Anatomy Lecture Block 3

9 regions of the abdomen

• right/left hypochondriac

• right/left lumbar

• right/left iliac

• epigastric

• umbilical

• hypogastric

4 quadrants of the abdomen

• right/left upper quandrant RUQ/LUQ

• right/left lower quandrant RLQ/LLQ

lateral group muscles and their innervation

• external abdominal oblique

• internal abdominal oblique

• transverse abdominis

INNERVATED BY 6 LOWER INTERCOSTAL NERVES AND L1

medial group muscles and their innervation

• rectus abdominis

• pyramidalis

INNERVATED BY 6 LOWER INTERCOSTAL NERVES AND L1

function of the lateral and medial group muscles

• compress abdominal viscera

• flex and rotate the trunk (via thoracic/flexion/extension via lumbar)

• expiratory muscles

external abdominal oblique characteristics

• lowest part of the aponeurosis

• origin of the inguinal ligament

  • continuous w/ the inguinal ligament

internal abdominal oblique

• cranial part

• middle part - aponeurosis helps make rectus sheath as 2 layers (anterior and posterior rectus abdominis)

  • inferior layer terminated 5cm below navel (at arcuate line)

• caudal part - continues in male into the spermatic cord as the cremaster muscle and its thin fibers reach around the round ligament in females

innervation of cremaster muscle

genital branch of genitofemoral nerve

cremastic reflexes

• afferent limb (sensory input)- femoral branch of genitofemoral

• efferent limb (motor output)- genital branch of genitofemoral

cremsasteric reflex origin, innervation, and clinical significance

• origin: caudal part of internal abdominal oblique mucsle

  • wraps around spermatic cord in males

  • consists of thin fibers that make up round ligament of uterus in females

• innervation: genital branch of genitofemoral nerve(sensory and motor)

• clinical significance:

  • twisted testes/mass in testes, we can palpate the upper thigh to see if we have contraction of the cremaster muscle (if we do, then both sensory/motor work properly)

rectus sheath

aponeurosis of lateral group adbominal muscles that surround the rectus abdominis anteriorly and posteriorly

location of the rectus sheath:

• anterior

• middle …encircles

• internal…posteriorly beneath

location of the rectus sheath:

• aponeurosis of external oblique is on the __ side of the rectus abdominis

• aponeurosis of internal oblique in the ___ splits into 2 layers and ___ the rectus abdominis (one part is posterior and the other, anterior)

• transverse abdominal muscle is ___ and continues ___

• the transversalis facia is ___ the transverse abdominal muscle

what is the origin of the inguinal ligament

the lowest (inferior part) aponeurosis of the external oblique muscle

contents of the rectus sheath

• rectus abdominal muscle

• inferior/superior epigastric vessels

• 5 lower intercostal nerves (including subcostal nerve)

location of the inguinal canal and its deep and superficial rings

parallel to the inguinal ligament and its opening

• deep inguinal ring - internal opening and a gap in the fascia transversalis

• superficial inguinal ring - gap in aponeurosis of the external abdominal oblique muscle

contents of the inguinal canal in men and females

• male - spermatic cord

• female - round ligament of the uterus and lymphatics

descent of the testis:

• spermatic cord

• scrotum … inguinal canal

• processus vaginalis … scrotum … tunica vaginalis

descent of the testis:

• testis are connected to the ______

• testis descend from the abdominal cavity into the ___ via the _____ during intrauterine life

• b4 descension of testis, part of the _______ (peritneum abdominal lining) travels through the canal to line the developing ___ and create space for the testis to sit and follow, ultimately becoming the ___ around the testis

cryptorchidism clinical significance and treatment

when the testis fails to descend into scrotum

• immediate fix eneded bc pendulous testes are temperature sensitive (5-7 than rest of the body); if stuck inside the body → cant become cool

treatment:

• normally developed testis - pass them through the inguinal canal into the scrotum

• underdeveloped testis - get rid of it

hydrocele of the cord

proccesus vaginalis doesnt close after descent of testis → fluid buildup around spermatic cord

treatment - remove fluid and suture

contents of the spermatic cord

• ductus (vas) defrens

• testicular artery

• ductus deferens artery cremaster artery

• pampiniform plexus

• autonomic nerve fibers

• genital branch of the genitofemoral nerve

• lymphatics

• cremaster muscle

pampiniform plexus

net-like blood vessels in the fibrous stroma that surround the testicular arteries

blood flow of testis:

blood flow of testis:

• artery goes into the testis and carries warm (98.6 farenheit) blood from the abdomen

• testis venous blood is cool and travels back to the heart

  • as blood comes across each other, warm blood coold down b4 it enters the testis via counter current exchange

