Pelvis and Perinuem

• 1. transmit upper body weight to the lower limbs providing a base for lower lib function
• 2. Support and protect the pelvic viscera
• 3. Form part of the birth canal during delivery

• formed by 2 hip bones anteriorly and laterally
• sacrum and coccyx posteriorly

ilium, ischium and pubis

at the acetabulum at about 16 years to form a single bone at about 16 years

• Formed by fusion of 5 sacral vertebral segments
• consists of base, apex, pelvic, dorsal, and lateral surfaces and a sacral canal

• upper surface of first sacral vertebra
• articulates with 5th lumbar vertebral body at lumbosacral joint

anterior projecting edge of the body

wide upper part on each side of sacral promontory

four pairs of pelvic sacral foramina that transmit the ventral rami of S1-4

• convex
• contains: median sacral crest, medial sacral crest, four pairs of dorsal sacral foramina, lateral sacral crest

3 or 4 spinous tubercles. in the middle of the sacrum

four small articular tubercles lateal to median sacral crest.

below the last median sacral spinous tubercles. bounded by the sacral cornua from the medial sacral crests on each side.

transmit the dorsal rami of S1-4

• broad upper part with a mostly L-shaped auricular surface that articulates with the ilium at the sacroiliac joint.
• Narrow lower part curves medially to the 5th sacral vertebral body at the inferior lateral sacral angle

narrow, articulates with the base of the coccyx at the sacrococcygeal joint

formed by the sacral vertebral foramina. Downward continuation of the vertebral canal. Four pairs of intervertebral foramina that are continuous with the pelvic and dorsal sacral foramina.

level of the second sacral vertebra

Contains cauda equina, filum terminale and meninges

filum terminale and S5 nerves

small triangular bone consisting of 4 fused vertebral segments. 2nds to 4th coccygeal vertebrae decrease in size and are fused bodies

upper surface of the 1st coccygeal vertebral body. Articulates with the apex of the sacrum.

project dorsolaterally from coccyx

project superolaterally from coccyx

plane bounded by the pelvic brim. Divided into the greater pelvis and the lesser pelvis

Extends along the promontory and ala of the sacrum, arcuate line of the ilium, pecten pubis, pubic crest and upper border of the symphysis pubis

located above the pelvic inlet between the iliac bones and is part of the abdominal cavity

sitated below the pelvic inlet and forms the pelvic cavity or simply the pelvis

diamond-shaped area extending from the symphysis pubis anteriorly tot eh coccyx posteriorly. Bound on each side by the ischiopubic ramus, ischiopubic ramus, ischial tuberosity and sacrotuberous ligament

transverse diameter is 13.5 cm

anteroposterior or conjugate diameter of outlet ~11 cm

fetal head turns 90° during delivery. Face to side as i passes through the inlet and faces posteriorly through the outlet

anterior superior iliac spines and upper end of the symphysis pubis are in the same vertical plane

• 1. (upper/deepest) Pelvic diaphragm.
• 2. (middle) urogenital diaphragm - muscles of the deep perineal space
• 3. (lower) muscles of the superficial perineal space.

levator ani, coccygeus

• deep transverse perinei mm,
• sphnicter urethra mm,
• bulbourethral glands (male
• VAN's organs

• superficial transverse perinei mm
• bulbospongiousus mm
• ischiocavernosus mm
• greater vestibular glands (female)
• erectile tissue, VAN's, organs

• 1. support the pelvic organs and contents
• 2. Withstand any increases in pressure in the abdominopelvic cavity
• 3. provide sphincter control of the perineal openings (urethra, vagina, and anus)

• diamond shaped area between the thighs.
• contrains the external genitalia and anal region.
• Separated from the pelvic cavity by the pelvic diaphram.
• = urogenital trianlge + anal triangle

anterior to the ischial tuberosities, contains the external urogenital organs

Posterior to ischial tuberosities, contains the end of the anal canal and anus

anus and external anal sphincter both by the inferior rectal branch of pudendal nerve (S2-4)

• large wednged shaped space on each side of the ans filled with fat.
• pudendal nerve, artery, and vein are found here

Mons pubis, labia majora, labia minora, vesitbule, bulbs of vestibule, clitoris, greater vestibular glands

the prepuce and frenulum of the clitoris

contains opening of the urethra and vagina

erectile tissue lying on each side of the vaginal opening

erectile tissue consisting of two crura and a body ending in the glans

secrete mucus for vaginal lubrication

penis, scrotume

• paired dorsal corpora cavernosa
• unpaired venral corpus spongiosum

attaches along the ischiopubic ramus by its crus

• the urethra and ending in the enlarged glas
• bulb is attaches to the perineal membrane

fibromuscular sac of skin containing the testes and lower parts of the spermatic cords

layer of smooth muscles that wrinkle the skin of the scrotum

• lie between Colle's fascia (membranous layer of the superficial fascia) and the inferior fascia of the urogenital diaphragm (perineal membrane)
• - Bulbospongiosus (bulbocavernosus) muscles
• - ischiocavernosus muscles

covering the corpus spongiosum in the male and bulbs in the vestibule in the female

cover the crura of hte penis and clitoris

• Both - maintain erection by compressing veins
• Male - bulbospongiousus helps empty the urethra after bladder has emptied
• Female - sphincter of the vaginal opening

pedendal nerve (S2-4) perineal branch

• lie between the superior and inferior fascias of the urogential diaphragm. Muscles + their fascia = urogenital diaphragm.
• sphrincter urethrae

surrounds the membranous urethra and must be voluntarily relaxed during urination

pudendal nerve (S2-4) perineal branch

funnel-shaped musculofibrous sheet that closes off the pelvic outlet and forms the floor of the pelvic cavity

retroperitoneal with the exception of the uterus. Pass through the pelvic floor and are anchored to it.

• rectum lies POST and passes through the anal region
• Urinary system lies anteriorly,
• Genital system takes an intermediate position
• both urinary and genital pass throught he urogenital region.

• lie of the POST abdominal wall embedded in perirenal fat.
• Right kidney lies slightly lower than the left

renal pyramids -> minor calyces -> majora calyces -> renal pelvis -> ureters -> bladder.

smooth muscle sac lying behind the symphysis pubis and pubic bones

nevck of bladder is anchored to the pubic bone by the pubovesical (female) and puboprostatic (male) ligaments

an equilateral triangle on the interior of the posterior wall. Angles are formed y the ureteric orifices above and the interal urethral orifice below

detrussor muscle

• sympathetic fibers from lower thoracis and upper lumbar segments.
• Parasympathetic fibers - conveyed by pelvic splanchnic nerves from S2-4

maintain tonus of the bladder neck

inhibits the bladder neck musculature and stimulate increased tonus of the detressor muscle of the bladder walls for urination

• female - 3-4 cm long. Pierces the ANT part of the urogenital diaphragm and opens in the vestibule.
• male - 18-20 cm long. Passes through the prostate (prostatic part), urogenital diaphragm (membranous part) and penis (spongy part)

In neck of bladder. Made of smooth muscle innervated by excitatory sympathetic and inhibitory parasympathetic nerves

Surrounds the membranous urethra and consists of skeletal muscle innervated by the pudendal nerve