Anatomy Flashcards
What is the arterial supply of the bladder?
branches of the internal iliac:
- superior vesical artery
- vaginal artery
- minor branches gluteal and obturator arteries
What is the venous drainage of the bladder?
- vesicle venous plexus -> internal iliac
What is the nerve supply of the bladder?
sympathetic:
- T10-L2
- detrusor relaxation during storage and bladder neck closure
parasympathetic:
- S2-S4
- voiding, i.e. detrusor contraction and relaxation of internal urethral sphincter
Lymphatic drainage of the bladder
internal iliac nodes
external iliac nodes
common iliac nodes
bladder wall structure
mucosa (transitional epithelium and lamina propria), submucosa, detrusor and adventitia
The plane of the pelvic inlet is at what angle to the horizontal?
60 degrees
Which vein does the left ovary drain into?
L ovarian vein travels through the suspensory ligament of the ovary and drains into the left renal vein
Which vein does the right ovary drain into?
R ovarian vein travels through the suspensory ligament of the ovary and generally joins the IVC
Venous drainage of the uterus
uterine vein -> internal iliac vein
Venous drainage of the vagina
Vaginal venous plexus -> internal iliac
Fallopian tubes venous drainage
Uterine and ovarian veins
cervix venous drainage
uterine veins -> internal iliac
small bowel venous drainage
hepatic portal vein & superior mesenteric vein -> liver sinusoid
large bowel venous drainage
inferior and superior mesenteric veins -> splenic vein and hepatic portal vein
kidney venous drainage
renal vein -> ÍVC
ureter venous drainage
renal veins and superior and inferior vesical veins -> IVC
venous drainage of spleen
splenic vein -> hepatic portal vein
liver venous drainage
hepatic vein and hepatic portal vein -> liver sinusoid
pancreas venous drainage
pancreaticoduodenal veins, pancreatic veins -> splenic vein
Ascending colon arterial supply
Superior mesenteric artery (right colic artery = main branch)
Transverse colon proximal 2/3 arterial supply
SMA (middle colic)
Transverse colon distal 1/3 arterial supply
Inferior mesenteric artery (ascending branch left colic)
Descending colon arterial supply
IMA (left colic)
sigmoid colon arterial supply
IMA (sigmoid arteries)
rectum upper 2/3 arterial supply
IMA (superior rectal)
rectum lower 1/3 arterial supply
Internal iliac (middle rectal)
Anal canal arterial supply
Internal pudendal (inferior rectal)
Where does the ovarian artery arise from?
Abdominal aorta
(May anastomose with the uterine artery)
Pudendal nerve origins
S2, S3, S4
Pudendal nerve terminal branches
Inferior rectal nerves
Perineal nerve
Dorsal nerve of the clitoris
Pudendal nerve muscles innervated
bulbospongiosus
ichiocavernosus
levator ani muscle group (iliococcygeus, pubococcygeus, puborectalis)
external anal sphincter
female external urethral sphincter
Innervation of the internal and external anal sphincters
Internal = innervated by pelvic splanchnic nerves (S4)
- sympathetic contraction,
- parasympathetic relaxation.
External = pudendal nerve (inferior rectal branch) & perineal branch of S4
Obturator nerve entrapment
Compression between head of the fetus and bony structures of the pelvis
- sensory loss = upper medal thigh
- motor loss = weakness leg adduction
Common peroneal nerve entrapment
Compression lateral head of fibula and leg bars (lithotomy position)
- sensory loss = foot and anterolateral leg
- motor loss = ‘foot drop’, loss of anterior compartment extensors
Lateral femoral cutaneous nerve entrapment
Occurs with advancing gestation
= sensory loss only - lateral thigh
Femoral nerve entrapment
from pressure from a fetus in a difficult birth
- sensory loss = anterior thigh and knee
- motos loss = quadriceps (SLR) weakness, loss of knee jerk
Testicular cell types
- Sertoli cells = secrete inhibin. Form blood-testis barrier. Have FSH receptors.
- Leydig cells = secrete testosterone. Have LH receptors.
Arterial supply of the testes
Testicular arteries
Cremasteric artery
Artery to vas deferens
Venous drainage of the testes
Testicular vein
Pampiniform plexus
Testicular lymphatic drainage
lumbar and para-aortic nodes
Testicular innervation
Spermatic plexus
T10 spinal segment
Labia Majora innervation
- Pudendal nerve provides cutaenous innervation to posterior external genitalia via one of its terminal branches, the perineal nerve (further branches into posterior labial nerves)
- The ilioinguinal nerve provides anterior sensation via the anterior labial nerves.
