Anatomy Flashcards
Attachments of the ovary
Mesovarium - attaches the anterior aspect of the ovary to the posterior layer of the broad ligament
Suspensory ligament of the ovary - also referred to as the infundibulopelvic ligament. Attaches superiolaterally. Contains ovarian vessels and nerves
Ovarian ligament - attaches ovary to uterine cornua
Immediate posterior relations of the ovary
Ureter and internal iliac artery
What is the ovarian bursa
peritoneal recess between the medial aspect of the ovary and the mesosalpinx
What is the mesometrium
Part of the broad ligament which extends upwards from the pelvic floor to the ovary and ovarian ligament
Boundaries of the ovary
Above- bifurcation of the iliac vessels
Lateral - the ovarian fossa, and the obturator nerves and vessels
Medial - the fallopian tube
Behind- the ureters and internal iliac artery
Contents of the broad ligament
Fallopian tube, round ligament and ovarian ligament
Anatomy of the broad ligament
- a fold of peritoneum related to either side of the uterus
- Reaches from the lateral pelvic wall creating a septum that divides the pelvis into the anterior region (containing the bladder) and posterior region (containing the rectum)
Size of the ovary
2x3x4cm
Anatomical position of the ovary’s long axis and attachments at the upper and lower poles
Long axis is vertical
- upper pole: infundibulopelvic fold (suspensory ligament of the ovary)
- Lower pole: ovarian ligament
Base of the breast
extends from 2nd rib to 6th rib and overlies the investing fascia of pectoralis major
Lymphatic drainage of the breast
> 75% occurs via the axillary nodes, which cluster around pectoralis minor and the axillary vessels
Remaining drainage is via the para-aortic nodes
Can also occur across the midline and below the diaphragm via interconnecting lymph channels
Blood supply of the breast
Mainly: lateral thoracic artery, which is a branch of the axillary artery. Feeds into the breast through lateral mammary branches
Lateral mammary branches may also arise from lateral cutaneous branches of the posterior intercostal arteries
Medial mammary branches arise from the internal thoracic artery, which is a branch from the first part of the subclavian artery
Structure of the breast
- Divided into 20 lobules, each containing a lactiferous duct
Lactiferous ducts extend in a radial manner toward the nipple, opening onto its surface
Areolar glands also open around the nipple and secrete an oily protective lubricant
Lobules are separated by fibrous tissue that form suspensory ligaments. They extend from the deep fascia covering pec major to the dermis of the skin
Development of the breast
Ducting system is fully established during puberty
Alveolar parts of this system also appear in puberty but the increase in breast size during puberty is due to increased fat deposition
Alveoli and ducts further develop in pregnancy to produce milk
Following pregnancy, breasts return to prep regnant state due to apoptosis and macrophage action
Postmenopause: breast atrophy and decreasing tautness of suspensory ligaments due to declining oestrogen’s
Autonomic nerve supply of the uterus
Sensory fibres of the uterine body and fundus run via the inferior and superior hypogastric plexuses to T11 and T12
Autonomic nerve supply of the cervix
Run via the pelvic splanchnic nerves to S2,3 and 4. Then to the hypogastric plexuses
Autonomic supply of the vagina
The upper vagina sensory fibres run via the pelvic splanchnic nerve to S2,3,4.
The lower vagina runs through the pudendal nerve to S2,3,4
Autonomic supply of the perineum
Fibres run through the pudendal nerve to S2,3,4.
Which classes of nerves supply the genital tract
Uterine body and fundus muscle is sympathetic
Lower part of the uterus (cervix) and upper vagina are parasympathetic (pelvic splanchnic)
Lower vagina and perineum are somatic (via pudendal)
Position of the urinary bladder
Lies in lesser pelvis, but can extend up into the abdominal cavity when distended
Apex is directed toward pubis symphysis, neck lies in the pelvic floor
What is the vesicourethral or utero-vesical pouch
A pouch formed by peritoneal reflection between the superior surface of the bladder and the uterus
What is the median umbilical ligament
It is a fibrous cord covered in a peritoneal fold that represents the closure of the upper end of the vesicourethral canal during embryonic development
What are the ligaments of the bladder
At the apex - median umbilical ligament (continuous with the urachus)
Laterally - the pubovesical ligaments
What are the pubovesical ligaments and where do they run
2 thickened bands pelvic fascia that run from the bladder to the inside aspect of the pubic bone, close to the midpoint of the symphysis.
What is the role of the pubovesical ligaments
Support the bladder neck
Play a role in urinary continence
Describe the mucous membrane of the bladder
Arranged in folds when the bladder is contracted, but smooths out when the bladder distends
What is the trigone and what does it represent
Triangular area on the posterior bladder wall between the distal ends of the ureters and the urethral outlet.
