Anatomy Flashcards
What is the only true female reproductive organ?
Ovaries
What makes up the pelvic cavity?
Ovaries, uterine tube, uterus, superior part of the vagina
Name the contents of the perineum
Inferior part of the vagina, perineal muscles, Bartholin’s glands, clitoris, labia
What is the peritoneum?
Thin, transparent serous membrane that lines the abdominal cavity and wraps around organs - covers superior aspect of organs
Name the two peritoneal pouches in females
Vesico-uterine
Recto-uterine (Pouch of Douglas)
What is the clinical significance of the Pouch of Douglas?
Most inferior part of the peritoneal cavity can collect excess fluid
How is the pouch of Douglas drained?
Though the posterior fornix of the vagina
Describe the broad ligament
Double layer of peritoneum that extends between the uterus and the lateral walls of the pelvic floor - helps to maintain the uterus in the midline position
Describe the round ligament
Embryological remnant attaches to the lateral aspect of the uterus, passes through the deep inguinal ring to attach to the superficial tissue of the perineum
Name the three layers of the uterus
- perimetrium
- myometrium
- endometrium
Where does implantation occur?
Body of the uterus
What is the common position of the uterus?
Anteverted and anteflexed
Describe the term anteverted and anteflexed
Cervix is tipped anteriorly relative to axis of the vagina
Uterus tipped anteriorly relative to axis of cervix
Name the common variation of uterus position
Retroverted and retroflexed
Describe the different parts of the uterine tubes
Isthmus, ampulla, infundibulum with fimbrae which open into the peritoneal cavity
What is the disadvantage of the uterine tubes opening into the peritoneal cavity?
Infection can enter here
How many fornix can be found in the vagina?
4
Anterior
Posterior
2 lateral
What two triangles can be separated by an imaginary line between the two ischial spines?
Urogenital
Anal
What is the function of the pelvic floor?
Provides support to pelvic organs and maintains continence
Name the two muscles of the pelvic diaphragm
- levator ani
- coccygeus
What are the three parts of the levator ani?
- puborectalis (pubic bone and anus)
- pubococcygeus (pubic bone and coccyx)
- iliococcygeus (ilium and coccyx)
Describe the perineal body
Collection of collagenous/elastic tissue into which the perineal muscles attach
Describe the action of levator ani
All tonically contracted most of the time, must relax to allow urination and defection
What nerve supplies the levator ani?
Pudendal nerve and nerve to levator ani
Which nerve innervates coccygeus?
Branches of S4 and S5
What two structures give additional support to the pelvic floor?
Endo-pelvic fascia
Pelvic ligaments
Name four pelvic ligaments
- uterosacral
- transverse cervical
- lateral ligament of bladder
- lateral rectal ligaments
Where can the deep perineal pouch be found?
Shallow compartment lies between the fascia covering the inferior pelvic diaphragm and the perineal membrane
Describe the contents of the deep perineal pouch
Part of urethra and vagina, bulbourethral gland in males, neuromuscular bundle (clitoris/penis), anterior extensions of ischioanal fat pads, muscles
Which muscles are found in the deep perineal pouch?
External urethral sphincter
Compressor urethrae
Deep transverse perineal muscle (males)
Band of smooth muscle (females)
Where is the perineal membrane?
Superficial to the deep perineal pouch
What is the perineal membrane made of and where does it attach?
Thin sheet of tough deep fascia.
Attaches laterally to the pubic arch and closes over the urogenital triangle
Where is the superficial perineal pouch?
Superficial to the perineal membrane
What does the superficial perineal pouch contain in women?
Clitoris and crura - covered by ischiocavernosus
Bulbs of vestibule - covered by bulbospongiosus
Bartholins glands, transverse perineal muscle branches of vessels and nerves
What does the superficial perineal pouch contain in men?
Bulb - corpus spongiosum (bulbospongiosus)
Crura - corpus cavernosum (ischiocavernosus)
Proximal spongy urethra, superficial transverse perineal muscle, pudendal nerves/vessels
Where does the breast extend to/from?
Ribs 2-6
What does the breast tissue sit on?
Deep fascia covering the pecs major and serratus anterior
Name the space found between the fascia and breast
Retromammary Space
How is the breast tissue attached to the skin?
Suspensory ligaments
Where does most lymph from the breast drain?
Ipsilateral axillary then supraclavicular nodes
Where can lymph from the inner quadrants of the breast drain?
Parasternal nodes
Where can lymph from the lower quadrants drain?
Abdominal nodes
What is the arterial supply to the breast?
- anterior intercostal branches of the internal thoracic artery from the subclavian artery
- branches of the axillary
- posterior intercostal arteries
What is the venous drainage of the breast?
Axillary vein and internal thoracic vein
What is the tissue extending to the mid-axillary line called?
Tail of Spence
What bones make up the lateral pelvic wall?
Pubis, ischium and ilium
Name three ligaments found in the lateral pelvic wall
Sacrospinous
Sacrotuberous
Obturator Membrane
What does the obturator membrane fill?
The obturator foramen - NVB passes through the canal
What do the sacrospinous and sacrotuberous ligaments form?
