Abdomin and pelvic anatomy deck Flashcards
What are the functions of the spleen
FISH
Filtration of encapsulated organisms
Immune function
Storage of platelets
Haematopoiesis in the fetus
What structures can be damaged during a splenectomy
Tail of the pancreas
Diaphragm
Left kidney
Splenic flexure of colon
Where do portosystemic anastomoses occur
BURP-L
Retroperitoneum
Upper anal canal
Bare area of liver
Lower end of oesophagus
Periumbilical area of abdomen
What are the most common areas for intra-abdominal collections
In the pelvis
Left and right paracolic and subphrenic gutters
Between loops of bowels
What organs are normally palpable in the abdomen
Lower pole of the right kidney and the aorta are the only ones that can be palpable in the normal setting
What are the important surface landmarks of the liver
Superiorly the nipple line
Inferiorly the 10th Rib
Left 5th intercostal space midclavicular line
Where is the spleen located
Behind ribs 9,10 and 11
Structures at L1 posterior to anterior
Vertebrae, spinal cord, aorta, SMA, neck of the pancreas, SMV, pylorus of the stomach
Boundaries of the epiploic foramen of winslow
Superiorly the caudate lobe of the liver
Anteriorly the free edge of the lesser omentum, with CBD, HPV and HAP
Inferiorly the 1st part of the duodenum
Posteriorly the IVC
What is the ligamentum teres a remnant of
The umbilical vein
Jejunum vs ileum
Jejunum has a thinner wall and fewer arcades, valvular conniventes are thicker and more prominent.
Pancreatic endocrine function
Alpha cells: glucagon
Beta cells: insulin
Delta cells: Somatostatin
What is the blood supply to the pancreas
Most of the pancreas is supplied by the splenic artery
Head is supplied by the sup and inferior pancreaticoduodenal artery (Superior is gastroduodenal from coeliac and inferior is from the SMA)
Venous drainage follows arteries to SMV and portal as well as splenic vein
What is the blood supply to the greater and lesser curvature of the stomach
Lesser is left and right gastric, the left comes from the coeliac and the right comes from the CHA
The greater curve is the left and right gastroepiploic, the right comes from gastroduodenal that comes from HAP and the left is from the splenic artery
What is Meckel’s diverticulum
Remnant of the vitellointestinal duct which connect the midgut to the yolk sac
Rule of 2s: 2% of the population, 2 inches long, 2 feet from the ileocaecal valve and is 2wice as common in males than in females
What are the relations of the kidneys
Retroperitoneal and extends from T12 to L3. It is bounded by the Gerotas fascia
Its relations are as follows:
The diaphragm
Psoas major
Quadratus lumborum
Transverse abdominis
12th rib
3 nerves from top to bottom: Subcostal, iliohypogastric and ilioinguinal
Where are the adrenals found
Anterior-superiorly in a separate encasing component of the gerotas fascia
Retroperitoneal organs
S: suprarenal (adrenal) gland
A: aorta/IVC
D: duodenum (second, third and fourth parts)
P: pancreas (except tail)
U: ureters
C: colon (ascending and descending)
K: kidneys
E: (o)oesophagus
R: rectum
What is achalasia
It is a motility disorder specifically affecting the myenteric plexus of the lower oesophagus causing incomplete relaxation due to loss of ganglia. It has dysphagia to both solids and liquids
What are the contents of the rector sheath
Rectus abdominis • Pyramidalis •Superior and inferior epigastric arteries and veins • Lymphatics •Ventral ramin of T7-T12 nerves • Fibro-fatty connective tissue
What is the anastomoses between the SMA and the IMA
Marginal artery of drummond
What is the surface marking of the appendix
1/3rd way from a line drawn between the ACIS and the umbilicus
What is the blood supply to the rectum
Sup - comes from IMA
middle comes from II
inf comes from IP
What is the surface markings of the liver
What is the surface marking of the gall bladder
It lies at the angle between the 9th costal cartilage and the lateral margin of the rectus abdominis
What is courvoisiers law
Painless jaundice and a palpable gall bladder is unlikely to be due to gall stone disease
What is Kehrs and boas sign
What crosses the ureters anteriorly as it descends into the abdomen
Gonadal vessels
What is the blood supply to the ureters
Renal arteries, internal iliac arteries, superior vesicular arteries and common iliac branches
What is the relation of the IVC to the aorta
Right and post proximally
Right and ant distally
What is the perineal body
The Perineal Body
The perineal body is an irregular fibromuscular mass. It is located at the junction of the urogenital and anal triangles – the central point of the perineum. This structure contains skeletal muscle, smooth muscle and collagenous and elastic fibres.
