SUGER anatomy Flashcards
what is the inguinal canal?
oblique passageway through the muscles of the anterior abdominal wall
lies superior to the medial half of the inguinal ligament
about 5cm long
name the two rings that the inguinal canal extend to
deep inguinal ring - aperture in the transversalis fascia
to the
superficial inguinal ring - aperture in the external oblique aponeurosis
anterior border of the inguinal canal
external oblique aponeurosis
laterally only - internal oblique aponeurosis
posterior border of the inguinal canal
transversalis fascia
medially only - medial fibres of the aponeuroses of the internal oblique and transversus abdominis (which together are known as the conjoint tendon)
roof of the inguinal canal
transversalis fascia
arching fibres of the internal oblique and transversus abdominis
floor of the inguinal canal
inguinal ligament - rolled up lower border of the external oblique
structures contained in the inguinal canal of females
round ligament of the uterus
ilioinguinal nerve
genital branch of the genitofemoral nerve
where are structures contained in the inguinal canal of males?
in males, the contents of the inguinal canal are all contained within the spermatic cord except for the ilioinguinal nerve
contents of the spermatic cord
two nerves
- genital branch of the genitofemoral nerve
- sympathetic nerve fibres
three arteries
- testicular artery
- cremasteric artery
- artery to the vas deferens
three fascial layers
- external spermatic fascia (derived from external oblique aponeurosis)
- cremaster muscle and fascia (derived from the internal oblique muscle)
internal spermatic fascia (derived from the transversalis fascia)
four other structures
- pampiniform venous plexus
- lymphatics
- vas deferens
- processus vaginalis (derived from the peritoneum)
inguinal hernia
hernia - abnormal protrusion of tissues or organs from one region into another through an opening or defect
inguinal hernia - protrusion of abdominal contents through the anterior abdominal wall into the inguinal canal
indirect or direct
indirect inguinal hernias
intra-abdominal contents are forces through the deep inguinal ring and into the canal
contents may also be forced into the superficial ring
from here, contents may be forced into the scrotum in males, or labia major in females
more common
more likely to get stuck in the canal and become irreducible
direct inguinal hernias
intra-abdominal contents are forced through the posterior wall of the inguinal canal (transversalis fascia) and directly through the superficial ring
less common
easier to reduce
describe scrotal skin
thin, wrinkles and more darkly pigmented than skin elsewhere
what is beneath scrotal skin?
superficial fascia
thin, involuntary muscle called the dartos
what divides the scrotum into right and left halves?
superficial fascia
what does each half of the scrotum contain?
testis
epididymis
lower part of the spermatic cord
function of the testes
male reproductive organs
produce sperm
secrete testosterone
layers of fascia surrounding the testes
external spermatic fascia
cremaster
internal spermatic fascia
same as layers covering the spermatic cord
what is the tunica vaginalis?
sac partially surrounding the testes
derived from the peritoneum
what is the epididymis?
describe its structure
coiled tube lying along the posterior border of each testis
expanded head superiorly, a body, a pointed tail lying at the lower pole of the testis
where are spermatozoa formed?
testis
where are spermatozoa stored?
epididymis
what carries sperm from the epididymis?
vas deferens, which carries sperm from the epididymis and travels with the testicular vessels in the spermatic cord
the testicular arteries are direct branches of which artery?
abdominal aorta
describe venous blood flow from the testes and epididymis on the left and right
to the pampiniform venous plexus, which forms the testicular vein
the right testicular vein joins the IVC
the left testicular vein joins the left renal vein then IVC
name conditions that can cause scrotal swellings
hydrocele
varicocele
epididymis-orchitis
testicular cancer
hydrocoele
painless swellings caused by accumulation of peritoneal fluid between the layers of the tunica vaginalis around the testis
when light is shone through a hydrocoele, it can be seen from the other side - called transillumination
varicocele
abnormal dilation of the pampiniform venous plexus
feel like a ‘bag of worms’ on palpation due to the dilated veins
on which side are varicoceles more common and why?
