SUGER anatomy Flashcards
(321 cards)
1
Q
what is the inguinal canal?
A
oblique passageway through the muscles of the anterior abdominal wall
lies superior to the medial half of the inguinal ligament
about 5cm long
2
Q
name the two rings that the inguinal canal extend to
A
deep inguinal ring - aperture in the transversalis fascia
to the
superficial inguinal ring - aperture in the external oblique aponeurosis
3
Q
anterior border of the inguinal canal
A
external oblique aponeurosis
laterally only - internal oblique aponeurosis
4
Q
posterior border of the inguinal canal
A
transversalis fascia
medially only - medial fibres of the aponeuroses of the internal oblique and transversus abdominis (which together are known as the conjoint tendon)
5
Q
roof of the inguinal canal
A
transversalis fascia
arching fibres of the internal oblique and transversus abdominis
6
Q
floor of the inguinal canal
A
inguinal ligament - rolled up lower border of the external oblique
7
Q
structures contained in the inguinal canal of females
A
round ligament of the uterus
ilioinguinal nerve
genital branch of the genitofemoral nerve
8
Q
where are structures contained in the inguinal canal of males?
A
in males, the contents of the inguinal canal are all contained within the spermatic cord except for the ilioinguinal nerve
9
Q
contents of the spermatic cord
A
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)
10
Q
inguinal hernia
A
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
11
Q
indirect inguinal hernias
A
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
12
Q
direct inguinal hernias
A
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
13
Q
describe scrotal skin
A
thin, wrinkles and more darkly pigmented than skin elsewhere
14
Q
what is beneath scrotal skin?
A
superficial fascia
thin, involuntary muscle called the dartos
15
Q
what divides the scrotum into right and left halves?
A
superficial fascia
16
Q
what does each half of the scrotum contain?
A
testis
epididymis
lower part of the spermatic cord
17
Q
function of the testes
A
male reproductive organs
produce sperm
secrete testosterone
18
Q
layers of fascia surrounding the testes
A
external spermatic fascia
cremaster
internal spermatic fascia
same as layers covering the spermatic cord
19
Q
what is the tunica vaginalis?
A
sac partially surrounding the testes
derived from the peritoneum
20
Q
what is the epididymis?
describe its structure
A
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
21
Q
where are spermatozoa formed?
A
testis
22
Q
where are spermatozoa stored?
A
epididymis
23
Q
what carries sperm from the epididymis?
A
vas deferens, which carries sperm from the epididymis and travels with the testicular vessels in the spermatic cord
24
Q
the testicular arteries are direct branches of which artery?
A
abdominal aorta
25
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
26
name conditions that can cause scrotal swellings
hydrocele
varicocele
epididymis-orchitis
testicular cancer
27
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
28
varicocele
abnormal dilation of the pampiniform venous plexus
feel like a 'bag of worms' on palpation due to the dilated veins
29
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
30
epididymis-orchitis
painful inflammation of the epididymis and testis
31
most common cause of epididymis in young people
sexually transmitted infections e.g chlamydia
32
most common cause of epididymis in older patients
urinary tract infections
33
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
34
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
35
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
36
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
37
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)
38
what encloses the three cylinders of erectile tissue comprising the penis?
deep fascia of the penis ('Buck's fascia')
39
what is the end of the penis called?
glans
40
what is the glans an expansion of?
corpus spongiosum
41
where does the penile urethra lie?
within the corpus spongiosum
42
what does the penile urethra carry?
urine and semen
43
what is the opening of the penile urethra called?
external urethral meatus
44
arterial supply to the penis
penile arteries
from the internal pudenal arteries
from the internal iliac arteries
45
innervation of the penis (spinal segments)
S2-S4
46
function of the dorsal nerve of the penis
general sensation and sympathetic innervation
47
what is the dorsal nerve a branch of?
pudendal nerve
48
function of parasympathetic stimulation to the penis
erection by dilating the arteries of the corpora
49
where do parasympathetic nerve fibres of the penis arise from?
peri-prostatic nerve plexus
50
which cylinders of erectile tissue are mainly responsible for the increase in size and rigidity of the penis during an erection?
corpora cavernosa
51
what happens to the corpora cavernous during an erection?
arterial blood flow increases
corpora become engorged with blood
52
main function of the corpora spongiosum
prevent compression of the urethra during an erection, which would prevent ejaculation
53
main function of the corpora cavernosa
increase size and rigidity of the penis during an erection
54
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
55
another name for adrenal gland
suprarenal gland
56
where do the adRENAL glands lie?
