11/15 Pelvis Anatomy Flashcards
What comprises the antero-inferior wall of the pelvic cavity?
Pubis and pubic symphysis
− Weight bearing
What comprises the lateral pelvic walls of the pelvic cavity?
Os coxae
Obturator foramen and membrane
What comprises the posterior wall of the pelvic cavity?
Bony wall and roof- sacrum and coccyx
Musculoligmantous posterolateral walls
(piriformis, sacrospinous and sacrotuberous ligaments)
What comprises the pelvic floor (inferior boundary) of the pelvic cavity?
Formed by the funnel shaped pelvic diaphragm- coccygeus and levator ani muscles and fascia
What does the pelvic inlet (superior pelvic aperture) divide? What defines it?
Divides the pelvis into greater and lesser pelvis
Defined by the pelvic brim
What composes the pelvic brim?
Sacral promontory, bilateral linea terminalis
What comprises the pelvic outlet (inferior pelvic aperture)?
Pubic arch, ischial tuberosities, sacrotuberous ligaments, and tip of the coccyx
What comprises the greater pelvis (false pelvis)?
Abdominal viscera
What composes the lesser pelvis (true pelvis)?
Between the pelvic inlet and outlet
Where is the lesser pelvis (true pelvis)?
Between the pelvic inlet and outlet
The pelvic girdle is a basin-shaped ring of bones that connects the
Vertebral column and femurs
Is the pelvic girdle stronger or weaker than the pectoral girdle?
Stronger
What are the functions of the pelvic girdle?
To bear and transport weight of upper body.
Provide attachment for the powerful muscles of locomotion, posture, abdominal wall, erectile bodies, and membranes.
Support and protect the abdominopelvic viscera.
What bones make up the pelvic girdle?
Ilium, ischium, pubis
What kind of cartilage separates the pelvic girdle bones?
Triradiate
The triradiate cartilage parts of the pelvic girdle are
Sacroiliac joint, pubic symphysis
At what age do the sacroiliac joint and pubic symphysis fuse the pelvic girdle?
13-16 years old
In anatomical position of the pelvic girdle, what lies in the same plane?
ASIS and anterior aspect of pubic symphysis lie in the same vertical plane
What do the sacrospinous ligament and the sacrotuberous ligaments of the pelvic girdle prevent?
anterioinferior rotation of the upper sacrum
What are the two ligaments of the pelvic girdle that prevent anterioinferior rotation of the upper sacrum?
Sacrospinous ligament, sacrotuberous ligament
What does the sacrospinous ligament connect?
Sacrum to ischial spine
What does the sacrotuberous ligament connect?
Posterior ilium, lateral sacrum and coccyx to ischial tuberosity
What do the sacrospinous and sacrotuberous ligaments form?
The greater and lesser sciatic foramen
What are the features of the male pelvis?
Narrow arch and angle
Greater pelvis- deep
Lesser pelvis- narrow and deep
Pelvic inlet- heart shaped
Large acetabulum
What are the features of the female pelvis?
Wide arch and angle
Greater pelvis- shallow
Lesser pelvis- wide and shallow
Pelvic inlet- oval and rounded
Smaller acetabulum
What are the pelvic arch and angle like in a male and female pelvis?
Male: narrow arch and angle (2nd and 3rd digits spread apart)
Female: wide arch and angle (thumb and 2nd digits spread apart)
What is the difference of the greater pelvis in a male versus female?
Male: deep
Female: shallow
What is the difference in the lesser pelvis in a male and female?
Male: narrow and deep
Female: wide and shallow
What is the difference in the pelvic inlet in males versus females?
Males: heart shaped
Females: oval and rounded
What is the difference in the acetabulum in males versus females?
Males: large
Females: smaller
What happens to the pelvic ligaments during pregnancy?
Increased levels of sex hormones and relaxin permits as much as 10-15% increase in diameter
Increased circumference of the lesser pelvis
Increased flexibility of the pubic symphysis
What ligaments relax due to relaxin in pregnancy?
ALL ligaments, not just in the pelvic region
How is the pelvic diaphragm/floor shaped? Where is it?
Bowl/funnel shaped muscular hammock, within lesser pelvis
What does the pelvic diaphragm/floor separate?
Separates the pelvic cavity from the perineum
Is the pelvic diaphragm/floor contracted? How so?
Always tonically contracted and is actively contracted during times of increased pressure (sneezing, jumping, etc.)
What is the pelvic diaphragm comprised of?
Coccygeus, Puborectalis, Pubococcygeus, Iliococcygeus, Fascia
What makes up the levator ani?
Puborectalis, Pubococcygeus, Iliococcygeus
What does the pelvic diaphragm attach to? What muscle does it divide?
Attaches to the overlying obturator fascia divides the obturator internus muscle into superior pelvic portion and inferior perineal portion
What is the puborectalis?
Thicker, narrower, medial part of the levator ani muscle.
U-shaped muscular sling that passes posterior to the anorectal junction.
Maintains fecal continence.
What does the pelvic floor support during birth?
