abdominal viscera, pelvis, and perineum Flashcards
what is the peritoneum?
a serous membrane derived from mesoderm which lines the abdominopelvic cavity and invests the viscera
what is the parietal peritoneum?
lines the internal surface of the abdominopelvic wall; therefore its vascular supply is from the body wall and its innervation is somatic
what is the visceral peritoneum?
invests certain organs, e.g. the stomach and intestine…its blood supply is similar to the viscera, and likewise, its innervation is autonomic
what is the peritoneal cavity?
a potential space between the parietal and visceral layers. A thin film of peritoneal fluid occupies this “space
in which sex is the peritoneal cavity completely closed?
male
why do females potentially get peritonitis?
there is a communication pathway to the exterior of the body – through the uterine tube, to the uterus, to the vagina. This represents a potential path for microorganism
what are mesenteries?
a double-layered peritoneum running from body wall to organ and represent a continuity between visceral and parietal peritoneum
what do mesenteries provide?
a means for neurovascular communication between organs and the body wall, also containing fat, lymph nodes and lymph vessels. Depending on their lengths, they can provide organs attached to them some mobility.
what is the “mesentery”?
the large fan-shaped mesentery of the small intestine
what are some other mesenteries?
the transverse mesocolon, the mesoappendix, the sigmoid mesocolon, mesoesophagus and mesogastrium
what do peritoneal “ligaments” consist of?
consist of a double layer of peritoneum that connects an organ to another organ or the body wall
which peritoneal “ligaments” connects 2 organs together?
the omenta
which peritoneal “ligaments” connects an organ to the body wall?
falciform, coronary, and triangular ligaments of the liver, suspensory ligament of the ovary or broad ligament of the uterus
what are the peritoneal ligaments known as omenta?
are simply named for the structures that are connected to one another. Both omenta have attachments to the stomach
what is the omentum?
a double-layered extension or fold of peritoneum that passes from the stomach and proximal part of the duodenum to adjacent abdominal organs
what is the great omentum?
a prominent peritoneal fold that hangs from the greater curvature of the stomach and proximal duodenum and reflects back to attach to the transverse colon and its mesentery
what is the lesser omentum?
connects the lesser curvature of the stomach and proximal duodenum to the liver, being comprised of the hepatogastric and hepatoduodenal ligaments
what is the portal tirad?
hepatic artery, bile duct, hepatic portal vein
where does the portal triad travel?
within the hepatoduodenal ligament at the free edge of the omentum.
what are the regions of the stomach and where are each?
cardia- where the esophagus empties
fundus- left bottom
body- between the fundus and the pylorus
pylorus- the canal and orifice
what is the second largest gland in the body?
liver
what are some functions of the liver?
processing nutrients absorbed through the gut, storing glycogen, manufacturing plasma proteins and continuously secreting bile.
where is bile stored?
in the gall bladder
what is food in the duodenum a stimulus for?
the gall bladder to contract and empty bile into the 2nd part of the duodenum
how many lobes is the liver divided into?
4 (large right lobe, smaller left lobe, caudate lobe and quadrate lobe)
what is the falciform ligament?
a double-layered peritoneal fold attaching the liver to the anterior abdominal wall and dividing the right and left lobes
what is the round ligament?
the obliterated umbilical vein. During fetal life, it was directly continued in the liver as the ductus venosus – which is non-functional after birth, but remains as the ligamentum venosum
what does the gall bladder do?
concentrates, stores and delivers bile
where does the gall bladder lie?
it lies in a fossa on the visceral surface of the liver between the right and left parts. The body of the gall bladder lies anterior to the duodenum, and the neck and cystic duct lie superior to it
what is the cystic duct?
only a few cm long and connects the neck of the gall bladder to the commonhepatic duct.
where is the bile duct formed?
where the cystic and common hepatic duct meet
what is the spleen?
an ovoid, purplish, pulpy mass of an organ in the upper left abdominal cavity. It is the largest lymphatic organ
what is the function of the spleen?
