Pelvis - Lecture 6 Flashcards
What is the Pelvic Outlet/Pelvic Diaphragm?
Bottom boundary of the Pelvic Cavity covered by the muscles of the Pelvic Diaphragm
Where is the Perineum located?
Inferiorly/Superficially to the Pelvic Floor
What regions are the Perineum divided into?
Imaginary Line between the Ischial Tuberosities divides the Perinum into:
- Urogenital Triangle
- Anal Triangle
What are the borders of the Perineum?
- Pubic Symphysis (Anteriorly)
- Coccyx (Posteriorly)
- Ischial Tuberosities (Laterally)
What is the Urogenital Triangle?
Anterior triangle of the Perineum that contains the openings for the Urinary and Reproductive Systems
What is the Anal Triangle?
Posterior triangle of the Perineum that contains the opening for the GI system
In the Anatomical Position, what orientation is the Urogenital Triangle?
Urogenital Triangle is in the Horizontal Plane
In the Anatomical Position, what orientation is the Anal Triangle?
Anal Triangle is angled more posteriorly in an oblique plane
The Pelvic Diaphragm is curved but the the Perineal Membrane and ligaments run across in straight lines which forms…
Anterior and Posterior Ischio-Anal Fossae and Recesses
Which space is larger, Anterior Ischio-Anal Fossa or the Posterior Ischio-Anal Fossa?
Posterior Ischio-Anal Fossa
Ischio-Anal Fossae and Recesses are normally filled with what?
Fat, but infections can form here
What are the connective tissue structures of the Perineum?
- Perineal Body
2. Perineal Membrane
Where is the Perineal Membrane located?
In the Urogenital Triangle running between the Ischiopubic Rami
What does the Perineal Membrane do?
It is a thin sheet of thick connective tissue that separates the Deep Pouch and Superficial Pouch of the Urogenital Triangle
What anchors to the Perineal Membrane and what openings does it have
Perineal Membrane:
- Anchors Erectile Tissue
- Has opening for Urethra and Vagina
What is the Perineal Body?
Thickening of connective tissue between the Urogenital Triangle and the External Anal Sphincter that serves as an important attachment point for muscles in the pelvic floor and Perineum
What are the boundaries of the Anal Triangle?
- Imaginary line between the Ischial Tuberosities (Anterior)
- Sacrotuberous Ligaments (Lateral)
- Coccyx (Posterior)
What is the muscular content of the Anal Triangle?
External Anal Sphincter
What innervates the External Anal Sphincter?
Inferior Rectal Branch (comes from Pudendal Nerve)
What surrounds the External Anal Sphincter in the Anal Triangle?
Fat from the Ischio-Anal Fossa
What are the boundaries of the Urogenital Triangle?
- Pubic Symphysis (Anterior)
- Pubic Rami (Lateral)
- Imaginary Line between the Ischial Tuberosities (Posterior)
The Deep Pouch is located…
Between the Pelvic Diaphragm and Perineal Membrane
“Deep to the Perineal Membrane”
The Superficial Pouch is located…
Between the Pelvic Diaphragm and Superficial Fascia of the Perineum
“Superficial to the Perineal Membrane”
For the most part, Perineal Muscles are…
Skeletal Muscles
What structures are located in the Male Deep Pouch of the Urogenital Triangle?
- Deep Transverse Perineal Muscle
- External Urethral Sphincter (Muscle)
- Membranous Urethra
- Cowper’s Glands (Bulbo-urethral glands)
What is function of the Cowper’s Glands (Bulbo-urethral) and where are they located?
Lubricating glands of the MALE Urethra located in the Deep Pouch of the Urogenital Triangle
What structures are located in the Female Deep Pouch of the Urogenital Triangle?
- Deep Transverse Perineal Muscle
- External Urethral Sphincter (Muscle)
- Urethra
- Vagina
What structures are located in the Male Superficial Pouch of the Urogenital Triangle?