Greater and lesser sciatic foramen
Name four muscles that are in the lateral pelvic wall
Levator ani
Obturator Internus
Piriformis
Coccygeus
Where does the levator ani attach?
Tendinous arch - band of thickened fascia from the obturator interns muscle
Where does the obturator internus tendon pass?
Between the superior and inferior gemellus
Describe the route of the piriformis muscle
Passes through the greater sciatic foramen and attaches to the greater trochanter of the femur
Why is the piriformis an important landmark?
Where the sciatic nerve emerges and the gluteal nerve divides
What is the major blood supply to the pelvis?
Internal iliac artery
What are the two exceptions to the internal iliac blood supply?
Gonadal artery - arises at L2 from abdominal aorta
Superior rectal artery - continuation of the inferior mesenteric
Describe the division of the internal iliac artery
Anterior - visceral
Posterior - parietal
What remnant is found relating to foetus blood supply?
Medial umbilical ligament from the umbilical artery which connected the internal iliac to the placenta
What branches arise from the posterior division of the internal iliac?
Gluteal arteries - inferior may come from the anterior division
What branches arise from the anterior division of the internal iliac?
Obturator artery
Superior vesicle arteries - supplies the bladder
Uterine artery - gives off vaginal artery
Internal pudendal
Which artery does the middle rectal artery arise from?
Internal pudendal
What arteries arise from the vaginal artery?
Inferior vesicle
Describe the two anastomoses in the pelvic blood supply
Uterine and ovarian
Uterine and vaginal
What structure lies close to the uterine artery and can be damaged during a hysterectomy?
Ureter - water under the bridge
Describe the differences between the right and left ureter
Right - lies more laterally and crosses external iliac
Left - lies more medially and crosses the common iliac
What two arteries supply the perineum ?
Internal pudendal
External iliac
What are the branches of the internal pudendal nerve in females?
Inferior rectal
Middle rectal
Dorsal artery of clitoris (where it terminates)
Perineal artery
What is the branch of the external iliac artery in females?
Labial arteries
In the male where do the inferior vesicle arteries arise?
Internal iliac artery
What two branches arise from the inferior vesicle arteries?
Prostatic branch
Artery to vas deferens
What are the branches of the internal pudendal nerve in males?
Perineal
Posterior scrotal
Deep artery
Dorsal artery of penis (termination)
What branch of the external iliac artery supplies the perineum in males?
Anterior scrotal
Name the three common venous drainage systems of the pelvis
Internal iliac vein to IVC
Superior rectal and into the portal-hepatic system
Lateral sacral and to the internal vertebral venous plexus
Describe the route of the obturator nerve
Formed from lumbar plexus (L2,3,4) and passes through extraperitoneal fatty tissue to the obturator canal
Describe the route of the pudendal nerve
S2,3,4 exits via the greater sciatic foramen posterior to the sacrospinous ligament and comes back into the perineum via the lesser sciatic foramen
What spinal levels does the nerve to the levator ani arise?
S3,S4
What are the pelvic sphlanic nerves?
Exit via the anterior rami of S2,3,4 carry parasypathetic innervation
Name the lymph nodes that the pelvis drains to
Lumbar/aortic Inferior mesenteric Common iliac External iliac Internal iliac Superficial inguinal Deep inguinal Sacral Pararectal
Generally where does the superior pelvic viscera drain lymphatically?
External iliac nodes
Generally where does the inferior pelvic viscera drain?
Internal iliac nodes
Where does lymph from the superficial perineum drain?
Superficial inguinal nodes
Where does lymph from the ovaries and testes drain?
Lumbar lymph nodes
Describe transperitoneal spread
Usually peritoneal layer can act as a barrier to infection but eventually disease can penetrate and the disease can travel in fluid or on the layer itself
State the functions of the bony pelvis
Supports upper body Transference of weight Attachment of muscles Attachment of external genitalia Protection of pelvic organs Passage of childbirth
What makes up the bony pelvis?
Hip bones (ischium, ilium, pubis)
Sacrum
Coccyx
Name the landmarks of the ilium
Iliac crest
ASIS
PSIS
Iliac fossa
Name the landmarks of the ischium
Ischiopubic rams
Ischial spine
Ischial tuberosity
Name the landmarks of the pubis
Ischiopubic ramus
Superior pubic ramus
Pubic tubercle
Pubic arch
How do you palpate the ischial spines?
4 and 8 o’clock internally
State the key differences between the male and female pelvis
AP and transverse diameter bigger in females
Subpubic angle wider in females
Pelvic cavity is more shallow in females
Greater sciatic notch is wider in females
Sacral promontory less pronounced in females
Female bones are thinner and males more robust
What makes up the pelvic inlet?
Sacral promontory
Ilium
Superior pubic ramus
Pubic symphysis
What makes up the pelvic outlet?
Pubic symphysis Ischiopubic ramus Ishchial tuberosities Sacrotuberous ligaments Coccyx
What are the key joints in the bony pelvis?