    • ONE ARTERY AND A VENOUS NETWORK AROUND IT

cremaster muscle

• Helps cool/heat the testes via contraction/relxation ultimatley manipulating blood flow through pampiniform plexus 

  • Relaxed -> testes falls further from body 

  • Contracted -> testes pulled closer to the body

direct/indirect inguinal hernias

both occur superior to the inguinal ligament

direct inguinal hernia

abdominal wall split in the Hesselbrach’s triangle → instestine loop comes out

• medial to epigastric vessels

• doesnt pass through the inguinal canal (parallels the spermatic cord)

• smaller in size

• low risk of strangulation/infarction (softer/malleable)

• acquired

• happens in Hesselbrach’s triangle (superficial opening location)

risk factors and treatment for direct inguinal hernias

• middle age men (40+ yrs old)

• smaller in size

• treatment:

  • doesn’t always require surgery

  • binding/brace then bedrest

  • laparoscopic cord and suture

indirect inguinal hernias

happens underneath the fascia of spermatic cord → pushed length of spermatic cord → compromised blood flow

• lateral to epigastric vessels

• passes through inguinal canal (inside the spermatic cord)

• high risk of strangulation/infarction

• congenital and also can be acquired

risk factors and treatment for indirect inguinal hernias

• younger ppl

• bigger in size

• treatment: requires surgery to pull loop of intestine back out into the abdominal cavity

femoral hernias

inferior to the inguinal ligament

• more common in females

• very painful

peritoneum

serous membrane lining the abdominal and pelvic cavities

• has greater and lesser sac

greater sac

main part of the peritoneal cavity

lesser sac (omental bursa)

diverticulum of the peritoneal cavity

• on the left side

• posterior to the stomach

mesentary

double layer of the visceral peritoneum that has vessels, nerves, and fat

• connects intestines to the posterior abdominal wall

mesenteric border

fixed, more vascular

anti-messenteric border

free border, less vascular

• where surgery is done

innervation of the peritoneum

• somatic nerves - parietal layer

• autonomic nerves - visceral layer (including mesentary)

what are retroperitoneal organs?

organs that are NOT covered by visceral peritoneum and are BEHIND the peritoneal cavity

retroperitoneal organs

• kidneys

• suprarenal glands

• uterine cervix

• descending, horizontal, and ascending duodenum

• pancreas

• ascending & descending colon

• upper 2/3 of rectum

what are intraperitoneal organs

organs that has a mesentery and are covered by the peritoneum

intraperitoneal organs

• stomach

• small intestine (jejunum, ileum, some superior duodenum)

• spleen

• liver

• gallbladder

• cecum w/ vermiform appendix (varies)

• large intestine (transverse and sigmoid colons)

peritoneum pathway:

• anterior

• inferior

• flaciform ligament

• anterior & inferior

• anterior

peritoneum pathway:

• it lines the ____ abdominal wall

• reflects upward to cover ____ surface of diaphragm

• reflects onto the liver → making the _______

• covers the ___ and ____ inferior surfaces of the liver

• continues downwards as the ___ layer of the lesser omentum (liver →stomach)

peritoneum over the stomach:

• anterior

• greater omentum

peritoneum over the stomach:

• covers the ____ surface of the stomach

• descends as the ______

lesser sac

• behind the stomach

• superior and inferior recess (pocket)

• has an opening, Epiploic foramen, which is beneath the portal triad

epiploic foramen (foramen of winslow) and its clinical signficance

opening to the lesser sac

• beneath the portal triad

• clinical significance: increase in abdominal fat/pressure → causes intestines to be pushed → upwards displacement of small intestines → small intestines loop pushed through the epiploic foramen and into the lesser sac → internal hernia and strangulation

epiploic foramen and surgical importance

• srugery done from greater sac

• right next to the porta hepatis

structures reachable through the epiploic foramen

• posterior liver surface

• cystic artery of gallbladder via lesser sac

• portal triad which is anterior to the foramen

importance of mesentary

• prevents adhesion of visceral and parietal peritoneum

• good amount of mobility → moves by peristaltic movement of viscera

• has fat, lymphocytes, and immune cells to protect against infection/inflammation in abdominal cavity (abdominal policeman)

• protects abdominal organs against injury and acts as insulator against loss of body heat

anterio, posteriorm superior, and inferior bounderies of epiploic foramen

• anterior - porta hepatis (portal triad): hepatic artery, common bile duct, and portal vein

• posterior - IVC and right crus of diaphragm

• superior - caudate lobe of liver

• inferior - first part of duodenum

abdominal policeman

immune cells that protect against infection/inflammatory conditions in abdominal cavity by wrapping around , separating the inflamed/healing parts and releasing inflammatory mediators to get helpuful immune cells