In fetal life, hematopoiesis was a function of the spleen, but after birth, removing old or damaged RBCs and platelets is its main function playing an important role in the recycling of iron and globin. It houses many lymphoid follicles for immune reactions as well.
what is the duodenum?
C-shaped and nestles the head of the pancreas. It begins at the pyloric orifice and ends at the duodenojejunal junction on the left side of the midline at approximately the L2 vertebral level. This junction is usually a 90 degree flexure – the duodenojejunal flexure.
what are the four divisions of the duodenum?
the superior, descending, horizontal and ascending
T/F: most of the duodenum is retroperitoneal
True
what is the pancreas?
an elongated accessory digestive gland that has both endocrine (insulinand glucagon, somatostatin) and exocrine (pancreatic juice containing digestive enzymes).
where does the pancreas lie?
retroperitoneally, posterior to the stomach. The body lies on the abdominal aorta and the L2 vertebral body.
where is the head of the pancreas?
cradled by the duodenum, resting on the IVC, right renal artery and vein and left renal vein.
where is the neck of the pancreas?
overlies the junction of the SMV and splenic vein – where the portal vein is formed
where is the tail of the pancreas?
lies anterior to the left kidney and is closely related to the splenic hilum
what are all of the jejunum and ileum attached to?
mesentery
where does most of the jejunum typically occupy?
the upper left quadrant of the abdominal cavity and the ileum the lower quadrants, often descending into the pelvis and ascending distally to reach the cecum
what are some regions of the large intestine?
cecum, appendix, ascending colon, the right colic (hepatic) flexure, transverse colon (on a mesentery), the left colic(splenic) flexure, sigmoid colon and the terminal part, the rectum
what is the rectosigmoid junction?
lies at the level of S3 vertebra (or “mid-sacral”),about 15 cm from the anus. The teniae end at this junction, the omental appendices stop and the edge of the sigmoid mesocolon occurs here
where are the kidneys?
retroperitoneal, against the posterior abdominal wall, deeply embedded in and protected by fat.
what are the functions of the kidneys?
Their main function is to produce urine which is carried to the urinary bladder via the ureters, but other important roles are fluid volume regulation (renin-angiotensin-aldosterone system) and erythropoietin production
what does each kidney have sitting superomedially on it?
a suprarenal gland
do the suprarenal glands function together or separately from the kidneys?
entirely separately
what are products of the suprarenal glands?
aldosterone, glucocorticoids, androgens (from the cortex) and catecholamines (from the medulla).
what are the ureters?
muscular ducts which carry urine to the urinary bladder
where do the ureters run?
inferiorly from the renal hila, posterior to the gonadal vessels, over the pelvic brim (near the bifurcation of the external/internal iliac aa.) to run on the lateral walls of the true pelvis and enter the urinary bladder (the portion of the ureter running within the wall of the urinary bladder before opening into it is the“intramural portion”.)
how is the pelvis divided?
pelvis major and pelvis minor
what does “pelvic cavity” refer to?
0only the lesser (minor) pelvis, inferior to the pelvic brim and superior to the pelvic diaphragm
what is the perineum?
refers to both the area of the surface of the trunk between the thighs and the buttocks, extending from the coccyx to the pubis, and also to the shallow compartment lying deep (superior) to this area (but inferior to the pelvic diaphragm.)
what is the pelvic diaphragm?
the muscular layer comprising the floor of the pelvic cavity – separating the lesser pelvis from the perineum. consists of two muscles the coccygeus and levator ani
what is the pelvic canal?
collectively, the passageway between the pelvic inlet, lesser pelvis and pelvic outlet, through which a baby typically enters the world
the pelvis has no external surface area because it is overlapped by which cavities or regions?