Represents the different developmental origins of the ureter and bladder. The inferior part is from the fusion of the 2 mesonephric ducts on the posterior wall (mesodermal)
How does the mucous membrane of the trigone differ to the rest of the bladder
At the trigone, the mucous membrane is more firmly adherent and doesn’t fold, therefore remains smooth despite contraction of the bladder
Describe the detrusor muscle
The detrusor muscle is the muscle of the bladder. It is smooth muscle arranged in 3 layers:
Outer longitudinal, middle circular sand inner longitudinal layer
How does the detrusor muscle form the sphincter vesicae
The middle circular layer of the detrusor muscle is thin over most of the bladder but thickens at the bladder neck, which forms the sphincter vesicae at the internal urethral orifice
Describe the innervation of the bladder
Receives both sympathetic and parasympathetic innervation within the pelvic plexus
Efferent parasympathetic fibres from the pelvic splanchnic nerves supply detrusor muscle and inhibitory fibres to the sphincter vesicae
What supplies the urethral sphincter
Pudendal nerve
What are the borders of the anal triangle
Posterior aspect of the perineal membrane superiorly
Laterally, the ischial tuberosities and the sacrotuberous ligaments
Where do the ischioanal fossae lie
In the anal triangle, the IA fossae lie laterally to the anal canal, which is in the centre
What are the anal columns and how do they change
The mucous membrane covering the upper part of the anal canal is thrown into folds, known as the anal columns
At the distal end of the anal canal, the anal columns are characterised by having anal valves and sinuses
What is the white line of the anal canal
The transition point between the internal anal sphincter and the subcutaneous part of the external sphincter
Describe the internal anal sphincter
It surrounds the upper 3/4 of the anal canal and lower external sphincter. It is formed by a thickening of the circular muscle of the rectum at the and-rectal junction
What are the 3 layers of the external anal sphincter
Deep layer, with fibres interdigitating with fibres of the puborectalis and muscles of the deep perineal pouch (via the perineal body)
Superficial layer - fibres inserted on the coccyx which contribute to the anococcygeal ligament
Subcutaneous - a thin, horizontal band around the distal part of the anal canal, which lies below the internal sphincter. Some fibres attach to the anococcygeal ligament and perineal body but there is no bony attachment
What is the anococcygeal ligament
A fibromuscular tissue body that separates the anus and the coccyx
What are the 4 main ligaments supporting the uterus
Uterosacral
Broad
Round
Transverse cervical
What are the boundaries of the recto-uterine pouch
Ant: posterior wall of the uterus
Post: rectum
Lat: peritoneal folds passing from the cervix to the posterior walls of the lesser pelvis
What forms the majority and minority of the tissue of the uterus
Bulk is smooth muscle, except for the cervix, which is dense connective tissue
Describe the cervix
Cylindrical lower third of the uterus comprised of dense connective tissue with a relatively unchanging mucosal layer. Has 2 os’s - one which communicates with the uterus (internal os) and one with the vagina (external os)
What changes are noted in the cervix in pregnancy
Increased vascularity and reduced rigidity
Mucus secretions thicken to prevent infection and form mucosal plug
Increased uptake of fluid by mucopolysaccharides which causes loosing of the dense collagen tissue, which allows cervical shortening
Describe the vagina
Muscular canal that lies between the cervix and vestibule and opens onto the perineum
Which muscles compose the anterior abdominal wall
External and internal oblique, transversus abdominis and the recti muscles
What are the origins and insertions of the external obliques
Arise from the outer surfaces of lower 8 ribs and interdigitate with fibres from the seratus anterior and latissimus dorsi
The fibres from the lower 2 ribs pass vertically down and insert on the anterior part of the iliac crest
The other fibres pass inferomedially and become aponeurotic at the level of the tip of the 9th costal cartilage
What is the linea alba and how does it form
It is a tendinous raphe that extends down the midline from the xiphoid process to the pubis symphysis
Aponeurotic fibres of the external oblique, internal oblique and transversus abdominis meet in the midline and fuse, forming the linea alba
At what level is the linea alba interrupted and by what
At the level of the umbilicus
It is interupted by the umbilical vessels, urachus and bite line duct in fetal life, which become:
Median umbilical ligament (remnant of urachus)
Ligamentum teres (umbilical vein), running from the umbilicus to the liver between the falciform ligament
Lateral umbilical ligament (fold of peritoneum encasing the inferior epigastric aa)
How does the external oblique contribute to the inguinal ligament
The lower fibres stretching from the ASIS to the pubic tubercle thicken and fold in on itself forming the inguinal ligament and the flow of the inguinal canal
What is the lacunar ligament and what does it form
At the medial end of the inguinal ligament, the fibres pass posteromedially to the pectineal line to form the lacunar ligament, which forms the medial boundary for the femoral ring
What is the origin of the internal oblique muscle
It arises from the lumbar fascia, lateral part of the inguinal ligament and anterior part of the iliac crest
How do the fibres of internal obliques run and insert
Posterior fibres (from lumbar fascia) ascend to the lower ribs and become continuous with the fibres of the external intercostal muscles Fibres from the iliac crest run superomedially and meet in the midline to contribute to the linea alba Fibres from the inguinal ring arch down and medially, crossing over the round ligament and become aponeurotic, and insert on the pubic crest and medial part of the pectineal line, to form the conjoint tendon (or falx inguinalis)
What is the conjoint tendon and its function
The conjoint tendon is comprised of aponeurotic portions of the internal oblique and transversus abdominis muscles, forming a fibrous tendon.
