Pelvis 427-460?

The 2 regions of the pelvis

False (greater) pelvis and true (lesser) pelvis

The superior region of the pelvis that’s related to the upper parts of the pelvic bones and lower lumbar vertebrae; generally considered part of the abdominal cavity.

False (greater) pelvis

The region of the pelvis that’s related to the inferior parts of the pelvic bones, sacrum, and coccyx, and has an inlet and an outlet.

True (lesser) pelvis

The bowl-shaped cavity that’s enclosed by the true pelvis; consists of the pelvic inlet, walls, and floor; continuous superiorly with the abdominal cavity and contains elements of the urinary, gastrointestinal, and reproductive systems.

Pelvic cavity

The structure that’s inferior to the floor of the pelvic cavity and its boundaries form the pelvic outlet; contains the external genitalia snd external openings of the genitourinary and gastrointestinal systems.

Perineum

Functions of the pelvis: contains and supports the _________ and anchors the _______

bladder, rectum, anal canal, and reproductive tracts; roots of the external genitalia

What structure is the rectum continuous with at what vertebral level, and terminates at what structure?

Sigmoid colon; SIII; anal canal

What female structure penetrates the pelvic floor and connects with the uterus in the pelvic cavity?

Vagina

A tube in the female reproductive system that extends laterally on each side toward the pelvic wall to open near the ovary.

Uterine (fallopian) tube.

Major glands associated with the male reproductive system that is contained in the pelvic cavity.

The prostate and two seminal vesicles.

What two reproductive structures are anchored to the bony margin of the anterior half of the pelvic outlet and a thick, fibrous, perineal membrane, which fills the area? These consists of erectile (vascular) tissues and associated skeletal muscles.

The roots of the external genitalia, the clitoris and penis.

Somewhat heart shaped and completely ringed by bone; bordered by the body of vertebra SI.

Pelvic inlet

What bony feature forms the posterior border of the pelvic inlet, projecting forward from the body of the S1 vertebra?

Sacral promontory

Wing-like transverse processes on each side of the sacral promontory that contribute to the margin of the pelvic inlet

Alae (wings)

The 2 ligaments that are important architectural elements of the walls of the pelvic cavity because they link each pelvic bone to the sacrum and coccyx.

Sacrospinous and sacrotuberous ligaments

The 2 notches that the sacrospinous and sacrotuberous ligaments convert into foramina on the lateral pelvic walls.

Greater and lesser sciatic notches.

The muscles that complete the walls of the pelvis, which arise in the pelvis and exit through the sciatic foramina to act on the hip joint.

Obturator internus and piriformis muscles

Diamond-shaped outlet that’s formed by both bone and ligaments; it’s limited anteriorly in the midline by the pubic symphysis.

Pelvic outlet

On each side, the inferior margin of the pelvic bone projects posteriorly and laterally from the pubic symphysis to end in a prominent tuberosity, the ____.

Ischial tuberosity

Structures in the pelvic outlet that can be palpated

Pubic symphysis, ischial tuberosities, and coccyx.

Separates the pelvic cavity from the perineum; formed by muscles and fascia

Pelvic floor

What two muscles attach peripherally to the pelvic walls, join at the midline connective tissue raphe, and form the largest components of the pelvic diaphragm?

Levator ani muscles

What bowl- or funnel-shaped structure is formed mainly by the levator ani muscles and completed posteriorly by the coccygeus muscles?

Pelvic diaphragm

Which muscles complete the pelvic diaphragm posteriorly, overlie the sacrospinous ligaments, and pass between the sacrum/coccyx and the ischial spine?

Coccygeus muscles

The coccygeus muscles pass between the margins of the sacrum and coccyx to attach to what prominent spine on the pelvic bone?

Ischial spine

The pelvic floor is supported anteriorly by ___

The perineal membrane and muscles in the deep perineal pouch.

A thick, triangular fascial sheet that fills the space between the arms of the pubic arch, and has a free posterior border.

Perineal membrane

Lined by peritoneum continuous with the peritoneum of the abdominal cavity that drapes over the superior aspects of the pelvic viscera, but in most regions, does not reach the pelvic floor

Pelvic cavity

Structure that lies inferior to the pelvic floor between the lower limb; its margin is formed by the pelvic outlet.

