Texas Marine Mammal Stranding Network

Dedicated to the conservation of marine mammals through rescue and rehabilitation, research and education.

Pathology Training 101

A very simple introduction to the terminology of a necropsy.

This first lesson will introduce the terms which are useful for descriptions of lesions and preparing a necropsy report. This list should be an invaluable addition to your field kit and will be beneficial to anyone doing a necropsy.

1. Always give the size (length and mass [if possible]), age, sex, type of animal, nutritional condition, and degree of composition.

2. Always do the necropsy the same way and in the same order. Use checklists and protocols to prevent omissions. If no lesions are observed in a particular tissue, indicate that. Summarize gross findings.

3. As you are doing the necropsy, ask yourself:

Is it normal?
Is it an artifact?
Is it postmortem autolysis?
Is it a parasitic lesion?
Is it a lesion of significance?

Ultimately you are going to describe Where is it?, How bad is it? and What is it?

All lesions should be described as to location, color, shape, size, consistency, and number or percent involvement of the organ.

The Terms of the Trade:


Dorsal: directed towards the back surface
Ventral: directed towards the abdominal surface
Caudal: situated more toward the hind end
Cranial: situated more toward the head end
Proximal: nearer to the point of reference, attachment or origin
Distal: farther from the point of reference
Medial: situated toward the medial plane
Lateral: situated away from the medial plane

Use primary colors with more specific descriptors such as dark, bright, light, pale, mottled etc.

Use metric units in three dimensions.

Use descriptive terms:

Nodular: rounded
Piriform: pear-shaped
Crescent: quarter moon shaped
Filiform: thread shaped
Fungiform: mushroom shaped
Spherical: round
Elliptical: not a perfect sphere
Reticular: net-like
Serpentine: coiled, twisted, winding
Tortuous: twisted, winding
Undulate: wavy
Lobulated: divided into lobules
Sessile: wide base
Pedunculated: narrow base
Crateriform: umbilicated
Ovoid: egg shaped
Discoid: disc or dome shaped
Pyramidal: pyramid shaped
Conical: cone shaped
Botryoid: shaped like a bunch of grapes
Lingulate: tongue shaped
Fusiform: spindle shaped
Stellate: star shaped
Polypoid: polyp shaped

Consistency and Texture:

Very important in the evaluation of the lungs (if it is firm, it probably indicates pneumonia). Important in other organs as well.
Soft: as your lips
Firm: as your nose
Hard: as your forehead
Resilient: springs back
Fluctuant: a wave-like motion
Gritty: sandy
Granular: grainy (small solid particles)
Inpissated: dried up

Number and Extent:
If number is 10 or less - give exact number. Otherwise use dozens or hundreds as appropriate. In cases of pneumonia, liver disease and in cases where portions of other organs are affected indicate the percentage of the organ that is involved.

The quantity and nature of the contents of any cavity should be described (color, odor, and consistency) and the volume of material indicated.

Diffuse: affects virtually the entire organ.
Focally Extensive: affects a large confluent area.
Multifocal: multiple small discrete areas are affected.

The cranial ventral 1/3 of the right lung is dark red and firm.
Beginning at a point 10 cm from the stomach and extending for 1 meter, the small intestine is twice normal size, dull yellow to brown, and gas-filled. Diffusely, the serosal surface is covered by a 2-3 cm thick layer of a light yellow, homogeneous, tacky material. The wall of the intestine is of normal thickness but is dark red. In addition to the gas, the lumen contains a dark brown to black watery, foul smelling fluid.

Back to Pathology Reports