Sacroiliac (synovial and syndymoses) Hip joint (synovial) Pubic symphysis (cartilaginous)
Describe the pelvic movement during pregnancy
SI joint rotates anteriorly and inferiorly causing the sacrum and coccyx to rise but the ligaments prevent this from going too far
What happens to the ligaments in late pregnancy?
Relax due to a hormone - relaxin
What tends to happen to ring bones in trauma?
They fracture in more than one place or combined with joint dislocation
Name the two fontanelles in foetus
Anterior - closes 18 months to 2 years
Posterior - closes 6 months to 1 year
What happens to the foetal skull during childbirth?
Moulding - movement of one bone over another to allow the head to pass through the pelvis
What is the foetal vertex?
Diamond - pariteal eminences and fontanelles
Define station
Distance of foetal head from the ischial spines
- negative if above
- positive if below
Describe the rotation of the baby during childbirth
- Head moves into
- Shoulders align with AP and baby faces thigh
What type of nerves supply the pelvis?
Body cavity
- sympathetic
- parasympathetic
- visceral afferent
What type of nerves supply the perineum?
Body wall
- somatic motor
- somatic sensory
Describe the innervation of superior aspect of pelvic organs/touching the peritoneum
Visceral afferents, run alongside the sympathetic fibres and enter the spinal cord between T11 and L2
Describe the innervation of inferior pelvic organs
Visceral afferents run alongside parasympathetic and enter the spinal cord at S2,3,4
What happens to structures that cross from pelvis to perineum?
Above levator ani - visceral afferents - S2,3,4
Below levator ani - somatic sensory - S2,3,4 (pudendal nerve)
At what level does the spinal cord become the caudal equina?
L2
When does the subarachnoid space end?
S2
How can L4 spinous process be identified?
Intercrestal Line
What does the needle to the epidural space pass?
Supraspinous ligament
Interspinous ligament
Ligamentum flavus
Epidural space - fat and veins
What does the needle to the spinal space pass?
Supraspinous ligament Interspinous ligament Ligamentum flavus Epidural Space Dura mater Arachnoid mater Subarachnoid space - filled with CSF
What do the sympathetic nerves supply all of?
Arterioles
What is the effect of blockage of the sympathetic nerves?
Vasodilation - reduced sweating, red, flushed, hypotension
How is the pudendal nerve located?
Ischial spine, travels lateral and behind the sacrospinous ligament
What is the purpose of episiotomy?
Posterolateral incision to prevent rectal damage and makes the tear towards the fat filled ischioanal fossa which is easier to repair
Name four abdominal wall muscles
External oblique
Internal oblique
Transversus abdominus
Rectus abdominus
Where does the external oblique attach and what direction does it run?
Lower ribs (5-12), iliac crest, pubic tubercle, linea alba Inferomedial direction
Where does the internal oblique attach and what direction does it run?
Attaches to lower ribs 10-12, thoracolumbar fascia, iliac crest, linea alba
Posteromedially
Where does the transverses attach?
Lower ribs 7-12, thoracolumbar fascia, iliac crest, linea alba
What fascia layers lie above and below transversus abdominus?
Neuromuscular plane - between muscle and IO
Transversalis fascia - internal lining deep to muscle
Describe the rectus abdominus
Made up of 3/4 smaller muscles with tendinous intersection
Attaches to xiphoi, costal cartilage and pubic bones
Describe the linea alba
Interweaving of aponeuroses, runs from xiphoïde process to pubic symphysis with lots of small vessels and nerves
What is the rectus sheath?
Deep to the superficial fascia, combined aponeuroses of anterolateral abdominal muscles
What nerves supply the abdominal wall muscles and where does this come from?
All enter from lateral direction.
7th-11th intercostal nerves to thoracoabdominal nerves
T12 - subcostal
L1 - iliohypogastric and ilioinguinal
What blood vessels supply the anterior wall?
Superior epigastric arteries from internal thoracic - in the rectus sheath
Inferior epigastric arteries from external iliac
What blood vessels supply the lateral wall?
Intercostal and subcostal arteries - continuation of posterior intercostal arteries
What is usually done during a LSCS?
Rectus muscles are separated laterally towards nerve supply
What layers will be passed during LSCS?
Fascia - sheath - rectus abdominus - peritoneum - retract bladder - uterine wall - amniotic sac
What layers are stitched following LSCS?
Uterine wall, visceral peritoneum, rectus sheath, skin
What layers are passed in a laparotomy?
Skin, fascia, linea alba, peritoneum
Which layers requiring stitching post laparotomy?
Peritoneum, linea alba, fascia and skin
What is the benefit/risk of a midline incision?
Benefit - relatively bloodless
Risk - wound complications
Describe the route of the epigastric artery
Emerges medial to deep inguinal ring and passes superomedially posterior to rectus abdominus
Where should lateral ports be placed?
Lateral to inferior epigastric artery
Where is the deep inguinal ring?
Half way between ASIS and pubic tubercle
Describe a vaginal hysterectomy
Local anaethetic around the cervix reflect bladder superiorly. Ligate arteries and ligaments and tubes. Remove uterus and cervix via vagina
Ligaments may be sutured to the vagina to prevent prolapse