- Ischiocavernous and Bulbospongiosus Muscles (Erectile Muscle)
- Superficial Transverse Perineal Muscle
- Crura (Erectile Tissue)
- Bulb of the Penis (Erectile Tissue)
- Part of the Spongy Urethra
What structures are located in the Female Superficial Pouch of the Urogenital Triangle?
- Ischiocavernous and Bulbospongiosus Muscles (Erectile Muscle)
- Superficial Transverse Perineal Muscle
- Crura (Erectile Tissue)
- Bulb of the Clitoris (Erectile Tissue)
- Bartholin’s Glands (Greater Vestibular Glands)
What are Bartholin’s (Greater Vestibular) Glands?
Lubricating glands of the Vagina located in the Superficial Pouch of the Urogenital Triangle
What are the muscles located in the Deep Perineal Pouch and what nerve innervates them?
- External Urethral Sphincter (voluntary)
- Deep Transverse Perineal Muscle
INNERVATED by Pudendal Nerve
What is the function of the Deep Transverse Perineal Muscle?
Sort of like a crossbeam that steadies the central tendon by serving as a place for some Perineal muscles to anchor
What is the function of the External Urethral Sphincter?
Allows voluntary inhibition of the Urethra via contraction and helps support pelvic organs
Erectile Tissue is composed of what types of tissue?
- Corpus Cavernosum
2. Corpus Spongiosum
What is the Crus of the penis?
Part of the Corpus Cavernosum that are attached to the Ischipubic Ramus and Perineal Membrane and continue on the Distal Shaft of the Penis
What is the Anatomical Position of the Penis?
Erect Penis
Top of Erection is Dorsal
Bottom of Erection is Ventral
What type of erectile tissue makes up the bulb of the Penis?
Corpus Spongiosum
What parts of the Penis make up the root and where do they attach?
- Crus- Corpus Cavernosum tissue attached to the Ischiopubic Ramus and Perineal Membrane
- Bulb- Corpus Spongiosum
Attach to Perineal Membrane
What is the Glans of the Penis?
The head of the Penis composed of Corpus Spongiosum that has the Urethra running through it to the External Urethra Orifice
Describe the Ventral side of the Penis Shaft
Corpus Spongiosum surrounding surrounding the Urethra
Penis Shaft is composed of
- 2 Columns of Corpus Cavernosum on the Dorsal side
2. Corpus Spongiosum surrounding the Urethra on the Ventral side
What causes an erection?
Parasympathetic signals dilating vessels allowing the Corpus Cavernosum on Dorsal side of Penis to fill with blood
What is the Erectile tissue called in females?
Clitoris
What are the root attachments of the Clitoris?
- 2 Crus (legs)
2. 2 Bulbs of the Vestibule
What are the Crura (2 Crus) of the Clitoris composed of and where do they attach?
- Made of Corpus Cavernosum 2. Attach to Ischiopubic Ramus and Perineal Membrane
What are the 2 bulbs of the Clitoris composed of and where do they attach?
- Made of Corpus Spongiosum
2. Attach to the Perineal Membrane on either side of the Vaginal Opening
What causes erectile tissue to grow in vitro making it larger in males than females?
Testosterone
What parts make up the Clitoris?
- Glans (open to Perineum)
- Body
- Crus
- Bulbs
Where are the Bartholin’s Glands located and what do they do?
- Located in the Superficial Pouch on the Posterior-Lateral Side of the Vaginal Opening
- Lubricate the Vagina
What are the Muscles located in the Superficial Perineal Pouch?
- Ischiocavernous Muscle
- Bulbospongiosus Muscle
- Superficial Transverse Perineal Muscle
Where is the Ischiocavernosus Muscle located and what is its function?
- Runs over Crus near Pubic Rami in the Superficial Pouch
2. Help direct blood into the Erectile Tissue
Where is the Bulbospongiosus Muscle located?
- Two muscles from the Perineal Body that come together in Men to surround the bulb and surround the Vaginal Opening and Clitoris in women
- Anchored to Perineal Body
What is the function of the Bulbospongiosus Muscle?
