Subcostal plane

The subcostal plane refers to a horizontal (or transverse) plane which lies just below the level of the costal margin, i.e., connecting the 10th costal cartilages of right and left sides with each other. Posteriorly, the position of subcostal plane equates to the body of the third lumbar (L3) vertebrae.

Please note that our abdomen is artificially divided into nine regions by imaginary planes. These include wo horizontal (superior and inferior) and two sagittal (right and left) planes. Of the horizontal planes the upper transverse plane is formed by either the subcostal plane or the transpyloric plane, while the lower horizontal plane is intertubercular (interconnecting the tubercles of iliac crest on right and left sides). The two sagittal planes extend vertically on right and left sides, connecting the mid-clavicular point with the middle of the inguinal ligament on either side. This regional division of abdomen makes it convenient to describe the location of viscera and the pathological lesions associated with them.

Of the nine abdominal regions, the three in the midline include the epigastric, umbilical and hypogastric (or suprapubic) regions. Epigastric is bounded on either sides by right and left hypochondrium. The umbilical is sandwiched between the right and left flank regions. Lastly, the suprapubic region is surrounded by groin or inguinal regions on its right and left sides.