ANATOMY Flashcards
At what spinal level does the Coeliac Trunk leave the aorta?
T12
At what level does the Superior Mesenteric Artery leave the Aorta?
L1
At what levels does the Inferior Mesenteric Artery leave the Aorta
L3
What vessels leave the Aorta at L1
SMA, middle adrenal (suprareneal), renal vessels
What vessels leave the Aorta at L2
Gonadals
At what spinal level does at the aorta birfucate
L4
Into which vessels does the stomach drain? (List all)
Left & Right Gastrics drain directly into the portal vein.
Short gastric vessels (fundus), and left gastro-epiploiec drain into the splenic vein –> portal vein. Right gastro-epipoloiec drains into the superior mesenteric –> hepatic portal vein.
Which vessels are involved with portal-caval anastomoses, and how are they clinically important?
Portal hypertension can cause distension of these veins, which can lead to rupture, clinical manifestations and discomfort to the patient.
- Oesophageal varices form due to anastomeses between left gastric vein & oesophageal vessels which drain into the azygous system.
- Paraumbilical anastomeses can lead to caput medusae. Small vessels in ligamentum teres anastomose with superficial epigastric & thoracoepigastric veins.
- Rectal anastomoses can lead to haemorrhoids as superior rectal veins anastomose with the middle/inferior rectal veins which drain to the internal pudendal –> internal iliac
What are the posterior relations of the kidney?
Diaphrahm, costo-diaphragmatic recess, ribs 11 & 12
What are the anterolateral relationships of the kidneys?
Right: adrenal glands, liver, descending duodenum, IVC, right colic flexure, small intestine
Left: adrenal gland, stomach, tail of pancreas, spleen, left colic flexure, small intestine
What are the inferior relationships of the kidney?
Psoas major, quadratus lumborum, transversus abdominis
What spinal levels are sympathetic innervation of the foregut from?
T6-T9
What spinal levels are sympathetic innervation of the midgut from?
T9-T11
What spinal levels are sympathetic innervation of the hindgut from?
T12-L2
What spinal levels generally innervate the pelvis/perineum organs?
Sympathetic - T10-L2/L3
Parasympathetic - S2-S4
Describe the blood supply to the kidney from the Abdominal Aorta to the Right Atrium
Renal vessels leave Aorta at L1 –> 5 segmental arteries –> interlobar arteries –> arcuate arteries –> interlobular arteries –> afferent arterioles –> glomerular capillaries –> efferent arterioles –> peritubular capillaries/vasa recta –> peritubular/vasa recta venules –> interlobular veins –> arcuate veins –> interlobar veins –> renal veins –> IVC (L1) –> RA
What spinal level of sympathetic innervation does the kidney receive?
T10-L2 (referred pain = loin to groin)
At which spinal levels are the kidney located?
T11-L3
At what spinal level is the renal hilum
L1
What are all the anatomically significant things at L1?
Pylorus of stomach/transpyloric plain (L1/L2)
SMA leaves Aorta
Renal vessels leave Aorta
Renal Hilum
Middle Adrenal vessels leave Aorta
Head of Pancreas in this region (direct irritation to L1/L2 spinal nerves in pancreatitis)
Name the layers which surround the kidney from the cortex outwards.
Cortex
Peri-renal fat
Renal Fascia
Para-renal fat
Does the kidney receive parasympathetic stimulation, and if it does, where is it from?
Yes - Vagus nerve to smooth muscle of renal pelvis and calyces. (from posterior vagal trunk)
Does the adrenal gland receive parasympathetic stimulation, and if it does, where is it from?
No it does not. Sympathetic only.
What are the branches of the internal iliac artery?
Anterior Division:
- Umbilical (obliterated leads to medial ligaments) which gives off superior vesicle
- Uterine/vaginal arteries in female
- Inferior vesicle arteries in male
- Internal pudendal artery –> inferior rectal
- Middle rectal
- Inferior gluteal (S1-2 or S2-3 more commonly)
- Obturator
Posterior Division:
- Iliolumbar Artery
- Lateral sacral
- Superior Gluteal (S1)
What forms the greater pelvic aperture?
Sacral promontory, arcuate line of ilium, pectin pubis of pubic bone
Which pelvis is the true pelvis? (Major/greater or minor/lessor?)
Minor/Lesser is true pelvis
Does the major or minor pelvis contain the pelvic contents?
