Week 21 & 22 - Male & Female Pelvis Flashcards
What two groups of muscles make up the pelvic floor?
- Levator ani
- Coccygeus
What are the functions of the pelvic floor?
- Separates pelvic cavity from perineum
- Supports pelvic viscera
- Reinforces external anal sphincter
Describe the perineum and its borders.
- Diamond-shaped region inferior to pelvic floor with anatomical borders including:
- Anterior – pubic symphysis
- Posterior – tip of the coccyx
- Laterally – inferior pubic rami and inferior ischial rami, and the sacrotuberous 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 males
- Laterally – medial surfaces of the thighs
- Posterior – superior end of the intergluteal cleft
What are the two triangular areas formed by the line between ischial tuberosities in the perineum?
- Urogenital triangle
- Anal triangle
What are the contents of the anal triangle?
- Anal aperture
- External anal sphincter muscle
- Ischioanal fossae (x2)
- Pudendal nerve
List the layers of the urogenital triangle from deep to superficial.
- Deep perineal pouch
- Perineal membrane
- Superficial perineal pouch
- Perineal fascia
- Skin
Describe the contents & boundaries of deep perineal pouch.
Boundaries:
- Superior – pelvic floor
- Inferior – perineal membrane
Contents:
- Part of urethra
- External urethral sphincter
- Vagina / bulbourethral glands
- Deep transverse perineal muscles
What is the function of the perineal membrane?
Provides attachment for muscles of external genitalia
What are the boundaries of the superficial perineal pouch?
- Superior – perineal membrane
- Inferior – superficial perineal fascia
- Posterior – perineal body
What are the contents of the superficial perineal pouch?
- Erectile tissues forming penis & clitoris
- 3 muscles - ischiocavernosus, bulbospongiosus & superficial transverse perineal muscles
- Greater vestibular glands
Describe the perineal fascia.
Continuity of abdominal fascia with two components:
- Deep fascia – covers superficial perineal muscles and protruding structures
- Superficial fascia – composed of two layers:
- Superficial layer – continuous with Camper’s fascia
- Deep layer (Colles’ fascia) – continuous with Scarpa’s fascia
What is the perineal body and its functions?
- Irregular fibromuscular mass located at junction of triangles
- Functions as a point of attachment for muscle fibres from the pelvic floor and perineum
How can infection spread from the anal aperture to the ischioanal fossa?
Infection can track laterally from anal mucosa through external anal sphincter, or from perianal hair follicles or sweat glands.
What is the pelvic pain line?
Divides pelvic pain into visceral (above the line) and somatic (below the line); corresponds to the peritoneum.
Describe the trigone of the bladder.
- Smooth triangular shaped segment of the urinary bladder wall
- Located along the posterior surface of the bladder and marks the point of opening for the two ureters
- Sensitive to stretch and expansion, which signals the brain to become aware of the “need” to urinate
What is the content of the spermatic cord?
- Vas deferens
- Testicular artery
- Cremasteric Artery & Vein
- Artery to Vas deferens
- Pampiniform plexus of veins
- Genital branch of Genitofemoral nerve
- Autonomic nerves
- lymphatics
- Processus vaginalis - fused in adults/projection of peritoneum forming pathway for testes decent
What are the layers of the spermatic cord?
- Internal spermatic fascia: derived from the transversalis fascia
- Cremasteric fascia: derived from the investing fascia of the internal oblique muscle
- External spermatic fascia: derived from the external oblique aponeurosis
What is the scrotum?
A cutaneous sac consisting of heavily pigmented skin and dartos fascia, which includes smooth muscle fibers responsible for its wrinkled appearance.
What is the purpose of testicular thermoregulation?
To maintain a temperature 3 degrees lower than abdominal temperature.
What roles do the cremaster and dartos muscles play in testicular thermoregulation?
- Cremaster muscle: pulls testes close to body
- Dartos muscle: wrinkles skin to reduce surface area for heat exchange
Describe the course of the ductus deferens.
- Begins in the tail of the epididymis
- Ascends posterior to the testis
- Penetrates the anterior abdominal wall via the inguinal canal
- Crosses over the external iliac vessels
- Enters the pelvis
- Passes along the lateral wall of the pelvis
- Joins the duct of the seminal gland to form the ejaculatory duct
Where are the seminal glands located?