AKA falx inguinalis
It lies behind the superficial inguinal ring of the inguinal canal which strengthens it
What is the origin of the transversus abdominis
Origin is the same as, but deep to, the internal obliques
Originates from the lumbar fascia, lateral part of the inguinal ligament and the anterior part of the iliac crest
How do the fibres of transversus abdominis run
Fibres are orientated horizontally across the abdomen to contribute to the linea alba
Fibres which originate from the inguinal ligament, pass over the round ligament to contribute to the conjoint tendon
The upper 4/5ths of the aponeurosis runs behind the rectus abdominis, but the lower part from the inguinal ligament and iliac crest run in front
Where does rectus abdominis originate and insert
Originates from the crest and tubercles of the pubis and runs superiorly, broadening as it ascends to insert on the costal cartilages of ribs 5,6 and 7
What are the 3 transverse tendinous insertions of the recti muscles
At the level of the xiphoid process, at the umbilicus and midway between the xiphoid process and umbilicus
How is the rectus sheath formed
Formed from the aponeuroses of the 2 obliques and transversus muscles
The Aponeurosis of the internal oblique divides into 2 laminae at the lateral border of rectus, with one passing superficially above rectus, and the other deep to it.
The transversus aponeurosis runs post, and ext oblique runs anterior to the recti muscles
What happens to the rectus sheath between the umbilicus and the pubis symphysis
A deficiency in the abdominal wall forms as all 3 aponeurosis pass over the rectus muscle, with only the transversals fascia posterior
What is the arcuate line
The point where the transversus and 1/2 thickness of the oblique aponeuroses pass deep to the rectis muscle, and then thins out. It is the point where the inferior epigastric vessels gain access to the rectus sheath
Where do the inferior epigastric arteries arise from
Arise from the external iliac arteries, superior to the inguinal ligament
What is the course of the inferior epigastric artery
Inclines medially from point of origin, and ascends to skirt around the medial margin of the deep inguinal ring before passing through the transversalis fascia at the arcuate line, where it runs up to anastomose with the superior epigastric artery above the level of the umbilicus
What does the inferior and superior epigastric artery supply
They give off small branches from position between the rectus sheath and muscle, which perforate the recti muscles to supply the muscle and skin of the abdomen
What are the 2 points of anastomosis of the inferior epigastric artery
The superior epigastric artery
Some branches of the lower posterior intercostal arteries
What venous structures accompany the inferior epigastric artery
The venae commitantes runs with the epigastric artery, which unite to form the inferior epigastric vein, which drains into the external iliac vein above the inguinal ligament
What are the borders of the inguinal canal
MALT
Superior (roof) - (M)uscles - internal oblique, transversus abdominis
Anterior - (A)poneuroses - external oblique, internal oblique
Lower (floor) - (L)igaments - inguinal, lacunar
PosT - 2Ts - Transversalis fascia, conjoint Tendon
What are the contents of the inguinal canal
The round ligament and the ilioinguinal nerve
Where is the inguinal canal in relation to the inguinal ligament
It is just superior to the medial half of the inguinal ligament
What forms the deep inguinal ring and where does it form
It is formed in the transversalis fascia midway between the ASIS and pubis symphysis
Transversus abdominis fibres arch over it superiorly to form ring, directly lateral to the inferior epigastric vessels
What forms the superficial inguinal ring and where
It is formed above the inguinal ligament, lateral to the pubic tubercle
It is formed by the opening of the external oblique aponeurosis, whose margins thicken to form the lateral and medial crura of the ring
What are the 3 surrounding layers of the round ligament and where do they arise from
Internal spermatic fascia is formed as the round ligament passes through the transversalis fascia at the deep ring
Gains cremasteric fascia as it passes through the internal oblique muscle (gives a degree of muscle fibres, M»F)
External spermatic fascia - as it passes through the external oblique aponeurosis, it gains the last layer
What is the origin and course of the ilioingiunal nerve
Originates from the anterior primary ramus of L1.