• move towards inflamed/infected area (o.e Appendicitis)

• why its important to move after abdominal surgery → otherwise adhesions of greater momentum → tears

collects … localized

because of the arrangement of the peritoneum, fluid in the abdominal cavity ___ and becomes ___ in certain regions

subphrenic spaces

between the diaphragm and the liver on both sides of the falsiform ligament

• inhaled anesthetic → increased serous fluid production that sits in subphrenic space → diaphragm irritation → respiratory problems (another reason for the importance of movement post-surgery)

paracolic gutters

besides the ascending/descending colon

right subhepatic space (pouch of morison)

between the liver and the right kidney

• lowest part of the abdominal cavity when lying flat (supine position)

• another site of fluid accumulation postoperative from lack of movement

left subhepatic space

equal to lesser sac

• fluid can become trapped behind the stomach

right and left infracolic spaces

below transverse mesocolon

• divided by the mesentery of the small intestine

• fluid can track into pelvis

rectouterine (douglas) pouch

possible fluid accumulation site w/ pelvic inflammatory disease

• in females

  • pelvic cavity

rectovesical pouch

fluid accumlation site in the pelvic cavity of males

peritonitis

inflammation along w/ pain of the peritoneum a4 an abdominal injury → can cause fluid from parietal peritneum to go into abdomen

• i.e stab wound or perforated appendicitis (fecal material/ e coli spills out into abdonimal cavity)

• can be acquired secondarily

ascites

abnormal accumlation of fluid in the abdominal cavity

• often seen in liver cirrhosis (end-stage liver cirrhosis) which compromises blood flow in liver

• more common

paracentesis

puncturing the peritoneal cavity to get rid of excess buildup fluid

• done via a catheter and massage done a4 to keep fluid from getting trapped in the compartments

anatomy of digestion tract

made of the esophagus, stomach, and intestine which come from the primordial foregut, midgut, and hindgut

foregut

• esophagus

• stomach to the 2nd part of duodenum

• liver

• billiary system

• gall bladder

• pancreas

midgut

• lower half of 2nd part of duodenum

• jejunum

• ileum

• colom (cecum, ascending and right 2/3 of transverse colon)

hindgut

• left 1/3 of transverse colon

• descending colon

• sigmoid colon

• rectum

• upper part of anal canal

blood supply of foregut, midgut, and hindgut

• foregut - celiac trunk

• midgut - superior mesenteric artery

• hindgut - inferior mesenteric artery

parasympathetic innervation of forgut and midgut (rest & digest)

• vagus nerve (CN X) - esophagus to 2/3 right of transverse colon

• pelvic sphlanchnic nerves (S2-S4) - 1/3 left of transverse colon down to the anal canal

sympathetic innervation of the hindgut (flight or fight)

• spinal segments (T5-L2) - from the lower esophagus to anus

esophagus characteristics

• 25-30cm long

• starts at C6 vertebra (cricoid cartilage)

• ends below the diaphragm at T10-T12

• enters the stomach at the cardia

function and innervation (sympathetic/parasympathetic) of the esophagus

• function: conveys bolus of food to the stomach

• innervation:

  • sympathetic - T5-L2 spinal segments

  • parasympathetic - vagus nerve

blood supply of the upper, middle, and lower parts of the esophagus

• upper(cervical): inferior thyroid artery

• middle (thoracic): 4-5 arteries from the thoracic aorta and bronchial arteries

• lower/adominal portion: left gastric artery (from celiac artery) and inferior phrenic artery (from abdominal aorta)

venous drainage of the upper, middle, and lower parts of the esophagus

• upper: inferior thyroid vein → brachiocephalic → SVC (SYSTEMIC CIRCULATION)

• middle: azygous vein → hemiazygos vein → SVC (SYSTEMIC CIRCULATION)

• lower: left gastric vein → portal vein (PORTAL CIRCULATION)

  • lower esophageal connection plays role in esophageal varices in liver cirrhosis

layers of the esophagus innermost → outermost

1. mucosa

2. submucosa

3. tunica muscularis/muscularis externa

4. adventitia/serosa

mucosa of the alimentary canal/esophagus

• stratified non-keratinized squamous epithelium that transitions to simple columnar in cardia)

  • muscularis mucosa - thin layer of smooth muscle

  • lamina propria - connective tissue

submucosa of the alimentary canal/esophagus

connective tissue that has blood vessels, lymphatics, and nerve fibers

muscularis externa/ tunica muscularis of alimentary canal/esophagus

2 layers of smooth muscle

• inner circular muscular layer that squeezes the tube

• outer longitudinal muscular layer that shorts it

serosa/adventitia of alimentary canal/esophagus

connective tissue that binds strcture to surroudning structures

hiatal hernias, its types, and treatment

hernias where part of the stomach herniates into the mediastinum through the esophageal hiatus of the diaphragm → pain w/ chest pains and cardiac ichemia