Perineum

What divides the perineum into 2 triangular regions?

Imaginary line between the ischial tuberosities

Anterior perineum that contains the roots of the external genitalia and, in women, the opening of the urethra and the vagina. In men, the distal part of the urethra is enclosed by erectile tissues and opens at the end of the penis.

Urogenital triangle

Posterior perineum that contains the anal aperture

Anal triangle

3 apertures in the pelvic wall that communicate with the lower limb:

Obturator canal, greater sciatic foramen, and lesser sciatic foramen.

Forms a passageway between the pelvic cavity and the adductor region of the thigh, and is formed in the superior aspect of the obturator foramen, between bone, a connective tissue membrane, and muscles that fill the foramen.

Obturator canal

Lies inferior to the pelvic floor, provides communication between the gluteal region and the perineum.

Lesser sciatic foramen

The pelvic cavity also communicates directly with the perineum through a small gap between what 2 structures?

Pubic symphysis and perineal membrane.

The pelvic inlet is angled at what angle forward relative to the horizontal plane?

50-60 degrees

Which 2 structures lie in the same vertical plane in the anatomical position?

Anterior superior iliac spines and superior edge of the pubic tubercle

What structure drains the kidneys, course down the posterior abdominal wall, and cross the pelvic inlet to enter the pelvic cavity, and continue inferiorly along the lateral pelvic wall and ultimately connect with the base of the bladder?

Ureters

In women, what crosses the ureter lateral to the cervix of the uterus?

Uterine artery

In men, what crosses over the ureter just posterior to the bladder?

Ductus deferens

In men, what is situated immediately anterior to the rectum, just aboved the pelvic floor?

Prostate gland

In both sexes, what can be evaluated during a rectal examination by a clinician?

Anal canal and lower rectum

In women, which structures are palpable?

Cervix and lower part of the body of the uterus

Easier way of palpation where the index and middle fingers of a clinician’s hand are placed in the vagina and the other hand is placed on the lower anterior abdominal wall; can also be used to examine the ovaries and uterine tubes.

Bimanual examination

What are the dermatomes of the perineum in both sexes?

Spinal cord levels S3 to S5, except for the anterior regions.

What nerves innervate the anterior regions of the perineum?

Spinal cord level L1 by nerves associated with the abdominal wall.

Which dermatomes are predominantly in the lower limb?

L2 to S2

What spinal cord levels innervate the external anal sphincter and external urethral sphincter?

S2 to S4

Much of the somatic motor and sensory innervation of the perineum is provided by what?

Pudendal nerve from spinal cord levels S2 to S4

The major nerve of the perineum and is directly associated with the ischial spine of the pelvis.

Pudendal nerve

Which structures separate the greater sciatic foramina from the lesser sciatic foramina on the lateral pelvic wall?

Ischial spines and attached sacrospinous ligaments

What structure can be palpated transvaginally in women snd is the landmark that can be used for administering a pudendal nerve block?

Ischial spine

Which parasympathetic innervation from spinal cords levels controls genital erection in both women and men?

S2 to S4

On each side, preganglionic parasympathetic nerves leave the anterior rami of the sacral spinal nerves and enter where on the lateral pelvic wall?

Inferior hypogastric plexus (pelvic plexus)

Which plexuses are inferior extensions of the abdominal prevertebral plexus that forms on the posterior abdominal wall in association with the abdominal aorta?

2 inferior hypogastric plexuses

Nerves derived from the inferior hypogastric plexuses penetrate the pelvis floor to innervate what?

Erectile tissues of the clitoris (women) and penis (men)

Where do the structures of the pelvic floor intersect with the structures in the perineum?

Perineal body

What structure is located at the center of the perineum, approved midway between the 2 ischial tuberosities?

Perineal body

Which muscles of the pelvic diaphragm converge at the perineal body?

Levator ani muscles

Which sphincters from the urogenital and anal triangles converge at the perineal body?

The skeletal muscle sphincters of the urethra, vagina, and anus

Which sex has a urethra that is short and passes inferiorly from the bladder through the pelvic floor and opens directly into the perineum?

