Flashcards in Perineum Deck (94):
Diamond shaped region between the thighs containing the external genitalia, anal canal, and the neurovascular structures that supply them
The perineum is bordered anteriorly by the
The perineum is bordered anterolaterally by the
The perineum is bordered posterolaterally by the
The perineum is bordered posteriorly by the
By extending a line from ischial tuberosity to ischial tuberosity, the perineum is divided into which two triangles?
1.) Urogenital (anterior)
2.) Anal (posterior)
Contains the anal canal in the midline with the ischioanal fossae on either side
Approximately 4cm in length extending between the anorectal junction (perineal flexure) and its opening
The mucosa of the proximal 2/3 of the canal is thrown into folds by underlying branches of the suerior rectal blood vessels. These folds are called called
The base of the anal column marks the transition between the
Hindgut (endoderm) portion and the proctodeum (ectoderm) derived distal 1/3
Marks the transition between the hindgut (endoderm) portion and the proctodeum (ectoderm) derived distal 1/3
Base of the anal canal
This area of transition is called the
Fecal continence is controlled by which two muscular sphincters?
1.) Internal anal sphincter
2.) External anal sphincter
Involuntary smooth muscle under autonomic controll
Internal anal sphincter
Voluntary skeletal muscle under somatic motor control
External anal sphincter
What is the embyonic derivation above the pectinate line
What is the motor innervation above the pectinate mind?
What is the sensory innervation of the anal canal above the pectinate line?
Visceral afferent and pressure
What is the arterial supply to the anal column above the pectinate line?
Superior rectal artery
What is the venous return from the anal canal above the pectinate line?
Superior rectal vein to hepatic portal venous system
What is the lymphatic drainage from the anal canal above the pectinate line?
Internal iliac nodes
Hemorrhoids of the anal canal ABOVE the pectinate line are
Internal and covered with mucosa
Hemorrhoids BELOW the pectinate line are
External and covered by skin
Fat-filled triangular shaped spaces that allow for the distension and contraction of the anal canal during defecation
The pelvic diaphragm and its inferior fascia form the MEDIAL wall of the
Form the lateral walls of the ischioanal fossae
Obturator internus muscle and its fascia
Formed within the fascia of the obturator internus muscle where it lines the LATERAL wall of the ischioanal fossae
The contents of the pudendal canal include:
Pudendal nerve and internal pudendal artery and vein
The internal pudendal artery and vein are passing through the pudendal canal as they travel to the
Inferior rectal branches of the pudendal nerve and internal pudendal artery and vein traverse the ischioanal fossae MEDIALLY to supply the
External anal sphincter, anal canal, and inferior aspect of pelvic diaphragm
The peroneal structures in the urogenital triangle are contained within which two pouches?
1.) Deep perineal pouch
2.) Superficial perineal pouch
Lies between the superior fascia of the urogenital diaphragm (roof) and the inferior fascia (perineal membrane) of the urogenital diaphragm (floor)
Deep perineal pouch
Formed by the deep pouch, its contents, and the fascial layers that enclose it
What are the muscles of the deep perineal pouch in both males and females?
Sphincter urethra and deep transverse perineal muscle
What are the viscera structures in the MALE deep perineal pouch?
Urethra and bulbourethral glands
What are the visceral structures in the FEMALE deep perineal pouch?
Urethra and vagina
Extends from deep to superficial between the perineal membrane of the urogenital diaphragm (facial roof) and the superficial perineal fascia (fascial floor)
Superficial perineal pouch
Constructing the SUPERFICIAL perineal pouch from deep to superficial, what is the FIRST layer?
Attach to the perineal membrane and ischiopubic rami
Constructing the SUPERFICIAL perineal pouch from deep to superficial, what is the SECOND layer?
Deep penile fascia (Buck's)
Covers erectile bodies
Deep penile fascia
Constructing the SUPERFICIAL perineal pouch from deep to superficial, what is the THIRD layer?
The skeletal muscle of the third layer covers part of the erectile bodies and attaches to the
Central tendon (perineal body)
Constructing the SUPERFICIAL perineal pouch from deep to superficial, what is the FOURTH layer?
Superficial perineal fascia
Constructing the SUPERFICIAL perineal pouch from deep to superficial, what is the FIFTH layer?
In the MALE and FEMALE, what are the muscles of the superficial perineal pouch?
Bulbospongiosus, ischiocavernosus, and superficial transverse perineal muscles
What is the main difference in the viscera of the superficial perineal pouch of the MALE?
Bulb of the penis, corpus spongiosum, crura of the penis, and corpa cavernosa
What is the main difference of the superficial perineal pouch of the FEMALE?