close to the upper pole of each kidney
57
where does the left adrenal gland lie?
behind the stomach and pancreas
58
where does the right adrenal gland lie?
behind the liver and IVC
59
list the blood supply of the adrenal glands
superior adrenal artery
middle adrenal artery
inferior adrenal artery
60
what is the superior adrenal artery a branch of?
inferior phrenic artery
61
what is the middle adrenal artery a branch of?
abdominal aorta
62
what is the inferior adrenal artery a branch of?
renal artery
63
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
64
structure of the adrenal glands
outer cortex
inner medulla
65
what does adrenal cortex produce?
steroid hormones e.g cortisol
66
list steroid hormones produced by the adrenal cortex
cortisol, aldosterone and testosterone
67
what does the adrenal medulla produce?
adrenaline
68
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
69
dimensions of the kidneys
11cm long, 7cm wide, 4cm thick
70
where do kidneys lie relative to the peritoneum?
outside the peritoneum - extra-peritoneal
more specifically, behind the peritoneum - retroperitoneal
71
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
72
what can be found at the renal hilum?
entry and exit points of renal vessels, nerves, lymphatics and the ureters
73
what are the right and left renal arteries branches of?
abdominal aorta
74
what do the right and left renal veins drain into?
IVC
75
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
76
functional units of the kidney
nephrons
77
function of nephrons
filter blood, reabsorbing water and solutes, secreting and excreting waste products as urine
78
where are the glomeruli found in the kidney?
cortex
79
where are the Bowman's capsules found in the kidney?
cortex
80
where are the proximal and distal tubules found in the kidney?
cortex
81
where are the collecting ducts found in the kidney?
partially in cortex
partially in renal pyramids
82
where are the loops of Henle found in the kidney?
renal pyramids
83
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
84
what are ureters and how do they function?
narrow tubes with muscular walls that transport urine by peristalsis
85
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
86
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)
87
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
88
what is hydronephrosis?
flow of urine from kidney is obstructed so the kidney fills with urine and swells
89
where is the pelvi-ureteric junction?
between the renal pelvis and ureter
90
where is the pelvic brim?
where the ureter runs over the pelvic brim, anterior to the iliac artery
91
where is the vesicle-ureteric junction?
where the ureter joins the bladder
92
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
93
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)
94
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
95
where does the posterior abdominal wall consist of?
lumbar spine
psoas muscle
quadrates lumborum muscles
96
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
97
which spinal nerves form the lumbar plexus?
L1-L4 and T12 contributes
98
what does the lumbar plexus innervate
skin and muscles of the abdominal wall and thigh
99
name branches of the lumbar plexus
iliohypogastric and ilioinguinal nerves
genitofumeral nerve
lateral femoral cutaneous nerve
femoral nerve
obturator nerve
100
what do the iliohypogastric and ilioinguinal nerves supply?
anterior abdominal wall muscles and skin of the external genitalia
101
what does the genitofemoral nerve supply?
skin of the external genitalia
102
what does the lateral femoral cutaneous nerve supply?
skin over the lateral thigh
103
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
104
does the obturator nerve supply?
muscles and skin of the medial thigh
105
what does the thoracic aorta become once it pierces the diaphragm at T12?
abdominal aorta
106
where does the thoracic aorta descend?
posterior abdominal wall just left of the midline
107
how does the thoracic aorta terminate, and at which spinal level?
bifurcates at L4
into left and right common iliac arteries
(bi-four-cates)
108
name unpaired branches of the abdominal aorta
coeliac trunk
superior mesenteric artery
inferior mesenteric artery
109
name paired branches of the abdominal aorta
renal, adrenal, gonadal and lumbar arteries
110
which veins form the IVC, and at which spinal level?
left and right common iliac veins
L5
111
where does the IVC ascend?
posterior abdominal wall just right of the midline
112
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
113
functions of the pelvis
supports the spine, torso and upper body
locomotion
housing and protecting the pelvic viscera
114
which bones comprise the pelvis?
three of them
- sacrum
- left and right hip bones (innominate)
115
which three bones fuse to form the hip bone?
ilium, ischium, pubis
116
articulations of the bony pelvis
hip joint
sacroiliac joint
pubic symphiisis
lumbosacral jont
sacrococcygeal joint
117
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
118
sacroiliac joint
between the sacrum and ilium of the hip bone
very stable and strong and supported by many ligaments
119
pubic symphysis
between the two pubic bones
almost no movement permitted here
120
lumbosacral joint
between the 5th lumbar vertebrae and the sacrum
an intervertebral disc lies between the two
121
sacrococcygeal joint
between the sacrum and coccyx
122
bony landmarks of the pelvis
iliac crest
ASIS
iliac tubercle
pubic tubercle
inguinal ligament
mid inguinal point
McBurney's point - base of appendix
123
what is the iliac crest?
top border of the ilium
124
intercristal line
and spinal level
line drawn between the highest points of the iliac crests when palpated from the back
L4/5
125
significance of the intercristal line
lumbar punctures are performed here
epidurals given here
126
what is the ASIS?
anterior superior iliac spine
most anterior part of the ilium
palpable in most people
127
most anterior part of the ilium?
