study of human anatomy. anatomy of the abdomen definition of abdomen a region of the body bounded by...

STUDY OF HUMAN ANATOMY

ANATOMY OF THE ABDOMENANATOMY OF THE ABDOMEN

DEFINITION OF ABDOMENDEFINITION OF ABDOMEN

• A region of the body bounded A region of the body bounded by the following regions:-by the following regions:-– Superiorly – thoraxSuperiorly – thorax

– Inferiorly – pelvis/perineumInferiorly – pelvis/perineum

– Posteroinferiorly – backPosteroinferiorly – back

– Inferolaterally – lower limbsInferolaterally – lower limbs

BONY LANDMARKS OF THE ABDOMENBONY LANDMARKS OF THE ABDOMEN

• Xiphoid processXiphoid process

• Costal margin – 7Costal margin – 7thth – 11 – 11thth costal costal cartilagescartilages

• Pelvic bonesPelvic bones

• L1 – L5 Lumbar vertebraeL1 – L5 Lumbar vertebrae

ABDOMINAL CAVITYABDOMINAL CAVITY

• extends btw thoracic extends btw thoracic diaphragm & pelvic diaphragm & pelvic diaphragm – diaphragm – abdominopelvic cavityabdominopelvic cavity

• upper part is under cover of upper part is under cover of the osteocartilagenous the osteocartilagenous thoracic cagethoracic cage

• occupied by organs of the occupied by organs of the digestive, urogenital, digestive, urogenital, endocrine & vascular endocrine & vascular structures.structures.

CONTENTS OF THE ABDOMINAL CAVITYCONTENTS OF THE ABDOMINAL CAVITY

ABDOMINAL WALLABDOMINAL WALL

PLANES OF THE ABDOMENPLANES OF THE ABDOMEN

• 4 planes divide the abdominal cavity into 9 regions4 planes divide the abdominal cavity into 9 regions– 2 vertical (midclavicular), midclavicular to midinguinal2 vertical (midclavicular), midclavicular to midinguinal– 2 transverse – ( subcostal & transtubercular) 2 transverse – ( subcostal & transtubercular)

• Subcostal – pass through 10Subcostal – pass through 10thth costal cartilage costal cartilage• Transtubercular – pass through iliac tubercleTranstubercular – pass through iliac tubercle

REGIONS OF THE ABDOMENREGIONS OF THE ABDOMEN

QUADRANTS OF THE ABDOMENQUADRANTS OF THE ABDOMEN

• 2 planes delineate the abdominal cavity into 4 quadrants2 planes delineate the abdominal cavity into 4 quadrants• 1 vertical – median1 vertical – median• 1 transverse – transumbilical 1 transverse – transumbilical

POSITIONS OF THE ABDOMINAL ORGANSPOSITIONS OF THE ABDOMINAL ORGANS

ANTEROLATERAL ABDOMINAL WALLANTEROLATERAL ABDOMINAL WALL

• Anterior & lateral walls Anterior & lateral walls extending from the thorax to extending from the thorax to pelvispelvis

• Consists of the Consists of the – (1) Skin(1) Skin– (2) Fascia - (2) Fascia -

Subcutaneous & deepSubcutaneous & deep– (3) Muscles(3) Muscles– (4) Transversalis fascia(4) Transversalis fascia– (5) Extraperitoenal fat (5) Extraperitoenal fat – (6) Peritoneum(6) Peritoneum

SKINSKIN

• Loosely attaches to the Loosely attaches to the superficial fascia, except at the superficial fascia, except at the umbilicus.umbilicus.

• Varies in texture - wrinkle, Varies in texture - wrinkle, rough, smooth, scars.rough, smooth, scars.

• Thin in front and thick at the Thin in front and thick at the backback

• Distribution of hair varies with Distribution of hair varies with sex, age and race.sex, age and race.

• Natural tension lines run Natural tension lines run horizontally around the body horizontally around the body wall.wall.

FASCIAFASCIA• (L. (L. panniculi – panniculi – apron)apron)

• Composed of fatty tissues and Composed of fatty tissues and fibrous connective tissuefibrous connective tissue

• Divided into two layersDivided into two layers– (1) Superficial(1) Superficial– (2) Deep – covers (2) Deep – covers

abdominal musclesabdominal muscles

• (1) Same as elsewhere and (1) Same as elsewhere and varies in amount of fat.varies in amount of fat.

• (1) Major site of fat storage.(1) Major site of fat storage.

• (1) Excessive fat deposition in (1) Excessive fat deposition in the lower anterior abdominal the lower anterior abdominal wall – wall – morbid obesitymorbid obesity

SUPERFICILA FASCIA/TISSUESUPERFICILA FASCIA/TISSUE

• Superior to umbilicusSuperior to umbilicus

– Consistent with other regionsConsistent with other regions

• Inferior to umbilicusInferior to umbilicus

– Reinforced by collagen and Reinforced by collagen and elastic fiberselastic fibers

– Thus 2 layers –Thus 2 layers –

• (1) Superficial fatty layer (1) Superficial fatty layer (Camper’s fascia)(Camper’s fascia)

• Same elsewhereSame elsewhere

• (2) Deep membranous layer (2) Deep membranous layer (Scarpa’s fascia)(Scarpa’s fascia)

• Membranous continues to the Membranous continues to the perineum – Colles’s fascia, not to perineum – Colles’s fascia, not to the thigh.the thigh.

