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MRCS A - Anatomy > Pelvis and Perineum > Flashcards

Pelvis and Perineum Flashcards

1
Q

Prostate in relation to rectum?

A

Prostate is anterior to rectum

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2
Q

In men does the ductus deferens cross the ureter?

A

Yes

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3
Q

2 important angles of the urethra?

A

Bends anteriorly via perineum

In external penis where it droops

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4
Q

What is the perineum innervated by?

A

S3-S5
Rectum is S5 in both genders
In men S3 = penis and scrote

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5
Q

Which ligaments support the lumbosacral joint

A

iliolumbar and lumbosacral - both attach to transverse process of L5

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6
Q

Which three ligaments support the sacro-iliac joint?

A

Anterior sacro-iliac = thickening of fibrous membrane from joint capsule

Interosseous ligament = strongest. Positioned poster-superior

Posterior sacro-iliac ligament = covers interosseous ligament

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7
Q

Which ligaments does the pelvic wall have?

What is so important about them?

A

Sacrospinous = attaches to margin of sacrum/coccyx, inserting on ischial spine

Sacrotuberous = Broad base attaches to PSIS + along sacrum/coccyx. Inserts ischial tuberosity
- This is superficial to the sacrospinous

These ligaments turn the sciatic notches into foramen

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8
Q

Which muscle divides the greater sciatic notch into 2?

A

Piriformis

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9
Q

What passes via obturator canal?

A

Obturator nerve and vessels

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10
Q

What passes through greater sciatic foramen?

A

Above piriformis = superior gluteal vessels and nerve

Below piriformis = inferior gluteal nerve and vessels, Pudendal nerve + internal pudendal vessels, then 4 more nerves:
Sciatic nerve
Posterior femoral cutaneous nerve
Nerve to quadratus femoris
Nerve to Obturator internus
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11
Q

What passes through lesser sciatic foramen?

A

Tendon of obturator internus

Pudendal nerve and internal pudendal vessels

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12
Q

Which muscles make up the pelvic floor?

A

Levator ani = pubococcygeus, puborectalis and iliococcygeus

Coccygeus

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13
Q

Pelvic floor muscles - origin, insertion + innervation

A
  1. Pubococcygeus:
    Origin = inner pubis and obturator fascia
    Insertion = Fuses medially at perineal body, attaches to coccyx and anococcygeal ligament.
  2. Iliococcygeus:
    Origin = Coccyx and anococcygeal ligament . Posterolaterally attaches to ischial spine and along tendinous arch of obturator fascia.
    Insertion = Anteromedially fuses with pubococcygeus
  3. Puborectalis:
    Origin = Extends from pubic bone
    Insertion = Forms U-shaped sling around anal canal.

INFERIOR RECTAL BRANCH OF PUDENDAL

Coccygeus - pulls coccyx forward post defecation
Origin = ischial spine + pelvic surface of sacrospinous ligament
Insertion = Lateral margin of coccyx
ANTERIOR RAMI OF S3/S4

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14
Q

What innervates the muscles of the deep pouch?

A

Perineal branch of pudendal nerves

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15
Q

Which parts of the rectum are extraperitoneal?

what surrounds the extraperitoneal parts of the rectum and why is this clinically significant?

A

Posterior upper third
Posterolateral middle third
Whole lower third

Surrounded by mesorectal fat = has LN’s
So must be dissected out if rectal cancer.

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16
Q

What level does sigmoid colon form rectum?

A

L3

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17
Q

What are the two fascial layers of the rectum?

A

Fascia of Denonvilliers = anterior = separates rectum and prostate

Waldeyers fascia = posterior = separates rectum and sacrum
- this must be dissected to mobilise mesorectum from sacrum and coccyx in LAR

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18
Q

Arterial supply to rectum?

Venous drainage?

A

SRA from IMA
MRA from internal iliac
IRA from internal pudendal

Superior rectal vein

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19
Q

Lymphatic drainage of the rectum?

A

Upper part = mesenteric

Lower part = internal iliac

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20
Q

Where does anal canal begin and stop?

A

From levator ani to anal verge

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21
Q

What is the structure and cell type of the upper 2/3rds of the anal canal?

Artery and vein?