ASIS
128
most lateral part of the ilium?
iliac tubercles
129
intertubecular line
line drawn between the iliac tubercles
130
what does the intertubecular line mark?
division of the lower third of the abdomen from the middle third
separates suprapubic and umbilical
separates iliac fossa and flanks
131
most medial part of the pubic bone
pubic tubercle
palpable
132
where does the inguinal ligament run?
ASIS to pubic tubercle
133
mid inguinal point
mid point of line drawn between from ASIS to pubic SYMPHYSIS (not pubic tubercle)
134
which artery is palpable at the midinguinal point?
femoral
135
differences between male and female anatomy
wider pelvic inlet in females
narrower, heart shaped pelvic inlet in males
obtuse angle formed by the inferior pubic rami in females, acute angle in males
wider and shorter sacrum in females
136
arterial supply of the pelvis
left and right internal iliac arteries
137
key branches of the internal iliac arteries
vesical arteries
uterine and vaginal arteries
middle rectal artery
internal pudendal artery
superior and inferior gluteal arteries
138
what do vesical arteries supply?
bladder
prostate and seminal vesicles in males
139
what does the internal pudendal artery supply?
exits the pelvis to supply the perineum
140
what do the superior and inferior gluteal arteries supply?
exit the pelvis to supply the gluteal region
141
venous drainage of the pelvis
several venous plexuses drain the pelvic organs
these plexuses unite and train into the internal iliac vein
142
nerves of the pelvis
sacral spinal nerves come together to form the sacral plexus
143
key nerves arising from the sacral plexus
sciatic nerve
pudendal nerve
superior and inferior gluteal nerves
pelvic splanchnic nerves
144
spinal segments of the sciatic nerve
L4-S3
145
spinal segments of the pudendal nerve
S2-S4
146
function of the pelvic splanchnic nerves
carry parasympathetic fibres from the S2-S4 spinal cord segments to the pelvic viscera
147
sympathetic innervation of the pelvic viscera
lumbar splanchnic nerves
148
what is the pelvic floor?
muscles supporting the pelvic organs from below
149
function of the pelvic floor
support pelvic floor
prevent herniation of the pelvic organs inferiorly, out of the pelvis
control continence of urine and faeces by providing a spinster action on the urethra and rectum respectively
aid in increasing intra-abdominal pressure
150
which muscles make up the pelvic floor?
levator ani
coccygeus
151
which small paired muscles form levator ani?
puborectalis
pubococcygeus
iliococcygeus
152
most anterior levator ani muscle
puborectalis
153
which muscle controls defecation and micturition?
puborectalis
154
where does iliococcygeus attach?
spines of ischium (not ilium) and the coccyx
155
innervation of levator ani
branch of S4 nerve and branches of the pudenal nerve
156
causes of pelvic floor weakness
childbirth
ageing
straining
obesity
157
where is the perineum?
immediately superficial and inferior to the pelvic floor
158
what is the perineum?
superficial region between the pubic symphysis and coccyx, and between the medial surfaces of the thighs
159
what shape is the perineum, and how is it divided?
diamond
into posterior anal triangle and anterior urogenital triangle
160
layers of the urogenital triangle
skin, perineal fascia, superficial perineal pouch, perineal membrane, deep perineal pouch
161
what is the perineal fascia a continuation of?
fascia overlying the abdominal wall muscles
162
what is the superficial perineal pouch?
potential space containing the erectile tissues of the penis or clitoris and 3 muscles
163
muscles of the superficial perineal pouch
ischiocavernosus - attached to the perineal membrane
bulbospongiosus - attached to the perineal membrane
superficial transverse perineal muscles
164
what is the deep perineal pouch?
potential space between the perineal membrane and the pelvic floor muscles
contains parts of the vagina, urethra and the external urethral sphincter
165
what sits between the two triangles of the perineum?
