Necropsy Procedures for Laboratory Animals

Abstract

Necropsy is the ultimate diagnostic destiny of most of the experimental animals. Necropsy is the systematic dissection of an animal after death, to establish the cause of disease by macroscopic and microscopic examination of tissues. Necropsy facilitates the conduct of appropriate serologic and microbiologic examinations and harvest of tissues and organs for histological evaluations. The necropsy and histology data are pivotal in laboratory animal research, toxicology, and pathology.

Appendix 1: Necropsy Lexicon

Localization		Findings		Distribution	Color/appearance	Consistency	Size/number	Shape
Left lateral lobe	Entire body surface	Abdominal size	Failed to collapse	Anterior	Black-brown	Soft	Enlarged	Round
Right lateral lobe	Fur	Abnormal shape	Focus(i)	Posterior	Clay-colored	Firm	Small	Rounded edges
Median lobe	Skin	Abnormal content	Gas-filled	Dorsal	Gray-white	Hard (reserved for mineral and bone)	Pinpoint	Elongated
Caudate lobe	Head region	Abnormal consistency	Foreign body/material	Ventral	Green	Flaky	Number (give number up to 5)	Oval
Right cranial lobe	Sub cutis	Abrasion(s)	Fracture/broken	Internal	Liver-colored	Friable	if more than 5 use >5	Linear
Right middle lobe	Panniculus muscle	Absence of hair	Hair loss	External	Tan	Pasty	<1 mm	Tortuous
Right caudal lobe	Eye region	Abscess(es)	Hernia	Cephalic	Red	Clumped/ caseous	1––3 mm	Lobulated
Right accessory lobe	Eyelid	Accentuated lobular pattern	Hyperinflation	Cranial	Yellow	Gelatinous	3––5 mm	Pedunculated
Left lobe	Nose region	Adhesion(s)	Ingesta-filled	Caudal	Orange	Grainy/granular	0.5––1 cm	Irregular
Left cranial lobe	Nostril	Autolysis	Intussusception	Well demarcated	Blue	Gritty	1––3 cm	Nodular
Left middle lobe	Cheek region	Calculus(i)	Lactating	Poorly demarcated	Purple	Foamy	3––5 cm	Cavernous
Left caudal lobe	Flank	Callus	Mass(es)	Focal	White	Thick	>5 cm
All lobes	Abdominal region	Cannibalized	Nodule(s)	Multifocal	Pale	Watery	<5 cm
Visceral surface	Inguinal region	Concretions	Not present	Diffuse	Opaque	Brittle
Parietal surface	Anal region	Contracted	Opacity	Center/central	Cloudy	Clotted
Phrenic surface (diaphragmatic)	Perianal region	Crust	Organ obscured by lesion	Periphery/peripheral	Translucent	Crepitant
Margin	Scrotum	Cyst	Parasite		Clear	Dry
Entire surface	Vulva	Deformity	Perforation		Mottled	Moist
Papillary process	Forelimb	Depressed area	Prolapse		Multi-colored	Smooth
Cranial pole	Hind limb	Displacement	Raised area/plaque		Dark	Rough
Caudal pole	Tip of tail	Dilatation	Rupture			Mucous/mucoid
Greater curvature	Base of tail	Discoloration	Scab			Viscous
Lesser curvature	Entire tail	Discharge	Scar			Stringy
Capsule	Mandibular region	Distended	Soiled			Rubbery
Cortex	Ear region	Diverticulum	Sore			Shiny
Medulla	External ear canal	Erosion	Torsion			Dull
Papilla	Auricle	Emaciation	Thickened
Cortico-medullary junction	Atrial appendage	Feces-filled	Undescended testis/testes
Pelvis	Ventricle	Fissure(s)	Urine-filled
Renal adipose tissue	Mucosa	Fistula	Vascularization
Hilus	Serosa	Fluid
	Lumen	Fluid-filled