The Perinium Flashcards
what are the anatomical borders of the perineum?
Anterior - pubic symphysis
Posterior - tip of the coccyx
Laterally - Inferior pubic rami and inferior ischial rami and the ascrotuberous ligament
Roof - Pelvic Floor
Base - skin and fascia
What are the surface borders of the perineum?
Anterior - Mons Pubis in females, base of the penis in men
Lateral - Medial surface of thighs
Posterior - superior end of the intergluteal cleft.
How can the perineum be subdivided?
Theoretical line drawn transversly between the ischial tuberosities, spit to anterior urogenital triangle and the posterior anal triangle.
What is contained in the anal triangle?
The anal triangle is the posterior aspect of the perineum.
Contains
1. Anal aperture (opening of the anus)
2. External anal sphincter muscle
3. Ischioanal fossae x2
4. Pudendal nerve
What are the Ischioanal fossae/Space?
Lateraly to the anus, contain fat and connective tissue.
Allow for the expansion f the anal canal during defecation.
What nerve roots form the pudendal nerve?
S2 to S4
What is are the layers of the urogenital triangle?
Anterior half of the perineum.
an additional layer of strong deep fascia, perineal membrane.
DEEP
1. Deep perineal pouch
2. Perineal membrane
3. Superficial perineal pouch
4. Perineal fascia
5. Skin
what is the perineal membrane?
Deep strong fascia that is found within the the Urogenital triangle.
perforated by the urethra (and the vagina in women)
provides a attachment for the muscels of the external genitalia
What is in the deep perineal pouch?
space between teh deep fascia and the perineal membrane.
Contains
- urethra
- external urethral sphincer
Female
- vagina
Men
- bulbourethral glands
- deep transverse perineal muscels
What is the superficial perineal pouch?
between the perineal membrane and the superficial perineal fascia.
contains the erectile tissues that form the penis or the clitoris.
three muscles
- Ischiocavernosus
- Bulbospongiosus
- Superficial transverse perineal
What are the greater vestibular glands (Bartholin’s glands)
Production of mucoid secreation to aid SI
Lateraly to the enterance of the vagina in the supercifical perioneal pouch.
Perineal fascial is made up of two layers, what are they?
Deep
- covers the superficial perineal muscels and protruding structures (penis and clitoris)
Superficial FASCIA
- SUPERFICIAL LAYER = continious with Campers
- Deep Layer aka Colles’ Fascia = continous with Scarpa’s fascia
What is the Perineal Body?
acts as a point of attachment for muscle fibres from the pelvic floor and the perineum
What muscels attach to the perineal body?
Levator ani
Bulbospongiosus muscle
Superficial and deep transvers perineal muscels
External anal sphincter
External urethral sphincer muscel fibers
What is cut in a episiotomy?
The perineal body
What muscel is refered to as the Diaphram of the pelvis?
Levator Ani
Below is the perinium, above is the abdo cavity
Common site for a peri-anal abbcess?
Ischioanal fossae
what are the Three aspects of the anal sphincter?
- internal anal sphincter (Inner circular muscle, involentary)
- Deep external sphincer
- Volentary fibers of Levator Ani
What part of the fetus demarcates the start of the anal canal?
Proctodeum (stratified squamous)
What epithelium is the proximal anal canal/Rectum?
Columnar Epithelium + goblet cells
Below the pectinate line
Hindgut
Cancer - adenocarcinom
What type if cancer are radiosensitive?
Stratified squamous
Adenocarcinoma are not as well managed with radiotherapy.
Blood supply to the Rectum
Top 1/3 - Superior rectal artery, branch of the IMA.
2/3 + 3/3 - Middle and Inferior rectal artery, branchs of the Interal Illiac arteries
Superior rectal vein - drains to portal system
Inferior veins - Drians to internal illiacs, into the systemic.
In middle there is a porto-systemic Anastamosis with increased portal hypertension = Varicies in rectum
Where do tumors at the anal verge, lymph drain to?
Inguinal lymph nodes
What are haemaroids?
Gross dilations of the terminal portion of superior haemaroidal/rectal veins/anasteomosis
typicaly at 3,7,11 o’clock.
At what level does the rectum start?
S3
How does the rectum differ from the colon Macroscopicaly?
The rectum does not have Taenia Coli, Haustra, omental appendicies.
Where is stool stored?
ampulla of teh rectum, most distal aspect of the rectum.
What is the perioneal coverings of the rectum?
1/3 - Anterior and lateral aspects of the rectum
2/3 - Just the anteior aspect of teh rectum
3/3 - Not covered
Where is the rectovescicular pouch ?
Inbetween the rectum and the posterior aspect of the bladder in men
where is the Pouch of dougless?
Inbetween the rectum and the posterior vagina.
What is the external anal sphincter inervated by?
Somatic inferior rectal nerves, that originate from the pudendal nerve (s2- s4)
What is the lymphatic drainage of the testes?
Drains to the para-aortic lymph nodes
as the testes decended downwards in embryolic life, dragging the vasacalature with them
they are supplied from branch of aorta so lymph is also aorta
what muscels make up the levator ani muscle?
Three paired muscels
1. Bubococcygenus
2. Puborectalis
3. Iliococcygeus
Describe the lymphatic drainage of the Penis?
Penile skin - superficial inguinal lymph nodees
Glans - deep inguinal lymph nodes
Erectile tissue - Internal iliac lymph nodes
generaly the Inguinal lymph nodes drain external genitalia in men