SUPERFICIAL FASCIASUPERFICIAL FASCIA

MUSCLES OF THE ANTEROLATERAL ABDOMINAL WALLMUSCLES OF THE ANTEROLATERAL ABDOMINAL WALL

• 5 pairs of muscles bilaterally – 3 5 pairs of muscles bilaterally – 3 flat, 2 verticalflat, 2 vertical

• (1) External oblique(1) External oblique• (2) Internal oblique(2) Internal oblique• (3) Transversus abdominis(3) Transversus abdominis• (4) Rectus abdominis(4) Rectus abdominis• (5) Pyramidalis(5) Pyramidalis

EXTERNAL OBLIQUE MUSCLEEXTERNAL OBLIQUE MUSCLE

• O: O: external surfaces of 5external surfaces of 5thth – 12 – 12thth ribs ribs

• I: I: linea alba, pubic tubercle, ant ½ of iliac crestlinea alba, pubic tubercle, ant ½ of iliac crest

• N: N: thoracoabdominal nerves (T7-T11 spinal nerves), subcostal nerve.thoracoabdominal nerves (T7-T11 spinal nerves), subcostal nerve.

• A: A: compresses the abdomen to provide support for abdominal organs.compresses the abdomen to provide support for abdominal organs.

INTERNAL OBLIQUE MUSCLEINTERNAL OBLIQUE MUSCLE

• O: O: thoracolumbar fascia, ant 2/3 of iliac crest, lat 1/3 of inguinal ligament.thoracolumbar fascia, ant 2/3 of iliac crest, lat 1/3 of inguinal ligament.

• I: I: inferior borders of 10inferior borders of 10thth – 12 – 12thth ribs, linea alba, pecten pubis, conjoint tendon. ribs, linea alba, pecten pubis, conjoint tendon.

• N: N: thoracoabdominal nerves (T6-T12 spinal nerves), L1 nervethoracoabdominal nerves (T6-T12 spinal nerves), L1 nerve

• A: A: compresses and supports abdominal visceracompresses and supports abdominal viscera

TRANSVERSUS ABDOMINIS MUSCLETRANSVERSUS ABDOMINIS MUSCLE

• O: O: thoracolumbar fascia, internal surfaces of 7thoracolumbar fascia, internal surfaces of 7thth-12-12thth costal cartilages, iliac crest, costal cartilages, iliac crest, lat 1/3 of inguinal ligament.lat 1/3 of inguinal ligament.

• I: I: linea alba, pubic crest, pecten pubis, conjoint tendon.linea alba, pubic crest, pecten pubis, conjoint tendon.

• N: N: thoracoabdominal nerves (T6-T12 anterior rami of spinal nerves), L1 nervethoracoabdominal nerves (T6-T12 anterior rami of spinal nerves), L1 nerve

• A: A: compresses and supports abdominal visceracompresses and supports abdominal viscera

RECTUS ABDOMINIS MUSCLERECTUS ABDOMINIS MUSCLE

• O: O: pubic symphysis & pubic crestpubic symphysis & pubic crest

• I: I: xiphoid process & 5xiphoid process & 5thth-7-7thth costal cartilages costal cartilages

• N: N: thoracoabdominal nerves (T6-T12 spinal nerves)thoracoabdominal nerves (T6-T12 spinal nerves)

• A: A: flexes trunk, compresses and supports abdominal organs, prevents pelvic flexes trunk, compresses and supports abdominal organs, prevents pelvic tiltingtilting

ABDOMINAL MUSCLESABDOMINAL MUSCLES

DEEP FASCIADEEP FASCIA

• Dense connective tissue layer , devoid of fat, that covers the muscles Dense connective tissue layer , devoid of fat, that covers the muscles and their aponeurosis.and their aponeurosis.

• 3 layers – superficial, intermediate & deep.3 layers – superficial, intermediate & deep.

DEEP FASCIADEEP FASCIA

PYRAMIDALIS MUSCLEPYRAMIDALIS MUSCLE

• Small, insignificant muscle.Small, insignificant muscle.

• Absent in 20% of peopleAbsent in 20% of people

• O: O: pubic crest, pubic symphysispubic crest, pubic symphysis• I: I: linea albalinea alba• N: N: subcostal nerve (T12)subcostal nerve (T12)• A: A: tenses the abdomentenses the abdomen

RECTUS SHEATHRECTUS SHEATH

• A strong incomplete fibrous A strong incomplete fibrous compartmentcompartment

• Formed by decussation and Formed by decussation and interweaving of the flat interweaving of the flat abdominal muscles.abdominal muscles.