- Directs blood flow into erectile tissue during an erection
- Pulsatile Ejaculation in men
- Clear Urine from Urethra after urination
Where is the Superficial Transverse Perineal Muscle located and what is its function?
- Located on the posterior side of the Superficial Pouch
2. Supports Perineal Body and anchors to it
What muscles anchor to the Perineal Body?
- Bulbospongiosus Muscle
- Superficial Transverse Perineal Muscle
- External Anal Sphincter
Facts about the Female Urethra
- Short
- Passes through Pelvic Floor Muscles
- Has internal and external Urethral Sphincters
- Urinary function only
What are the parts of the Male Urethra?
- Pre-prostatic Urethra
- Prostatic Urethra
- Membranous Urethra
- Spongy Urethra
What is the Pre-prostatic Urethra?
- First part of the Urethra that exits Bladder before entering Prostate
- Has Internal Urethral Sphincter
What is the Prostatic Urethra?
- Part of Urethra that passes through the Prostate
2. Entrance of the Reproductive System via the Ejaculatory Duct
What is the Membranous Urethra?
- Part of the Urethra that passes through the Deep Pouch
2. Surrounded by External Urethral Sphincter (Skeletal muscle voluntary control)
What is the Spongy Urethra?
- Part of the Urethra that passes through the Superficial Pouch
- Travels through Corpus Spongiosum
- Expands at the tip
- Ends at the External Urethral Orifice
What is the difference between Male and Female Urethras?
In Men:
- Longer
- Bends twice
- Passes through Corpus Spongiosum (Erectile Tissue)
What is the Detrusor Muscle?
Layer of muscle in the Bladder Wall that is activated by Autonomic Nervous System
How does the Parasympathetic Nervous System control Urination?
- Contracts Detrusor Muscle in walls of Bladder
2. Relaxes Internal Sphincter
How does the Sympathetic Nervous System control Urination?
- Relaxes Detrusor Muscle in walls of Bladder
2. Contracts Internal Sphincter
What is the Female External Genitalia called?
Vulva
What is included in the Vulva?
- Mons Pubis
- Labia Majora
- Labia Minora
What is the Mons Pubis
Fatty mound of tissue on the Anterior side of the Pelvis
What is the Labia Majora?
Outer Labia
- Surrounds Labia Minora
- Meets anteriorly to form Mons Pubis
- Meets posteriorly to form Posterior Commissure
- Same tissue as Scrotum
What is the Vestibule of the Vagina?
Area that contains the openings of the Vagina and Urethra
Describe the positions of the Urethral and Vaginal openings in relation to each other
Urethral Opening is Anterior
to the Vaginal Opening in the Vestibule of the Vagina
Where does the Labia Majora connect posteriorly?
Posterior Commissure which is over the Perineal Body
What is the Labia Minora
Surrounds the Vestibule of the Vagina
What is the only part of the Clitoris that can be seen?
Glans (Head) of the Clitoris
What is the Prepuce?
- Hood or foreskin of the Clitoris
2. Foreskin of the Glans Penis
Where does the Labia Minora connect anteriorly?
Anteriorly Labia Minora connects to form the Frenulum and Prepuce
Where does the Labia Minora connect posteriorly?
Fourchette
What is the Hymen?
Remnant tissue of embryological structure that can cover the Vaginal Opening
What is the Raphe of the Scrotum?
The midline where the two pieces of the Scrotum came together and fused that spans from anus to the penis
What are the parts of the External Male Genitalia (Penis)?
- Root
- Body
- Glans
- External Urethral Orifice
What is unique about the Anterior Abdominal Wall below the Umbilicus?
Along with the Urogenital Triangle, Anterior Abdominal Wall below the Umbilicus is the only place in the body with TWO layers of Superficial Fascia
What are the two layers of Superficial Fascia in the Anterior Abdominal Wall below the Umbilicus?
- Camper’s Fascia- Superficial fatty layer
2. Scarpa’s Fascia- Deeper membranous thicker layer
What do you call the two layers of Superficial Fascia in the Urogenital Triangle?