perineal body
166
function of the perineal body
dense mass of fibrous tissue and muscle sitting tin the centre of the perineum
attachment for almost all the personal and pelvic floor muscles
includes levator ani, external anal sphincter, external urethral sphincter, superficial and deep transverse perineal muscles and bulbospongiosus
167
what do 'crura of the clitoris' and 'crura of the penis' mean?
the parts of the corpora cavernous that are attached to the ischial rami
168
what is the bulb of the penis?
part of the corpus spongiosum that sits on the perineal membrane in males
169
what happens to the corpus spongiosum in females?
splits into two parts that flank the vaginal opening
they rest on the perineal membrane
170
which muscles cover the corpus cavernosa?
ischiocavernosus muscles
171
which muscle covers the corpus spongiosum?
bulbospongiosus muscle
172
function of ischiocavernosus muscle
stabilise the erect penis and clitoris
173
arterial supply of the perineum
internal pudendal artery
174
what is the internal pudendal artery a branch of?
internal iliac artery
175
innervation of the perineum
pudendal nerve (S2-S4)
autonomic nerves
176
what does the pudendal nerve innervate?
muscles in the perineum and skin of the external genitalia
177
how do the internal pudendal artery and pudendal nerve enter the perineum?
greater and lesser sciatic foramina of the pelvis
178
episiotomy
pre-emptive incision made just lateral to the perineal body
avoids damage to the perineal body or uncontrolled tear through the anal sphincter
179
function of the vas deferens
carry sperm from the epididymis up the spermatic cord and through the inguinal canal into the pelvis
180
what is the seminal vesicle
lobulated sac
4cm long
lies lateral to the ampulla of the vas deferens
secrete a thick alkaline fluid which forms the bulk of seminal fluid (semen)
duct of the seminal vesicle joins the vas deferens to become the ejaculatory duct, which pierces the back of the prostate gland to enter the prostatic urethra
181
prostate gland
spherical fibromuscular gland lying against the neck of the bladder
pierced by the urethra and ejaculatory ducts
secretions from here are added to the seminal fluid during ejaculation
182
arterial supply of the vas deferens, seminal vesicle and prostate
internal iliac artery
183
benign prostatic hyperplasia
the prostate gland completely encircles the urethra
with age, benign enlargement of the prostate is common - benign prostatic hyperplasia (BPH) or benign prostatic enlargement (BPE)
this may lead to compression of the urethra and inability to pass urine (urinary retention) - requires catheterisation to drain the urine
184
prostatic malignancy
venous blood from the prostate passes into a plexus of veins which lie anterior to the sacrum and communicate with veins which run up to the azygos vein in the chest
these veins communicate with veins in the vertebral bodies which explains why prostate cancer commonly metastasises to the vertebrae
185
digital rectal exam (DRE)
also known as 'per rectum' exam (PR)
involves pushing a finger into the rectum via the anus and flexing it anteriorly to palpate the prostate which sits immediately anterior to the anal canal and rectum
a hard, craggy prostate is concerning
186
uterus function and structure
8cm long
fundus, body and cervix
blastocyst implants in the endometrium - lining - in the body of the uterus
middle muscular layer - myometrium - becomes distended as pregnancy continues
uterus covered in a fold of peritoneum which adheres to itself at the sides of the uterus to form the broad ligament
187
space behind the uterus but anterior to the rectum
rectouterine pouch (pouch of Douglas) - lined with peritoneum
deepest point in the peritoneal cavity
common site for the accumulation of intraperitoneal fluid or pus
188
where do branches of the axillary artery reside?
one above pec minor, two behind it, three below it
189
fate of the axillary artery
becomes brachial artery as it crosses the inferior border of teres major
190
how is the axillary vein formed?
union of the deep veins of the arm with the basilic vein
191
what does the axillary vein drain?
upper limb
192
with which vein is the axillary veiin continuous with?
subclavian
193
how can we stop bleeding from the axilla?
compress severed vessel against the humerus
194
innervation of the upper limb?
brachial plexus
195
which spinal segments form the brachial plexus?
C5, C6, C7, C8, T1
196
list the segments of the brachial plexus?
roots, trunks, divisions, cords, branches
really thirsty drink cold beer
197
where are the brachial nerve roots found?
neck
198
where are brachial plexus nerve trunks found?
neck
199
which roots form the superior trunk?
C5 and C6
200
which nerve root forms the middle trunk?
C7
201
which nerve roots form the inferior trunk?
