Abdomen 1 Flashcards
Bone Boundaries of Abdomen
- Lumbar vert
- Pelvic Bones/Inlet
- Inf Thoracic Wall (costal margin, Rib XI-XII, xiphoid process)
Arcuate Ligs
- Median Arcuate Lig - midline, crosses aorta, joins R/L crus to make opening, at L3
- Medial Arcuate Lig - at L1, goes over psoas major
- Lateral Arcuate lig - at L1 -> rib XII, over quadratus lumborum
- all 3 form tight seal btwn abdomen = thorax
Pelvic Inlet Margins
Posteriorly: sacrum
Anteriorly: pubic symphysis
bilaterally: bony rim on pelvic bone
4 quadrant Pattern
- draw line thru umbilicus + midline
- McBruney’s point = 2/3 away from umbilicus to ASIS (sign of appendicitis)
- upper R = liver, gall bladder, diaphragm, right costal margin
- lower R = cecum + appendix, R ASIS/Inguinal lig/pubic tubercle
- lower L = descending + sigmoid colon, L ASIS/Inguinal lig/pubic tubercle
- upper L = spleen + stomach
Iliac Crest
- inf bony boundary
- separates post ab wall from glutes
Inguinal Lig
- btwn ASIS + tubercle
- separates ant ab wall from thigh
Muscular Wall
- Psoas major + iliacus -> thigh, hip join flexors
- Rectus abdominis -> inf thoracic wall to pelvis, 6 pack muscles
- continuity in ab wall from thick fascia + aponeuroses
- fascial wall separates ab wall from peritoneum
Foregut
- omental bursa/lesser sac = ventral mesentery mem, connects liver to stomach
- greater omentum/greater sac
- omental foramen/epipoic foramen - connects greater to lesser sac
- development of these + connection important to prevent infection spread
Midgut
- 270 degree CCW rotation, develops quickly, runs out of space = herniates, pushes out where umbilicus will be
- superior mesenteric artery = midline, separates small intestine from large intestine
- after herniating, draws intestines back to abdomen
- midgut pt -> cecum = iliocecal junction -> inf R cavity (upper R -> lower R quadrant)
- large intestine flipped over small intestine
Hindgut
majority of colon + superior rectum
Appendix
retrocecal -> as it descends, gets tucked up behind cecum
Groin in anterior wall
- Gubernaculum -> processus vaginalis (becomes scrotum or labia majora)
- males: inguinal canal (spermatic cord cnxn of testes to ab) + spermatic cord (has structures from ab -> testes)
- females: gubernaculum becomes round lig of uterus, ends in labia majora
Transpyloric Plane
- horizontal plane, transect body at L1 (pancreas also at L1)
- midway btwn jugular notch/pubic symphysis
- crosses opening of stomach into duodenum = pyloric opening
- shows position of kidney hila (L higher than R -> crosses thru inf L hilum, sup R hilum)
Hepatic Portal Sys
art -> cap bed 1 -> vein -> cap bed 2 -> vein venous blood (GI, panc, gall, spleen) -> inf liver via portal vein -> cap bed liver -> short hepatic veins -> IVC
Portacaval Anastomoses Locations
- inf end of esophagus, inf rectum, umbilicus
- liver contacts diap (bare liver), GI conacts post ab wall (retro GI), post panc
Innervation of ab viscera by pre-vert plexus
- branches -> to target tissues w/vessels from aorta
- has symp (T5-L2), parasymp (vagus + S2-S4), + sensory parts (parallel motor paths)
- vagus (CN X) = foregut + midgut, S2-S4 = hindgut
Superficial fascia of ab wall
- subcutaneous fatty CT
- in lower region of ant ab wall, below umbilicus, forms 2 layers:
- superficial fatty layer (camper’s fascia) + deep membranous layer (Scarpa’s fascia)
Camper’s Fascia
- Cont. over inguinal lig w/thigh superficial fascia
- Male - cont. over penis to scrotum = Dartos fascia
- Female - superficial fat layer, part of labia majora
Scarpa’s Fascia
- deep thin mem layer w/no fat
- Inferiorly: Continues to thigh below inguinal lig, becomes fascia lata
- Midline: attached to linea alba + pubic symphysis
- Continues to ant perineum = Superficial perineal fascia
Fundiform ligament
- Extensions of scarpa’s fascia attached to pubic symphysis pass inferiorly to sides of penis /clitoris to form fundiform lig
External Oblique Attachments/Innervation
- Attachment = outer lower 8 ribs (ribs V-XII)
- Lateral iliac crest -> aponeurosis ending in midline (linea alba)
- Innervation = ant. rami of T7 to T12
Assoc ligs of External Oblique
- Inguinal lig – inf border of aponeurosis of external oblique
- Lacunar lig – extension off inguinal ligament, medial side, attaches to pubic bone at pectin pubis
- Pectineal lig - on top of pectineal line
External Oblique Function
• Fn = compress ab contents, both muscles- flex trunk
○ Each site - bend trunk, turn ant part to opp side
• Fibers run lat sup to med inf (hands in pocket)
Internal Oblique Attachments
- Thoracolumbar fascia
- Iliac crests
- lateral 2/3 of inguinal lig
- Inferior border of lower 3 or 4 ribs
- Aponeurosis ending in linea alba
- Inferiorly to pubic crest and pectineal line