A

Columnar epithelium

6-10 longitudinal folds = columns of Morgagni
At the bottom of these = sinuses
3 major sinuses at 3, 7 and 11-o-clock where major arteries feed the vascular plexi

Superior rectal artery and vein

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22
Q

Does the upper 2/3rds of the anal canal have sensation?

What is its lymphatic drainage?

A

No sensation

Internal iliac nodes

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23
Q

What is the anal transitional zone?

A

Area between columnar and squamous zones

= dentate line

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24
Q

Lower third of the anal canal - cell type, sensation, vasculature and lymphatics?

A

Non-keratinsing squamous epithelium = NO GLANDS
Exquisitely sensitive

Middle and inferior rectal arteries and veins

Superficial inguinal LN’s

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25
Internal vs external anal sphincter?
Internal = smooth muscle continuous with the circular muscle of rectum - surrounds upper 2/3rds of canal - sympathetic nerve supply External = striated muscle which also surrounds internal one but extends more distally - S234: S2/3 = inferior rectal branch of pudendal, S4 = perineal branch
26
Embryologically where does the ureter develop from?
Out-pouching of the mesonephric duct in embryo
27
Are the ureters intra or retroperitoneal?
Retro
28
What crosses the ureter?
``` Men = ductus deferens Women = uterine artery ```
29
Relation of ureter to bifurcation of iliacs?
Anterior
30
Arterial supply of the ureter?
``` Proximal = renal arteries Middle = aortic branches, gonadal branches and common iliacs Distal = Internal iliac ```
31
Lymphatic drainage of ureter?
``` upper = para-aortic nodes Lower = common iliac does ```
32
What is connected to the apex of the bladder? What is this a remnant of?
Median umbilical ligament = ascends superiorly to umbilicus Embryological remnant of urachus
33
Is bladder retroperitoneal? Clinical significance ?
Yes, although peritoneum is draped on the top of it As bladder distends it will separate transversalis fascia from peritoneum = can use suprapubic catheter without penetrating peritoneum.
34
What fixes the neck of the bladder in place?
``` Men = Puboprostatic ligament Women = pubovesical ```
35
Arterial supply to bladder? Venous supply to bladder?
Inferior and superior vesicle arteries = branch of internal iliacs Venous: Men = vesicoprostatic plexus Women = Vesicouterine plexus
36
Lymphatics of the bladder?
Mainly external iliac nodes
37
Female urethra: External urethral sphincter innervation + lymphatic drainage ?
Pudendal nerve Whole female urethra drains to the internal iliac nodes
38
Four parts of the male urethra?
1. pre-prostatic - Between bladder and prostate, stellate lumen - only about 2cm long - Has striated muscle to prevent retrograde ejaculation = internal sphincter 2. Prostatic part: - surrounded by prostate - midway has circular elevation = seminal colliculus 3. Membranous part: - Narrowest part - surrounded by external sphincter = first point of resistance - traverse perineal membrane 4. Spongy part / penile part: - Travels through corpus spongiosum - covered by bucks fascia - Dilated at origin as infrabulbar fossa, dilated at navicular fossa too in glans of penis
39
Which section of male urethra is covered in bucks fascia?
Penile / spongy part
40
Which part of male urethra has the internal and external sphincter? Muscle type?
Pre-prostatic = internal = striated muscle Membranous = external
41
Lymphatic drainage of male urethra?
Penile / spongy part = deep inguinal Prostatic / membranous = internal iliac
42
What peritoneal pouch is formed where the peritoneum sits between the bladder and uterus?
Vesicouterine pouch
43
What pouch forms where the peritoneum sits between the rectum and uterus?
Recto-uterine pouch / POUCH OF DOUGLAS
44
What is the ligament called, formed by the large fold of peritoneum lateral to each uterus?
Broad ligament
45
What are the 3 parts to the broad ligament?
Mesometrium = extends from lateral pelvic wall to the uterus Mesosalpinx = suspends uterine tubes Mesovarium = Posterior extension attaching to ovaries
46
What is the suspensory ligament of the ovary called? What does it contain?