C8 and T1
202
what does each trunk divide into, and where?
anterior and posterior division
under the neck
203
what are the brachial plexus nerve cords named after?
position relative to the axillary artery
204
what forms the lateral cord?
anterior divisions of the superior and middle trunks
205
what forms the posterior cord?
posterior divisions of all the trunks
206
what forms the medial cord?
anterior division of the inferior trunk
207
where are the terminal branches of the brachial plexus located?
axilla
208
origin of the axillary branch
branch from the posterior cord
209
origin of the radial branch
continuation of the posterior cord
210
origin of the musculocutanous branch
branch from the lateral cord
211
origin of the ulnar branch
branch from the medial cord
212
origin of the median branch
formed by branches from the lateral and medial cords
213
what does the axillary nerve innervate?
deltoid
teres minor
small region of skin over the upper lateral arm
214
which spinal nerves is the axillary nerve supplied by?
C5 and C6
215
why is the axillary nerve vulnerable?
runs close to the surgical neck of the humerus
vulnerable to injury in fractures of the surgical neck of the humerus or dislocation of the humeral head
216
what does the radial nerve innervate?
triceps in the posterior arm
all of the muscles in the posterior compartment of the forearm - thesee muscles are extensors of the wrist and digits
regions of skin over the arm, forearm and hand
217
which spinal nerves supply the radial nerve?
C5-T1
218
deepest point in the peritoneal cavity
rectouterine pouch
219
how does the cervix communicate with the uterine cavity?
internal os
220
how does the cervix communicate with the vagina?
external os
221
recesses around the cervix
vaginal fornices
222
what stabilises the cervix?
levator ani muscle
ligaments running from the lateral wall of the cervix to the pelvic wall at the base of the broad ligament
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where does fertilisation occur?
Fallopian (uterine) tubes
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length of Fallopian tubes
10cm
225
where do Fallopian tubes run?
upper border of the broad ligament
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structure of the Fallopian tubes
narrow isthmus near the uterus
dilated ampulla laterally
leads to funnel shaped infundibulum
free edge of the infundibulum is broken up into finger-like projections - fimbriae, which are draped over the ovary
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ovary size
4cm long, 2cm wide
228
what connects the broad ligament and ovary?
short mesentery - mesovarium
229
where does the ovary frequently lie?
ovarian fossa
formed by the angle between the internal and external iliac arteries
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length of the vagina
10cm
231
where do the upper two thirds of the vagina lie?
pelvic cavity
232
where does the lower third of the vagina lie?
perineum
233
arterial supply of the ovary?
ovarian artery - direct branch of abdominal aorta
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blood supply of the female pelvic organs (minus the ovary)
internal iliac artery
235
collective term for all parts of the female external genitalia
vulva
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blood supply to the vulva
internal pudendal arteries - branches of the internal iliac arteries
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innervation of the vulva
four nerves
- ilioinguinal
- genital branch of the genitofemoral
- genital branch of the pudendal
- posterior cutaneous nerve of the thigh
the erectile tissues are innervated by parasympathetic nerves
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mons pubis
mound of fatty tissue located in front of the pubic symphysis causing an elevation of the hair-bearing skin
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labia majora
prominent hair bearing folds of skin that meet at the mons pubis anteriorly
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labia minora
smaller, hairless folds of skin located medial to the labia major
fuse together anteriorly to form the hood of the clitoris
form the boundaries of the vestibule
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clitoris
pea sized-, highly sensitive tissue comprised of erectile corpora cavernous and corpus spongiosum
becomes engorged during sexual arousal
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vestibule
area between the labia minora
contains the vaginal opening, urinary meatus and vestibular glands
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vaginal introitus
vaginal opening
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hymen
membrane partially covering the vaginal opening
may be absent
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urinary meatus
opening of the urethra
lies posterior to the clitoris, but anterior to the vaginal opening
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vestibular glands
greater and lesser
greater
- Bartholin's glands
- lie just posterior to the vaginal opening and secrete a lubricant into the vagina during sexual arousal
lesser
- Skene's glands
- lie near the urethral opening
- function debated - may lubricate the vaginal opening or urethra or have an antimicrobial effect
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ectopic pregnancy
blastocyst implants outside the uterus
usually uterine tubes
pain and bleeding
the pregnancy cannot progress and must be removed
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endometriosis
endometrial tissue, which lines the inside of the uterus, is found outside the uterus
most commonly
- ovaries
- uterine tubes
- uterine ligaments
- rectouterine pouch
can also be found outside the pelvis e.g thorax
symptoms
- chronic pelvic pain
- cyclical pain related to menstruation
- pain during intercourse
diagnoses using diagnostic laparoscopy
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gynaecological cancers
symptoms
- pelvic pain
- abdominal vaginal discharge
- abnormal vaginal bleeding
- urinary disturbance
- abdominal swelling
- fatigue and weight loss
females aged 25-64 are regularly invited for a cervical smear
involves taking a sample of cells from the cervix to see if particular types of human papillomaviirus (HPV) are present - associated with the development of cervical cancer
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is the urinary bladder intraperitoneal, infra peritoneal or retroperitoneal?
infra peritoneal - below the peritoneum
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arterial supply of the urinary bladder
vesical arteries - branches of the internal iliac artery
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venous drainage of the urinary bladder
vesical veins - drain into the internal iliac vein
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function of the urinary bladder
stores urine and helps squeeze the urine out during micturition
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how much urine can the bladder store?
