Pelvic Structure / Viscera

Front 1

Pelvic Girdle

Back 1

Basin shaped ring of bone connecting vertebral column to femurs in the thighs. It is formed by three bones:
- right and left hop bones (large irregular shaped bones that articulate with femurs
- sacrum: strong triangular bone securely wedged between hip bones


Hip bones unite anteriorly at the pubic symphysis (cartilaginous joint at the midline)

Articulation between hip bones and sacrum is via the incredible strong sacroiliac joints.

Front 2

Functions of the pelvic girdle

Back 2

- Transfer weight from upper limb/torso to the lower limbs
- Protect reproductive organs
- Protect neurovascular structure that supply pelvic organs and lower limbs

Front 3

Osteology of Hip Bone

Back 3

Each hip bone is made of three smaller bones:
- ileum
- ischium
- pubis

By early adulthood these have fused together (20-25 years old)

The fusion site is the acetabulum, the cup shaped socket tat articulates with the head of the femur.

Ilium is top part of bone, ischium is inferior part of bone.

Pubis is anterior (touches pubic symphysis) part of bone.

Pubis and ischium surround a large opening, the obturator foramen.

Front 4

Sacrum

Back 4

Five fused sacral verterbrae.

Base is located superiorly. Articulates with 5th lumbar verterbra.
Apex articulates with coccyx (tailbone).
Sacral promontory is anterior superior aspect of sacrum. It is an important obstetrical landmark.
Four ventral foramina allow passage of ventral rami of spinal nerves.
Superior articular facets articulate with 5th lumbar verterbra.

Front 5

Osteologic features of the pelvic girdle

Back 5

Iliac crest: superior border of the ilium. Provides attachment for abdominal muscles.

Anterior Superior Iliac Spine (ASIS): subcutaneous, palpable. Inguinal ligament attaches here. Can be bruised in sports injuries.

Pubic tubercle: small, well defined tubercle on pubic bone, serves as medial attachment of the inguinal ligament.

Anterior Inferior Iliac Spine: located just below the ASIS.

Iliac Fossa: depression occupying the anterior surface of the ilium. Serves as attachment site for iliacus muscle.

Front 6

More osteologic features of the (posterior ) pelvic girdle (5)

Back 6

- Ischial tuberosity: large tuberosity on posterioinferior part of ischium, where hamstrings and sacrotuberous ligament attach.

- Median sacral crest: fused spinal processes of the sacral verterbrae

- sacral hiatus: represents the absence of lamina and spinous processes of S5 vertebra

- sacral cornua are the rudimentary inferior articular processes of S5. They are important landmarks when performing sacral epidurals.

Front 7

Yet more osteologic features of the pelvic girdle

Back 7

- Ischial spine: pointed triangular protrusion projecting posteromedially from the ischium, separates greater and lesser sciatic notches (GSN/LSN). Greater is above, lesser is below.

Ischiopubic Ramus: bar-like structure formed by the fusion of rami of the ischium and pubis.

Pubic arch: angle formed by inferior rami of the pubic bones as they approach the pubic symphisis - wider in females.

Front 8

Pelvic joints

Back 8

Pubic symphysis: articulation between the hip bones, with an intervening fibrocartilagenous disc.

Sacroiliac joint: bilateral synovial articulations between the ileum and the sacrum. Sacrum like wedge between ileacus bones. Helps transfer weight from head, upper limbs and trunk to the lower extremity.

Clinical note: both the sacroiliac joints and pubic symphysis loosen during the latter months of pregnancy under the influence of the hormone relaxin as an aid in parturition.

Front 9

Sacroiliac joint

Back 9

- Sacroiliac ligaments: dorsal/ventral, help strengthen/stabilize sacroiliac joints

Iliocolumbar ligaments: runs from transverse processes of L4/L5 to iliac crest and base of sacrum.

Interosseous ligament: extremely strong ligament deep to dorsal sacroiliac ligament.

Front 10

Other pelvic ligaments

Back 10

Bony pelvis bound together by:
- sacrotuberous ligament: extremely tough ligament from lateral sacral margins to ischial tuberosity.
- sacrospinous ligament: extremely tough ligament, from lateral sacrum/coccyx to ischial spine.

Both provide resilience to sacroiliac joint when there is weight increase on joint (like when you jump).

Ligaments convert sciatic notches into greater and lesser sciatic foramen. These are gateways for structures leaving/entering the pelvis.y

Front 11

Female versus male pelvis

Back 11

FEMALE
Larger, broader, lighter, less pronounced markins, ovarl or round pelvic inlet, shallower iliac fossa, pubic arch more than 90 degrees.