Minor/lesser/true contains pelvic contents
Does the superior pelvic aperture (inlet) or inferior pelvic aperture (outlet) divide the pelvis into true & false pelvis?
Greater/Inlet divides it.
What makes up the inferior pelvic aperture (pelvic outlet)
Pubic symphysis –> ischiopubic rami –> sacrotuberous ligaments –> tip of coccyx
Names the joints of the pelvis
Sacrioiliac (x2), pubic symphysis
What type of joints are the sacroiliac joints?
Synovial plane joints with a posterior fibrous component.
What type of joint is the pubic symphysis?
Secondary cartilaginous with hyaline cartilage on syphyseal surface and united by fibrocartilage.
What are the 6 ligaments of the Sacroiliac joints?
- Iliolumbar
- Anterior sacroiliac
- Posterior sacroiliac
- Sacrotuberous
- Sacrospinous
- Interosseus
In which plane are the ASIS and pubic tubercles orientated?
Coronal
In which plane are the pubic symphysis and coccyx orientated?
Horizontal
What planes/angles are the pelvic inlet and outlet from the horizontal?
Inlet: 60degrees Outlet: 10degrees
What are the differences between the male and female pelvis?
Female pelvis has:
- wider superior and inferior apertures,
- wider sciatic notch,
- narrower depth of true pelvis
- thinner/lighter bones.
What are the two measurements used for the superior pelvic aperture and the inferior aperture?
Anteroposterior
Transverse
superior aperture AP is called “Conjugate”
There are three different ‘conjugate’ measurements of the superior pelvic aperture. Describe them and their lengths.
True Conjugate: Superior pubic ramus symphysis –> Sacral promontory. Only made on radiographic films. 11cm or more.
Diagonal Conjugate: Inferior pubic symphysis –> sacral promontory. Estimated using internal examination. 11.5cm or more.
Obstetric Conjugate: Thickest part of pubic symphysis –> sacral promontory. Usually 10cm or more.
Which is the shortest measurement of the pelvic aperture? Diagonal, Obstetric or True?
Obstetric (10cm) shortest.
Diagonal = 11.5cm True = 11cm
Where are the preganglionic cell bodies of the parasympathetic neurons innervating the pelvis/perineum located?
Lateral horns of S2-S4.
Describe the general path the parasympathetic neurons travel from the S2-S4 spinal cord to the pelvic viscera.
Preganglionic cell bodies in lateral horns of S2-S4. Fibres exit via ventral horn –> ventral roots –> spinal nerve –> pelvic splanchnic nerves –> pelvic plexus (R&L inferior hypogastric) –> synapse in intramural ganglia within organs. Post ganglionic fibres are very short.
What is the sympathetic innervation of the adrenal glands?
T5-T9
Describe the general path the sympathetic fibres travel from the spinal cords to their target organs in the pelvis/perineum.
Located in lateral horn of T10-L2/3. Travel out of spinal cord via ventral horn –> ventral root –> white rami communicans –> sympathetic chain (no synapse) –> grey rami communicans –> splanchnic nerves –> synapse on pre-aortic ganglia (eg coeliac, renal, IM, SM etc). Post synaptic fibres split into two bundles (L & R) and descend to L & R superior hypogastric plexus (just below bifurcation of aorta; sympathetic only) and then continue to inferior hypogastric plexus (pelvic plexus, mixed with parasympathetic) from where they travel with arteries to their target viscera.
Describe the viscera pain afferents of the pelvis.
Pain follows sympathetics above pelvic pain line, parasympathetics below
What is the pelvic pain line?
The pelvic pain line is approximately at the lowest level of the peritoneum. It is the point where pain fibres change from following sympathetic fibres (above the line) to parasympathetic fibres (below the line).
What are the branches of the lumbosacral plexus?
Sciatic nerve - L4-S3
Superior Gluteal nerve L4-S1
Inferior Gluteal nerve L5-S2
Pudendal S2-S4
(note Obturator nerve is also located in the true pelvis)
Internal Iliac veins have communications with two areas of clinical importance. What are they?
- Portal-caval anastomoses between middle-superior rectal vein provides a communication with the portal circulation.
- Communications with vertebral plexus via lateral sacral veins allows for spread of pelvic cancers to the vertebrael column
What are the muscles of the pelvic floor?
