Anatomical body planes

In the last post we covered the anatomical terms for directions. Now we'll discuss planes - not the flying kind, but planes that divide the body into two. Planes can be important when considering medical imaging, embryology (how an embryo develops) and descriptions of body motion.

Please note that different terminology seems to be used about humans and about non-human animals. Here I focus on the terminology used about animals.

Median plane: Median plane divides the body into the right and left half, exactly from the center. 

Sagittal plane: If one divides the body just off the median plane, that would be called a sagittal plane. It still divides the body into right and left, but not from the center. The halves are not identical anymore.

Dorsal plane: Dorsal plane divides the body to dorsal and ventral areas, cutting lenghtwise through the midsection of the body.

Transverse plane: Transverse plane is a local plane, meaning that it's in the right angle to the axis of the thing we're looking at. If you're looking at a leg, the transverse plane would go from the front of the leg to the back, at the right angle to the leg itself. If you're looking at the body, the transverse plane is from the back to the stomach (at a right angle to the spine).

The planes are used when talking about the entire animal. When talking about a skeleton, two more distinctions can be made. Now we'll have axial skeleton, which comprises of the head, the vertebral column (spine) and the ribcage. Ventrally to the axial skeleton is the appendicular skeleton, comprising of the limbs.