Vagina, vestibular bulb, greater vestibular gland, and crura of clitoris
Covers the erectile bodies and skeletal muscle of the superficial perineal pouch
Deep Penile Fascia (Buck's)
Forms the floor of the superficial perineal pouch and goes by a number of different names
Superficial perineal fascia
The part of the superficial perineal fascia that covers the penis
Superficial penile fascia
The part of the superficial perineal fascia that covers the scrotum
The part fo the superficial perineal fascia that is the region between the external ginitalia and the anal triangle
The superficial perineal fascia is continuous with the fascia of the anterior abdominal wall called the
What are the 4 types of superficial perineal fascia?
What are the 2 types of deep penile fascia
1.) Buck's (erectile)
2.) Investing (Muscle)
Can lead to extravasation of blood and/or urine
A urethral tear as it enters the bulb of the penis that also tears the Buck's fascia would allow fluid extravasation into the
Superficial pouch and the anterior abdominal wall
Pyrimidal shaped structure centrally located between the urogenital triangle and the anal triangle
Central tendon of the Perineum (Perineal Body)
The central tendon of the perineum (perineal body) consists of fibrous tissue and some smooth muscle and serves as an important attachment site for
Perineal and pelvic diaphragm muscles
We an see the importance of the perineal body as pelvic visceral support because when the perineal body is damaged, we see an increased incidence of
Prolapse of the pelvic viscers
Procedure where physicians cut the perineal body to prevent uncontrolled tearing during delivery
What are the perineal muscles that attach to the central tendon of the perineum (perineal body)?
Deep and superficial transverse perineal, bulbospongiosus, and external anal sphincter muscles
Which muscles of the pelvic diaphragm attach to the central tendon of the perineum (perineal body)?
Pubococcygeus and puborectalis
The arteries of the perineum are branches of the
Internal pudendal artery
The internal pudendal artery arises in the pelvis from the
Internal Iliac Artery
The internal pudendal artery exits the pelvis via the
Greater sciatic foramen
The internal pudendal artery exits the pelvis via the greater sciatic foramen to enter the
The internal pudendal artery then passes from the gluteal region to the ischioanal fossa via the
Lesser sciatic foramen
In the ischioanal fossa, the internal pudendal artery runs within the pudendal canal to reach the
Venous drainage of the erectile bodies is via the
Deep dorsal vein of the penis and clitoris
The deep dorsal vein of the penis and clitoris drain through a gap in the
The deep dorsal vein of the penis and clitoris drain through a gap in the urogenital hiatus into the
Prostatic venous and vesicle venous plexuses, respectively
Which types of innervation does the perineum receive?
Somatic, sympathetic, and parasympathetic innervation
The perineum receives SOMATIC innervation via the
Pudendal nerve (S2, S3, S4)
The pudendal nerve follows the same course as the
Internal pudendal artery and vein
The inferior rectal branch of the pudendal nerve provides MOTOR innervation to the
External nal sphincter and pelvic diaphragm
The inferior rectal branch of the pudendal nerve provides SENSORY innervation to the
Skin of the anal triangle
The dorsal nerve of the penis/clitoris provides SENSORY innervation to the
Dorsum of the penis/clitoris
The perineal branch of the pudendal nerve provides MOTOR innervation to
ALL muscles of the ddep and superficial perineal pouches
The Perineal branch of the pudendal nerve provides SENSORY innervation to the
Deep and superficial pouches and perineal skin
In the perineum, SYMPATHETIC innervation is primarily responsible for
How many pathways of SYMPATHETIC innervation are there in the perineum?
In BOTH pathways PREGANGLIONIC SYMPATHETIC NEURONS CELL BODIES ARE LOCATED AT
L1 and L2 levels of spinal cord
In pathway ONE, axons travel in
Lumbar splanchnic nerves to superior hypogastric plexus
In pathway ONE, axons travel in lumbar splanchnic nerves to the superior hypogastric plexus and then enter the pelvis via
In pathway ONE, PREGANGLIONIC SYMPATHETIC axons synapse on POSTGANGLIONIC cell bodies in the
Inferior hypogastric plexus
In pathway ONE, postganglionic axons join the
Internal pudendal artery (to travel to perineum)
In pathway TWO, axons travel down through sympathetic chain and synapse on cell bodies located in
Paravertebral ganglia (S2, S3, and S4)
In pathway TWO, postganglionic axons join ventral rami of spinal nerves S2, S3, and S4 and travel to the perineum in the
In the perineum PARASYMPATHETIC innervation is primarily responsible for
Dilating arteries of erectile bodies to stimulate erection
PREGANGLIONIC PARASYMPATHETIC axons from cell bodies in S2, S3, and S4 reach the inferior hypogastric plexus by travelling on
Pelvic splanchnic nerves
In the inferior hypogastric plexus, PARASYMPATHETIC axons synapse and then travel in