Infundibulopelvic ligament Ovarian vessels, nerves and lymphatics = all enter at superior pole
47
What ligament attaches to the inferior pole of the ovary? What does this ligament continue as within the broad ligament?
Ligament of ovary This continues anterolaterally in the broad ligament as ROUND LIGAMENT OF UTERUS
48
What is the main structural support of the uterus?
Central perineal tendon.
49
Fascia of the cervix?
Pubocervical ligament = cervix to anterior pelvic wall Transverse cervical / cardinal = cervix to lateral pelvic wall - most important in stabilisation!! Uterosacral = Cervix to posterior pelvic wall
50
Lymphatic drainage of the vagina?
Superior = iliac nodes Inferior = superficial nodes
51
Organ sites that metastasise to para-aortic LN's early?
Testis Ovaries Uterine fundus
52
Lymphatic drainage of uterus, ovaries and cervix ?
Ovaries and uterine fundus = para-arotic via gonadal vessels Uterine body = Iliac LN's via broad ligament Cervix = iliacs
53
Blood supply of uterus?
Uterine artery = branch of internal iliac
54
3 arteries, 3 nerves and 3 others of the spermatic cord PLUS where they come from / what they do?
Arteries: 1. Testicular artery = branch of abdominal aorta, supplies testis and epididymis 2. Cremasteric artery = from inferior epigastric 3. Artery of vas. deferens = arises from inferior vesicle artery Nerve: 1. Sympathetic = lie on the arteries 2. Genital of GF = supplies cremaster (3. ilioinguinal) Other: 1. Vas deferens = transmits sperm and accessory gland secretion 2. Pampiform plexus = venous plexus, drains into R or L testicular vein 3. Lymphatics - to lumbar or para-aortics
55
Testes embryology - where do they start, where in 3rd month, where at 7th month?
Posterior wall L2 third month = iliac fossa 7th = deep inguinal ring
56
What surrounds the testis?
Tunica vaginalis The parietal layer is adjacent to the internal spermatic fascia
57
What is the tunica vaginalis derived from?
Peritoneum
58
What surrounds the seminiferous tubules and interstitial tissue? What do the seminiferous tubules form and what does this lead to
Tunica albuginea Seminiferous tubules form retes testis this then leads to efferent ductules > head of epididymis
59
Artery and venous supply of testis?
Testicular artery arises from aorta just below renal arteries Pampiform plexus L goes to left renal R directly to IVC
60
LN's of the testis?
Para-aortic
61
Course of the vas deferens?
Ascends in scrotum then passes through inguinal canal exiting deep ring Then bends medially around inferior epigastric artery Crosses external iliac vein and artery to enter pelvic inlet Crosses ureter Joined by seminal vesicle = ejaculatoy duct Penetrates prostate and feeds into prostatic part of urethra
62
Arterial supply of scrotum? Lymphatic drainage? Sensory innervation?
Anterior and posteiror scrotal arteries Inguinal's Anterior = ilioinguinal Posterior - pudendal
63
Layers you cut through in scrotal surgery?
``` Skin Dartos fascia External spermatic fascia Cremasteric fascia / muscle Internal spermatic fascia Parietal layer of tunica vaginalis ```
64
Where do the posteiror and median lobes of the prostate sit in relation to the urethra?
Posterior
65
What separates the rectum and prostate?
Denonvilliers fascia
66
Prostate - arterial supply, venous supply + LN's? Innervation of prostate?
Inferior vesical artery from internal iliac Prostatic venous plexus Internal iliac LN's Inferior hypogastric plexus
67
Which roots make up the lumbar plexus?
L1-L3 + part of L4
68
Ilioinguinal nerve - root and course?
L1 Descends around abdominal wall in plane between transversus abdominus and internal oblique Then passes via inguinal canal
69
Ilioinguinal nerve - innervation?
No motor function in thigh, but innervates abdominal wall muscles Sensory = anteromedial thigh and adjacent perineum
70
Genitofemoral nerve - root and course?
L1/L2 Descends anteroinferiorly through the psoas muscle, then passes on the anterior surface of psoas Femoral branch passes under inguinal ligament Genital branch enters inguinal canal
71
Genitofemoral nerve - innervation?
No motor, but in men genital branch innervates cremasteric muscle of spermatic cord Sensory: Genital = anterior perineum Femoral = anterior central upper thigh