- The genital branch of the genitofemoral nerve contributes some fibres to the skin of the mons pubis and labia majora.
1st degree tear
Laceration limited to superficial perineal skin, vaginal mucosa and frenulum of labia minora
2nd degree tear
Extends to perineal muscle and fascia but spares anal sphincter
3rd degree tear - as for 2nd degree, but extends to involve external anal sphincter
3A - partial tear anal sphincter < 50% thickness
3B - partial tear anal sphincter >50% thickness
3C - internal sphincter is torn
4th degree tear
As for 3rd degree, plus rectal mucosa is torn
Pudendal nerve - roots and course
S2,3,4 -> exits the pelvis via the greater sciatic foramen, travels behind the sacrospinous ligament before re-entering the pelvis via the lesser sciatic foramen.
Contents of the greater sciatic foramen
Sciatic nerve
Superior gluteal nerve
Inferior gluteal nerve
Pudendal nerve
Posterior Femoral Cutaneous nerve
Nerve to Quadratus femoris
Nerve to obturator internus
Superior gluteal artery and vein
Inferior gluteal artery and vein
Internal pudendal artery and vein
Piriformis muscle
Average diameters within the pelvic inlet
Anteroposterior - sacrum to pubic symphysis = 11cm
Oblique - SIJ to iliopectineal eminence = 12cm
Transverse - widest point on the iliopectineal lines = 13cm
Contents of the femoral triangle
Femoral nerve and terminal branches
Femoral sheath
Femoral artery and branches
Femoral vein and its proximal tributaries incl SFJ (saphenofemoral junction)
Deep inguinal lymph nodes and lymphatic vessels
Medial umbilical ligament = remnant of what?
Remnant of fetal umbilical arteries
Median umbilical ligament = remnant of what?
Remnant of urachus
Inguinal canal - contents and boundaries
In females - the round ligament of the uterus + the ilioinguinal nerve.
Posterior wall = transversalis fascia reinforced by conjoint tendon (AKA inguinal falx)
Anterior wall = aponeurosis of external oblique, laterally reinforced by internal oblique.
Floor = inguinal ligament, lacunar ligament, iliopubic tract
Ilioinguinal nerve - what spinal segment is it derived from?
L1
- one of the most common nerve injuries associated with pelvic surgery
- muscle innervation: transversus abdominis, internal oblique
- sensory: anterior labial nerves
iliohypogastric nerve (spinal segments and innervation)
segments: T12-L1
- muscle innervation: transversus abdominis, internal oblique
- sensory innervation: upper buttock, skin mons pubis
Genitofemoral
L1,L2
- muscle innervation: cremaster in males
- sensory innervation: femoral branch L1 (upper proximal thigh)
- genital branch L2 (small area scrotum)
Lateral femoral cutaneous
L2, L3
Lateral thigh (no motor innervation)
Obturator
L2-L4
- muscle innervation: obturator externus, adductor longus, adductor brevis, gracilis, pectineus, adductor magnus
- sensory: cutaneous branch (medial thigh)
Femoral nerve
L2-L4
- muscle innervation: iliopsoas, pectineus, sartorius, quadriceps femoris
- sensory: anterior cutaneous branches (anterior thigh), saphenous (medial lower leg)
Autonomic sympathetic nerve supply to the uterus and pelvis is from which spinal nerves?
