8.3 Large Animal Anatomy

Overview

Anatomical terms in large animal medicine are very important to help describe the location of injuries, so it is crucial to have a general knowledge of these topographical markers. Many of the terms are used across large animal species, but a few are more commonly used in some species than others.

The general layout of the skeleton of large animals is very similar to the human skeleton. The table below lists anatomical terms for large animals, along with their human counterpart. One of the main differences between ungulates and humans is the number of toes and fingers. Horses stand on the equivalent of our middle finger while cows, sheep, goats, and pigs stand on the equivalent of two fingers.

From Head to Toe

The following table discusses some of the common anatomy landmarks you will hear in large animal medicine and some of the species they are commonly used for.

If “all” is used in the “Common Species” column, it means this term is used in cattle, horses, sheep, goats, and pigs.

Anatomical Term Common Species Definition
Muzzle Horses, cows, sheep, goats The most rostral portion of the head; the nose and lips
Snout Pigs The nose
Poll Horses, cows, sheep, goats Most dorsal aspect of the head
Forelock Horses Portion of the mane that extends over the face
Mane Horses Longer, coarser hair growing from the dorsal aspect of the neck
Crest Horses, cows, sheep, goats Dorsal aspect of the neck
Withers Horses, cows, sheep, goats Highest point of the back, where the neck meets the back
Shoulder All Equivalent to human shoulder

Joint where the scapula (shoulder blade) meets the humerus (front limb)
Elbow All Equivalent to human elbow

Joint where the humerus meets the radius and ulna (front limb)
Knee/carpus All Equivalent to the human wrist

Carpus is the name of the joint, but it is colloquially referred to as the “knee” in ungulates (front limb)
Cannon bone Horses Equivalent to the human hand or foot bone extending from the wrist or ankle to the knuckles or toes

Bone extending from the carpus towards the fetlock

This term is used on all four limbs
Fetlock All Equivalent to human joint between hand/foot bones and finger/toe bones

This term is used on all four limbs
Pastern Horses Length of the limb between the fetlock and the hoof, on all four limbs
Coffin bone Horses Bone equivalent to human’s most distal finger/toe bone

This bone is encapsulated within the hoof

Term used in all four limbs
Flank All Lateral aspect of the caudal trunk of the body
Hook Cows, sheep, goats Cranial protruding aspect of the pelvis
Pin Cows, sheep, goats Caudal protruding aspect of the pelvis
Tail All Anatomy differs depending on species, but in general caudal extension of spine +/- extra hair
Dock Sheep Refers to a sheep’s tail that has been surgically removed
Stifle All Equivalent to human knee

Joint between the femur and the tibia/fibula (hind limb)
Hock/tarsus All Joint equivalent to human ankle

Tarsus is the name of the joint, but it is colloquially referred to as the “hock” in most animals (hind limb)
Dewclaw Pigs, cows, sheep, goats Two residual “toes” extending from the fetlock. Non-weight-bearing
Udder Horses, cows, sheep, goats Collection of mammary glands on the caudal-ventral portion of the body
Teat All Duct from the udder for milk to be excreted (nipple)
Sole All Underside (palmar/plantar) aspect of the hoof

This term is used in all four limbs

Other species-specific terms you might hear include:

  • Horns: Part of the integumentary system – hard protrusions from the heads of certain cows, goats, and sheep
  • Wool: Specialized term for the thick curly hair of a sheep
  • Frog: Triangle of soft tissue on the underside of a horse’s hoof used for cushioning and balance

 

Comparative Anatomy – Horses vs. Humans

Animals and humans share the same general skeletal layout. In Figure 8.2, the bones are colour-coded to show how the skeletons compare.

 

Figure 8.2 Comparison between full equine and human skeleton
Figure 8.3 Bones of the human hand

 

Figure 8.4 Bones of the cow and horse forelimb, colour-coded to the human hand

 

Figure 8.5 Bones of the distal hindlimb of a horse and a cat

Cattle

The following images will show the locations of the terms discussed above on both a diagram and a picture of a cow.

Figure 8.6 Anatomical terms for a cow

 

Organ locations

The internal organ systems were discussed in Chapters 3 and 4, so here is a model showing where those organs are located inside the body of a cow.

Figure 8.7 Internal organs of a cow
Figure 8.8 Skeleton and internal organs of a cow

Sheep

The following image will show the locations of the terms discussed above on an image of a lamb.

Figure 8.9 Anatomical terms for a lamb. Note: This lamb’s tail has NOT been docked, therefore we do not call it a dock.

Goats

The following image will show the locations of the terms discussed above on an image of a goat.

Figure 8.10 Anatomical terms for a goat

Horses

The following image will show the locations of the terms discussed above on an image of a horse.

Figure 8.11 Anatomical terms for a horse
Figure 8.12 Anatomical terms for a horse’s hoof

Skeletal Follow-Up

 

Figure 8.13 Horse skeletal system

Pigs

The following images will show the locations of the terms discussed above on both a diagram and a picture of a pig.

Figure 8.14 Anatomical terms for a pig

 

Exercises

 

Image Credits (images are listed in order of appearance)

Comparative view of skeletons of man and horse adapted by Mcapdevila, CC BY 3.0.

Scheme human hand bones by Mariana Ruiz Villarreal, CC0.

Various nail walkers’ toes by Ineuw, CC0.

Hock (PSF) by Pearson Scott Foresman, CC0.

Holsteiener BRW by Les Meloures, CC BY-SA 3.0.

Vintage Holstein cow by Unknown, CC0.

Modelo didatico bovino correto alt by Museum of Veterinary Anatomy FMVZ USP, CC BY-SA 4.0.

Didactic model of a cow by Museum of Veterinary Anatomy FMVZ USP, CC BY-SA 4.0.

Labelled sheep by Matéa David-Steel, NorQuest College. Used with permission.

Fluttering Bird, a Nigerian dwarf dairy goat by HeatherLion, CC BY-SA 3.0.

Tori horse universal by Rozpravka, CC0.

Sabot saint by Zorgglob, CC0.

Horseanatomy by WikipedianProlific, CC BY-SA 3.0.

Truie landrace by Zeilog, CC BY-SA 3.0.

Line art drawing of a hog by Unknown, CC0.

Overview of sheep and lamb in fence near Hostákov, Vladislav, Třebíč District by Frettiebot, CC0.

Haflinger horse on pasture in the Netherlands by Paula Jantunen, CC0.

 

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Introduction to Veterinary Terminology Copyright © by Kelly Robertson, RVT and Dr. Matéa David-Steel, DVM is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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