Tuesday, October 21, 2008


The histological remains of an embryonic chicken undergoing endochondral ossification is quite a beautiful site. (The images come from Dr. Thomas Caceci, who details the properties of bone formation as part of a histology course.)

The Chicken in the Egg

Using specialized staining techniques, this skeleton takes on two very contrasting colors as a result of the cellular make up in the various structures. The dark red is calcified or hardened bone whereas the lighter blue shows cartilaginous features that are not yet bone.

Through this process of bone formation from cartilage, bones elongate and like animals, we grow. In adulthood, this image would have a stark contrast where the majority would appear to be stained red. Looking at the junction of bone and cartilage, we enter the world of histology.


Affectionately called "histo," this course in cellular anatomy is rather beautiful. At first exposure it is difficult to see past the bubbly circles, fancy colors, and wavy lines. The meanings of each are crucial to understanding what you see in the microscope. When the initial shock of looking at what appears to be the drawing of a toddler, it is actually exciting to understand the defining features of a histology slide. Perhaps it is the nerd in me, however, this is where we see photographs of medical pathologies.

This is what we commonly view when we are attempting to identify and study structures. This image captures the border between the hard bone and the soft cartilage (aka. the epiphyseal plate). A close look would show the cartilage cells maturing as they progress towards the bony portion.

We study skin, glands, bones, and every other part you could imagine. Each has identifying characteristics that "tell a story." Not all stains are created equal and a variety of colors are available to bring out unique attributes in each slide.

Physicians use histology for the purpose of finding illness or its causes. Muscle histology for example is performed from a muscle biopsy or sample and can be used to diagnose specific diseases identifiable in the specimen. Histology jobs are common in laboratories as many tests will determine the doctor's treatment.


Many great resources are available if you are looking to brush up on your cellular knowledge or simply enjoy unique images. A microscope and expensive slides are not necessary. Histology atlases and other texts have phenomenal photographs that may be interesting even if you are not taking a course. To think that our bodies are made up of such tiny structures that are vital to proper functioning is mind-boggling.


  1. Cool, I really like anatomy, and I think histology might be a way to go further with that. Good post.

  2. Cud you suggest a method to study the skeletal structure of newly hatched chicken. Normal x-ray pics dont look colorful like the stained ones you have posted here.


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