left
left testicular vein drains into the left renal vein before it drains into the IVC
epididymis-orchitis
painful inflammation of the epididymis and testis
most common cause of epididymis in young people
sexually transmitted infections e.g chlamydia
most common cause of epididymis in older patients
urinary tract infections
testicular torsion
twisting of the testis on the spermatic cord
can lead to ischaemia of the testis
surgical emergency
can lead to necrosis and loss of the affected testis
very painful
testicular cancer
excellent prognosis if detected and treated early
surgery to remove the testis and a length of cord - orchidectomy
if testicular cancer metastasises, it likely follows the lymphatic drainage which follows the testicular arteries back to lymph nodes around the aorta
therefore, testicular cancer metastases first to the para-aortic or retroperitoneal lymph nodes
cryptorchidism
undescended testis
during foetal development, the testes form in the abdomen and descend through the inguinal canal to reach the scrotum before birth
if this fails to occur, the infant is born with one or both testes absent from the scrotum, and the affected testes will be stuck somewhere along the path of descent
spermatogenesis is optimal just below core body temperature, therefore testes only function in the scrotum
also an increased risk of testicular cancer if the undescended testis is left inside the abdomen
therefore, undescended testes are often brought into the scrotum surgically
vasectomy
male sterilisation
scrotum is incised and the vasa deferentia are located on each side and separated, before ligating, cauterising or clamping each end
prevents the passage of sperm from the testes
name the three cylinders of erectile tissue comprising the penis
2 x corpora cavernosa dorsally (along the top of the penis)
1 x corpus spongiosum ventrally (along the bottom)
what encloses the three cylinders of erectile tissue comprising the penis?
deep fascia of the penis (‘Buck’s fascia’)
what is the end of the penis called?
glans
what is the glans an expansion of?
corpus spongiosum
where does the penile urethra lie?
within the corpus spongiosum
what does the penile urethra carry?
urine and semen
what is the opening of the penile urethra called?
external urethral meatus
arterial supply to the penis
penile arteries
from the internal pudenal arteries
from the internal iliac arteries
innervation of the penis (spinal segments)
S2-S4
function of the dorsal nerve of the penis
general sensation and sympathetic innervation
what is the dorsal nerve a branch of?
pudendal nerve
function of parasympathetic stimulation to the penis
erection by dilating the arteries of the corpora
where do parasympathetic nerve fibres of the penis arise from?
peri-prostatic nerve plexus
which cylinders of erectile tissue are mainly responsible for the increase in size and rigidity of the penis during an erection?
corpora cavernosa
what happens to the corpora cavernous during an erection?
arterial blood flow increases
corpora become engorged with blood
main function of the corpora spongiosum
prevent compression of the urethra during an erection, which would prevent ejaculation
main function of the corpora cavernosa
increase size and rigidity of the penis during an erection
erectile dysfunction
inability to achieve or maintain an erection during sexual activity
caused by a variety of factors
- nerve pathways and reflexes
- controlled blood flow in and out of the corpora of the penis
- psychological arousal
management
- identifying the cause
- treating the cause
- or medications such as sildenafil (Viagra) which increases blood flow to the corpora of the penis
another name for adrenal gland
suprarenal gland
where do the adRENAL glands lie?
close to the upper pole of each kidney
where does the left adrenal gland lie?
behind the stomach and pancreas
where does the right adrenal gland lie?
behind the liver and IVC
list the blood supply of the adrenal glands
superior adrenal artery
middle adrenal artery
inferior adrenal artery
what is the superior adrenal artery a branch of?
inferior phrenic artery
what is the middle adrenal artery a branch of?
abdominal aorta
what is the inferior adrenal artery a branch of?