Posterior to the prostate in the rectovesical pouch.
What do the seminal glands secrete?
A thick alkaline fluid with fructose and a coagulating agent.
What are the ejaculatory ducts formed by?
The union of the ducts of the seminal glands with the ductus deferens.
How do the ejaculatory ducts open into the prostatic urethra?
They open on the seminal colliculus by tiny, slit-like apertures.
What are the lobes of the prostate?
- Anterior
- Median/middle
- Posterior
- Left lateral
- Right lateral
What do the prostatic ducts open into?
The prostatic portion of the urethra through 10-12 openings.
What is the function of the prostate?
Produces thin, milky fluid rich in citric acid and acid phosphatase, contributing about 30% of the volume of seminal fluid.
What are the relations of the prostate?
- Superiorly: Continuous with the neck of the bladder
- Inferiorly: Apex lies on the upper surface of the urogenital diaphragm
- Anteriorly: Related to the symphysis pubis
- Posteriorly: Related to the anterior surface of the rectal ampulla
- Laterally: Embraced by the anterior fibers of the levator ani
What is the function of the bulbo-urethral glands?
- Produces pre-ejaculate
- Provides lubrication for the urethra and tip of the penis
- Neutralizes residual acidity in the male urethra
What is the role of the gubernaculum in the descent of the testes?
It shortens and guides the testes to the scrotum.
Outline the journey of sperm from production to ejaculation.
- Seminiferous tubules
- Straight tubules
- Rete testis
- Efferent ductules
- Epididymis
- Vas deferens
- Ampulla of deferens
- Ejaculatory duct
- Prostatic urethra
What is benign prostatic enlargement?
A condition common in males older than 50 years, possibly caused by hormonal imbalance, leading to urinary symptoms.
What complications can arise from benign prostatic enlargement?
- Back pressure effects on the ureters and kidneys
- Infection of stagnant urine in the bladder
What is a spermatocele?
Cystic dilation of epididymis, contains sperm, usually asymptomatic/painless, may require surgery if symptomatic.
Most common in 30-50 year olds and can be palpated separately from testes.
What is a varicocele?
Enlargement of veins in pampiniform plexus in scrotum, often on left side due to perpendicular angle of left testicular vein draining into left renal vein.
May elevate intra-testicular temperature.
What are the two types of testicular torsion?
Intravaginal and extravaginal.
Intravaginal occurs within tunica vaginalis, while extravaginal involves twisting of testis, cord, and processus vaginalis as a unit.
What are the common symptoms of testicular torsion?
- Acute scrotal pain
- Nausea and vomiting
- Tender & swollen
- High riding
- Scrotal erythema
- No cremasteric reflex
Immediate surgical intervention is required.
What are the layers of the ovary?
- Thin fibrous capsule - (tunica albuginea)
- Germinal epithelium - (simple cuboidal)
- Cortex - (oocyte & follicular development)
- Medulla - (loose connective tissue with blood vessels & lymphatics).
The cortex is responsible for oocyte and follicular development.
What ligaments are attached to the ovary?
- Mesovarium
- Suspensory ligament
- Round ligament.
The round ligament is a remnant of the upper part of the gubernaculum.
What are the functions of the ovaries?
Produce ova and female sex hormones (estrogen & progesterone).
These hormones are crucial for reproductive health.
What is the blood supply to the ovaries?
Ovarian arteries, which form from abdominal aorta at level L1, divide into ovarian & tubal branches.
Ovarian veins drain to IVC on right and left renal on left.
What is the four parts of the uterine tube?
- Fimbriae – finger-like, ciliated projections which capture the ovum from the surface of the ovary.
- Infundibulum – funnel-shaped opening near the ovary to which fimbriae are attached.
- Ampulla – widest section of the uterine tubes. Fertilization usually occurs here.
- Isthmus – narrow section of the uterine tubes connecting the ampulla to the uterine cavity.
Highly folded mucosa with ciliated columnar epithelium surrounded by smooth muscle layers.
What are the three layers of the wall of the body of the uterus?