Anatomically, the perineal body lies just deep to the skin. It acts as a point of attachment for muscle fibres from the pelvic floor and the perineum itself:
* Levator ani (part of the pelvic floor).
* Bulbospongiosus muscle.
* Superficial and deep transverse perineal muscles.
* External anal sphincter muscle.
* External urethral sphincter muscle fibres.
What are the contents of the greater sciatic foramen
Contents
The greater sciatic foramen is divided into two parts by the presence of the piriformis muscle – the suprapiriform and infrapiriform foramina.
* Suprapiriform foramen:
o Superior gluteal artery and vein
o Superior gluteal nerve
* Infrapiriform foramen:
o Sciatic nerve
o Pudendal nerve
o Inferior gluteal artery and vein
o Inferior gluteal nerve
o Posterior femoral cutaneous nerve
o Nerve to obturator internus
o Nerve to quadratus femoris
What are the contents of the lesser sciatic foramen
Contents
The following structures pass through the lesser sciatic foramen:
* Internal pudendal artery and vein
* Pudendal nerve (note the pudendal nerve first leaves the pelvis via the greater sciatic foramen, and then re-enters via the lesser sciatic foramen)
* Obturator internus tendon
* Nerve to obturator internus
What are the ligaments of the SI joint
The ligaments of the sacroiliac joint reinforce the synovial capsule. There are three main ligaments:
* Interosseous sacroiliac ligament – located posteriorly and superiorly to the joint, spanning between the ilium and sacrum. It is the strongest of the ligaments.
* Posterior sacroiliac ligament – also located posteriorly to the joint, covering the interosseous ligament.
* Anterior sacroiliac ligament – thickening of the anterior component of the joint capsule. It is relatively thin and weak.
What is the triadiate cartilage
The joining of three bones, ilium, ischium and pubis
What is the nervous innervation to the bladder
Nervous supply
* Sympathetic – hypogastric nerve (T12 – L2). It causes relaxation of the detrusor muscle, promoting urine retention.
* Parasympathetic – pelvic nerve (S2-S4). Increased signals from this nerve causes contraction of the detrusor muscle, stimulating micturition.
* Somatic – pudendal nerve (S2-4). It innervates the external urethral sphincter, providing voluntary control over micturition.
Describe the branches of the internal iliac
I Love Going Places In My Very Own Underwear!
Mnemonic
I: iliolumbar artery
L: lateral sacral artery
G: gluteal (superior and inferior) arteries
P: (internal) pudendal artery
I: inferior vesical (vaginal in females) artery, and superior vesical artery
M: middle rectal artery
V: vaginal artery (females only)
O: obturator artery
U: umbilical artery and uterine artery (females only)
Describe the layers of the scrotum
A handy mnemonic to recall the layers of the scrotum is:
* Some Damn Englishman Called It The Testes
Mnemonic
* S: skin
* D: dartos fascia and muscle
* E: external spermatic fascia - derived from the aponeurosis of the external oblique muscle.
* C: cremasteric fascia - derived from the internal oblique muscle.