- Levator Ani (Puborectalis, Pubococcygeus, Iliococcygeus)
2. Cocycgeus (ischiococcygeus)
What are the attachments of the levator ani?
Pubis, ischial spine and tendinous arge (inner surface of obturator internus) to the perineal body, coccyx and anococcygeal ligament.
What are the three parts of levator ani? One of these muscles also has three parts, what are they?
- Puborectalis
- Iliococcygeus
- Pubococcygeus (three parts include puboperinealis, puboanalis and in males there is puboprastatitcus, females this is pubovaginalis)
What is the innervation of the pelvic floor/diaphragm?
Levator ani - nerve to levator ani (S4), inferior and coccygeal plexus.
Coccygeus - S4-5 sacral segments
What are the attachments of Coccygeus?
Ischial spine –> coccyx. Internal surface of sacrospinous ligament.
What are the muscles of the pelvic wall, and what are their innervation? Which muscles leaves through the greater sciatic foramen, and which through the lesser?
- Piriformis (nerve to piriformis S1-2). Exits through greater sciatic foramen and attaches to the greater trochanter of the femur.
- Obturator internus (nerve to obturator internus (L5-S1). Exist through lesser sciatic foramen and attaches to trochanteric fossa.
Describe the endopelvic fascia.
It is located superior to the pelvic floor/diaphragm. It is continuous with the transversalis fascia. Contains multiple thickenings to support the pelvic viscera.
What supports pelvic viscera?
Endoplevic fascia & Pelvic floor/diaphragm (Levator ani & Coccygeus).
What contributes to sphincter mechanisms of continence?
Pelvic floor.
Describe the perineum
Triangle shaped region between the thighs and buttocks. Subdivided into anal triangle & urogenital triangle.
What are the boundaries of the perineum?
Pubic symphysis, ischiopubic rami, ischial tuberosities, sacrotuberous ligament, coccyx, obturator internus.
What are the boundaries & contents of the Ischioanal fossa (within anal triangle).
BOUNDARIES: Perineal skin, ischial tuberosities, obturator internus (wall), levator ani (roof), external/internal anal sphincters (medial walls).
CONTENTS: Mainly fat & pudendal canal
Where is the pudendal canal, and what does it contain?
Located in the ischioanal fossa within the anal triangle of the perineum. Contains pudenal nerve, internal pudendal vessels. It lies against the obturator internus, on the lateral wall of the fossa.
What are the borders of the anal triangle?
Ischial tuberosities (line between them), sacrotuberous ligament, coccyx.
Contents of anal triangle?
Ischioanal fossa (contains pudendal canal), anal canal from recto-anal junction (S3) to anus.
The anal canal contains anal columns, anal sinuses and anal valves. What are these?
Anal columns = contain terminal branches of superior rectal vessels.
Anal valves = where the anal columns terminate and folds of mucosa pouch out to form the ‘pectinate’ line.
Anal sinuses are located just above the anal valves and produce mucous to aid defecation.
What is the pectinate line?
It is formed by the anal valves all lining up and marks the place where innervation, lymphatics and epithelium all change.
What is the epithelium, lymphatic flow and innervation ABOVE the pectinate line?
Innervation: Autonomic
Blood supply: Superior rectal arteries from inferior mesenteric artery and veins drain to portal system
Lymphatic: Drain to internal iliac nodes.
Epithelium: Columnar epithelium
WHat is the epithelium, lymphatic flow and innervation BELOW the pectinate line?
Innervation: Somatomotor/sensory
Blood supply: Internal iliac (middle rectal arteries and internal pudendal –> inferior rectal artery). Draining back to IVC.
Lymphatics: Draining to superficial inguinal nodes, which drain to external iliacs.
Epithelium: Stratified squamous.
What innervates the internal anal sphincter?
Autonomic innervation.
What are the parts of the external anal sphincter, and what innervates them?
Deep, Superficial and subcutaneous parts. Puborectalis fuses with the ‘deep’ and forms a ‘sling’ that kinks the rectum when contracted and helps with continence (Puborectalis relaxes during defecation).
It is innervated by the inferior rectal nerve (from pudendal nerve S2-S4).
To what does the superficial layer of the external anal sphincter attach?
Perineal body & anococcygeal ligament.
What are the borders of the urogenital triangle?
Pubic symphysis, ischiopubic rami, Ischial tuberosities (line between them)