28. Male and Female Perineum Flashcards
Viewed from below, the perineum is a diamond-shaped area located between the thighs — what are the lateral, posterior, and anterior boundaries of the perineum?
Lateral = ischiopubic rami and sacrotuberous ligament
Posterior = coccyx
Anterior = pubic symphysis
The perineum can be described as a 3D structure which has superior and inferior limits. The superior boundary, or _____ _____ separates the perineum from the pelvic cavity. The inferior boundary is the surface of the skin associated with the ______ _____ and anal canal
Pelvic diaphragm; external genitalia
The perineum can be divided into 2 triangles by drawing an imaginary horizontal line between the 2 _____ _______. In the midline, this line will pass through the ____ ______.
What are the 2 named triangles this line makes?
Ischial tuberosities; perineal body
Urogenital triangle; anal triangle
What are the boundaries of the urogenital triangle?
Pubic symphysis
Ischiopubic rami
Imaginary line drawn between ischial tuberosities
What are the boundaries of the anal triangle?
Coccyx
Sacrotuberous ligaments
Imaginary line drawn between ischial tuberosities
The _____ ______ are wedge-shaped spaces on either side of the anal canal
Ischiorectal fossae
What are the boundaries of the ischiorectal fossae including the lateral walls, superomedial walls, and bases?
Lateral wall = obturator internus and ischium
Superomedial wall = levator ani and anal canal
Base = skin of perineum
The ____ ___ is 4 cm long and continuous with the rectum. It is oriented in a posteroinferior direction, due in part fo the anterior pull of the _______ m. It terminates at the anus
Anal canal; puborectalis
2 sets of anal sphincters surround the anal canal. The _______ is a layer of circular smooth muscle found in the upper 2/3 of the anal canal; it is controlled by _______ fibers from ______ nerves
Internal anal sphincter; parasympathetic; pelvic splanchnic
The ________ is composed of circular skeletal muscle which surrounds the lower 2/3 of the anal canal. These muscle fibers are attached to the _____ ligament posteriorly, and the ________ anteriorly. It is consciously controlled by the ______ n., a branch of the ______ n.
External anal sphincter; anococcygeal; inferior rectal; pudendal
What anatomical distinction makes distension of the anal canal possible during defecation?
Made possible bc the ischiorectal fossae are filled with fat (in other words, there are no vital organs in close proximity to interfere with its distention)
On the lateral walls of the ischiorectal fossae are the ____ _____, located on the medial surface of the ____ ___ m.
Pudendal canals; obturator internus
Contained within the pudendal canals are the _____ n. and the _______ a. and v. Passing from the pudendal canal to the anal canal are the _______ artery, vein, and nerve which travel through the ischiorectal fossae
Pudendal; internal pudendal; inferior rectal
The urogenital triangle can be divided into _____ and _____ spaces
Deep; superficial perineal
[pouches or spaces]
The deep perineal pouch in the urogenital triangle include the _____ _____, a continuous sheet of muscle that spans the gap between the ischiopubic rami. The superior fascia and inferior fascia of the perineal membrane are fused along the anterior and posterior borders. The ____ _____ is attached to the midpoint of the posterior border
Urogenital diaphragm; perineal body
In women, the urogenital diaphragm is split into two halves by the vagina. Contained within this diaphragm are the following:
The first part of the urethra in ______, and the membranous urethra in _____.
Deep perineal muscles: in males, the external urethral sphincter surrounds the _________ urethra. It relaxes to allow urination to occur or when ejaculation occurs. The ___________ m. inserts in the perineal body in both males and females.
The _______ glands in males have ducts which empty into the ______ urethra; during sexual excitement they secrete a clear mucous which lubricates the urethra prior to ejaculation
Females; males
Membranous; deep transverse perineus
Bulbourethral; penile
The superficial perineal space is a potential space deep to the perineal skin that covers the external genitalia. In females, this space is split in 2 halves by the _____ of the vagina.
Vestibule
What are the contents of the superficial perineal space in males?
Root of penis + right and left crura Bulb of penis Ischiocavernosus m. Bulbospongiosus m. Superficial transverse perineus m.
In males, the _____ m. (bilateral) surround the free surface of each _____ of the root of the penis. They attach to the ischiopubic rami and insert into the _____ _____ which is comprised of erectile tissue
Ischiocavernosus; crus; corpora cavernosa
How do the ischiocavernosus and bulbospongiosus mm. help to maintain an erection in males?
They compress the veins which drain the corpora cavernosa
The _____ m. in males arises from the perineal body and raphe of the penis, then wraps around the bulb and posterior part of the _____ ______, which is also comprised of erectile tissue. It aids in compressing/emptying the urethra of urine or semen.