Emerges from the lateral border of posts major - crosses quadratus lumborum - perforates transversus abdominis close to the anterior part of the iliac crest - runs in the neuromuscular plane until it pierces the internal oblique to enter the inguinal canal through the superficial ring - distributed to skin on the medial aspect of the thigh and skin covering mons pubis and part of the labia majora
What happens if the ilioinguinal nerve is damaged
Damage to the nerve causes weakening of the conjoint tendon, which can predispose to a direct hernia
What does the ilioinguinal nerve supply
Medial skin of thigh
Skin of mons pubis and part of the labia majora
Fibres of the internal oblique and transversus abdominis (– conjoint tendon)
What are the two superficial fascial layers found in the femoral triangle
Superficial fascia - continuous with the superficial fascia of the abdomen
Deep fascia - fuses with the deep fascia of the thigh (fascia lata) below the inguinal ligament
What lies between the two fascial layers in the femoral triangle
The superficial inguinal LNs and the long saphenous vein
What are the borders of the femoral triangle
Inguinal ligament superiorly, sartorius laterally and adductor longus medially
What are the contents of the femoral triangle
Lat to medial:
Femoral nerve
Femoral branch of the genitofemoral nerve, which exits from the femoral sheath
Femoral sheath containing femoral artery > femoral vein > femoral canal, which contains the deep inguinal LNs and lymphatics
What forms the femoral sheath
The continuation of the transversalis fascia in front of the femoral vessels and the fascia covering the ilacus muscle behind the, which fuse with the fascia on the outside of the vessels to form the femoral sheath
What 2 things pierce the femoral sheath and where
The lateral wall is pierced by the femoral branch of the genitofemoral nerve and the medial wall by the great saphenous vein where it enters the femoral vein
How is the epithelium of the urethra structured
Thrown in folds, with the largest fold on posterior wall = urethral crest
What forms the paraurethral ducts and where are they located
There are numerous mucus-secreting glands that open into the urethra. At the distal end, they cluster together and open into the paraurethral duct.
The paraurethral duct runs downwards in the submucosal tissue and opens on the lateral aspect of the external urethral orifice bilaterally
Describe the muscle structure of the urethra
Smooth muscle in the urethra is continuous with the bladder but there are only2 layers:
Internal longitudinal layer
External circular layer, which contains fibres of the sphincter vesicae proximally and sphincter urethrae distally
Describe the different epitheliums in the urethra
Proximally, the urethra is composed of transitional epithelium
Distally, composed of nonkeratinised stratified squamous epithelium
What lies beneath the mucousal membrane of the urethra
Thin layer of erectile tissue which contains smooth muscle fibres, elastic CT and a venous plexus
What is the blood supply and innervation of the urethra
Blood supply: perineal branches of the internal pudendal artery, which then drains via similar branches
Autonomic innervation via the pelvic plexus
Describe the passage of the ureters
Originate at the kidney - descend along psoas major - cross in front of the genitofemoral nerve, and is crossed by the ovarian vessels anteriorly.
Enters the pelvis anterior to either the end of the common iliac artery or proximal end of the internal iliac artery, then follows the lateral pelvic side wall to the greater sciatic notch
At the level of the ischial spine, it runs medially in the fascia of the pelvic floor to reach the lateral aspect of the bladder
It is crossed superiorly by the uterine vessels as they enter the broad ligament at the level of the cervix
What are the 3 coats of the ureter
Outer: Proximally, it is a fibrous coat that is continuous with the capsule of the kidney, which merges into the bladder wall distally
Intermediate: inner longitudinal and outer circular smooth muscle in the upper 2/3; outer longitudinal layer added in the distal 1/3. All of the intermediate layer is internal ed with connective tissue therefore not clearly defined
Inner: mucosal layer in folds, consisting of fibrous and elastic tissue and covered with transitional epithelium
Describe the blood supply of the ureter
Receives blood supply from several arterial anastomoses.
