Lecture 2.6 Pelvis And Perineum

Front 1

Pelvic Region

Back 1

Area of transition b/w trunk and lower limbs

Enclosed by bones, ligaments and muscles.

Front 2

Pelvic Girdle

Back 2

Ilium, Pubis, Ischium. These three bones are fused together.

Front 3

Joints of the Pelvic Girdle

Back 3

Sacroiliac joint (b/w ilium and sacrum) Sacrospinous ligament

Sacrotuberous ligament

Greater sciatic Foramen- formed b/w ligaments

Lesser sciatic Foramen- below. Formed b/w sacrospinous lig and sacrotuberous lig

Front 4

Pelvic inlet

Back 4

Marked by

the arcuate line of ilium

Pecteneal line of pubis

Superior

Open to abdominal cavity

Front 5

Pelvic outlet

Back 5

marked by the

ischial tuberosities

pubic symphysis and arch, coccyx

Inferior

Closed by pelvic diaphragm (levator ani and coccygeus)

Front 6

Sex differences in pelvis

Back 6

See picture

Front 7

Pelvic cavity

Back 7

Funnel shaped space bound by bones of pelvis.

-Greater pelvis: b/w ala of ilium and pelvic inlet

-Lesser pelvs: b/w pelvic inlet and pelvic outlet

Continous with abdominal cavity

Conatins urinary bladder, terminal part of ureters, pelvic genital organs and rectum

Front 8

Perineum

Back 8

Triangular area of trunk b/w thighs and buttocks extending from the pubis to coccyx. Seen best in lithotomy position (diamond shaped) separated from pelvic cavity by the pelvic diaphragm

Front 9

Perineum contents

Back 9

2 parts:

1. urogenital triangle/region

2. Anal triangle/region

Males: Penis, Scrotom, Anus

Females: Vulva (clitoris and Vagina), Anus

Front 10

Muscles of Pelvic Wall and Floor

Back 10

Obturator internus, Coccygeus, Piriformis and Levator Ani (puberctalis, pubococcygeus, and iliocyccygeus)

Front 11

Greater Sciatic Foramen

Back 11

B/w ligaments, Piriformis runs throug this along with nerves and arteries going to the gluteal region.

Front 12

Pelvic Diaphragm

Back 12

Levator Ani + Coccygeus

Forms floor of pelvic, supporting abdominiopelvic organs

Aids in urinary and fecal continance

Front 13

Tendinous arch of levator ani

Back 13

Formed from the thicken fascia of obturator internus muscle.

Origin of levator ani muscle.

Front 14

Function of pelvic diaphragm

Back 14

Supports abdominopelvic viscera during couging, sneezing etc. Also raises the pelvic floor during urination, vomiting, coughing and weight lifting increasing the intra-abdominal pressure.

Aids in urinary and fecal continance

During parturition, it supports the fecal head while the cervix dialates for delivering a baby

Front 15

Walls of pelvic cavity

Back 15

Posterior (sacrum, piriformis)

anterior (pubic rami, pubic symphysis)

lateral (obturator internus)

Inferior (levator ani muscles, coccygeus)

Superior (open to abdominal cavity)

Front 16

List of arteries in pelvis

Back 16

Aorta, common iliac, external iliac (becomes femoral in lower limb), internal iliac, iliolumbar, lateral sacral, superior gluteal, inferior gluteal, internal pudendal, middle rectal, superior vesical, inferior vesical, and umbilicial A.

Front 17

Blood supply to pelvic viscera

Back 17

Umbilical A---> superior vesical aa.

Inferior vesical A (males)/ Uternine A (females)

Middle Rectal A

Front 18

Blood supply to walls of pelvis

Back 18

Lateral sacral A

Iliolumbar A

Front 19

How does blood exit pelvis?

Back 19

Exits to perineum:

Internal pudendal A---> inferior rectal A

Exits to lower limb:

Obturator A

Superior gluteal A

Inferior gluteal A

**Gonads (testies and ovaries receive blood from abdominal aorta, rectum receives blood from inferior mesenteric A (superior rectal)

Front 20

Peritoneal recesses

Back 20

Deepest points of the peritoneal cavity, these are sites where infection and fluids typically collect.

Males: rectovesicle pouch

Females: rectouterine pouch (of douglass) and vesicouterine pouch

Front 21

Rectum Anal Canal and Anus

Back 21

Rectum: superior to levator ani

Anal canal: inferior to levator ani

Anus: Opening

Front 22

Urinary System

Back 22

Ureters: drain urine from kidneys to urinary bladder

Urinary bladder: temporarily stores urine

Urethra: conducts urine from urinary bladder to exterior

** in adults, urinary bladder is in the retropubic space w/in lesser pelvis. in children bladder is in abdomen, enters greater pelvis @ age 6 and lesser pelvis @ age 16.