Bulbospongiosus; corpus spongiosum
______ _____ fascia covers the muscles in the superficial perineal space
Deep perineal
What muscle is located in the superficial perineal space, along the posterior border of the UG diaphragm?
Superficial transverse perineus m.
The body, or shaft, of the penis consists of skin and three bodies of erectile tissue, including the _______ and bilateral _______. ____ fascia covers the 3 sets of erectile tissue
Corpus spongiosum; corpora cavernosa; Buck’s
The superficial perineal space in females contains the vulva or external genitalia, which includes what major structures?
Labia majora Labia minora Mons pubis Vestibule of vagina Clitoris Bartholin’s glands Superficial transverse perineus m.
The labia majora unite anteriorly to form the ______. The labia minora surround the vestibule of the vagina, which contains the external urethral orifice, vaginal orifice, openings of the _____ glands, and the ________ _____ glands. The urethra contains an external urethral sphincter which relaxes to allow urination to occur.
Mons pubis; paraurethral; greater vestibular
The clitoris is the female homologue to the penis in males. What are the major parts of the clitoris?
Two crura
Two corpora cavernosa
One body
One glans clitoris
Each crus of the clitoris is continuous with a ________, which is composed of erectile tissue. These 2 parts are surrounded by an _________ m., which contracts during sexual arousal to slow the return of venous blood from the corpus cavernosum
Corpus cavernosum; ischiocavernosus
In females, the 2 corpora cavernosa unite to form the ______. The _______ is attached to the body and is axternally visible
Body of the clitoris; glans clitoris
In addition to the vulva, the superficial perineal space in females includes several important strucures which are deep to the skin. These include:
The _____ of the vestibule, which are located deep to the skin of the labia minora and are comprised of erectile tissue. Each one is covered by a _______ m., which is attached to the perineal body. During sexual arousal this muscle compresses the bulbs of the vestibule to slow the return of venous blood.
_______ glands, which produce a clear mucous during sexual arousal which lubricates the vulva
_______ mm. which attach to the perineal body
Bulbs; bulbocavernosus
Greater vestibular (Bartholin’s)
Superficial transverse perineus
Arterial supply to the perineum is provided by two major vessels:
The ______ a., which is a branch of the ______, enters the perineum via the lesser sciatic foramen and then enters the pudendal canal. It gives branches to the anal canal and ischiorectal fossa, deep perineal space, and superficial perineal space. Included in its important branches are the _____ arteries, which supply the erectile tissues and dorsal arteries of the penis and clitoris.
The ______a., a branch of the _______, sends deep and superficial branches to the scrotum and penis in the male, and the labia majora and clitoris in the female
Internal pudendal; internal iliac a.; helicine
External pudendal; femoral
The _______ n. Sends branches to all perineal structures supplied with blood from the internal pudendal a.
Pudendal n. (S2-S4)
What 4 modalities are included in the pudendal n. (S2-4) supplying the perineal region?
Preganglionic parasympathetics (GVE) — glands and smooth muscle
Somatic motor fibers (GSE) — skeletal m.
Somatic sensory fibers (GSA) — sensation in perineal skin, distal portion of anal canal, distal vaginal canal
Postganglionic sympathetic fibers (GVE) — glands and smooth muscle
In addition to the pudendal n., what other n. supplies the perineal region with cutaneous branches?
Posterior femoral cutaneous n.
The superficial perineal space, distal portions of the vagina, and anal canal (below the pectinate line) drain to the _______ nodes.
The deep perineal space, proximal portion of vagina, proximal portion of anal canal (above pectinate line) drain to _____ nodes
Superficial inguinal
Internal iliac
_______ = surgical incision made in the area between the vagina and anus during the last stages of labor and delivery to expand the opening of the vagina to prevent a perineal tear during delivery
Episiotomy
What are the 4 types of episiotomy, which one is the most common?
Mediolateral episiotomy
What structures are cut during a typical episiotomy?
Posterior vaginal wall
Bulbocavernosus m.
Superficial transverse perineus m.
Skin and associated subcutaneous fascia
To repair an episiotomy, the obstetrician places 3 layers of sutures in what order?
- Vaginal wall
- Muscle layer
- Subcutaneous fascia and skin
What are the 4 types of episiotomy?
Medio-lateral (most common)
Midline
Lateral
J-shaped
What autonomic plexus supplies the prostate, vesicle, utero-vaginal region, and rectum?
Inferior Hypogastric plexus
What foramina do the internal pudendal vessels and pudendal n. pass through?
Greater and lesser sciatic foramina