Supports the fetal head while the cervix is dilating in preparation for birth
Which muscles of the pelvic floor are more likely to be torn?
Pubococcygeus and puborectalis
What are some of the consequences of damage to the pelvic floor during childbirth?
The muscles damaged during childbirth encircle and support the urethra, vagina, and anal canal. Weakening of these results in stress incontinence and/or prolapse of pelvic organs.
What kinds of pelvic floor dysfunctions can males have?
Male urinary dysfunction, erectile dysfunction, chronic pelvic pain
What is male urinary dysfunction?
leaking urine after expression, incontinence, constipation and other issues
What is male erectile dysfunction?
difficulty achieving and/or maintaining an erection
What are the peritoneal pouches
Peritoneum
Supravesicular
Paravesicular
Vesicouterine/rectovesicle
Broad ligament/ureteric folds
Rectouterine/rectovesical
Pararectal
1
Peritoneum
2
Supravesicular
3
Paravesicular
4
Vesicouterine/rectovesicle
5
Broad ligament/ureteric folds
6
Rectouterine/rectovesical
7
Pararectal
What is the pelvic fascia a continuation of?
The endoabdominal fascia
What types of pelvic fascia are there?
Membranous (parietal and visceral)
Endopelvic (loose and condensed)
What types of membranous pelvic fascia are there?
Parietal and visceral
What is the parietal membranous fascia and what does it cover?
Deep fascia
Lines the inner aspect of the muscles forming the walls and floor of the pelvis
What is the visceral membranous fascia and what does it cover?
Adventitia
Ensheathes the pelvic organs
What is the area where the parietal and visceral layers of membranous pelvic fascia meet? Where is it?
Tendinous arch of pelvic fascia
Bilateral band from pubis to sacrum
What is the tendinous arch of pelvic fascia called in males/females?
Males: puboprostatic ligament
Females: pubovesical ligament
What is the endopelvic fascia and what does it do?
Abundant CT between two membranous layers.
Acts as “packing material” for pelvic viscera.
What are the types of endopelvic fascia?
Loose areolar endopelvic fascia
Condensed endopelvic fascia
What is the loose areolar endopelvic fascia and where is it?
Loose areolar CT, fatty.
Found near the retropubic and retrorectal spaces
What is the condensed endopelvic fascia?
Pelvic ligaments- CT, SM and neurovascular bundles
A
Umbilical artery (anterior division)
B
Where does it run
Obturator artery
runs antero-inferiorly on the obturator fascia on the lateral wall of the pelvis
C
Superior vesical
Superior portion of bladder
E
Lateral sacral
F
Where does it go?
Inferior gluteal
usually passes between S2 and S3; inferior to piriformis
G
Inferior vesical
(Male only - inferior portion of bladder)
H
Where does it go?
Internal pudendal
passes inferolaterally, anterior to piriformis and sacral plexus. Leaves the pelvis between the piriformis and coccygeus.
I
Middle rectal
I
Middle rectal
J
Where does it go?
Superior gluteal
Passes between the lumbrosacral trunk and S1 ventral ramus
A
Superior gluteal
B
Umbilical
C
Obturator
D
Superior vesical
E
Uterine
(Female only)
F
Iliolumbar
G
Inferior gluteal
H
Lateral sacral
Far right unlabeled
Internal pudendal
I
Middle rectal
J
Vaginal
What spinal levels does the obturator nerve come from?
L2-4
Where does the obturator nerve pass?
Obturator canal
What does the obturator nerve divide into?
anterior and posterior contributions to supply the medial thigh muscles
What roots is the lumbosacral trunk from?
L4-5
How is the lumbosacral trunk formed?
Descending part of L4 nerve unites with anterior ramus of L5, forming the lumbosacral trunk
Where does the lumbosacral trunk go?
Passes along anterior ala of sacrum to join the sacral plexus
What roots does the sacral plexus come from?
L4-S3
What does the sacral plexus continue as?
Sciatic nerves, pudendal nerves
What does the coccygeal plexus come from?
S4-5, coccygeal nerves
Where is the coccygeal plexus and what does it supply?
Lies on the pelvic surface of the coccygeus.
Supplies coccygeus muscle, part of levator ani and the sacrococcygeal joint.
What are the four primary groups of lymphatic nodes for drainage of the pelvis?
External iliac, internal iliac, sacral, common iliac
receive lymph mainly from the inguinal lymph nodes but also pelvic viscera. These nodes drain into the common iliac nodes
External iliac nodes
clustered around the anterior and posterior divisions of the artery. Receive lymph drainage from the inferior pelvic viscera, deep perineum, and gluteal region. These drain into the common iliac nodes
Internal iliac nodes
located in the concavity of the sacrum, adjacent to the median sacral vessels. Receive lymph from postero-inferior pelvic viscera and drain to either internal or common iliac nodes
Sacral nodes
superior to pelvic brim along the common iliac blood vessels. Receive lymph drainage from external iliac, internal iliac and sacral nodes. Drain next to the lumbar nodes.
Common iliac nodes
What nodes drain into the common iliac nodes?
External iliac nodes, internal iliac nodes, sacral nodes
