Abdomen

AbdomenAbdomen is the part of the

trunk between the thorax and pelvis.

It is covered by the musculoaponeurotic walls anterolaterally, the diaphragm superioly, and muscles of the pelvis inferiorly, which are suspended between and supported by the inferior thoracic skeleton, pelvic girdle and semirigid lumbar vertebrae posteriorly.

Abdomial RegionsTwo vertical lines

midclavicular linesTwo horizontal lines

subcostal plane and trans tubercular plane

R. & L. Hypochondriac

Epigastric R. & L. Lumbar Umbilical R. & L. Iliac Hypogastric or

pubic

Abdominal wall The wall consists of skin and

subcutaneous tissue(superficial fascia) composed of fat,muscles and their aponeuroses and deep fascia, and parietal peritoneum

Inferior to umblicus, the subcutaneous tissue has two layers Superficial fatty layer(camper fascia) Deep membranous layer(scarpa fascia)

The membranous layer continues inferiorly to perineal region as superficial perineal fascia(colles fascia)

Muscles of the abdominal wall3 flat muslces(external oblique,internal

oblique and transverse abdominal) and 2 vertical muscles(rectus abdominus and pyramidalis)

EsophagusEsophagus, a muscular tube is continuous

with laryngopharynx.The pharyngoesophageal junction has the

superior esophageal sphinchter, a constriction producted by the cricopharyngeal part of the inferior constrictor muscle, is the narrowest part of esophagus

When the esophagus is empty it has a slit like lumen which expands when the food bolus descends.

The cervical esophagus lies between trachea and cervical vertebral column.

The esophagus remains posterior to the arch of aorta, left main bronchus and left atrium and then it passes through the esophageal hiatus in the diaphragm at the level of T10 vertebrae.

thoracic esophagusThe thoracic esophagus has 3

constrictions because of the compression of

Cervical constriction: at the beginning of phryngo-esophageal junction

Thoracic constriction: compound constriction caused by the compression of arch of aorta and left main bronchus

Diaphragmatic constriction: when it passes thru the diaphragm

Abdominal esophagus

Abdominal esophagus after passing through the esophagus is only 1.25cm long and it ends in the cardiac orifice of the stomach.

Gastro esophageal junction lies at the levl of t11 at the tip of xiphoid process.

Immediately superior to this junction, the diaphragmatic musculature forms the physiologic eesophageal sphincter

stomachThe stomach is the expanded part of the

alimentary tract between the esophagus and the small intestine.

Its functions are1. Acts as a resorvoir of food2. Enzymatic and mechanical digestion An empty stomach is only slightly larger

than large intestine which it is capable of considerable expansion that it can hold 2-3 L of food.

Stomach The stomach has 4 parts Cardia: the part

sorrounding the cardiac orifice

Fundus: the dilated superior part

Body: the major part of stomach between the fundus and the pyloric antrum.

Pyloric part: funnel shaped outflow region of stomach

Small intestinePrimary site for

absorption of nutrients.

Has 3 parts:1. Duodenum2. Jejunum3. ileum

DuodenumShortest,widest and

more fixed part of small intestine

Bile and main pancreatic ducts enter through Hepatopancreatic ampulla

Celiac trunk and superior mesentric artery supplies the blood.

Jejunum and ileum together is 6-7 m long.

Superior mesentric artery(direct branch of aorta) supplies the jejunum and ileum

Large intestine Water is absorbed from

indigestible residues of liquid chyme, converting it into feces.

It consists of 1. Cecum2. Appendix3. Ascending colon4. Transverse5. Descending6. Sigmoid7. Rectum8. Anal canal

Cecum and appendixCecum is blind

intestinal pouch approximately 7.5cm in both length and breadth, located in the right lower quadrant.

Appendix is a blind intestinal diverticulum containing masses of lymphoid tissue

Appendix arises from the postero medial aspect of the ceum inferior to the ileocecal junction.

The cecum is supplied by the ileocolic artery, the terminal branch of SMA.

The appendicular artery, the branch of ileocolic artery supplies the appendix

colonThe ascending colon is narrower than

cecum.Ileocolic and right colic arteries, the

branches of SMA supplies the ascending colon.

The transverse colon is 45 cm long and is most mobile part of large intestine, extending from right to left colic flexure

Middle colic artery,branch of SMA supplies the transverse colon.

Descending colon passes anterior to the lateral border of left kidney

Sigmoid colon is characterized by the S-shaped loop of variable length

The arterial supply is thru left colic and sigmoid arteries, branches of inferior mesentric artery.

Rectum is the fixed terminal part of large intestine,has 3 sharp lateral flexures

Superior,intermediate and inferior.