Esphagus Stomach Duodenum Gross Anatomy

8/8/2019 Esphagus Stomach Duodenum Gross Anatomy

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1. Review the esophagus: commencement, termination, location, length, constrictions, relations, neurovascular supply Commencement:

y

opposite the sixth cervical vertebra; it is continuous above with the

laryngeal part of the pharynxy

begins at the inferior border of the cricoid cartilage

Termination:

y

end by entering the stomach (cardiac orifice) left 7th costal cartilage oropposite T11

Location:

y

It is between the trachea and the spine

Length:

y

25-30 cm long in a normal adult

Constrictions:

1. at the beginning by the cricopharyngeus muscle2 .

where the aortic arch and the left bronchus cross its anterior surface3 .

where the esophagus passes through the diaphragm into the stomach atthe 1 0 th thoracic vertebra

Relations:

y

Inferiorly to the level of the roots of the lungs

o

Left vagus lies anterior to it

o

Right vagus lies posterior to it

y

A t the opening in the diaphragm it is accompanied by

o

two vagi

o

branches of the left gastric blood vessels

o

lymphatic vessels

y

In the neck

o

P osteriorly

vertebral column

o

Laterally

lobes of the thyroid gland

o

A nteriorly

trachea

recurrent laryngeal nerves

y

In the thorax

o

A nteriorly

Trachea

left recurrent laryngeal nerve

left principal bronchus

pericardium

o

P osteriorly

bodies of the thoracic vertebrae

thoracic duct

azygos veins

right posterior intercostal arteries

descending thoracic aorta at its lower end

o

Right side

mediastinal pleura

terminal part of the azygos vein

o

Left side

left subclavian artery


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aortic arch

thoracic duct

mediastinal pleura

y

In the abdomen

o

A nteriorly

left lobe of the liver

o

posteriorly

left crus of the diaphragm

NVS:y

The upper segment is innervated by the recurrent laryngeal nerves. The smooth fibers in the lower segment areinnervated by sympathetic fibers from the 6th -10 th thoracic ganglia; with para -sympathetic fibers from the vagus.

y

The inferior thyroid arteries supply the cervical segment, while the thoracic aorta takes care of the thoracic part. Thediaphragmatic and abdominal segments are supplied by branches from the esophageal branch of the left gastricartery.

y

Veins draining the blood from the upper segments join tributaries to the superior vena cava; while those from thelower segments communicate with the veins that join the portal vein.

2 . Discuss the stomach as to its shape, location, parts, relation, peritoneal attachments, NVS Shape: J - shaped Location: left upper quadrant, epigastric, and umbilical regions, and much of it lies under cover of the ribs; between theesophagus and the small intestine P arts:

y

Fundus:

o

dome -shaped

o

projects upward and to the left of thecardiac orifice

o

usually full of gas

y

Body/C orp us Vent ricul i :

o

level of the cardiac orifice to the levelof the incisuraangularis (a constantnotch in the lower part of the lessercurvature)

y

P yl oric ant r um:

o

from the incisuraangularis to thepylorus

y

P yl or us:

o

most tubular part

o

pyloric sphincter - thick muscular wall

o

pyloric canal - cavity of the pylorus

y

Cardia:

o

part surrounding the cardiac orifice

y

Lesser curvature:

o

shorter concave border

y

G reater curvature:o

convex border

Relation:y

G astric curvatures

y

Lesser curvature

o

Right border of stomach

o

from the cardiac orifice to the pylorus

o

suspended from the liver by the lesser omentum

y

G reater curvature


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o

four or five times longer

o

starts from the

left of the cardiac orifice

over the dome of the fundus

along the left border of thestomach to the pylorus

o

gastrosplenicomentum (ligament)

from the upper part of thegreater curvature to thespleen

o

greater omentum

from the lower part of thegreater curvature to thetransverse colon

T r ansve r se se ct ion of the lesse r sa c showi ng thea rr angement of the peri t oneum i n the for mat ion of thelesse r omentum, the gast ro sp len icomentum, and thesplen icor enal l i gament. A rrow i nd icates the po si t ion of theop en i ng of the lesse r sa c.

y

A nteriorly:

o

anterior abdominal wall

o

left costal margin

o

left pleura and lung

o

diaphragm

o

left lobe of the liver

y

P osteriorly:

o

lesser sac

o

diaphragm

o

spleen

o

left suprarenal gland

o

upper part of the left kidney

o

splenic artery

o

pancreas

o

transverse mesocolon

o

transverse colon

S t r uctu r es s i tuated on the po ste rior abd om i nal w all beh i nd thest oma ch.