T10 - L1 (inferior hypogastric plexus, AKA pelvic plexus)
- Supplies the uterus and cervix
- Labour pains are therefore referred to these dermatomes (lumbo-sacral region, lower abdomen and loins)
- Labour pain is referred to T11 and T12 in the early stage of labour
- Pain then spreads to adjacent dermatomes, T10 and L1
- Eventually sacral dermatomes S2-S4 are involved during the second stage of labour and delivery
Parasympathetic nerves of the vagina and pelvic outlet
Pudendal nerve (S2, S3, S4)
Genito-femoral nerve (L1 and L2)
Perineal branch of posterior femoral nerve (L2, L3, and L4)
Lymphatic drainage of the vagina
Lower vagina -> inguinal nodes
upper vagina -> internal and external iliac nodes
Lymphatic drainage of the breast
Axillary (75%) and parasternal (25%)
Lymphatic drainage of the ovary
Para-aortic nodes (primarily lateral aortic nodes)
Lymphatic drainage of the fallopian tubes
Para-aortic nodes
Lymphatic drainage of the cervix
external iliac lymph nodes, and ultimately para-aortic lymph nodes
Lymphatic drainage of the uterus
internal iliac lymph nodes, fundus to para-aortic lymph nodes, lumbar and superficial inguinal lymph nodes
Contents of the broad ligament
Fallopian tubes
Ovarian artery
Uterine artery
Ovarian ligament
Round ligament of uterus
Lumbar plexus - spinal roots
contributions from spinal nerves T12-L4
Iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, obturator, femoral
Piriformis
L5 - S2
origin: sacrum
insertion: greater trochanter
Action: external rotation of the hip
Blood supply: superior and inferior gluteal arteries and lateral sacral arteries
Bladder contraction during voiding (micturating) is mediated via innervation of which of the following pathways
Parasympathetic fibres from S2, S3, S4 nerve roots (pelvic sphlachnic nerves)
This also causes relaxation of the urethral sphincter (under somatic control)
The superficial inguinal ring is an aperture in which structure
Aponeurosis external oblique
(the conjoint tendon reinforces the ring posteriorly)
Contents of the inguinal canal
Round ligament of the uterus + the ilioinguinal nerve
Where is the arcuate line and what happens to the rectus sheath either side of it?
1/3 of the distance from the umbilicus to the pubic crest.
Above the arcuate line, the rectus is enclosed within the internal oblique (i.e. the internal oblique divides into two lamellae to encompass it). Whereas, below the arcuate line, all the aponeuroses are anterior to the rectus, with transversalis fascia directly behind
Cervical lymphatic drainage
Primarily drained by external iliac nodes
How many seminiferous tubules would you expect to find in a testicular lobule?
1-3 seminiferous tubules
How many lobules would you expect to find in each testis?
250-400
Which dermatomes is labour pain referred to in early stage of labour?
T11-T12
(then spreads to adjacent T10 and L1 dermatomes as labour progresses)
(Sacral dermatomes S2-S4 are involved during second stage)
sympathetic nerves to the uterus and pelvis
inferior hypogastric plexus (AKA pelvic plexus) - T10-L1 -> supplies uterus and cx.
Parasympathetic nerves to the pelvis
Vagina and pelvic outlet are supplied by the pudendal nerve, genito-femoral nerve and perineal branch of the posterior femoral nerve. Pudendal = main contributor (nerve roots S2-S4, hence these dermatomes are involved in second stage).
Nerve roots of pudendal nerve
S2, S3, S4
Nerve roots of genito-femoral nerve
L1 and L2
Nerve roots of perineal branch of posterior femoral nerve
L2, L3, L4
Normal functional bladder capacity =
400-600mL
First urge to void is typically felt when bladder is approx 150mL full
Inferior mesenteric vein drains into
Splenic vein
Superior mesenteric vein drains into
hepatic portal vein
Bladder smooth muscle structure
3 layers:
inner and outer layers of longitudinal smooth muscle with a middle circular smooth muscle layer
The rectus sheath contains:
rectus abdominis and pyramidalis muscles
Blood supply of the rectum
Upper 2/3 = superior rectal (from IMA)
Lower 1/3 = middle rectal (from internal iliac a)
Anal canal = inferior rectal (from internal pudendal a)
Superficial perineal pouch (contained between perineal membrane and deep perineal facia) contents: (muscles, other)
Muscles:
- Ischiocavernosus
- Bulbospongiosus
- Superficial transverse perineal muscle
Other:
- Crura of clitoris
- Vestibular bulbs
- Greater vestibular glands
What is the embryological origin of the round ligament
Gubernaculum
Describe the course of the round ligament
Originates at the uterine horns where the fallopian tubes attach. Leaves the pelvis via deep inguinal ring -> inguinal canal -> attach to mons pubis
Pelvic floor muscles
Coccygeus + Levator ani
Levator ani = puborectalis, pubococcygeus, iliococcygeal
Sensory supply of the clitoris is via branches of which nerve?
Pudendal (divides into inferior rectal, perineal and dorsal nerve of the clitoris)
Dorsal nerve of the clitoris = sensory innervation.