renal artery
describe the venous drainage of the right and left adrenal glands
both drains by a single vein on each side
right adrenal gland drains into the IVC directly
left adrenal gland drains into the renal vein then the IVC
structure of the adrenal glands
outer cortex
inner medulla
what does adrenal cortex produce?
steroid hormones e.g cortisol
list steroid hormones produced by the adrenal cortex
cortisol, aldosterone and testosterone
what does the adrenal medulla produce?
adrenaline
phaeochromocytoma
rare hormone producing tumour of the adrenal medulla
secretion of excess adrenaline causes symptoms and signs related to hyperactivity of the sympathetic nervous system e.g hypertension, tachycardia, excessive sweating
dimensions of the kidneys
11cm long, 7cm wide, 4cm thick
where do kidneys lie relative to the peritoneum?
outside the peritoneum - extra-peritoneal
more specifically, behind the peritoneum - retroperitoneal
describe the layers of tissue surrounding the kidneys
renal capsule
embedded in perinephric (perirenal) fat
this fatty layer is covered by renal fascia
the next layer outwards is paranephric (pararenal) fat
what can be found at the renal hilum?
entry and exit points of renal vessels, nerves, lymphatics and the ureters
what are the right and left renal arteries branches of?
abdominal aorta
what do the right and left renal veins drain into?
IVC
describe the internal aspect of the kidney
outer cortex
inner medulla organised into pyramids
innermost calyces
renal columns are medullary extensions of renal cortex between renal pyramids
renal sinuses contain fat and are located below renal columns
functional units of the kidney
nephrons
function of nephrons
filter blood, reabsorbing water and solutes, secreting and excreting waste products as urine
where are the glomeruli found in the kidney?
cortex
where are the Bowman’s capsules found in the kidney?
cortex
where are the proximal and distal tubules found in the kidney?
cortex
where are the collecting ducts found in the kidney?
partially in cortex
partially in renal pyramids
where are the loops of Henle found in the kidney?
renal pyramids
describe the path of urine from the collecting ducts to the bladder
from collecting ducts, urine travels down the pyramid towards the renal papilla (apex of the pyramid)
urine enters a minor calyx
minor calyces merge to form a major calyx
major calyces merge to form the renal pelvis, which is continuous with the ureter
ureters carry urine to the urinary bladder
what are ureters and how do they function?
narrow tubes with muscular walls that transport urine by peristalsis
where do the ureters run?
anterior to psoas major on the posterior abdominal wall
cross the pelvic brim to enter the pelvis
enter the bladder on its inferomedial aspect
kidney stones
made from calcium oxalate
risk factors
- high urine calcium concentration
- dehydration
- obesity
- certain medications
excruciating, pulsatile pain felt from loin to groin
can cause hydronephrosis
most common in three places where the ureter narrows:
- pelvic-ureteric junction (PUJ)
- pelvic brim
- vesico-uretic junction (VUJ)
why does kidney stone pain present from loin to groin?
pain fibres supplying ureters originate from T12 - L2 nerves so pain is referred to these dermatomes
what is hydronephrosis?
flow of urine from kidney is obstructed so the kidney fills with urine and swells
where is the pelvi-ureteric junction?
between the renal pelvis and ureter
where is the pelvic brim?
where the ureter runs over the pelvic brim, anterior to the iliac artery
where is the vesicle-ureteric junction?
where the ureter joins the bladder
UTIs
usually caused by bacteria (often e coli) entering the urinary bladder via the urethra
more common in females as female urethra is much shorter
infection of the urinary bladder is called cystitis
symptoms include pain on passing urine and the sensation of having to pass urine more frequently
infection may spread proximally to the kidney - pyelonephritis
symptoms of pyelonephritis
- fever
flank pain
nausea and vomiting
renal cancer
three types based on their histological origin
renal cell carcinomas - RRC, originate from lining of nephron
transitional cell carcinomas - TCC, arise from the epithelial lining inside the kidney
Wilms’ tumours originate from renal stem cells
all present with a triad of symptoms
- flank pain
- palpable mass in the abdomen
- haematuria (blood in urine)
why is a left sided varicocele concerning?
left testicular vein drains into the left renal vein which may be compressed or obstructed by a renal tumour
where does the posterior abdominal wall consist of?
lumbar spine
psoas muscle
quadrates lumborum muscles
name structures running down the posterior abdominal wall
IVC
aorta and associated plexuses and lymph nodes
sympathetic trunks on either side of the lumbar spine
which spinal nerves form the lumbar plexus?