400-600ml
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where do the ureters drain into the bladder?
posterior aspect of the bladder near the base
triangular area with a smooth wall called the trigone
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how is reflux from the bladder to the ureters prevented?
ureters enter the bladder at an angle, forming a rudimentary valve
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folds of mucosa on the inside wall of the bladder
rugae
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function of rugae
allow bladder to stretch without tearing when it fills
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smooth muscle in the wall of the bladder?
detrusor
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function of the detrusor muscle
contracts to forcibly expel urine
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which sphincters control the release of urine
internal and external urethral sphincters
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location of the internal urethral sphincter
base of the bladder where it opens into the urethra
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what kind of muscle is the internal urethral sphincter made up of?
involuntary smooth muscle
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what kind of muscle is the external urethral sphincter made up of?
skeletal muscle
voluntary
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where is the external urethral sphincter in males and females?
just after the prostate in males
in the deep perineal pouch in females
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somatic innervation of the urinary sphincters
nerve name and segments
function
branches of the pudendal nerve (S2-S4)
allows conscious control of the external urethral sphincter
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sympathetic innervation of the urinary bladder and urethral sphincters
nerve name and segments
function
branches of the hypogastric nerve (sympathetic chain, T12-L2)
causes relaxation of the detrusor and contraction of the internal urethral sphincter, allowing storage of urine
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urethra function
carries urine from the internal urethral orifice of the bladder to the external urethral orifice
carries semen in men
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where is the external urethral orifice in males and females?
males - tip of the penis
females - vestibule
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where is the micturition centre?
sacral spinal cord
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describe the bladder stretch reflex - spinal micturition complex
as the bladder fills, stretch of the bladder wall is detected and this is relayed to the sacral spinal cord via visceral afferent fibres
in the sacral spinal cord, these fibres synapse directly onto motor neurons
the motor neurons stimulate bladder contraction via parasympathetic fibres in the pelvic splanchnic nerves
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how do older children and adults inhibit the bladder stretch reflex arc?
inputs from the cerebral cortex
developing descending pathways that inhibit the reflex
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pathways that are disrupted by an injury to the spinal cord above the sacral level e.g T10
consequences of disruptions to these pathways
ascending pathways conveying the sensation of bladder filling to the brain - patient is no longer aware of bladder filling
descending pathways that exert voluntary, inhibitory control over the external urethral sphincter - external sphincter is permanently relaxed
reflex arc still functions below the injury but the patient does not have any inhibitory control over it
the patient does not realise they need to pass urine and the bladder automatically empties as it fills
patient is incontinent of urine
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consequences of an injury to the spinal cord or caudal equina at or below the level of the sacral micturition centre
the reflex arc itself is disrupted
bladder fills with urine without emptying
internal urethral sphincter permanently contracted
as the bladder continues to fill, the pressure in the bladder eventually exceeds the strength of the internal urethral sphincter and urination will occur
this type of incontinence is 'overflow incontinence'
if the pressure inside the bladder does not overcome the sphincter, the patient develops urinary retention
eventually urine may back up to the ureters and kidneys if a urinary catheter is not placed
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most distal part of the gastrointestinal tract
anal canal
276
length of the anal canal
4cm
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which triangle of the perineurium does the anal canal lie in?
anal triangle
278
which sphincters control defecation?
internal anal sphincter
external anal sphincter
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which type of muscle is the internal anal sphincter made of?
involuntary smooth
280
what type of muscle is the external anal sphincter composed of?
voluntary skeletal
281
what divides the superior and inferior parts of the anal canal?
dentate line
also called pectinate line
282
what is the dentate/ pectinate line?
divides the superior part of the anal canal from the inferior part
283
what is the superior part of the anal canal derived from?
endoderm
284
what is the inferior part of the anal canal derived from?
ectoderm
285
arterial supply of the anal canal above the pectinate line (superior)
inferior mesenteric artery (artery of the hindgut) via the superior rectal artery
286
venous drainage of the anal canal
portal venous system towards the liver
287
what is the lumen of the superior anal canal lined with?
