Pelvis and perineum Flashcards
Label
What are the anterior, posterior and lateral boundries of the pelvic outlet?
Anterior= pubic arch
Posterior= Tip of the coccyx
Lateral= ischial tuberosities
Which parts of the pelvis are termed the true and false pelvis?
What type of joint is the sacroiliac joint?
Synovial plane joint
What type of joint is the pubic symphysis
Secondary cartilagenous joint
Identify male vs female pelvis
Fill in the differences of male vs female pelvis
What 2 muscles make up the majority of the pelvic floor
- Levator ani
- Coccygeus
Through which foramina does obturator internus leave the pelvis through?
Lesser sciatic forament
Which pelvic floor muscle is made of 3 separate muscles & name these muscles
Levator ani
- Puborectalis
- Iliococcygeus
- Pubococcygeus
Give two functions of the pelvic diaphragm/ floor:
Support of abdominopelvic viscera (bladder, intestines, uterus etc.) through their tonic contraction.
Resistance to increases in intra-pelvic/abdominal pressure during activities such as coughing or lifting heavy objects.
Urinary and faecal continence.The muscle fibres have a sphincter action on the rectum and urethra. They relax to allow urination and defecation.
What is the innervation of the pelvic diaphragm/ floor?
Anterior rami of S4/5…… branches of the pudendal nerve (roots S2, S3 and S4).
2,3 and 4 to keep poo of the floor
What is a cystocele
Anterior vaginal prolapse
Supportive tissues around the bladder and vaginal wall weaken and stretch, allowing the bladder and vaginal wall to fall into the vaginal canal. Usually, the muscles and connective tissues that support the vaginal wall hold the bladder in place.
What is a rectocele
Posterior vaginal prolapse
Supportive wall of tissue between a woman’s rectum and vaginal wall weakens. Without the support of these pelvic floor muscles and ligaments, the front wall of the rectum sags and bulges into the vagina, and in severe cases, protrudes out of the vaginal opening.
Why is injury to the pelvic floor damaging
Weakening of the levator ani & pelvic fascia may decrease support for the vagina, bladder, uterus, or rectum or alter the position of the neck of the bladder and the urethra. These changes may cause urinary stress incontinence,
What is an episotomy
An episiotomy is a cut made along your perineum by your doctor during labor. Your doctor may need to cut your vaginal opening to allow more room for your baby to be born safely and without harm.
Which part(s) of the rectum drain(s) into the portal circulation?
..Upper one third of rectum: drained by superior rectal vein….
Which part(s) of the rectum drain(s) into the systemic circulation?
.. Lower ⅔rds rectum & anus, draining into the middle & inferior rectal veins ..
Why might haemorrhoids be associated with cirrhosis of the liver?
A back up of blood flow to the liver due to liver cirrhosis, leads to a backup of draining veins which will dilate, thus causing haemorrhoids…
Haemorrhoids= swollen/dilated veins in the anus
With which venous plexus does the prostatic venous plexus communicate with on its posterior side?
what is the clinical significance of this
Internal vertebral venous plexus..
This means that prostate cancer can spread easily to the vertebrae
What structure(s) in the male are supplied by the genital branch of the genitofemoral nerve & what is its clinical significance
Cremaster muscle & anterior scrotal skin..
The pudendal nerve arises from the sacral plexus and follows the course of the pudendal artery to innervate the skin and the muscles of the perineum.
From which segmental level(s) does the pudendal nerve arise?
S2-S4
What bony landmarks are used when performing a pudendal nerve block during labour?
Ischial spine
Label
Label the 3 muscles that form levator ani
What does the perineal nerve innervate & what is it a branch of
Branch of peudendal nerve
Innervates the levator ani muscles & external urethral sphincter
Function of the pedudendal nerve
voluntary/somatic control of faecal and urinary continence
What is the autonomic nerve supply to the pelvis?
Originates from the pelvic plexus (or inferior hypogastric)
Where does the sympathetic supply of the pelvis originate from
L1 & L2 via the hypogastric nerve & terminal aspect of the sympathetic trunk
→ provide sympathetic supply to all internal pelvic organs.
In a male they supply the vas deferens, seminal vesicles, prostate and epididymis.
In a female they supply the ovaries, uterus, fallopian tubes and vagina.
Where does the parasympathetic supply of the pelvis originate from?
Pelvic splanchnic nerves (S2 to S4).
What do the hypogastric and pelvic splanchnic nerves merge to form
Inferior hypogastric plexuses, which consists of both sympathetic and parasympathetic nerve fibres.
In the thorax the greater, lesser and least splanchnic nerves are sympathetic/parasympathetic
Sympathetic nerves
In the pelvis the pelvic splanchnic nerves are sympathetic/parasympathetic
Parasympathetic nerves
After rectal surgery, why are some men unable to ejaculate?
The bulbocavernosus muscle is responsible for ejaculation. This muscle resides in the area between the anus and the genitals, hence during rectal surgery it is at risk of damage..
The perineal nerve has been damaged
What are the four primary lymph nodes of the pevlis
External iliac lymph nodes
Internal iliac lymph nodes
Sacral lymph nodes
Common iliac lymph nodes
What does the External iliac lymph nodes drain
Pelvic viscera, especially the superior parts of the middle to anterior pelvic organs and inguinal lymph nodes..
What does the internal iliac lymph nodes drain
Gluteal region, deep perineum and inferior pelvic visera
Where do the sacral lymph nodes drain
Postero-inferior pelvic viscera and drain either to internal or common iliac nodes.
Where do the common iliac lymph nodes drain
Drainage from the three main groups: external, internal and sacral lymph nodes
What type of muscle is the internal urethral sphincter
Smooth muscle
> involuntary
What type of muscle is the external urethral sphincter
Skeletal muscle
> voluntary control
What structures pass through the greater sciatic foramen
- Superior gluteal artery and vein
- Superior gluteal nerve
- Sciatic nerve
- Pudendal nerve
- Inferior gluteal artery and vein
- Inferior gluteal nerve
- Posterior femoral cutaneous nerve
- Nerve to obturator internus
- Nerve to quadratus femoris
What structures pass through the lesser sciatic foramen
- Internal pudendal artery and vein
- Pudendal nerve (note the pudendal nerve first leaves the pelvis via the greater sciatic foramen, and then re-enters via the lesser sciatic foramen)
- Obturator internus tendon
- Nerve to obturator internus