MALE
Taller, narrower and more massive. More pronounced markings. Heart shaped pelvic inlet, narrower pubic arch (70 degrees, called pubic ANGLE).

Ischial tuberosities close together.

Front 12

Ligaments of Female Pelvis

Back 12

Peritoneium drapes over pelvic organs, which are retroperitoneal.

Rectouterine pouch is space between uterus and rectum.

Vesicouterine pouch is space between bladder and uterus.

Front 13

Broad ligament of Uterus

Back 13

Two layers of peritoneum extending from lateral uterus to lateral pelvic wall.
Holds uterus in position and contains uterine tube, uterine vessels, round ligament of uterus, ovarian ligament, ureter, autonomic nerves, lymphatics.

Three parts: mesovarium, mesosalpinx, and mesometrium.

Mesovarium: fold of peritoneum connecting anterior ovary with posterior layer of broad ligament. Gives attachment to ovary without actually containing it.

Mesosalpinx: fold of broad ligament that suspends the uterine tube.

Mesometrium: major part of broad ligament below mesosalpinx and mesovarium.

Front 14

Round ligament of uterus

Back 14

Attaches to uterus in front of and below the attachment of uterine tube.
Represents the remains of the lower gubernaculum.

Runs within broad ligament, hold uterus turned forward (anteverted) and anteflexed (bent forward).

Enters inguinal canal at deep ring, emerges at superficial ring and is lost in subcutaneous tissue.

Front 15

Other ligaments of female pelvis

Back 15

- Ovarian ligament: fibromuscular cord extending form ovary to uterus below uterine tube through broad ligament. AKA ovary proper ligament.

- Suspensory ligament of ovary: band of peritoneum that extends upwards from ovary to pelvic wall. Transmits ovarian artery/vein/nerves/lymphatics.

- Rectouterine ligament: in rectouterine fold. Holds cervix back and upwards.

- Other include pubocervical, sacrocervical, pubovesical and LATERAL or TRANSVERSE cervical ligaments. (aka cardinal ligament or Mackenrodt's ligament).

Front 16

Lateral cervical ligament of uterus

Back 16

AKA transverse cervical, cardinal, Mackenrodt's ligaments.

Fibromuscular condensation of pelvic fascia from cervix and lateral vagina to pelvic walls.
Extends laterally below base of broad ligament.
Contains smooth muscle, uterine vessels, nerves.

Front 17

Ovary

Back 17

On posterior side of (but not enclosed by) broad ligament. Suspended by mesovarium.

Oocyte expelled into peritoneal cavity, then uterine tube.

Supplied by ovarian artery (within) suspensory ligament and anastomoses with branches of uterine artery.

Drained by ovarian vein.

Front 18

Uterine tube

Back 18

aka fallopian tube.
Extends from uterus to ovary. Connects uterine cavity to peritoneal cavity.
Transports spermatozoa.

Fertilization takes place here, usually in infundibulum (funnel) or ampulla.

Front 19

Uterus

Back 19

Anteverted (angle of 90 degrees between vagina and cervical canal).

Anteflexes (angle of 160 degrees at junction of cervix and body).

Some variation in position of uterus. (can be retroflexed, retrocessed, anteflexed too much).
Retroversion has degrees of severity.

Supported by pelvic diaphragm, urethral sphincter muscle and ligaments:
- round ligament
- broad ligament
- lateral ligament
- pubocervical ligament
- sacrocervical ligament
- rectouterine ligament

Front 20

Vascular supply of uterus/structure of uterus

Back 20

Supplied mainly by uterine artery and secondarily by ovarian artery.

Divided into cervix (external os, cervical canal, internal os), isthmus, body and fundus.

Front 21

Sampson artery

Back 21

Anastomosis of uterine/ovarian arteries at the round ligament.

Dissected during hysterectomies.

Front 22

Vagina

Back 22

From vestibule to cervix.
Supported by levator ani, ligaments (lat., pubocervical, sacrocervical), urethral sphincter, muscle and perineal body.

Receives blood from vaginal branches of uterine artery, vaginal artery from internal iliac artery.

Dual lymphatic drainage (upper 3/4 into internal iliac nodes, lower 1/4 into perineum, superficial inguinal nodes).