columnar epithelium
288
innervation of the internal anal sphincter
sympathetic fibres from the sympathetic trunk
parasympathetic fibres via the pelvic splanchnic nerves
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arterial supply of the inferior part of the anal canal
middle and inferior rectal arteries which originate from the internal iliac arteries
290
venous drainage of the anal canal below the pectinate line (inferior)
enters the systemic venous system
does not pass through the portal system
291
innervation of external anal sphincter
pudendal nerve (somatic)
292
what is the lining of the inferior part of the anal canal?
stratified squamous epithelium
293
which sphincter encircles the superior anal canal?
internal anal sphincter
294
which sphincter encircles the inferior anal canal?
external anal sphincter
295
haemorrhoids
veins form 'cushions' on the walls of the anal canal to aid faecal continence
they are known as haemorrhoids or 'piles' and are normal
they can become excessively swollen and inflamed - this is pathological
bleed when passing stool
pathology caused by
- excessive straining
- constipation
- squatting
- pregnancy
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when are haemorrhoids painless and painful?
painless above the pectinate line
painful below the pectinate line
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The inguinal canal is a potential weakness in the anterior abdominal wall. What factors normally prevent herniation of the abdominal contents through the inguinal canal?
* The criss-crossing orientation of the muscle fibres of the abdominal wall.
* The oblique orientation of the canal.
298
2. What is a varicocele?
* Dilated veins in the pampiniform venous plexus.
299
Some indirect inguinal hernias are congenital (meaning “present at birth”) even though they may not appear until later in life. Explain the embryology of these hernias.
* The testis develops just below the kidney and travels down into the scrotum during intra-uterine development. As it passes from the abdomen through the abdominal wall it takes a pouch of peritoneum with it. Usually this pouch becomes disconnected from the peritoneal cavity and forms the tunica vaginalis around the testis.
* However, sometimes the pouch remains connected to the peritoneal cavity and bowel can enter the pouch to form a hernia.
300
Where might you look for an undescended testis? Is it worth surgically correcting this anomaly?
* The testis develops just below the kidney and travels down the posterior abdominal wall, through the inguinal canal and into the scrotum during intra-uterine development. An undescended testis will be somewhere along this path.
* Spermatogenesis needs to take place at lower than body temperature so moving an undescended testis to the scrotum is necessary to allow spermatogenesis. There is also an increased risk of cancer in undescended testes.
301
Testicular pain may radiate to the loin. Why?
* The nociceptive (pain sensation) nerve fibres to the testis are sympathetic and follow the testicular artery from the aortic sympathetic plexus which is formed from the T11 and T12 nerve roots. Pain is felt in the distribution of the cutaneous nerve of these segments (dermatomes) as a referred pain.
302
6. Which nerves provide sensory innervation to the scrotal skin?
* The anterior 1/3 of the scrotum is supplied by the ilioinguinal nerve (from L1).
* The posterior 2/3 is supplied by the pudendal nerve (from S2, S3, S4).
303
What veins do the right and left gonadal veins drain into?
* Right directly into the inferior vena cava
* Left into the left renal vein, then inferior vena cava.
304
2. What is a polar artery? Explain why polar arteries exist
* An accessory renal artery usually supplying the lower pole of the kidney.
* As they develop in utero, the kidneys ascend. As they do so, they receive their blood supply from more superior vessels and the more inferior vessels degenerate. Polar / accessory arteries result if the inferior vessels persist, rather than regress.
305
3. Where would you palpate an abdominal aortic aneurysm?
* In the epigastrium or upper-umbilical region.
306
4. Describe the relationship of the ureter to bony landmarks of the abdomen and pelvis (useful for finding the ureter on an X-ray).
* The ureter runs anterior to the tips of the transverse processes of L3, L4 and L5 vertebrae, over the sacroiliac joints and just medial to the lateral pelvic wall.
307
1. Where do the femoral, obturator and sciatic nerves pass from the abdomen into the thigh?
* Femoral nerve: under the inguinal ligament halfway between the pubic tubercle and anterior superior iliac spine.
* Obturator: through the obturator canal.
* Sciatic: posteriorly through the greater sciatic foramen into the buttock and then the thigh.
308
2. Which muscle maintains the angle between the anal canal and rectum?
* Levator ani is the whole sheet of muscle and its anterior part (called puborectalis) maintains the angle.