• types:

  • sliding hiatal hernia

  • para-esophageal hiatal hernia

• treatment: both fixed via surgery (fundoplication) to reinforce LES barrier

sliding hiatal hernia

when abdominal part of esophagus, cardia and fundus slide up through the esophageal hiatus → pressure on LES → LES pushes open → regurgitation and heart burn

para-esophageal hiatal hernia

part of the fundus and peritoneum passes through the esophageal hiatus into thoracic cavity

• no regurgitation

fundoplication

operation to correct gastroesophageal reflux, reinforce barrier to reflux LES

• upper portion of stomach (fundus) wrapped (plicated) around lower portion of esophagus and anchored securely below the diaphragm

radiofrequency treatment

radiofrequency energy causes tiny burns at G-E junction that heal and form scar tissues which tightens the weaken valve or LES

• endoscope supplied by electrodes are used

esophageal atresia

distal end of esophagus is closed

• esophagus is supposed to be continuous

• we just need to close the tubes together

tracheoesophageal fistula

abnormal connection between the esophagus and traches w/ epithelial cells

• milk from nerborn esophagus goes into respiratory track → severe problems

• we need to sever the connection

malignancy

frequency at transition between epithelia types

esophageal cancers

• low in north america

• higher in iran and china bc of irritation of mucosa from hot tea and opium use

diverticulum

where all 3 wall layers (mucosa, submucosa, and tunica muscularis) protrude to form little pouches

• most common in large intestines

zenker’s diverticulum

upper esophagus, dysphagia (difficulty swallowing), and halitosis (bad breath), regurgitation → food gets trapped

• complications - ulceration, bleeding, and inflammation

• treatment - surgery in the esophagus, diet changes for large intestine

achalasia (cardiospasm)

neuromotor disorder of the LES that causes retrosternal pain

• LES cant open/relax to let food pass into stomach bc of weakness of secretomotor function/peristaltic movement→ food cant be swallowed into esophagus → increased LES pressure

• loss of ganglion cells in myenteric plexus (analogus to Hirschsprung’s disease)

• dysphagia for both solids and liquids

• dilated proximal esophagus

• aperistalsis

risk factors and treatment of achalasia (cardiospasm)

• risk factors: congenital (not all fibers show up in submucosa) or developmental (from trauma/stroke)

• treatment:

  • drinking cold/warm thing can stimulate LES to open up

  • often need mechanical assistance at the hospital

  • if patient cant swallow → feeding tube via stomach

columnar … metaplasia

barret’s esophagus is the damage to ___ cell metaplasia of the ___ epithelium

cause and effect of barret’s esophagus

result of acid injury/chemical burn

• LES doesnt close proplerly → gastric secretion regigurgitation (hydrochloric acid)

GI tracts’ innnvervation system

GI tract has built-in nervous system w/ two plexuses called the submucosal plexus of meissner and myenteric plexus of auerbach

submucosal plexus of Meissner:

secretomotor function of mucus for lubrication and facilitation of molecule movement (feces and foods) and absorption

myenteric plexus Auerbach:

muscle fibers that cause peristaltic movement of smooth muscle

• a branch talks to each muscler fiber

autonomic innervation of digestive tract

• parasympathetic - stimulates/increases

  • via vagus CN X and pelvic splanchnics S2-S4

• sympathetic - inhibits/decreases

  • via T5-L2

stomach

most dilated part of alimentary tract in upper left quadrant of the abdomen

• between the esophagus and lesser intestine

• functions as food reservoir and involved in enzymatic digestion

stomach charasterics

• has longitudinal smooth layer and oblique smooth muscle layer (which helps w/ mechanical digestion/physically breaks things up)

• has rugae which helps expand surface area in the stomach other than in lesser curvature

• has cells that specialize in secreting hydochloric acid and enzymes that weaken bonds within protein molecules for further digestion in small intestine

hypertrophic pylroic stenosis

progressive hypertrophy of circular muscles in pyloric sphincter → narrow pyloric lumen → obstruction of food passage

• seen in male infants (first child) and they have:

  • nonbilious vomiting after feeding

  • small olive sized knot in right costal margin seen via palpation

what does nonbilious vomiting tell us?

it tells us we cant move smth out of stomach and into the duodenum or that bile cant move from the duodenum and upwards → ULTIMATELY THERES A BLOCKAGE

longitudinal pyloromyotomy

hypertrophic pyloric stenosis treatment where we take the longitudinal smooth muscle out of the pyloric sphincter and leave the mucosa intact