Perineal nerve = sensory innervation to skin of labia majora, minora and vestibule
Femoral nerve palsy
Quadriceps weakness
Anterior thigh sensory disturbance (L3, L4, L5 dermatomes)
Ureters receive autonomic supply from which spinal segments?
T11 - L2
(Explains ureteric colic giving classic ‘loin to groin’ pain)
Arterial supply of the ureter
Renal artery
Uterine/vaginal arteries
Gonadal artery (ovarian artery)
Middle rectal artery
Superior vesical artery
Numbness and groin pain + sensory deficit in the anterior aspect of the labia - which nerve has likely been damaged during surgery?
Ilioinguinal (L1) -> anterior labial nerves
What is the inferior border of the deep perineal pouch
Perineal membrane (separates the deep and superficial perineal pouches)
The testis receive innervation from which spinal segment
T10
The levator ani are innervated by which spinal nerves?
S3/S4 (mainly S4)
- via the pudendal, perineal and inferior rectal nerve.
What artery supplies the Levator ani
Inferior gluteal artery
Which artery is associated with the midgut
Superior mesenteric
(Foregut = coeliac trunk, Hindgut = inferior mesenteric)
Contents of deep perineal pouch (muscles, other)
Muscles:
- Deep transverse perineal muscle
- External sphincter muscle of urethra
- Compressor urethrae muscle
- Urethrovaginal sphincter
Other:
- Proximal portion of urethra
- Bulbourethral glands
What type of joint is the pubic symphysis
Secondary cartilaginous
Boundaries of the femoral triangle
Superior: inguinal ligament
Medial: medial border of adductor longus
Lateral: medial border of sartorius
Floor: pectineus, adductor longus and iliopsoas
Roof: fascia lata (cribiform fascia at the saphenous opening)
(Transversalis fascia forms part of the roof of the inguinal canal)
How many lobes does the typical breast contain?
15-20
alveoli = the basic component of the mammary gland
= lined with milk-secreting cuboidal cells surrounded by myoepithelial cells
Alveoli form groups called lobules.
Lobules form lobes.
Each lobe has a lactiferous duct that drains into openings in the nipple -> each breast typically contains 15-20 lobes
Branches of the pudendal nerve:
perineal, inferior rectal, and dorsal nerve of the clitoris
(S2, S3, S4)
What is the motor function of the pudendal nerve:
Innervate the muscles of the perineum and pelvic floor:
- bulbospongiosus and ischiocavernosus muscles
- Levator ani muscle
- external anal sphincter
- External urethral sphincter
Contents of the greater sciatic foramen
Nerves:
- Sciatic nerve
- Superior and inferior gluteal nerves
- Pudendal nerves
- Posterior femoral cutaneous nerve
- Nerve to quadratus femoris
- Nerve to obturator internus
Vessels:
- Superior gluteal artery and vein
- Inferior gluteal artery and vein
- Internal pudendal artery
Muscles:
- Piriformis
Uterine venous drainage
Uterine vein -> internal iliac
Ovary venous drainage
Ovarian vein -> L ovarian into L renal, R ovarian into IVC
Vaginal venous drainage
Vaginal venous plexus -> hypogastric veins
Fallopian tubes venous driange
Uterine and ovarian veins
Cervical venous drainage
Uterine veins -> internal iliac
Small bowel venous drainage
Hepatic portal vein & superior mesenteric vein -> liver sinusoid
Large bowel venous drainage
Inferior and superior mesenteric veins -> splenic vein and hepatic portal vein
Kidney venous drainage
Renal vein -> IVC
Ureter venous drainage
Renal veins and superior and inferior vesical veins -> IVC
Bladder venous drainage
Vesical venous plexus -> internal iliac
Stomach venous drainage
Gastric veins, gastroepiploic veins and short gastric veins -> splenic and SMV
Spleen venous drainage
Splenic vein -> hepatic portal vein
Liver venous drainage
hepatic vein and hepatic portal vein -> liver sinusoid
Pancreas venous drainage
Pancreaticoduodenal veins, pancreatic veins -> splenic vein
Testicular blood supply
3 arteries:
- testicular arteries (that branch direct from the aorta)
- cremasteric artery (that branches from inferior hypogastric)
- artery to vas deferens (branch of internal iliac)
