ANAT301 ABDOMEN 1

Partitions of the Abdomen •

 Abdomen topographically described using:

 • Partitions into 4 quadrants

 • Partitions into 9 regions

 • Partitions serve as landmarks for identifying organs & other structures of abdomen

 • Example: appendix is located on the lower right quadrant

Quadrant Partitions:

-Sagittal midline (median) plane – vertical imaginary line

-Trans-umbilical (transverse) plane – horizontal imaginary line, intersects sagittal plane

-Intersection = through the umbilicus between the L3 & L4 vertebral levels

•Divides abdomen into 4 quadrants:

-Right upper quadrant

-Right lower quadrant

-Left upper quadrant

-Left lower quadrant

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Regional Partitions

 • Divides abdomen into even smaller sections

 • Lines involved 2 imaginary vertical planes & 2 imaginary horizontal planes:

 • Vertical planes Paired, correspond to the midclavicular lines -which descend to mid-inguinal point

 • Subcostal (upper horizontal) plane inferior to the costal margin, through level of L3.

 • Transtubercular (lower horizontal) plane between the two tubercles of the iliac crest, through the level of L5

Regional Partitions

 • Names of regions on the left & right sides

  • Hypochondriac Regions

  • Lumbar Regions

 -Iliac Regio

• Names of regions in the middle

- Epigastric Region

  • Umbilical Region

  -Hypogastric Region

 • Mnemonic: Hector Loves Isabel Every Unceasing Hour

@@Surface Anatomy@@

 Abdomen is bounded by:

  • Caudally ilium & pubic bone of the pelvis

  • Anteriorly abdominal wall musculature

  • Posteriorly bounded lumbar vertebrae (L1-L5)

• In the ant. median plane the abdominal wall extends from the xiphoid process (T9) to pubic symphysis (level of coccyx)

• Superolateral margins -costal margins formed by the 7-10thcostal cartilages

 • Subcostal plane - transverse margin passing through the lowest part of the costal margin

• Infra-sternal/subcostal angle - between the R & L costal margins where the xiphoid process is found in its depression (T9).

Surface Anatomy

 • Abdomen is divided into right & left by a vertical groove marking the location of the Linea alba

• Umbilicus - irregular depression central to the median furrow

• Linea semilunaris- curved vertical groove lateral, corresponds with the lat. margins of the rectus abdominis muscle

 • Transverse furrows(3) -correspond with the tendinous intersections of the rectus abdominis muscle