Proximally, the renal aa, then ovarian, common iliac and superior vesical
Describe the innervation of the ureter
Receives innervation through branches off renal, aortic, presacral and pelvis autonomic plexuses
Which muscles contribute to the pelvic wall and their attachments
Piriformis: sacrum to greater trochanter
Obturator internis: nferior margin of the superior pubic ramus and from the pelvic surface of the obturator membrane
Components of the pelvic floor
Pelvic diaphragm
Perineal membrane
Deep perineal pouch
Which muscles contribute to the pelvic diaphragm
Levator ani
Coccygeus
Where do the pelvic diaphragm muscles attach
From the posterior surface of the pubis anteriorly, then attach along the fascia of the obturator interns muscle to the ischial spine along the tendinous arch, then attach posteriorly to the coccyx
What is the urogenital hiatus
A U-shaped defect in the elevator ani anteriorly, which allows passage of the urogenital organs through the pelvic floor to the perineum
What are the functions of the levator ani muscles
Maintain the 90 degree anorectal angle
Resist rises in intrapelvic pressure
Support the pelvic viscera
Keeps the rectum and vagina closed
What are the origins and insertions of levator ani
Origin: posterior aspect of pubis, tendonous arch and ischial spine
Inserts: coccyx and at the anococcygeal ligament
What is the anococcygeal ligament
a midline raphe formed where the levator ani meets in the midline, posterior to the anus
Components of levator ani
Pubococcygeus = divides into pubovaginalis, puboperinealis, puborectalis, puboanalis
Ileococcygeus
Describe the coccygeus muscle
Lies over the sacrospinous ligament
Forms the posterior part of the pelvic diaphragn
Originates from the ischial spine and inserts laterally on the coccyx and adjacent margins of the sacrum
Functions to support the pelvic floor
Innervated by anterior branches of the rami of L4 and 5
What innervates elevator ani
branches of the pudendal nerve
What is the perineal membrane and where does it attach
It is a thick, triangular shaped fascial structure deep to the pelvic diaphragm that attaches along the pubic arch with a free border posteriorly
Function of the perineal membrane
To provide attachments for some roots of the external genitalia
What is the transverse perineal ligament
A thickened area of the perineal membrane at the apex
What is the deep perineal pouch
A fascial capsule lying above the perineal membrane but below the pelvic diaphragm. Ischioanal fossae partially occupy the space between the deep pouch and the pelvic floor muscles, therefore deep perineal pouch is very small
Contents of the deep perineal pouch
Deep transverse perineal muscles External urethral sphincter Compressor urethrae Sphincter urethrovaginalis Perineal body
What is the perineal body
A fibromuscular body sitting on the free posterior end of the perineal pouch (central point of the perineum), connecting structures of the perineum to structures of the pelvic cavity and maintaining the integrity of the perineum through muscular attachments
What are the attachments of the deep transverse perineal muscles
Attaches laterally to ischopubic ramus, inserting on the perineal body
Describe the compressor urethrae
Only found in females
Originates from the sides of ischiopubic ramus and meets anterior to the urethra
Aids external urethral sphincter
Describe the sphincter urethrovaginalis
Extends from the perineal body around the vaginal opening and then blends with the compressor urethrae muscle
What is the perineum
A diamond-shaped space at the bottom of the pelvis, between the thighs that encompasses the anus and genitals
What are the borders and divisions of the perineum
Ant: pubic symphysis
Lat: ischial tuberosities
Post: coccyx
Ceiling: pelvic floor
Walls: ischiopubic rami and sacrotuberous ligament
Divided into anterior urogenital triangle and posterior anal triangle
Contents of the urogenital triangle
Contains the perineal membrane
Upturned anterior and posterior edges with in-between space forms the deep perineal pouch
What is Colles fascia and what is its significance
Fascial layer just deep to the skin
Space between the colles fascia and perineal membrane forms the superficial perineal pouch, which contains bulbospongiosus, ischiocavernosus and superficial transverse perineal muscles
Division of perineal muscles
Superficial: bulbospongiosus, R&L ischiocavernosus and R&L transverse perineal
Deep: urethral sphincter, deep transverse perineal muscles (urogenital diaphragm)
Where are the deep perineal muscles found
In-between 2 fascial layers:
Superficially, the superior fascia of the urogenital diaphragm and inferiorly. by the (thicker) perineal membrane; (which creates the deep perineal pouch)
Describe the blood supply of the perineum
Main supply is from the internal pudendal artery, which leaves the pelvis at the greater sciatic notch, around the ischial spine to the perineum through the pudendal canal, and branches off from the medial aspect to supply that region
Distal branch of the internal pudendal is the perineal artery, which branches into the posterior labial branches (-labia), aa to the bulb of vestibule (- erectile tissue of vestibule), deep aa of clitoris (- corpus cavernous), dorsal aa of clitoris (- dorsal glans and prepuce of clitoris)
Inferior rectal aa leaves the proximal pudendal canal, running medially along the sischioanal fossa to supply the anal canal and skin
Innervation of the perineum
Inferior rectal N –> external anal sphincter , lower part of the anal canal and perianal skin
Perineal nerve runs with the artery and divides into posterior labial branches –> superior to perineal membrane; and muscular branches –> ischiocavernosus, dorsal nerve of clitoris suns deep to perineal membrane and supplies clitoris
What are the borders of the false pelvis
Anterior superior iliac spine
Lumbar vertebrae/ base of sacrum posteriorly
Borders of the pelvic inlet
Running post –> ant:
sacral promontory, sacral alar, arcuate line, pectineeal line, superior pubic rami and body of pubis to pubic symphysis
Borders of pelvis outlet
Ant –> post
pubic symphysis, ischiopubic rami, ischial tuberosities, sacrotuberous ligament, coccyx
Describe the ligaments of the sacroiliac joint
Ventral sacroiliac ligament: not a true ligament rather a thickening of the joint capsule
Dorsal sacroiliac ligament: from the intermediate and lateral crests of the sacrum, pass down to the posterior superior iliac spine and the inner lip of the iliac crest
Interosseous ligament: unites the hip bones and sacrum, occupies the space between the back of the joint. Covered by the dorsal sacroiliac ligament and between lies the Doral primary rami of the sacral nerves
Describe the ovarian artery
Direct branch off the aorta
At the ovarian hilum, it divides into smaller branches, one which supplies the ovary which then joins to anastomose with the ovarian branch of the uterine artery
Also gives off multiple branches that supply the distal tube, which then anastomoses to the tubal branch of the uterine aa
Describe the uterine artery
Direct branch off the internal iliac aa anterior division
It courses medially on the elevator doss until 1.5-2cm from the uterocervical junction, where it then becomes tortuous and ascends in the broad ligament, where it gives off branches to supply the uterine tissue
The branches form multiple arcuate aa which run just below the serial surface and anastomose with each other in the midline.