- Camper’s Fascia- Superficial fatty layer
2. Colles’ Fascia- Deeper membranous thicker layer ONLY in the UG Triangle
What is Dartos Fascia?
The Deep membranous thick layer of Superficial Fascia unique to the Penis and Scrotum
In the Scrotum, Dartos Fascia is associated with smooth Dartos Muscle that…
Causes wrinkling of the Scrotum
What are the names and locations of the Deep layer of Superficial Fascia in the Anterior portion of the Abdomen below the Umbilicus?
- Scarpa’s Fascia- Anterior Abdominal Wall below Umbilicus
- Colles’ Fascia- Urogenital Triangle
- Dartos Fascia- Penis and Scrotum
What is the main source of Innervation in the Perineum?
Pudendal Nerve
The Pudendal Nerve comes from…
Sacral Plexus (S2-S4) starting inside Pelvis
Describe the path of the Pudendal Nerve
- Exits Pelvic Cavity through the Greater Sciatic Foramen
- Curves around Ischial Spine passing through Gluteal region
- Reenters Perineum through Lesser Sciatic Foramen
What are the branches of the Pudendal Nerve?
- Inferior Rectal Nerve
- Perineal Nerve
- Dorsal Nerve of the Penis/Clitoris
What does the Pudendal Nerve travel with?
- Internal Pudendal Artery (branches from Anterior Trunk)
2. Internal Pudendal Vein
What is innervated by the Inferior Rectal Nerve?
- External Anal Sphincter (skeletal)
- Part of the Pelvic Diaphragm
- Anal Triangle
What is innervated by the Perineal Nerve?
Muscles of the Deep and Superficial Pouches of the Urogenital Triangle (External Urethral Sphincter, Ischiocavernosus, Bulbospongiosus)
What is innervated by the Dorsal Nerve?
Penis or Clitoris
Pudendal Nerve is the major sensory nerve of the Perineum meaning?
It has sensory control for the skin over skeletal muscles that it innervates
What is the Visceral Tissue in the Perineum?
Erectile Tissue
What are the Cavernous Nerves?
Nerves that dilate the arteries in the Corpus Cavernosum and constrict the veins
What effects does Sympathetic control have on Erectile Tissue?
- Ejaculation
- Contraction of the Ducts
- Secretion from Glands
Where does blood supply to the Perineum come from?
- Internal Pudendal Artery (larger)
2. External Pudendal Artery
Where does the Internal Pudendal Artery originate?
Branch of the Anterior Trunk of the Internal Iliac Artery
What is the main artery of the Perineum?
Internal Pudendal Artery
What branches come from the Internal Pudendal Artery?
- Inferior Rectal Artery
- Perineal Artery
- Deep Artery of the Penis/Clitoris
- Dorsal Artery of the Penis/Clitoris
Where are the Deep Arteries located on the Penis?
Run through the center of the Corpus Cavernosum tissues on the Dorsal side of the Shaft
Where are the Dorsal Arteries located on the Penis?
On the Dorsal Surface of the Shaft
The dilation of which Blood Vessels in erectile tissue leads to an erection?
Deep Arteries
What is the function of the External Pudendal Artery?
Provides blood to skin over Perineum:
- Anterior Scrotum
- Anterior Labia Majora
Where does the External Pudendal Artery originate?
Common Iliac Artery > External Iliac Artery > Femoral Artery
Superficial structures of the Perineum like skin drain lymph to the…
Superficial Inguinal Nodes
Deep structures of the Perineum like erectile tissue drain lymph to the…
Deep Inguinal Nodes
Organs inside the Pelvic Cavity drain lymph to the…
Internal or External Iliac Nodes
The Gonads drain lymph to…
Aortic Nodes in the Abdomen
What are the bones that you sit on?
Ischial Tuberosities
During, Pregnancy how can the Pelvis can widen?
The Pelvis can widen Laterally due to the relaxation of the joints of the Pelvis