Perimetrium, myometrium, endometrium.
The endometrium has three phases: proliferative, secretory, and menstrual.
What structures attach to the uterine horn/cornu?
- Round ligament (anteriorly)
- Uterine tube (centrally)
- Ovarian ligament (posteriorly)
Why is the cervix the least mobile part of the uterus?
Passive support from attached ligaments, including cardinal and uterosacral ligaments.
These ligaments provide structural support during various physiological changes.
What is the blood supply to the uterus?
Uterine arteries and collateral supply from ovarian arteries.
Uterine veins form a plexus that drains into internal iliac veins.
What are the functions of the vagina?
- Canal for menstrual fluid
- Forms inferior part of birth canal
- Adjusts during intercourse/birth
- Prevents bacterial growth
- Receives penis and ejaculate
Communicates superiorly with cervical canal and inferiorly with vestibule.
What muscles compress the vagina?
- Pubovaginalis
- External urethral sphincter
- Urethrovaginal sphincter
- Bulbospongiosus.
What are the relations of the vagina?
- Anterior - fundus of urinary bladder and urethra,
- lateral - levator ani and ureters,
- posterior - anal canal, rectum, and recto-uterine pouch.
What is the blood supply and venous drainage of the vagina?
Uterine arteries supply superior vagina, while vaginal and internal pudendal arteries supply middle and inferior parts.
Venous drainage occurs through the uterovaginal venous plexus.
What is the innervation of the vagina?
- Inferior 1/5 receives somatic innervation from deep perineal nerve;
- autonomic innervation from uterovaginal nerve plexus.
What structures are included in the female urogenital triangle?
- Mons pubis,
- labia majora,
- labia minora,
- clitoris,
- bulbs of vestibule,
- greater & lesser vestibular glands.
- Urethra & Vaginal orifices
- Perineal Body
- Vestibule of Vulva
- Hymen
What part of the female reproductive system receives somatic innervation?
Vagina and uterus
Only part receiving somatic innervation is the vagina, through the deep perineal nerve from the pudendal nerve.
What nerves are involved in the autonomic innervation of the uterus and vagina?
Uterovaginal nerve plexus from inferior hypogastric plexus
What are the functions of the vulva/pudendum?
- Sensory and erectile tissue for sexual arousal and intercourse
- Direct the flow of urine
- Prevent entry of foreign material into the urogenital tract
What is the anatomical significance of the labia majora?
- Protect clitoris, urethra, and vaginal orifices
- Pass inferoposteriorly from mons pubis to anus
- Filled with loose subcutaneous tissue containing smooth muscle
- Thicker anteriorly at the anterior commissure
- Merge posteriorly to form the posterior commissure in nulliparous women
Describe the labia minora.
- Fat-free, hairless skin
- Enclosed in pudendal cleft
- Surround vestibule of vagina
- Contains erectile tissue and small blood vessels
- Medial laminae form frenulum of clitoris
- Lateral laminae form prepuce of clitoris
What are the parts of the clitoris?
- Root
- Cylindrical body
- Glans clitoris
What is the neurovasculature of the clitoris?
- Dorsal arteries
- Large dorsal nerves
- Large central dorsal vein
What is the vestibule of the vagina?
- Surrounded by labia minora;
- Contains orifices of urethra and vagina, and ducts of vestibular glands
What are the characteristics of the bulbs of vestibule?
- Paired masses of elongated erectile tissue
- Lie along sides of vaginal orifice
- Covered by bulbospongiosus muscles
Where are the greater and lesser vestibular glands located?
- Greater vestibular glands: posterolateral to vaginal orifice
- Lesser vestibular glands: between urethral and vaginal orifices
What is the arterial supply of the vulva?
- External pudendal artery
- Internal pudendal artery (labial and clitoral branches)
What nerves provide sensory innervation to the vulva?
- Anterior labial nerves (ilioinguinal nerve, genital branch of genitofemoral nerve)
- Posterior labial nerves (pudendal nerve, posterior cutaneous nerve of thigh)
- Ilioinguinal
- Genital branch of Genitofemoral
- Pudendal
- Posterior cutaneous of thigh
What is the lymph drainage of the vulva?