From the arcuate arteries, radial arteries are given off at right angles, which run through the myometrium to the endometrium.
When radial aa reach the junction between the endometrium and myometrium, they divide into the basal branches (short and straight) and spiral arteries (long and convoluted, which respond to hormonal changes)
Level of bifurcations of the iliac aa
Aorta bifurcates into common iliac at L4/L5
Common iliac bifurcates at level of sacroiliac joint into internal and external iliac aa
Divisions of the external iliac artery
- Deep circumflex iliac artery
- inferior epigastric artery
Path and termination of external iliac artery
Runs along the medial border of psoas major enters the thigh under the inguinal ligament midway between the ASIS and pubis symphysis, where it continues as the femoral aa
Branches of the internal iliac artery
Divides into anterior and posterior divisions
Posterior:
- Iliolumbar aa
- superior gluteal aa
- lateral sacral aa
Anterior:
- Umbilical aa, which gives off superior vesicular aa, aa to to vas deferens; then obliterates to form the medial umbilical ligament
- Obturator aa
- uterine aa
- vaginal aa
- middle rectal aa –>muscular wall of lower part of rectum
- inferior vesical aa –> bladder fundus and distal ureter
- inferior gluteal aa –> structures in post thigh, gluteal region
- internal pudendal aa, which gives off inferior rectal aa, perineal aa, posterior labial branches, aa of the bulb of the vestibule, urethral aa, dorsal aa of clitoris, deep aa of clitoris
Describe the course of the internal iliac artery
Arises anterior to the sacroiliac joint
Crossed anteriorly by the ureters as they enter the pelvis
Continues to the level of the upper margin of the greater sciatic notch, then divides into anterior and posterior divisions.
Posterior division runs through the upper part of the greater sciatic foramen and divides into its 3 terminal bbranches
Anterior division runs into the pelvis and gives off numerous branches
Describe the pudendal canal
Sits on the lateral wall of the sischioanal fossa, containing the pudendal artery, 2 veins and the pudendal nerve
Inferior rectal aa branches off pudendal at the start of the canal
Perineal aa branches off at anterior end of the pudendal canal
What is the corona mortis
The point of anastomosis between the branch off of the obturator aa and branch off of the inferior epigastric aa
Where does the urogenital diaphragm lie and what does it consist of
Inferior and external to pelvic diaphragm
Stretches across and connects the ischopubic rami, below the pelvic diaphragm
Consists of the superior fascia of the UGD deep perineal pouch and perineal membrane
Which muscles converge on the perineal body
4 paired: - superficial transverse perineal muscles - deep transverse perineal muscles - bulbospongiosus - pubococcygeus 2 unpaired: - external anal sphincter - longitudinal muscle of the rectum and anal canal
Degrees of the uterine axis
Anteversion at 90 - uterus relative to vagina
Anteflexion at 125 - uterus relative to cervix
Describe the transverse cervical ligaments
Sit above the levator ani
Run from the cervix to the lateral pelvic sidewall, near to the root of the internal iliac vessels
Runs around the uterine vessels
Isn’t a true ligament - more a condensation of CT around the neurovascular structures
Helps maintain the angle between the vaginal axis and the anteverted uterus
Describe the uterosacral lifaments
Folds of peritoneum that extend posteriorly from the cervix to the walls of the lateral pelvis
Contain smooth muscle and fibrous tissue
Attach to the anterior surface of the sacrum
Form a true ligament of the uterus
Describe the round ligament
A flat, fibromuscular band within the broad ligament that runs anterioinferior to the fallopian tube
Runs anterior and laterally, through the deep inguinal ring, through the inguinal canal and out the superficial inguinal ring, to fuse to the labia majora
Describe the broad ligament
Fold of peritoneum connected to the lateral border of the uterus, extending to the lateral pelvic sidewall, which divides the abdomen into anterior region containing bladder, and posterior region containing rectum
Divided into 4 parts:
- Suspensory ligament of the ovary extending from the infundibulum of tube and upper pole of ovary to the lateral pelvic sidewall, containing the ovarian vessels, nerve and lymphatics
- mesosalpinx
- mesovarium (attaching posteriorly to ovary)