* I: internal spermatic fascia – derived from transversalis fascia
* T: tunica vaginalis
* T: tunica albuginea
What is the area of the prostate that can be felt on DRE
Peripheral zone
What are the zones of the prostate glands
- Central zone – surrounds the ejaculatory ducts, comprising approximately 25% of normal prostate volume.
o The ducts of the glands from the central zone are obliquely emptying in the prostatic urethra, thus being rather immune to urine reflux. - Transitional zone – located centrally and surrounds the urethra, comprising approximately 5-10% of normal prostate volume.
o The glands of the transitional zone are those that typically undergo benign hyperplasia (BPH) - Peripheral zone – makes up the main body of the gland (approximately 65%) and is located posteriorly.
o The ducts of the glands from the peripheral zone are vertically emptying in the prostatic urethra; that may explain the tendency of these glands to permit urine reflux. -> Hence More inflammation and hence more Carcinomas here -> This is the area that can be felt on a DRE
What is the histology of the vagina
The vagina is composed of four histological layers (internal to external) (SEFA):
* Stratified squamous epithelium – this layer provides protection and is lubricated by cervical mucus (the vagina itself does not contain any glands).
* Elastic lamina propria – a dense connective tissue layer which projects papillae into the overlying epithelium. The larger veins are located here.
* Fibromuscular layer – comprising two layers of smooth muscle; an inner circular and an outer longitudinal layer.
* Adventitia – a fibrous layer, which provides additional strength to the vagina whilst also binding it to surrounding structures.
What is the function of the seminal vesicles
- Alkaline fluid – neutralises the acidity of the male urethra and vagina in order to facilitate the survival of spermatozoa.
- Fructose – provides an energy source for spermatozoa.
- Prostaglandins – have a role in suppressing the female immune response to foreign semen.
- Clotting factors – designed to keep semen in the female reproductive tract post-ejaculation.
Overall contributes to 70% of the volume of semen
Histological structure of the uterus
- Peritoneum –Also known as the perimetrium.
- Myometrium
- Endometrium – inner mucous membrane lining the uterus. It can be further subdivided into 2 parts:
o Deep stratum basalis: Changes little throughout the menstrual cycle and is not shed at menstruation.
o Superficial stratum functionalis: Proliferates in response to oestrogens, and becomes secretory in response to progesterone. It is shed during menstruation and regenerates from cells in the stratum basalis layer. (Functionalis changes and hence is is functional in the menstrual cycle!)
How does the ureters travel into the bladder and what is the significance
Oblique manner posteriolaterally and then goes 2cm into the detrusor muscle. Hence, this makes a one way valve system when the detrusor muscle contracts to prevent backflow of urine
Where does a spigalean hernia develop
Spigelian hernia, also known as the lateral ventral hernia, is herniation through the aponeurotic layer between the rectus abdominis muscle medially and the semilunar line laterally (this aponeurotic layer is called the Spigelian fascia).
Describe the umbilical folds
There is one midline peritoneal fold (median) and 2 lateral (medial and lateral)
What is the median umbilical fold
It is a ridge of peritonium covering the median umbilical ligament which is the remnant of the urachus
What is the medial umbilical fold
Peritoneal coverings over the medial umbilical lig, remnant of the umb artery
Name the structure that lies lateral to the umbilical fold
Inferior epigastric arteries
What is the difference between primary and secondary retroperitoneal organs
Primary are the ones that originate in the retroperitoneum (kidney)
Secondary are the ones that have an initial mesenteric attachment and then only have the anterior surface covered by peritoneum (ascending and descending colon, middle 3rd of the rectum, pancreas except the tail, adrenal glands)
Name infraperitoneal/ subperitoneal organs
Lower 1/3rd of the rectum
distal ureter
Urinary bladder
What are some of the causes of cryprorchidism
Agenesis
Incomplete descenet
Intra-abdominal arrest
Ectopic
Describe the course of the ureter
Arises from the renal pelvis
Tranvels downwards along with transverse processes of L1 - L5
Enters the pelvis ant to the SI joints and bifurcation of the CI
At the level of the ischial spine, runs forwards and medially to enter the posterolateral aspect of the bladder
What is the most common renal stone
Ca oxalate 85%
What are the posterior relations of the head, neck and the body and tail of the pancreas
Head: IVC, renal veins, right renal artery and bile ducts
Body: Aorta, SMA, Left kidney, renal vessels and suprarenal glands
Tail: Spleen, left kidney, left colic flexure
What are the splenic ligaments
Gastrosplenic ligament: Between the greater curvature of the stomach and the spleen, contains the short gastric and left gastroepiploic vessels
Splenorenal ligament: Between hilum of spleen and the left kidney, splenic vessels
Splenocolic
Splenophrenic
What is the splenectomy prophylaxis
pneumococcus, haemophilus influenza and meningococcus vaccine ideally 2 weeks pre-op in elective and 2 weeks post op in emergency
Children require antibiotic prophylaxis at least until 15, adults require till 2 years post splenectomy
What is supplied by the anterior branch of the internal iliac
Muscles of the thigh, pelvis and perinium
Organs of the pelvis
What do the levetor ani muscles attach to
attaches to the bodies of the pubic bones anteriorly, ischial spines posteriorly and to a thickened fascia of the obturator internus muscle.