Superficial and deep inguinal nodes
What is a cystocele?
Prolapse of the bladder into the anterior wall of the vagina
What is a rectocele?
Prolapse of the rectum into the posterior wall of the vagina
What is enterocele?
Small bowel prolapse pushing at the top of the vagina
What is endometriosis?
Condition where tissue similar to the lining of the uterus grows outside the uterus
What is the position of the uterus in relation to the pelvis?
- Antiverted
- Antiflexed
What forms the antero-inferior wall of the pelvic cavity?
Bodies and rami of the pubic bones and the pubic symphysis
It participates in bearing the weight of the urinary bladder.
What muscles form the pelvic floor?
Coccygeus and levator ani
The pelvic diaphragm consists of these muscles and their associated fascias.
How is the pelvic diaphragm attached?
- Laterally – attached to the tendinous arch of levator ani
- Posterolaterally – attached to the ischial spine
- Posteriorly – attached to the caudal sacrum and coccyx
- Anteriorly – attached to the posterior surface of the pubis
- Midline – fibers form a midline levator raphe
This forms the tendinous arch of the levator ani.
What are the components of the levator ani?
- Puborectalis
- Pubococcygeus
- Iliococcygeus
Each part has distinct attachments and functions.
What is the function of the puborectalis muscle?
Maintains fecal continence
It forms a U-shaped muscular sling around the anorectal junction.
What is the primary action of the coccygeus muscle?
Supports pelvic viscera and flexes coccyx
It forms a small part of the pelvic diaphragm.
What are the attachments of the obturator internus muscle?
- Pelvic surfaces of the ilium and ischium
- obturator membrane
Innervated by the nerve to obturator internus (L5, S1, S2).
True or False: The piriformis muscle assists in holding the head of the femur in the acetabulum.
True
It also rotates and abducts the hip joint.
What divides the obturator internus muscles into superior pelvic and inferior perineal portions?
The attachment of the pelvic diaphragm to the overlying obturator fascia
This division is important for understanding the structure and function of these muscles.
What is the role of the levator ani during urination and defecation?
Must relax to allow urination and defecation
Increased intra-abdominal pressure for defecation is provided by contraction of the diaphragm and abdominal wall muscles.
Fill in the blank: The lateral pelvic walls are formed by the right and left ________.
hip bones
Each hip bone includes an obturator foramen closed by an obturator membrane.
What ligaments are associated with the posterior pelvic wall?
- Anterior sacro-iliac ligament
- Sacrospinous ligament
- Sacrotuberous ligament
These ligaments are associated with the sacro-iliac joints and piriformis muscles.
What is the pelvic diaphragm’s appearance and function?
Hammock-shaped structure that supports the abdominopelvic viscera
It stretches between the anterior, lateral, and posterior walls of the lesser pelvis.
What is the primary innervation of the levator ani?
- Nerve to levator ani (branches of S4)
- Inferior anal (rectal) nerve
- Coccygeal plexus
This innervation is crucial for the function of the pelvic diaphragm.
What is the function of the iliococcygeus muscle?
Forms part of the pelvic floor and blends with the anococcygeal body
It is often poorly developed and appears more aponeurotic than muscular.
What is the proximal attachment of the Obturator internus?
Pelvic surfaces of the ilium and ischium; obturator membrane
The proximal attachment refers to where the muscle originates.
What is the distal attachment of the Obturator internus?
Greater trochanter of the femur
The distal attachment is where the muscle inserts.
What is the innervation of the Obturator internus?
Nerve to obturator internus (L5, S1, S2)
Innervation refers to the nerve supply that stimulates the muscle.
What is the main action of the Obturator internus?
Lateral rotation of the hip
The main action describes the primary movement facilitated by the muscle.
Fill in the blank: The main action of the Obturator internus is _______.
lateral rotation of the hip
True or False: The Obturator internus is innervated by the femoral nerve.
False
The Obturator internus is innervated by the nerve to obturator internus.
What is the origin of the Piriformis muscle?
- Anterior surface of the sacrum (between the S2 and S4)
- Gluteal surface of ilium (near posterior inferior iliac spine)
- Sacrotuberous ligament
The Piriformis muscle plays a crucial role in hip joint movement.