72
Femoral nerve - root and course?
L2-L4 Passes through gap between inguinal ligament and pelvic bone Enters femoral triangle
73
Innervation of femoral nerve?
Motor = anterior thigh, illiacus and pectineus Sensory = Anterior thigh, anteromedial knee + medial leg/foot
74
Obturator nerve - root and course?
L2-L4 travels within the psoas major, and emerges from medial part Passes posterior to common iliac artery, medial to internal iliac artery Passes through obturator canal
75
Obturator nerve innervation?
Medial muscles of thigh EXCEPT adductor magnus head attached to ischium + pectineus Also innervates obturator internus Sensory = upper medial thigh
76
Lateral cutaneous nerve - root and path?
L2, L3 Passes between inguinal ligament and pelvic bone
77
Lateral cutaneous nerve innervation?
Parietal peritoneum in RIF | Anterolateral thigh.
78
What makes up the sacral plexus?
Anterior rami of S1-S4 | Lumbosacral trunk = L4/L5
79
What muscle is the sacral plexus formed anteriorly too?
Piriformis muscle
80
Sciatic nerve - roots and course?
L4-S3 Leaves pelvis via greater sciatic foramen, inferior to piriformis Descends between superficial and deep gluteal muscles Then passes into gluteal region = Common peroneal and tibial
81
What does common peroneal supply vs tibial nerve?
Common peroneal: Motor = short head of biceps, anterior and lateral leg compartments Also extensor digitorum brevis + contributes to first dorsal interossei Sensory = Skin on anterolateral leg and dorsal foot Tibial: Motor = Posteiror hamstrings EXCEPT short head of biceps, posterior compartment of the leg, muscles in sole of the foot Sensory = Posterolateral and medial foot + sole of foot
82
Pudendal nerve - roots and course?
S2-S4 Leaves pelvis below piriformis, via greater sciatic foramen Immediately curves around the sacrospinous ligament where it joins ischial spine, and passes via the lesser sciatic foramen Accompanied by internal pudendal vessels
83
What does pudendal nerve innervate?
Skin and muscles of perineum Includes external urethral sphincter + anal sphincter and levator ani Sensory = Skin of perineum + penis / clitoris
84
Superior gluteal nerve - roots and course?
L4-S1 Leaves greater sciatic foramen above the piriformis Travels in plane between gluteus medium and minimum
85
What does superior gluteal nerve supply?
Gluteus medius and minimus Terminates innervating tensor fascia lata
86
Inferior gluteal nerve - roots and course?
L5-S2 Leaves pelvic cavity via greater sciatic foramen below piriformis Penetrates gluteus maximus
87
Inferior gluteal nerve supplies?
Gluteus maximus
88
Nerve to obturator internus and superior gemellus - roots and course?
L5-S2 Leaves via greater sciatic foramen inferior to piriformis. Then passes around ischial spine and via lesser sciatic foramen
89
Nerve to quadratus femoris and inferior gemellus - roots and course?
L4 - S1 Greater sciatic foramen, inferior to piriformis Passes anterior to plane of deep gluteal muscles
90
Posterior cutaneous nerves - roots and course?
S1, S3 Leaves via greater sciatic foramen inferior to piriformis Immediately medial to sciatic nerve Descends through gluteal region deep to gluteus maximus
91
Posteiror cutaneous nerve innervation?
Skin on posterior thigh
92
Perforating cutaneous nerve - root and course?
S2, S3 Unusual route and penetrates directly through sacrotuberous ligament to reach inferior buttocks
93
Perforating cutaneous nerve innervation?
Skin over gluteal fold
94
How does the nerve to piriformis leave the pelvic cavity?
It doesn't, oiiiii
95
Hypogastric plexus - route and what it eventually innervates?
Starts as superior hypogastric plexus anterior to L5, near aortic bifurcation Enters pelvis as 2 hypogastric nerves. Crosses pelvic inlet medial to internal iliac vessels Forms inferior hypogastric plexus when hypogastric nerves are joined by the splanchnic nerves ``` Inferior hypogastric plexus gives rise too: Rectal plexus Uterovaginal plexus Prostatic plexus Vesical plexus ``` Terminal branches innervate erectile tissue of penis/clitoris
96
Penile erection - parasympathetic vs sympathetic innervation?
``` Parasymp = erection Sympathetic = Ejaculation and detumescence ```
97