- mesometrium (extends from the pelvic floor to the ovary and ligament of the ovary)
What are the contents of the broad ligament
Fallopian tube (in the upper free margin) Round ligament (anterior-inferiorly) Proper ligament of the ovary (postern-inferiorly) Uterine artery around the lateral wall of the uterus, with the uterine artery branches, uterovaginal LN plexus and ovarian LN plexus
Describe the pubovaginalis muscle
Fibres of the 2 elevator muscles that meet in the midline; the most anterior fibres running from the pubis symphysis to the perineal body across the sides of the vagina
Provide a supplementary but significant sphincter
Describe the puborectalis muscle
A sling of muscle formed by levator ani muscles arising laterally and passing inferomedially around the rectoanal junction
Help to maintain the rectoanal angle
What is the tendinous arch of levator ani
A result of fascial contributions from the levator ani muscle fascia and the fascia covering the obturator internis muscle
Nerves arising from the lumbar plexus and root contributions
Subcostal (T12)
Iliohypogastric (T12/ L1)
Ilioinguinal (L1)
Genitofemoral (L1, L2)
Lateral femoral cutaneous (L2,3) *posterior division
Obturator (L2-4)
Femoral (L2-4) * posterior division
Lumbrosacral trunk (L4,5) –> sacral plexus
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Describe the course of the femoral nerve and innervation
Exits from the lateral aspect of psoas major and runs along iliac muscle, under the inguinal ligament, then divides into anterior and posterior divisions
Supplies muscle and skin in the thigh region, and the iliac and nerve to pectineus while in the pelvis
Describe the course of the obturator nerve and innervation
Emerges from the medial border of psoas, lies behind the common iliac aa @ the pelvic brim, then continues laterally onto obturator internis, then runs above obturator aa and into the obturator canal. Exits the pelvis to supply the adductor muscles and the skin on the medial aspect of thigh. Supplies the parietal peritoneum around ovary when in pelvis
Describe the course of the genitofemoral nerve
Fibres run through psoas major, exit at L3/4, where they are covered in parietal peritoneum
Run laterally to ureter then divide into genital and femoral
Genital: crosses external iliac aa and enters deep inguinal ring, through inguinal canal with round ligament, to the skin of mons pubis and labia majora
Femoral: runs lateral to the external iliac aa, passes deep to the inguinal ligament and into the femoral sheath, lateral to the femoral aa to supply the skin in the upper region of the femoral triangle
Describe the course of the subcostal and iliohypogastric nerves
Cross the quadratus lumborum, to pierce transversalis fascia and run in the neurovascular plane to supply the transversus abdominis and internal oblique, as well as the skin on the lower abdomen
Describe the course of the lumbrosacral trunk
Related to the medial aspect of psoas muscle. Crosses the pelvis brim anterior to the sacroiliac joint and joins the ventral primary ramus of S1
Contributing rami to lumbar plexus
T12- L5
Rami contributing to the sacral plexus
L4- S4
Where is the sacral plexus
Lies on the piriformis, behind the interior iliac vessels, ureter and GIT
What are the two major divisions
Upper group (L4-S2, and part of S3) = sciatic nerve Lower group (S2-4) = pudendal nerve
Describe the course of the pudendal nerve
Leaves the pelvis through the greater sciatic foramen, winds around the ischial spine medial to the internal pudendal aa and deep to the sacrospinous ligament to enter the perineum through the lesser sciatic foramen –> pudendal canal –> vulva and perineum
Branches of pudendal nerve
Inferior rectal –> crosses ischioanal fossa to supply external anal sphincter, dorsal end of anal canal and perianal skin
Divides into perineal and dorsal nerve of clitoris in the perineum
Sensory branches to the lower part of the vagina through the sensory fibres in the inferior rectal nerve and posterior labial branches of perineal nerve
Main function of pudendal nerve
Maintains sphincter function and muscular support to viscera
Nerves arising from sacral plexus and their roots
SIPPS Superior gluteal (L4,L5,S1) Inferior Gluteal (L5, S1-2) Posterior cutaneous nerve of the thigh (S1-3) Pudendal (S2-4) Sciatic (L4-5, S1-3)
What drains into the external iliac LNs
Inguinal LNs
Deep infra-abdominal part of the abdominal wall
Adductor region of the thigh