Front 23

Urinary bladder muscles/sphincters and innervation

Back 23

Wall of bladder made of detrusor muscle. Internal (involuntary) and external (voluntary) urethral spincters help maintain continence. Sympat. innerv(T11-L2) maintain continence by contraction of internal sphincter

Parasymp innerv (S2-S4) allows urination by relaxing internal sphincter and contracting detrusor muscle.

Front 24

Male urethra parts (superior to inferior)

Back 24

Intramural part

Prostatic urethra

Intermediate part

Spongy urethra

Front 25

Ductus Deferens (Vas deferens)

Back 25

Takes a pathway superior, then posterior to the bladder to transmit sperm from epididymus (stores sperm prior to ejaculation) of testis to ejaculatory duct where is joins the duct of the seminal gland. The ejaculatory duct then opens into the prostatic urethra.

Front 26

% of semen made where

Back 26

65%-75% of semen is made of the fluid secreted by the seminal glands. 25%-30% of semen is made of secretions from the prostate gland. Sperm is only 2-5% of semen. Bulbourethral gland secrete a lubricating fluid during sexual arousal (>1% of semen)

Front 27

Corpus cavernosum

Back 27

Erectile tissue- spongy tissue that fills with blood to become swollen. @ base of penis corpus cavernosum is called crus of penis

Front 28

Corpus spongiosum

Back 28

Erectile tissue-spongy tissue that fills with blood to become swollen. Spongy urethra runs thru this. At the base of the penis corpus spongiosum is called the bulb of the penis. @ tip of penis, it expands into glans of the penis.

Front 29

Muscles @ base of penis

Back 29

Help maintain erection

Ischiocavernous m. covers the crus of the penis.

bulbospongiosus m. covers the bulb of the penis

These muscles are innervated by pudendal N (S2-S4)

Front 30

Female pelvic viscera

Back 30

Female urethra is short. Vaginal canal lies b/w urethra and bladder (anteriorly) and anal canal and rectum (posteriorly)
Vaginal canal ends in an expanded fornix that surround the cervix of the uterus.

Front 31

Orientation of uterus

Back 31

The uterus is normally bend anteriorly (anteverted). Turning backward of the uterus is called retroverted uterus; usually seen in older women.

Front 32

Broad ligament

Back 32

Secures Uterus, uterine tubes and ovaries to lateral pelvic walls. Double layer of peritoneum.

Front 33

Parts of uterus

Back 33

Uterine tube recieves and conveys the ovum from the ovary to the uterine cavity

Prolapsed uterus results when uterus descends abnormally into vagina.

Front 34

Erectile tissues in female

Back 34

Homologous to erectile tissues of males. Penis and clitoris are homologous structures.

Front 35

Female genitalis

Back 35

Ischiocavernosus muscle covers crus of clitoris.

Blulbospongiosus muscle covers bulbs of vestibule (the vestibule is the region between the labia minora)

Front 36

Innervation of pelvis and perineum SEXUAL FUNCTION

Back 36

Parasympathetic: S2-S4, erection- relaxation of smooth muscles in the walls of arteries allowing blood to fill erectile tissue.

Sympathetic T12-L2, ejaculation in males, contraction of smooth muscles in walls of vas deferens, seminal vesicles, prostate and urethra orgasm in females- rhythmic contractions of the smooth muscles in the walls of vagina

Voluntary (somatic) control (S2-S4, pudendal n.) contract bulbospongiosus and ischiocavernosus to assist in erection

Somatic Sensory (S2-S4 pudendal N) general sensation to external genitalia for arousal

Front 37

Innervation for pelvis and perineum DEFECATION and URINATION

Back 37

Parasympathetic (S2-S4): relaxation of smooth muscle internal sphicters of bladder and rectum, contraction of smooth muscles in walls of these organs

Sympathetic (T12-L2): contraction of smooth muscle internal sphincter to maintain continence.

Voluntary (somatic) control (S2-S4, pudendal N,): contraction of striated muscle external sphincters to maintain continence

Visceral Sensory: stretch for defecation and urination reflexes and pain/cramping.

Front 38

Pelvic Pain Line

Back 38

Above Pelvic pain line: returns via sympathetic nerves to T12-L2

Below Pelvic pain line: returns via parasympathetic nerves to S2-S4

Front 39

Hormones

Back 39

Functions of ovaries, uterus, and testies are controlled primarily by hormones- ovulation, spermatogenesis, uterine contractions during menstration and childbirth.