The abdominal cavity anteriorly, the gluteal region posteriorly, the perineal region inferiorly
the auricular surfaces of the sacrum and ilium are what kind of joint?
synovial, their irregular surfaces interlock. the mobility is very little
what are the anterior sacroiliac ligaments?
the thin anterior fibers of the capsule
what are the posterior sacroiliac ligaments?
external continuations of deeper interosseus ligaments – very strong fibers connecting the tuberosities of the sacrum and ilium that create a syndesmosis. they pull the ilia inward when body weight drives the sacrum downward
what do the iliolumbar ligaments do?
strengthen the lumbosacral joints by spanning from the TPs of L4,5 to the ilium
where does the sacrotuberous ligament run?
from the posterior ilium and the lateral sacrum and coccyx to the ischial tuberosity
where does the sacrospinous ligament run?
from the lateral sacrum and coccyx to the ischial spine
what do the sacrotuberous and sacrospinous ligament do?
resist the anterior/inferior rotation of the sacrum from body weight. they create the greater and lesser sciatic foramina
what is the greater sciatic foramen?
an opening for structures entering or leaving the pelvis
what is the lesser sciatic foramen?
an opening for structures entering or leaving the perineum
what are the apertures associated with the lesser pelvis?
pelvic inlet, pelvic outlet, and obturator foramina
what is the anterior wall of the true pelvis?
the pubic symphysis, the bodies and superior/inferior rami of the pubic bones – it bears the weight of the urinary bladder
what are the lateral wall of the true pelvis?
the os coxae (hip bones), obturator foramina covered by the obturator membrane and attached to it, the obturator internus muscle. The thickened central fascia overlying this muscle is called the tendinous arch –which provides attachment for the pelvic diaphragm.
what is the posterior wall of the true pelvis?
the sacrum and coccyx, piriformis muscle and ilium (medial edge of greater sciatic notch)
what does the pelvic diaphragm do?
supports the abdominopelvic viscera, resists increases in intraabdominal pressure and relaxes to allow defectation and urination.
what is the pelvic diaphragm?
a bowl-shaped or funnel-shaped structure spanning the pelvic outlet. It consists of 2 muscles, the coccygeus and levator ani muscles and their fascias. The pelvic diaphragm separates the pelvic cavity from the perineum
what muscles make up the levator ani?
iliococcygeus, pubococcygeus, and puborectalis
what are the two triangles the perineum is divided into?
urogenital triangle and anal triangle
what are the osseofibrous structures which are boundaries to the perineum?
pubicsymphysis anteriorly
inferior pubic rami and ischial rami (“ischiopubicrami”) anterolaterally
ischial tuberosities laterally
sacrotuberousligaments posterolaterally
inferior most sacrum and coccyx posteriorly
what divides the 2 triangles of the perineum?
A transverse line connecting the anterior ends of the ischial tuberosities
what is the urogenital triangle closed by?
a tough fascia- perineal membrane
what is the major feature of the anal triangle?
the anal orifice
what is the perineal body?
an irregular mass of collagen and elastic fibers, as well as skeletal and smooth muscle. It serves as a common attachment point for many muscles
why does the male and female musculature of the perineum differ in development?
because the presence of the vaginal canal
what is found in the deep perineal space?
the external urethral sphincter and compressor urethae m
is the deep transverse perineal m present in both males and females?
no only males
what muscles does the perineal body serve as a common attachment point for?
the bulbospongiosus muscles, external anal sphincter, superficial and deep transverse perineal muscles and slips of muscle from the external urethral sphincter, levator ani and muscular coat of the rectum
what are kegel exercises for?
strengthening the pelvic floor muscles, preventing incontinence and other reasons, involve contractions of these muscles around the focal point of the perineal body
what are the ischioanal fossae?
wedge-shaped, fascia-lined spaces between the skin of the anal region and the pelvic diaphragm. They are filled with fat and loose connective tissue
what is the anal canal?
the terminal part of the large intestine, and the alimentary tract overall.It spans from the superior aspect of the pelvic diaphragm (where the puborectalis muscle wraps around) to the anus.
what is the internal anal sphincter?
a thickening of the circular layer of muscle in the proximal 2/3 of the anal canal. It maintains involuntary tone through sympathetic stimulation and relaxes with parasympathetic stimulation. [Internal urethral sphincter must relax while detrusor m. of urinary bladder is contracting for voiding.]
