORY DUCT.
What are the corpus cavernosa?
Sponge-like regions of erectile tissue which contain most of the blood in the penis during an erection.
What is the anatomy of the prostate urethra?
Where urinary and reproductive tracts meet.
INTERNAL URETHRAL SPHINCTER: smooth muscle well organised.
EXTERNAL URETHRAL SPHINCTER: skeletal muscle.
PROSTATIC UTRICLE: small indentation that is the homologue (shared ancestry between a pair of structures) of the uterus and controls opening of the ejaculatory ducts.
What is the structure of the male urethra?
Preprostatic part, prostatic, membranous and spongy part of the urethra.
What are the three areas of narrowing/obstruction that you should be concerned about in the navigation of a catheter?
- Tip of the urethral catheter can become lodged in the prostatic utricle.
- The external urethral orifice.
- 90 degrees bend at the perineal membrane.
What is the blood supply of the prostate?
Prostatic branch of the inferior vesical artery, which is a branch of the internal iliac artery.
What is the blood supply of the bladder and ductus deferens?
Superior and inferior vesical artery, which is a branch of the internal iliac artery.
What are the bony landmarks of the perineum? Shape?
Diamond-shaped area between pubic symphysis, ischial tuberosities and coccyx.
What is the living anatomy of the perineum?
Diamond-shaped area between the thighs when the person lies on the back with thighs flexed and abducted.
What is the ischio-anal fossa? Function?
Ischio-anal fossae = fat-filled spaces separating anal canal and levator ani from the pelvic walls, found in the anal triangle of the PERINEUM. They allow recto-anal and vaginal expansion.
What is found in the lateral wall of the ischio-anal fossae?
In their lateral wall is the pudendal neuro-vascular bundle supplying the perineum including the lower rectum.
What is the vasculature that crosses the ischio-anal fossae? Clinical implication in females during childbirth?
Inferior rectal vessels and nerves cross the fossa. They may be cut if an episiotomy (surgical cut made at the opening of the vagina during childbirth) is carelessly placed. These vessels and nerves arise from the pudendal canal, a fibrous sheath on the lateral wall of the fossa within which the pudendal nerve and the internal pudendal vessels run forward from the posterior pelvis to the anterior perineum.
What are the structures of the superficial perineum in males?
- CRUS OF PENIS: the first 1/4th portion of the corpora cavernosa, where the sponge-like structures diverge.
- PERINEAL BODY: is the central tendon which forms the junction between the two perineal triangles – found between the bulb of the penis and the anus.
- PERINEAL MEMBRANE: erectile tissues and associated skeletal muscle are associated with the perineal membrane.
- CORPUS SPONGIOSUM: median erectile tissue mass – bulb of penis.
- CORPORA CAVERNOSA: lateral erectile tissue masses attached to ischiopubic rami.
- BOTH: the median and lateral erectile tissues meet to form the shaft and head (GLANS OF PENIS) of the penis (or clitoris in females).
- The erectile tissue within perineum is surrounded by SKELETAL MUSCLE.
What are the SKELETAL muscles associated with the superficial perineal structures in men? (x3)
Remember, these are all SUPERFICIAL muscles of the perineum. They are skeletal, and contract during ejaculation.
- ISCHIOCAVERNOSUS MUSCLE: stabilisation of the erect penis – associated with the proximal part of the corpus cavernosum. It COVERS the corpora cavernosa crura (legs).
- BULBOSPONGIOUSUS MUSCLE: covers the bulb of the penis (bulb of the corpus spongiosum).
- SUPERFICIAL TRANSVERSE PERINEAL MUSCLE: includes the muscle under the perineal membrane, and all converge onto the perineal body – the central perineal tendon.
What are the structures of the deep perineum in males?
Photo.
What are the structures and anatomy of the anal triangle of the perineum?
Photo.
What is the blood supply of the rectum?
Receives one pair of arteries from the INFERIOR MESENTERIC ARTERY (superior rectal artery) and two pairs from the INTERNAL ILIAC ARTERY (middle and inferior rectal artery).
What is the anatomy of the spermatic cord?
OUTSIDE –> INSIDE: external spermatic fascia, cremasteric fascia, internal spermatic fascia (from the external oblique, internal oblique and transversalis fascia of the anterior abdominal wall respectively).
From the deep inguinal ring of the inguinal canal.
What is the anatomy of the testis?
Spermatozoa are produced in the seminiferous tubules and migrate to the rete testis and efferent ductules. Then, they emerge at the head, body and tail of epididymis and travel inferiorly into the vas deferens.
What is the structure of the penis – excluding vasculature?
- Corpus cavernosum are paired, and corpus spongiosum are the spongy structures of the penis shaft.
- The corpus spongiosum contains the urethra and split into bulb, root, body and glans. NB: glans is part of the corpus spongiosum.
- The frenulum of prepuce is the posterior fold of tissue that attaches skin to the head of the penis.
- Penis has a deep and superficial fascia.
- The crura (crus/legs) of the corpora cavernosa attach to the ischiopubic ramus – the crura are roots, and the area where the two crus join is called the body.
- Navicular fossa is an area where catheters can get caught.
What is the blood supply of the penis? (x4 + x1)
- MAIN SUPPLY: INTERNAL PUDENDAL ARTERY from the internal iliac.
- DEEP ARTERY supplies the corpora cavernosa.
- DORSAL ARTERY supplies the skin and connective tissue.
- ARTERY OF THE BULB supplies the bulb, corpus spongiosum, glans and urethra.
- Branches of the cavernous spaces are usually called helicine arteries.
How is the pelvis and perineum innervated? (x2 and x1)
Pelvic contents supplied by autonomic nerves only.
- Sympathetic from lower thoracic and upper lumbar (T10 – L2) segments via hypogastric plexuses.
- Parasympathetic from S2-S4 outflow = joins the inferior hypogastric plexus.
Perineum is supplied by the pudendal nerve which is SOMATIC by comparison, and originates from S2-S4.
What are the stages of erection and ejaculation? And associated nervous stimulation?
- Erection – PNS.
- Secretion – PNS.
- Emission – SNS.
- Ejaculation – somatic.
- Detumescence – SNS (somatic).
What is the plexus associated with pudendal nerve S2-S4?
Lumbosacral plexus.
What is the anatomical route of the pudendal nerve?
Passes briefly from pelvis to buttock, thus passing behind the fibrous posterior edge of Levator ani (the sacrospinous ligament). It passes forward below the Levator ani, first in the lateral wall of the ischioanal fossa (posterior perineum) then branching to anterior perineum, penis/clitoris and scrotum/vulva.
What are the tissues surrounding the kidneys?
Surrounded by psoas major, quadratum lumborum and erector spinae muscles posteriorly (posterior abdominal walls). Anteriorly, there is the peritoneum and the renal fascia.
Surrounded entirely by pararenal fat.