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P eritoneal attachments:y

parietal peritoneum

o

anterior abdominal wall surfaces

o

lateral abdominal wall surfaces

o

posterior abdominal wall surfaces

o

inferior surface of diaphragm and pelvis

y

visceral peritoneum

o

surfaces of intraperitoneal organs (i.e., stomach, jejunum, ileum, transverse colon, liver, spleen)

o

anterior aspect of retroperitoneal organs (i.e., duodenum, L & R colon, pancreas, kidneys, adrenal glands)

P eri t oneal l i gaments and mesente ric r ef lect ions i n the adult.T hese atta chments pa r t i t ion the abd omen i nt o ni ne po tent i al spa ces: ri ght and le f t sub phr en ic, subhe pat ic,supr amesente ric and i nfr amesente ric spaces, ri ght and le f t pa r aco l ic gutte r s, pelv i s, and omental bu r sa (sh ow n i n i nset on ri ght).

y

peritoneal cavity divided into 2 parts

o

greater sac

main compartment and extends from the diaphragm down into the pelvis

o

lesser sac

smaller and lies behind the stomach

y

in free communication with one another through an oval window called the opening of the lesser sac, or the epiploicforamen

y

intraperitoneal - almost totally covered with visceral peritoneum

y

Retroperitoneal - lie behind the peritoneum and are only partially covered with visceral peritoneum

y

P eritoneal ligaments - two - layered folds of peritoneum that connect solid viscera to the abdominal walls

o

Liver is connected to the diaphragm by

falciform ligament

coronary ligament

right and left triangular ligaments

NVS:

y

all arteries derived from branches of the celiac artery

o

left gastric artery

from the celiac artery

supplies the lower third of the esophagus and the upper right part of the stomach.

o

right gastric artery

from the hepatic artery

supplies the lower right part of the stomacho

short gastric arteries

from the splenic artery

supply the fundus

o

left gastroepiploic artery

from the splenic artery

supply the stomach along the upper part of the greater curvature

o

right gastroepiploic artery


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from the gastroduodenal branch of the hepatic artery

supplies the stomach along the lower part of the greater curvature

y

veins drain into the portal circulation

o

left and right gastric veins

drain directly into the portal vein

o

short gastric veins and the left gastroepiploic veins

join the splenic vein

o

right gastroepiploic vein

joins the superior mesenteric vein

y

Nerve Supply

o

sympathetic fibers derived from the celiac plexus

o

parasympathetic fibers from the right and left vagus nerves

y

anterior vagal trunk

o

formed in the thorax mainly from the leftvagus nerve

o

divides into branches that supply theanterior surface of the stomacho

hepatic branch

o

pyloric branch

y

posterior vagal trunk

o

formed in the thorax mainly from the rightvagus nerve

o

divides into branches that supply mainly theposterior surface of the stomach

o

celiac and superior mesenteric plexuses andis distributed to the intestine as far as thesplenic flexure and to the pancreas


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y

sympathetic innervation of the stomach carries a proportion of pain - transmitting nerve fibers

y

parasympathetic vagal fibers are secretomotor to the gastric glands and motor to the muscular wall of the stomach

y

pyloric sphincter receives motor fibers from the sympathetic system and inhibitory fibers from the vagi

3. Discuss the duodenum as to its shape, length, location, parts, relations, NVS Shape:C -shaped tube Length:( 25 cm) long Location:lies mostly in the upper retroperitoneum; situated in the epigastric and umbilical regions; commences @ duodeno -pyloric junction; ends @ 2 nd lumber vertebra Relations:1st P art

y

pylorus and runs upward andbackward on the transpyloricplane at the level of the firstlumbar vertebra

y

A nteriorly: The quadrate lobe of the liver and the gallbladder

y

P osteriorly: The lesser sac (firstinch only), the gastroduodenalartery, the bile duct and portalvein, and the inferior vena cava

y

Superiorly: The entrance into thelesser sac (the epiploic foramen)

y

Inferiorly: The head of thepancreas (Fig. 5-2 6)

2 nd P arty

Runs vertically downward in frontof the hilum of the right kidneyon the right side of the second

and third lumbar vertebraey

halfway down its medial border,the bile duct and the main pancreatic duct pierce the duodenal wall

y

They unite to form the ampulla that opens on the summit of the majorduodenal papilla

y

accessory pancreatic duct, if present, opens into theduodenum a little higher up on the minor duodenalpapilla

y

A nteriorly: The fundus of the gallbladder and theright lobe of the liver, the transverse colon, and thecoils of the small intestine

y

P osteriorly: The hilum of the right kidney and theright ureter

y

Laterally: The ascending colon, the right colic flexure,

and the right lobe of the livery

M edially: The head of the pancreas, the bile duct, andthe main pancreatic duct

P oste rior r elat ions of the du odenum and the pan cr eas. T he numbe r s r epr esent thefour pa r ts of the du odenum.


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3 rd P art

y

runs horizontally to the left on the subcostalplane, passing in front of the vertebralcolumn and following the lower margin of the head of the pancreas

y

A nteriorly: The root of the mesentery of thesmall intestine, the superior mesentericvessels contained within it, and coils of jejunum

y

P osteriorly: The right ureter, the right psoasmuscle, the inferior vena cava, and the aorta

y

Superiorly: The head of the pancreas

y

Inferiorly: Coils of jejunum

4 th P arty

runs upward and to the left to theduodenojejunal flexure

y

Flexure is held in position by a peritoneal fold, the ligament of Treitz, which is attached to the right crus of the diaphragm

y

A nteriorly: The beginning of the root of the mesentery and coils of jejunum

y

P osteriorly: The left margin of the aorta and the medial border of the left psoas muscle

P an cr eas and ante rior r elat ions of the k i dneys.