what is the external anal sphincter?
voluntary and covers the distal 2/3 of the anal canal. It attaches to the perineal body and the anococcygeal ligament.
what is the pudendal canal (alcock canal)?
a horizontal passageway within the fasica of the obturator internus muscle. It is found on the lateral wall of the ischioanal fossa
where do the pudendal nerve and internal pudendal artery and vein go?
inferior to ischial spine, loop around the ischial spine to enter the pudendal canal and course toward the perineum
what is the chief sensory nerve of the perineum?
the pudendal nerve
where does the uterus lie?
between the anteriorly situated urinary bladder and the posterior rectum
what is pelvic laxity?
With decreased tone of the pelvic floor (usually post-menopausal when estrogen function wanes) or possibly pelvic floor injury (e.g.childbirth), female pelvic organs may “drop” resulting in rectocele (rectum protruding against posterior vaginal wall), uterine prolapse (uterus“telescoping” through vagina), or cystocele (urinary bladder protruding against the anterior vaginal wall).
what are notable pelvic structures in males?
rectum, urinary bladder, seminal vesicles, prostate, ductus deferens
what is a BPH (benign prostatic hyperplasia)?
a common condition in elderly males characterized by increased number of cells and cellular elements in the prostate, increasing the size of the gland, but compressing the urethra passing through it. This results in a myriad of “obstructive voiding symptoms:” urinary frequency, nocturia, urgency, hesitancy, straining to urinate, decreased stream of urine, dribbling, feeling of incomplete emptying of urinary bladder. The main problems are from back-pressure: distended urinary bladder, detrusor hypertrophy, urine retention, dilated ureters and even renal failure
where do the major neurovascular structures lie in the pelvic wall?
extraperitoneally against the posterolateral pelvic wall
where is the sacral plexus?
in the lesser pelvis, lying mostly on the anterior surface of the piriformis muscles.
what are the two main nerves of the sacral plexus?
sciatic and pudendal
where does the sciatic nerve run?
leaves the pelvis through the greater sciatic foramen continues posteriorly through the gluteal region and thigh to innervate the leg and foot
where does the pudendal nerve run?
leaves the greater sciatic foramen, it hooks around the ischial spine and sacrospinous ligament to enter the perineum through the lesser sciatic foramen
where does the obturator nerve run?
from the lumbar plexus runs through the pelvis, not innervating anything. It runs on the lateral pelvic wall in extraperitoneal fat toward the obturator foramen and through the obturator canal to reach the medial thigh
what does the coccygeal plexus give rise to?
the nerves that innervate the coccygeus muscle and parts of the levator ani. Anococcygeal nerves are sensory to the skin between the coccyx and anus
what do the autonomics of the pelvis consist of?
Sacral sympathetic trunk – nerves that emerge from here travel to the lower limbs (within the sciatic n.).
Hypogastric plexuses – the most important route by which sympathetic fibers reach pelvic structures.The hypogastric nerves carry sympathetic fibers, but merge with pelvic splanchnics (presynaptic parasympathetic fibers) from sacral levels
what are the cavernous nerves?
parasympathetic fibers do not reach the body surface. They arise from the prostatic plexus in males (vesical plexus in females) and supply the corporacavernosa – when stimulated, these structures engorge with blood
what are the somatic nerves of the pelvis?
Sciatic – innervates flexors of knee, all muscles of leg and foot
Superior gluteal – innervates gluteus medius and minimus mm.
Nerve to quadratus femoris and inferior gemellus – speaks for itselfInferior gluteal – to gluteus maximus m.
Nerve to obturator internus and superior gemellus – speaks for itself
Nerve to piriformis – speaks for itself
Posterior femoral cutaneous – skin of part of buttocks, most superior medial and posterior thigh
Perforating cutaneous – “inferior cluneal” (skin of buttocks)
Pudendal – sensory to external genitalia, muscular branches to perineal muscles, external urethral and anal sphincters
Pelvic splanchnics – to pelvic viscera via many plexuses
Nerves to levator ani and coccygeus – speak for themselves