• Internal oblique Internal oblique aponeurosis splits into two aponeurosis splits into two layers: layers: anterioranterior & & posterior posterior and invest the rectus and invest the rectus abdominis muscle.abdominis muscle.


• Anterior wall – external oblique, Anterior wall – external oblique, anterior layer of internal obliqueanterior layer of internal oblique

• Posterior wall – transversus Posterior wall – transversus abdominis and posterior layer of abdominis and posterior layer of internal oblique.internal oblique.

• All aponeuroses fuse in the All aponeuroses fuse in the midline – midline – linea alba.linea alba.

• In the midline, it contains the In the midline, it contains the umbilical ring. A defect where umbilical ring. A defect where fetal umbilical vessels pass to fetal umbilical vessels pass to the placenta. the placenta.

• Splitting of internal oblique, Splitting of internal oblique, lateral to rectus abdominis – lateral to rectus abdominis – semilunar line.semilunar line.


• Posterior wall ends slightly below the umbilicus – Posterior wall ends slightly below the umbilicus – arcuate line of arcuate line of Douglas.Douglas.

• The rectus abdominis is covered by the transversalis fascia posteriorly.The rectus abdominis is covered by the transversalis fascia posteriorly.

CONTENTS OF THE RECTUS SHEATHCONTENTS OF THE RECTUS SHEATH

• Contents of the Rectus Contents of the Rectus Sheath.Sheath.– Rectus abdominis Rectus abdominis

musclemuscle– PyramidalisPyramidalis– Superior & inferior Superior & inferior

epigastric vesselsepigastric vessels– Intercostal nerves Intercostal nerves

(T7-T11)(T7-T11)

ENDOABDOMINAL FASCIAENDOABDOMINAL FASCIA

• A membranous and areolar sheets.A membranous and areolar sheets.

• Named according to muscle or Named according to muscle or aponeurosis it lines.aponeurosis it lines.

• Transversalis fascia as it lines the Transversalis fascia as it lines the transversus abdominis muscle.transversus abdominis muscle.

• A variable amount of fat separates the A variable amount of fat separates the fascia above from the peritoneum – fascia above from the peritoneum – extraperitoneal fat.extraperitoneal fat.

• Peritoneum – a single layer of Peritoneum – a single layer of epithelial cells and connective tissue.epithelial cells and connective tissue.

NERVES OF THE ANTEROLATERAL ABDOMINAL WALLNERVES OF THE ANTEROLATERAL ABDOMINAL WALL

• (1) thoracoabdominal (1) thoracoabdominal nerves (T7 – T11)nerves (T7 – T11)

• (2) Subcostal nerve (2) Subcostal nerve (anterior ramus of T12)(anterior ramus of T12)

• (3) Iliohypogastric(3) Iliohypogastric

• (4) Ilioinguinal(4) Ilioinguinal

VESSELS OF THE ANTEROLATERAL ABDOMINAL WALLVESSELS OF THE ANTEROLATERAL ABDOMINAL WALL

• (1) superior epigastric artery (1) superior epigastric artery

• (2) musculophrenic artery (2) musculophrenic artery

• (3) 10(3) 10thth & 11 & 11thth post intercostal post intercostal arteriesarteries

• (4) subcostal artery(4) subcostal artery

• (5) inferior epigastric(5) inferior epigastric

• (6) deep circumflex iliac(6) deep circumflex iliac

• (7) superficial circumflex iliac(7) superficial circumflex iliac

• (8) superficial epigastric (8) superficial epigastric

VEINS & LYMPHATICS OF THE ANTEROLATERAL ABDOMINAL WALLVEINS & LYMPHATICS OF THE ANTEROLATERAL ABDOMINAL WALL

• (1) Subcutaneous venous plexus(1) Subcutaneous venous plexus

• (2) Paraumbilical veins(2) Paraumbilical veins

• (3) Lateral thoracic vein(3) Lateral thoracic vein

• (4) Superficial epigastric veins(4) Superficial epigastric veins

• (5) superficial circumflex iliac(5) superficial circumflex iliac

• (6) superior & inferior epigastric(6) superior & inferior epigastric

• (7) deep circumflex iliac (7) deep circumflex iliac

• (8) posterior interocstal (11th) & (8) posterior interocstal (11th) & subcostal veinssubcostal veins

FUNCTIONS OF THE ABDOMINAL MUSCLESFUNCTIONS OF THE ABDOMINAL MUSCLES

• Form a strong expandible Form a strong expandible support for the wallsupport for the wall

• Support organs from injuriesSupport organs from injuries

• Compress to increase Compress to increase intraabdominal pressure to intraabdominal pressure to facilitate expulsionfacilitate expulsion

• Move trunk to maintain postureMove trunk to maintain posture

• Assists in breathingAssists in breathing

study of human anatomy. anatomy of the abdomen definition of abdomen a region of the body bounded by...

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