What is the insertion point of the Piriformis muscle?
Greater trochanter of the femur
The greater trochanter is a key site for muscle attachment.
Which spinal nerves innervate the Piriformis muscle?
- Nerve to the Piriformis
- (Anterior rami of S1 and S2)
These rami are essential for the motor control of the muscle.
What are the primary actions of the Piriformis muscle?
Rotates the hip joint laterally and abducts it; assists in holding the head of the femur in acetabulum
These actions are vital for hip stability and movement.
What is the origin of the Coccygeus muscle?
Ischial spine
The ischial spine serves as a critical reference point for pelvic muscles.
What is the insertion point of the Coccygeus muscle?
Inferior end of the sacrum and coccyx
This insertion helps support pelvic structures.
Which spinal nerves innervate the Coccygeus muscle?
Branches of S4 and S5 spinal nerves
These nerves contribute to the muscle’s functionality.
What are the primary functions of the Coccygeus muscle?
Forms small part of pelvic diaphragm that supports pelvic viscera; flexes coccyx
The Coccygeus muscle contributes to pelvic stability.
What is the origin of the Levator ani muscle?
- Body of pubis
- Tendinous arch of obturator fascia
- Ischial spine
This broad origin allows for significant functional capacity.
What is the insertion point of the Levator ani muscle?
- Perineal body
- Coccyx
- Anococcygeal ligament
- Walls of the prostate or vagina
- Rectum
- Anal canal
This extensive insertion supports various pelvic structures.
Which nerves innervate the Levator ani muscle?
- Nerve to levator ani (branches of S4)
- Inferior anal (rectal) nerve
- Coccygeal plexus
These nerves are crucial for muscle contraction and relaxation.
What are the primary functions of the Levator ani muscle?
Forms most of pelvic diaphragm that helps support pelvic viscera and resists increases in intra-abdominal pressure
The Levator ani is essential for maintaining pelvic organ position.
What is the parietal peritoneum?
The lining of the abdominal cavity that continues into the pelvic cavity but does not reach the pelvic floor.
What structures are covered by peritoneum in the pelvic cavity?
Only the superior and superolateral surfaces of pelvic viscera are covered by peritoneum.
Which structures are considered intraperitoneal?
In Females
- Uterus (Perimetrium)
- Uterine tubes (except ostia)
- Ovaries (suspended by a mesentery)
What type of epithelium covers the ovaries?
Germinal epithelium, which is a special, relatively dull epithelium of cuboidal cells.
What allows the bladder to expand in the anterior abdominal wall?
A loose areolar (fatty) layer between the transversalis fascia and the parietal peritoneum.
What is the supravesical fossa?
The level at which the peritoneum reflects onto the superior surface of the bladder.
What is the recto-uterine pouch?
The ‘pocket’ formed between the uterus and the rectum.
In females, what is the median recto-uterine pouch described as?
The inferiormost extent of the peritoneal cavity.
What are pararectal fossae?
Lateral extensions on each side of the rectum that are often deeper than the median recto-uterine pouch.
What forms the recto-uterine folds?
Prominent peritoneal ridges formed by underlying fascial ligaments.
What does the broad ligament of the uterus separate?
The paravesical fossae and pararectal fossae on each side.
How does the pelvic peritoneal cavity communicate with the external environment in females?
Via the uterine tubes, uterus, and vagina.
What is the rectovesical pouch?
The pouch formed when the central peritoneum reflects superiorly onto the anterior surface of the inferior rectum.
How does the depth of the female recto-uterine pouch compare to the male rectovesical pouch?
The female recto-uterine pouch is normally deeper.
What is the ureteric fold?
A gentle peritoneal fold formed as the peritoneum passes over the ureter and ductus deferens.
What structures are not in contact with the peritoneum in males?
- Male reproductive organs (except for testis in its tunica vaginalis)
- Seminal glands and ampullae of the ductus deferens
What are the peritoneal coverage characteristics of the rectum in both sexes?
- Superior third: anterior and lateral surfaces covered
- Middle third: anterior surface covered
- Inferior third: subperitoneal
Where is the rectosigmoid junction located?
Near the pelvic brim and is intraperitoneal.