309
3. Describe the location and contents/role of the superficial perineal pouch and perineal membrane.
* Superficial perineal pouch - a potential space immediately superficial to the perineal membrane that contains the erectile tissues of the penis or clitoris and also 3 muscles: ischiocavernosus, bulbospongiosus and the superficial transverse perineal muscles.
* Perineal membrane - a strong fibrous membrane located between the perineal pouches that provides support for the attachment of ischiocavernosus and bulbospongiosus and through which the urethra and vagina pass.
310
4. Which nerve carries pain sensation during childbirth? Which landmark used to locate this nerve for a nerve block with local anaesthetic?
* Pudendal nerve
* The ischial spine is palpated trans-vaginally, and local anaesthetic is injected in the tissues around it.
311
5. The femoral artery and vein are targets for blood sampling in time-critical clinical situations where getting a blood sample from peripheral veins is not possible or proving very difficult. Describe the bony landmarks that clinicians can use to identify the approximate location of the femoral vessels.
* The mid-inguinal point: palpate the anterior superior iliac spine and the pubic symphysis. Approximately halfway between these points is the location of the femoral artery.
* Pulsation of the femoral artery is palpable here, but it may not be palpable in cardiac arrest, so knowing the landmarks is useful for ‘blindly’ attempting to get a blood sample in critical situations.
* The femoral vein is situated immediately medial to the artery at this location.
312
6. Identify the structures labelled A, B, C, D and E in the diagram.
From top left of the diagram to top right:
* Anterior superior iliac spine
* Pubic symphysis
* Acetabulum
From bottom left of the diagram to bottom right:
* Sacrotuberous ligament
* Ischial tuberosity
313
1. Why may inflammation of the ovary cause pain along the medial aspect of the thigh?
* The ovary sits alongside the lateral pelvic wall very close to the obturator nerve.
* The obturator nerve innervates the skin of the medial thigh.
* Irritation of the obturator nerve by ovarian pathology leads to referred pain felt in the medial thigh.
314
2. What is a retroverted uterus?
* The uterus normally lies tilted forwards over the bladder (anteverted).
* Retroversion is when it is tilted backwards and may lie against the anterior wall of the rectum or sacrum.
315
3. What maintains the normal position of the uterus?
* Tone in the levator ani muscles
* Transverse cervical ligaments (cardinal ligaments)
* Pubocervical ligaments
* Sacrocervical ligaments
* Broad ligaments
316
4. To which lymph nodes would cervical cancer spread?
* The blood supply to the cervix is from the internal iliac arteries and so it is the lymph nodes alongside these arteries which will be involved in spread of cervical malignancy.
317
5. What structures may be palpable during examination through the vagina?
* Anteriorly: base of bladder, urethra
* Laterally: ureter, levator ani muscle, ovary by bimanual palpation
* Posteriorly: rectum, rectouterine pouch, perineal body.
318
6. Why is the ureter in danger of being damaged during a hysterectomy (removal of the uterus)?
* The ureter runs immediately under the uterine artery which is ligated during hysterectomy (‘water under the bridge’). Care must be taken not to injure or ligate the ureter.
319
7. What feature stops urine passing back up the ureter to the kidney when bladder pressure is high during urination?
* The ureter passes through the bladder wall obliquely forming a flap valve. This prevents the reflux of urine into the ureter.
320
8. Where does the bladder lie when full?
* The fundus of the bladder lies immediately above the pubis symphysis.
* Note that there is no peritoneum between the abdominal wall and bladder so a needle or a catheter can be inserted into a full bladder straight through the anterior abdominal wall if necessary. This is called a ‘suprapubic aspiration’ or ‘suprapubic catheter’ respectively.
321
9. A 25-year-old woman involved in a car crash suffered complete transection of her spinal cord at the level of T6. Do you think she is able to tell when her bladder is full? Does her bladder empty via muscle contraction or does it simply “overflow”?
* No conscious sensation is possible as the spinal cord has been disconnected from the higher centres.
* Her bladder will empty by muscle contraction via the spinal micturition reflex. As the bladder fills it is detected by the sensory nerves entering the cord at S2-4. Once the bladder is sufficiently full, these sensory nerves will stimulate the motor nerves to contract the detrusor muscle and relax the sphincters, thereby causing micturition. This is an automatic reflex of the bladder and is the same as found in children before they are ‘potty-trained’.
* As children learn to control this reflex, they develop the ability to send inhibitory fibres down the spinal cord to prevent this reflex from automatically causing micturition without their control.
* In this patient, the inhibitory impulses from the brain cannot reach the bladder anymore because they’ve been cut off due to the spinal cord injury, so once micturition is initiated it cannot be suppressed.