Internal oblique Innervation/Function
- Innervation = ant rami of T7-L1
- Fn = compression of abdominal contents, both muscles - flex trunk, each site - bend trunk and turn ant part to same side
Transversus Abdominis Attachments
○ Thoracolumbar fascia ○ Medial lip of iliac crest ○ Lateral 1/3 of inguinal ligament ○ Costal cartilage of lower 6 ribs (ribs VII to XII) ○ Aponeurosis ends in linea alba Pubic crest and pectineal line
Transversus Abdominis Innervation + Fn
Ant rami of T7-L1
compresses ab contents
Rectus Abdominis
• Attachments
○ Pubic crest, Pubic tubercle, Pubic symphysis (all part of anterior pubic bone)
○ Costal cartilage or rib V to VII
○ Xiphoid process
• Innervation = anterior rami of T6~ T7 to T12
• Fn = compress ab contents, flex VC, tense ab wall (stabilizes back)
Pyramidalis
- Attachments = front of pubis, pubic symphysis, linea alba
- Innervation = ant ramus of T12
- Function = tenses linea alba -> pubic bone not moving
Rectus Sheath
- aponeurotic fusion of external/internal obliques and transversus abdominis muscle
- upper 3 Qs - surrounds rectus abdominis
- lower 1 Q - entirely in front of rectus abdominis
- Arcuate Line (image above) = transition from half internal oblique aponeuroses (and others) going behind to going in front
Internal thoracic artery
- off subclavian after 6th intercostal space - splits to 2 branches:
- Musculophreic a. (follows costal margin)
- Superior epigastric a. (straight down, deep to rectus abdominis)
Aorta
- branches at T7-T12 follow nerves ->
- Lower intercostal aa.
- Subcostal a. (T12)
- External + internal iliac artery
External Iliac Artery
- Inf epigastric a. (anastomoses w/sup epigastric a., also deep to rectus abdominis, near inguinallig)
- Landmark for inguinal hernias
- Deep circumflex iliac a. (supports iliacus and all attached to iliac crest)
Femoral Artery
- from external iliac, superficial, supplies muscles at iliac crest ->
- Superficial circumflex iliac a.
- Superficial epigastric a. - superficial up abdomen
Superficial Vein Drainage
- Above umbilicus → axillary v.
- Below umbilicus → femoral v.
- Paraumbilical vein (have portal cnxns -> caput medusa)
Superficial Lymph vessel drainage
- above umbilicus → anterior axillary nodes
- Below umbilicus → superficial inguinal nodes
Groin
- Layers go w/processus vaginalis, pulled down, become part of spermatic cord = cnxn from ab to scrotum
- Don’t want ab contents going down to scrotum = potential for inguinal hernia
Deep Inguinal Ring
- lateral to epigastric vessels like inf. epigastric art
- Transversalis fascia → internal spermatid fascia (male) + Inner layer (female)
- Superficial to CT layer (extra peritoneal fat) + peritoneum
Superficial (External) Inguinal Ring
• Ext. oblique aponeurosis (spermatic cord thru it)
○ Lateral crus – lateral to superficial ring
○ Medial crus – medial to superficial ring
• Forms ext. spermatic fascia of spermatic cord/round ligament
Boundaries of Inguinal Rings
- Ant wall = external oblique aponeurosis
- lateral wall = internal oblique
- Forms cremaster fascia + muscle/fascia of spermatic cord/round lig.
• Post wall = Transversalis fascia – full length, Conjoint tendon – medial 1/3 (brings it all together)
• Roof = from arching fibers of transversus abdominis and internal oblique muscles
• Floor = Inguinal ligament
M/F derived from External Oblique Aboneurosis
Male spermatic cord: External spermatic fascia
Female round ligament: outer layer
M/F derived from Internal Oblique Muscle
Male spermatic cord: Cremaster fascia and muscle
Female round ligament: diminishes from prox to dist
M/F derived from Transversalis fascia
Male spermatic cord: Internal spermatic fascia
Female round ligament: inner layer
M/F derived from superior vesical a.
Male spermatic cord: Artery of ductus deferens
M/F derived from aorta
Male spermatic cord: Testicular a.
Female round lig: Ovarian a.
M/F derived from R IVC + L renal vein
Male spermatic cord: Pampiniform plexus
Female round ligament: Ovarian vein
M/F derived from L1 + L2
Male spermatic cord: Genitofemoral n.
Female round ligament: Genitofemoral n.
M/F derived from genital branch in inguinal canal
Male spermatic cord: Cremasteric muscle innervation
Female round ligament: Supplies round lig
M/F derived from femoral branch
Male spermatic cord: Sensory medial thigh
Female round ligament: same
M/F derived from ilioinguinal nerve from L1
Male spermatic cord: Prosimomedial aspect of thigh + perineal region
Female round ligament: same
Portcaval Anastomses Function
- block of hepatic portal vein = portal hypertension
- anastomoses dilate = blood from tributaries bypass liver, enter caval sys, return to heart
- portal hypertension = hemorrhoids, caput medusa, ascites + bloating