L1-L4 and T12 contributes
what does the lumbar plexus innervate
skin and muscles of the abdominal wall and thigh
name branches of the lumbar plexus
iliohypogastric and ilioinguinal nerves
genitofumeral nerve
lateral femoral cutaneous nerve
femoral nerve
obturator nerve
what do the iliohypogastric and ilioinguinal nerves supply?
anterior abdominal wall muscles and skin of the external genitalia
what does the genitofemoral nerve supply?
skin of the external genitalia
what does the lateral femoral cutaneous nerve supply?
skin over the lateral thigh
what does the femoral nerve supply?
muscle and skin of the anterior thigh and is often a target for nerve blocks to provide pain relief for lower limb fractures or surgery
does the obturator nerve supply?
muscles and skin of the medial thigh
what does the thoracic aorta become once it pierces the diaphragm at T12?
abdominal aorta
where does the thoracic aorta descend?
posterior abdominal wall just left of the midline
how does the thoracic aorta terminate, and at which spinal level?
bifurcates at L4
into left and right common iliac arteries
(bi-four-cates)
name unpaired branches of the abdominal aorta
coeliac trunk
superior mesenteric artery
inferior mesenteric artery
name paired branches of the abdominal aorta
renal, adrenal, gonadal and lumbar arteries
which veins form the IVC, and at which spinal level?
left and right common iliac veins
L5
where does the IVC ascend?
posterior abdominal wall just right of the midline
AAAs
triple a’s are abdominal aortic aneurysms
bulging of the aorta caused by a weak point in the blood vessel wall
risk factors
- smoking
- alcohol
- hypertension
- atherosclerosis
diagnosed if the diameter of the aorta exceeds 3cm
if it ruptures, intra abdominal bleeding occurs
high mortality
if they are found incidentally, they are monitored to see if they increase in size
treatment such as surgery or stunting may be offered if they become too large
functions of the pelvis
supports the spine, torso and upper body
locomotion
housing and protecting the pelvic viscera
which bones comprise the pelvis?
three of them
- sacrum
- left and right hip bones (innominate)
which three bones fuse to form the hip bone?
ilium, ischium, pubis
articulations of the bony pelvis
hip joint
sacroiliac joint
pubic symphiisis
lumbosacral jont
sacrococcygeal joint
hip joint
between the head of the femur and the acetabulum (socket) of the pelvis
the ilium, ischium and pubis of the hp bone fuse at the acetabulum
sacroiliac joint
between the sacrum and ilium of the hip bone
very stable and strong and supported by many ligaments
pubic symphysis
between the two pubic bones
almost no movement permitted here
lumbosacral joint
between the 5th lumbar vertebrae and the sacrum
an intervertebral disc lies between the two
sacrococcygeal joint
between the sacrum and coccyx
bony landmarks of the pelvis
iliac crest
ASIS
iliac tubercle
pubic tubercle
inguinal ligament
mid inguinal point
McBurney’s point - base of appendix
what is the iliac crest?
top border of the ilium
intercristal line
and spinal level
line drawn between the highest points of the iliac crests when palpated from the back
L4/5
significance of the intercristal line
lumbar punctures are performed here
epidurals given here
what is the ASIS?
anterior superior iliac spine
most anterior part of the ilium
palpable in most people
most anterior part of the ilium?
ASIS
most lateral part of the ilium?
iliac tubercles