Women

Which sex has a urethra that passes through the prostate before the coursing through the deep perineal pouch and perineal membrane and then becomes enclosed within the erectile tissues of the penis before opening at the end of the penis?

Men

The 2 angles of the penile part of the male urethra

Fixed angle and distal angle

Location of the fixed, more important angle where the male urethra bends anteriorly after the perineal membrane

Root of the penis

When does the distal angle where the unattached part of the penis curves inferiorly disappears?

When the penis is erect

What do the bones of the pelvis consist of?

Right and left pelvic (hip) bones, sacrum, and coccyx

The sacrum articulates superiorly with what vertebral level and at what joint?

LV; lumbosacral joint

The pelvic bones articular posteriorly with the ____ at the ____ joint and with each other anteriorly at the ____

Sacrum; sacro-iliac joints; pubic symphysis.

Bone that is irregular in shape and has 2 major parts separated by an oblique line on the medial surface of the bone

Pelvic bone

The 2 major parts of the pelvic bone separated by an oblique line on the medial surface of the bone

False (greater) and true (lesser) pelvis

The pelvic bone above this oblique line represents the lateral wall of the ____, which is a part of the _____.

False pelvis; abdominal cavity

The pelvic bone below this oblique line represents the lateral wall of the _____, which contains the ___

True pelvis; pelvic cavity

The lower thirds of the oblique line and contributes to the margin of the pelvic inlet.

Linea terminalis

What is the large articular socket on the lateral surface of the pelvic bone, which together with the head of the femur, forms the hip joint?

Acetabulum

What is inferior to the acetabulum?

Obturator foramen

the obturator foramen, most of which is closed by what flat connective tissue membrane?

Obturator membrane

What remains open superiorly between the obturator membrane and adjacent bone, providing a route of communication between the lower limb snd pelvic cavity?

Obturator canal

The posterior margin of the pelvic bone is marked by two notches separated by the ischial spine:

Greater and lesser sciatic notch.

The posterior margin of the pelvic bone terminates inferiorly as the large ____.

Ischial tuberosity

The irregular anterior margin of the pelvic bone is marked by what 3 structures?

Anterior superior iliac spine, anterior inferior iliac spine, and pubic tubercle

Components of the pelvic bone

Ilium, pubis, and ischium

At birth, the elements of the pelvic bone are connected by ___ in the area of the ____

Cartilage; acetabulum

At what age does the elements of the pelvic bone fuse into a single bone?

Between 16 and 18 years old

Component of the pelvic bone that is the most superior in position

Ilium

The ilium is split into upper and lower parts by what?

A ridge on the medial surface

Posteriorly, the medial ridge of the ilium is… [sharp or rounded]?

Sharp

Anteriorly, the medial ridge of the ilium is... [sharp or rounded?]

Rounded

What is the rounded, anterior part of the medial ridge called?

Arcuate line

What shape is the articular facet on the sacral surface of the ilium?

L-shaped

What is the purpose of the expanded, roughened area posterior to the sacral facet?

Ligament attachment (supports sacro-iliac joint)

The arcuate line forms part of what 2 structures?

Linea terminalis and pelvic brim

The portion of the ilium lying inferiorly to the arcuate

line is the ____ part of the ilium and contributes to the

wall of the _____.

Pelvic; lesser/true pelvis

What does the upper part of the ilium expand to form into, which provides bony support for the lower abdomen, or false pelvis? This part of the ilium provides attachment for muscles functionally associated with the lower limb.

Flat, fan-shaped wing

The anteriormedial surface of the wing of the ilium is concave and forms the ____.

Iliac fossa

Part of the wing of the ilium that is marked by lines and roughenings and is related to the gluteal region of the lower limb

External (gluteal) surface of the wing

The superior margin of the ilium is thickened to form what?

Prominent crest (iliac crest)

The iliac crest terminates anteriorly as ____ and posteriorly as ____.

Anterior superior iliac spine; posterior superior iliac spine

A prominent tubercle that projects laterally near the anterior end of the crest

Tuberculum of the iliac crest

The posterior end of the iliac crest thickens to form what?

Iliac tuberosity