Penile erection - which are the somatic nerves, what nucleus they relay from and muscles innervated?
Dorsal penile and pudendal Efferent fibres via Onuf's nucleus Ischiocavernous and bulbocavernous
98
Where does internal iliac originate, and where does it divide into anterior and posteiror trunk?
Originates at L5/S1 just anterior to the sacroiliac joint Divides into posterior and anterior trunks at superior border of greater sciatic foramen
99
Internal iliac posterior trunk - branches and supply?
Iliolumbar: - Divides into iliac and lumbar branch - iliac = skin and muscles in RIF Lumbar = psoas and quadratus lumborum Lateral sacral: - Medial and inferior branches - Supply muscle and skin behind sacrum Superior gluteal: - leaves pelvic cavity above piriformis via greater sciatic foramen - Divides into superficial and deep branches - Deep travels between medium and minimus - superficial Passes on deep surface of maximus
100
Anterior trunk branches of internal iliac artery?
``` Umbilical Superior vesical Inferior vesical (men) - vaginal artery in women = equivalent Inferior gluteal Middle rectal Internal pudendal Obturator Uterine (women) ```
101
Anterior trunk of internal iliac - Umbillical Path Embryology
Continues inferiorly before ascending on anterior abdominal wall to reach umbilicus In foetus it is very large, in adults it becomes a fibrous cord This cord is called medial umbilical ligament
102
Anterior trunk of internal iliac - superior vesical What does it supply?
Superior aspect of bladder and distal ureter In men also supplies ductus deferens
103
Anterior trunk of internal iliac - inferior vesical Men or women? What it supplies?
Men Female equivalent = vaginal artery Bladder ureter, seminal vesicle and prostate / vagina
104
Anterior trunk of internal iliac - Obturator artery Path and supply?
Leaves pelvis via obturator canal Supplies adductor region
105
Anterior trunk of internal iliac - Internal pudendal Path and supply?
Greater sciatic foramen then the lesser sciatic foramen passing over sacrospinous ligament as it joins ischial spine Erectile tissue
106
Anterior trunk of internal iliac - inferior gluteal Path
Passes between anterior rami of S1/S2/S3 Leaves greater sciatic foramen inferior to piriformis
107
Anterior trunk of internal iliac - Uterine artery Path Supply what it anastomoses with
Travels medially in base of the broad ligament to reach cervix Crosses ureter and passes superior to lateral vaginal fornix Anastomoses with. ovarian artery
108
What are the ovarian arteries a branch of and what do they travel in?
Branch of aorta Travel in suspense sort ligament of the ovaries = infundibulopelvic ligament
109
Whats the vein draining clitoris / penis?
Single deep dorsal vein
110
Left vs right ovarian vein drainage?
Left into renal vein | Right into IVC
111
Borders of the perineum?
tip of coccyx posteriorly Pubic symphysis anteriorly Laterally = ischiopubic ramus anteriorly, sacrotuberous ligament posteriorly Roof = levator ani
112
How do we divide the perineum into two?
line between two ischial tuberosities Anterior = urogenital triangle Posteiror = anal triangle
113
Contents of anal triangle?
External anal sphincter = S234
114
Contents of urogenital triangle?
Males = bulb and crura of penis, superficial transverse perineal muscles and posteiror scrotal arteries and nerves Females = Internal pudendal becomes posteiror labial artery, Muscles again, crura of clitoris, greater vestibular gland
115
Three branches of the pudendal nerve and what they innervate?
Infeiror rectal = external anal sphincter + skin of anal triangle Perineal = Skeletal muscles in perineal pouch + branches into scrotal / labial nerves Dorsal nerve of penis / clitoris = sensory
116
As the internal pudendal artery and pudendal nerve pass around ischial spine, which lies lateral?
Artery lies lateral
117
Where do the testicular artery and cremasteric artery branch from?
``` Testicular = aorta Cremasteric = from the infeiror epigastric of the external iliac ```
118
Layers of spermatic cord?
Internal spermatic fascia = Transversalis fascia Cremasteric fascia = Internal oblique External spermatic fascia = External oblique

MRCS A - Anatomy (7 decks)

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