Ent r an ce of the b i le du ct and the ma i n and access or y pan cr eat ic du cts i nt o the se cond pa r t of the du odenum. N o te the sm oo th l i ni ng of the fir st pa r t of the du odenum, the p l icae circ ula r es of these co nd pa r t, and the maj or du odenal papi lla.

Atta chment of the roo t of the mesente r y of the small i ntest i ne t o the po ste rior abd om i nal w all. No te that i t extends fro m the du oden o jejunal f lexu r e on le f t of the a or ta, d ow nw a r d and t o the ri ght t o thei leoc ecal jun ct ion. T he su pe rior mesente ric a r te r y l i es i n the roo t of the mesente r y


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NVS:A rteries

y

superior pancreaticoduodenal artery

o

a branch of the gastroduodenal artery

o

supplies upper half

y

inferior pancreaticoduodenal artery

o

a branch of the superior mesenteric artery

o

supplies lower half

Veinsy

superior pancreaticoduodenal vein

o

drains into the portal vein

y

inferior vein

o

joins superior mesenteric vein

Nervey

derived from sympathetic and parasympathetic (vagus) nerves from the celiac and superior mesenteric plexuses

Lymph Drainagey

follow the arteries and drain upward via pancreaticoduodenal nodes to the gastroduodenal nodes and then to theceliac nodes and downward via pancreaticoduodenal nodes to the superior mesenteric nodes around the origin of thesuperior mesenteric artery.

4 . Discuss the mucosal lining and muscular walls of the esophagus, stomach, duodenum. Esophagus

y

upper 1/ 3 striated muscle

y

2 / 3 smooth muscle

y

2 layers of fibers

o

Inner circular

o

O uter longitudinal

y

Thinner layer anteriorly due to posterior fibro - muscular wall of trachea

Stomachy

mucosa is a thick layer with a soft, smooth surface that is mostly reddish brown in life but pink in the pyloric region.

y

In the contracted stomach the mucosa is folded into numerous folds or rugae, most of which are longitudinal. Theyare most marked towards the pyloric end and along the greater curvature.

y

The rugae represent large folds in the submucosal connective tissue rather than variations in the thickness of themucosa covering them, and they are obliterated when the stomach is distendedy

submucosa is a variable layer of loose connective tissue. It contains thick bundles of collagen, numerous elastin fibres,blood vessels and nervous plexuses, including the ganglionatedsubmucosal ( M eissner's) plexus.

y

muscularisexterna is a thick muscle coat immediately under the serosa, with which it is closely connected bysubserous loose connective tissue. From innermost outwards, it contains oblique, circular and longitudinal layers of smooth muscle fibres. The layers are not always easily separated: the circular layer is poorly developed in theoesophageal region, but is thickened at the distal pyloric antrum to form the anular pyloric sphincter; the outerlongitudinal layer is most pronounced in the upper two -thirds of the stomach; the inner oblique layer is most obviousin the lower half.

y

The actions of the muscularisexterna of the stomach produce a churning movement that mixes food with the gastricsecretions. When the muscles contract, they reduce the volume of the stomach and throw the mucosa intolongitudinal folds or rugae (see above). The folds flatten as the stomach distends with food and the musculaturerelaxes and thins. M uscle activity is controlled by a network of unmyelinated autonomic nerve fibres and their ganglia

which lie between the muscle layers in the myenteric ( A uerbach's) plexus.Duodenum

y

mucous membrane of the duodenum is thick

y

first part of the duodenum it is smooth

y

remainder of the duodenum it is thrown into numerous circular folds called the plicaecirculares

y

the site where the bile duct and the main pancreatic duct pierce the medial wall of the second part is a small,rounded elevation called the major duodenal papilla

y

accessory pancreatic duct, if present, opens into the duodenum on a smaller papilla about 0 .75 in. (1.9 cm) above themajor duodenal papilla.


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5 . Map out the topography of the stomach and duodenum in the abdomen of a live individual using the regions andquadrants as reference.

StomachThe stomach lies in a curve within the left hypochondrium and epigastrium although, when distended and pendulous, it may lie

as far down as the central or hypogastric regions. The epigastrium is the usual place to auscultate for a succussion splash'caused by chronic gastric stasis in upper intestinal obstruction.DuodenumThe first part of the duodenum sometimes lies just above the trans -pyloric plane, depending on its mobility and length. Thesecond part usually lies in the transpyloric plane just to the right of the midline, and the third part usually lies in the subcostalplane across the midline. The fourth part often lies in the transpyloric plane to the left of the midline, although its positionvaries according to the length of its mesentery.

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Esphagus Stomach Duodenum Gross Anatomy