Describe the course of the ureters
The ureters start at the renal pelvis – the most posterior of the renal hilum structures (vein, artery, pelvis from anterior to posterior). They are retroperitoneal for their entire course, and there is an equal length of ureter in the abdomen and in the pelvis. The abdominal ureter descends almost vertically downwards, anterior to the psoas major muscle, just overlapping the transverse processes of the lumbar vertebrae. Each ureter is crossed anteriorly by the gonadal artery and vein. The genitofemoral nerve passes behind the ureter (which explains the referred pain to the testes with ureteric calculi). At the pelvic brim, the ureters pass anterior to the external iliac artery (ureter, artery, vein from anterior to posterior). The left ureter has the apex of the sigmoid mesocolon as its anterior relation at the pelvic brim. The pelvic ureter then descends posteroinferiorly on the lateral pelvic wall, anterior to the branches of the internal iliac arteries, and then curves anteromedially to enter the posterolateral surface of the bladder. Just before entering the bladder the ureter is crossed anteriorly by the vas deferens in the male or the uterine artery in the female.
What are the posterior relations of the kidney
diaphragm (superiorly) quadratus lumborum (inferiorly) psoas major (medially) transversus abdominis (laterally).
What is the anatomy of the kidney
The dilated upper portion of the ureter is called the renal pelvis. This is formed by two or three major calyces, which are formed by the confluence of several minor calyces. Each minor calyx has a renal papilla draining into it, which is formed by the apices of several pyramids of renal medulla. The darker renal medulla is surrounded by the lighter-coloured renal cortex. The renal columns of cortex project inwards between the pyramids.
How many nephrons are there per kidney?
1 million
What structures lie at the transpyloric plane
termination of the spinal cord aorta gives off the superior mesenteric artery lateral border of the rectus abdominis muscle as it crosses the costal margin duodenojejunal junction L1 vertebra neck of the pancreas hila of the kidneys formation of the portal vein
What is the route and branches of the SMA
The superior mesenteric artery provides the blood supply to the embryological midgut structures. The superior mesenteric artery arises from the abdominal aorta at the transpyloric plane (L1) behind the body of the pancreas. It then passes anterior to the uncinate process of the pancreas and third part of the duodenum – that is, the pancreas and duodenum are wrapped around the superior mesenteric artery and vein. The branches are: inferior pancreaticoduodenal middle colic right colic several jejunal and ileal arteries ileocolic.
What muscle is the lumbar plexus related to and how?
The nerves of the lumbar plexus are divided according to how they exit the psoas major muscle:
Lateral:
− iliohypogastric nerve (L1) − ilioinguinal nerve (L1) − lateral cutaneous nerve of thigh (L2, L3) − femoral nerve (L2, L3, L4).
Anterior: − genitofemoral nerve (L1, L2).
Medial: − obturator nerve (L2, L3, L4) − lumbosacral trunk (L4, L5)
What are the peritoneal relations of the rectum
The superior third of the rectum has peritoneum anteriorly and laterally. The middle third of the rectum has peritoneum anteriorly only. The lower third of the rectum has no peritoneum.
What contributes to the rectal varicies in alcoholics
Portosystemic part of the superior rectal vein and the systemic part is the inferior and middle rectal veins
Which hiatal hernias are more common, sliding or rolling
sliding 90%
Where do the abdominal muscles attach
Attach to 5th to 12 ribs, pubic symphysis, iliac crest