Front 23

Male GI equivalent of rectouterine pouch

Back 23

Rectovesical pouch

Front 24

Arteries of Rectum

Back 24

- Superior rectal (from IMA)
- Middle rectal (from ant. division of internal iliac artery)
- Inferior rectal (from internal pudendal artery)
- Median sacral artery

Front 25

Veins of rectum

Back 25

- Superior rectal vein (to portal system)
- Middle rectal (to caval aka systemic system)
- Inferior rectal (to systemic)

Front 26

Rectum Characterisitics

Back 26

- From sigmoid colon to anal canal
- Follows curvature of sacral canal
- Ampulla is lower dilated part, where feces is stored
- Proximal 1/3 covered with peritoneum on ant., left and right sides.
- Middle 1//3 covered with peritoneum on anterior side
- Distal 1/3 not covered by peritoneum.

Three folds (superior, middle and inferior) define borders of 1/3s.

Front 27

Anal canal

Back 27

Below diaphragm and ends at anus.

Anal columns are separated by anal sinuses and anal valve.

Above line (at bottom of anal columns), we have mucous membrane, simple columnar epithelium, visceral sensory innervation (less sensitive), venous drainage to portal system, internal hemorrhoids and lymphatic drainage to internal iliac nodes.

Below pectinate line we have skin, stratified squamous epithelium, general sensory innervation (very sensitive), systemic drainage, external hemorrhoids, lymphatic drainage to superficial inguinal nodes.

Front 28

Anal canal sphincters

Back 28

Internal sphincter: thickening of circular smooth muscle in lower rectum.

External anal sphincter: skeletal muscle, subcutaneous, superficial and deep parts. Closer to anal canal.

Front 29

Ureter

Back 29

Muscular tube that transmits urine by peristaltic waves.

Three constrictions:
- at junction with pelvis of ureter in kidney
- at pelvic brim
- at junction with bladder

Vascularized by:
- aorta and renal, gonadal, common and internal iliac, umbilical, superior and inferior vesical, middle rectal arteries.

In male, passes posterior and inferior to vas deferens.

In females runs below branches of uterine artery.
Sometimes accidentally clamped during hysterectomies, along with the uterine vessels.

Front 30

Bladder

Back 30

Exits into urethra

Front 31

Bladder

Back 31

Situated below peritoneum.
Extends upwards above pelvic brim as it fills.

Trigone:
Triangle bounded by 2 uretic orifices and internal urethral orifice.

Front 32

Detrusor Muscle

Back 32

Bundles of smooth muscle fibers that form the bladder.
Supplied by superior and inferior vesical arteries (and partly from vaginal artery in female)

Drained by vesical (aka prostatic) plexus of veins.

Front 33

Testis and Epididymis

Back 33

Develops retroperitoneally and descends into scrotum retroperitnoneally.

Parietal layer of tunica vaginalis covers insides, including epididymis.

Visceral layer of tunica vaginalis covers the testes directly.

Inside, the outermost layer is tunica albuginea

The rete testis are innermost funnels, which lead into efferent ductules. These finally lead into the head->body->tail of the ductus deferens.

Front 34

Testis

Back 34

Produces spermatozoa and sex hormones.
Supplies by testicular artery, drained by pampiniform plexus of veins.
Lymphatic drainage: scrotum into superficial inguinal nodes, while testis drain into lymph vessels that ascend the testicular vessels and drain into lumbar nodes.

Front 35

Epididymis

Back 35

Matures/stores sperm.
Propulses then into vas deferens.

Front 36

Ductus deferens

Back 36

Thick walled tube, enters pelvis at deep inguinal ring lateral to inferior epigastric a.

Goes above ureter, dilates to become ampulla.

Stores spern and contains fructose which is a nutrient for spermatozoa.

Front 37

Seminal Vesicles

Back 37

Lobulated glandular structures that are diverticula of the ductus deferens.

Lie inferior and lateral to ampullae of ductus deferens against base of bladder.

Produce alkaline constituent of seminal fluid.

Front 38

Prostate Gland

Back 38

At neck of bladder.
Glandular tissue, smooth muscle and fibrous tissue.
Secretes prostate-specific antigen (PSA), prostaglandins, citric acid, acid phosphatase and proteolytic enzymes.

Front 39

Anatomy of Prostate

Back 39

Prostatic urethra runs through it.
Below we have the prostatic utricle, flanked by two seminal colliculi.

These connect to sinuses on the side.

Lower down we have two ejaculatory ducts that later join with urethra.

Front 40

Prostatic Urethra

Back 40

Contain ejaculatory duct openings, which deliver sperm from vas deferens and secretions from seminal vesicles.

Prostatic ducts open here too, deliver secretions from prostate gland.

Prostatic utricle is blind pouch, invagination similar to uterus and vagina in female.