Pelvic viscera (glans penis/clitoris, membranous urethra, prostate, bladder fundus, cervix, uterus, vagina)
What drains into pre-aortic LNs
GIT -
coeliac LNs
Supra-mesenteric LNs
Infra-mesenteric LNs (which receives from para-rectal nodes)
Where is the cisterns chyli
Located at the anterior vertebral bodies of L1 and 2
What drains into the lateral aortic LNs
Kidneys and suprarenal glands
Testis/ ovaries
Posterior abdominal wall
Common iliac LNs
What drains into the sacral LNS
Posterioinferior pelvic viscera
Prostate vessels
Uterus and vaginal vessels
Posterior perineum
What drains into the internal iliac LNs
All pelvic viscera
Deep parts of perineum
Gluteal muscles and posterior thigh
What drains into the deep inguinal LNs
Deep lymphatic vessels of the femoral vein
Glans penis/ clitoris
Few afferents from the superficial inguinal group
What drains into the lower/ vertical sub-group
Superficial vessels of the lower limb, except for the posterior and lateral lower limb
What drains into the horizontal subgroup
Gluteal region and adjoining infra-abdominal wall
Superficial vessels from external genitalia
Lower anal canal and perianal region
Uterine vessels running in the round ligament
What are the two divisions of the superficial inguinal LNs
Horizontal subgroup
Vertical or lower subgroup
Where are the two divisions of the superficial inguinal LNs located
Horizontal - along the inferior border of the inguinal ligament
Vertical/ Lower - on the femoral vein below the great saphenous branch
Where are the deep inguinal LNs located
Lies in the femoral canal within the femoral sheath, and courses medial to the femoral vein
Sits on the medial aspect of the femoral vein
Lymphatic drainage of the pelvis
Superficial inguinal LNs - deep inguinal LNs (which drains into external iliac LNs) and external iliac LNs - common iliac LNs (which also receives from internal iliac LNs and sacral LNs) - lateral (para) aortic LNs - lumbar trunk - cisterns chilli - thoracic duct
Describe the pain pathway from the uterus
Afferent fibres from the uterus run to the hypogastric plexus to lumbar splanchnic to lower thoracic and upper lumbar levels of the spinal cord
Where do afferents from the cervix and vagina run
to the pelvic splanchnic plexus
What forms the inferior hypogastric plexus
Mixed plexus formed by contributions from the vesicle, uterovaginal and rectal plexuses
AKA pelvic plexus
Describe the parasympathetic nerves of the pelvis
Arise from 2-4th sacral nerve roots –> parasympathetic nerves
Forms the pelvic splanchnic nerves
Difference between pelvic splanchnic and pudendal nerve
Roots are the same (S2-4)
Pelvic splanchnic = parasympathetic
Pudendal = somatic
Describe the sympathetic system of the pelvis
Superior hypogastric plexus sits above the aortic bifurcation (L4/5)/ at sacral promontory, which is formed from the thoracic and lumbar splanchnic nerves, which leave the sympathetic ganglion chain. Also sends off fibres to the ovarian and ureteric plexuses
SHP bifurcates with the aorta into the R&L hypogastric nerve which descends into the pelvis towards the IHP
What are the sacral splanchnic nerves
Fibres that run out of the sympathetic chain alongside the aorta to join the pelvis via the ganglion impar and enter the IHP
What is the thoracic contribution to the pelvis sympathetic innervation
Thoracic contribution comes from T10-12
Thoracic preganglionic sympathetic fibres arise in the thoracic, enter the abdomen through the crura of the diaphragm - synapse in the gangia related to the main aortic branches, esp the coeliac and aorticorenal
What is the lumbar contribution to the pelvic sympathetic innervation
From L1-2
Lumbar chain consists of 4 ganglia lying on the lateral aspect of the lumbar vertebrae and contribute to the superior hypogastric plexus
Describe the inferior hypogastric plexus
Is a continuation of the L&R hypogastric nerves
Also joined by parasympathetic fibres of pelvic splanchnic nerves
Sits in the fascia surrounding the rectum and runs along the pelvic floor to the pelvic viscera
Fibres lie on either side of the rectum, cervical and vaginal fornices and posterior bladder
It sends fibres to the broad ligament and support;oes the pelvic viscera and hindgut
- fibres in the broad ligament contribute to the uterovaginal plexus, which surrounds the uterus, vagina and cervix
It is responsible for uterine contraction and vasoconstriction (S) or opposite with paraS, but hormonal regulation can alter or override the ANS stimulation
