Chapter VIII. Embryology or Development of the Foetus 81
PREFACE
There are a number of excellent works on Veterinary Anatomy, and many of them will amply repay the student for the time taken to master them, but for quick reference none seem to contain the wants of the veterinary practitioner and student for which this humble little work is primarily intended.
It has been my endeavor to briefly describe each organ as found in the healthy animal; its functions, etc., in a condensed yet complete form. I am positive that the student or veterinary practitioner will find its pages highly instructive as well as profitable and interesting.
In compiling this work a few authorities have been consulted and quoted, while it has not been practical to give individual credit for the use of ideas and language, a general acknowledgement is here made:
Veterinary Science, Hodgins and Haskett.
Veterinary Anatomy, Strangeways.
CHARLES J. KORINEK, V. S.
DESCRIPTIVE ANATOMY
Osteology is a term applied to that section of descriptive anatomy which treats of the bones. _Arthrology_, to the consideration of the joints or modes of union between the bones, while by _Myology_ is meant the doctrine of the muscular system. _Splanchnology_ treats of the viscera, _Angiology_ of the circulatory and absorbent systems. _Neurology_ deals with the nervous system. _Aesthesiology_ with the organs of sense; while _Embryology_, as before stated is the consideration of the animal frame at periods preceding its birth.
In this work the various departments are discussed in the order here given. The structures which are the subject of the first three divisions are sometimes classed together as the _Organs of Locomotion_; for bones form the frame work of the body and often act as levers; the joints connect the bones, permitting more or less motion between them; while the muscles move the bones, and so produce motion of a part of the body--or it may be locomotion, or change of situation in the entire frame.
In the study of comparative Anatomy the terms _analogy_ and _homology_ are frequently met with. Although these words are unfrequently used indiscriminately, the following differences should be noted. Organs are said to be analogous when, though differing in structure, they perform the same function; but when their functions are different, which, in the broad sense, they correspond in structure or form, they are said to be homologous. Thus the middle finger of the human hand is the homologue of the anterior (front) digit of a horse, because they have the same general structure, and relation to the rest of the limb; but as the functions they perform are quite dissimilar, they cannot be termed analogous. Again, the lungs of a mammal are analogous to the gills of a fish, for, though they differ widely in structure, position and form, and are therefore not homologous, their ultimate use is the same--each of them being an apparatus in which is carried on the process of purifying the blood.
DISSECTION.
Students must dissect as many animals as possible, so as to familiarize themselves with the _frame work or structure_, and the location of the _digestive, nervous and blood systems_, as it will aid materially in the art or process of determining the nature of various diseases.
During cool weather an animal for dissecting purposes can be kept for a considerable length of time without preservatives
It is well to have a copy of Anatomy at hand when dissecting for it will show the location of the various organs and explain their functions.
EXPLANATION OF PLATE I
SKELETON OF THE HORSE
1. Skull, or skeleton of the head. 2. Cervical vertebræ or neck bones. 3. Dorsal vertebræ or back bones. 4. Lumbar vertebræ or loin bones. 5. Sacral vertebræ or rump bones. 6. Coccygeal vertebræ or tail bones. 7. Pelvic or hip bones. 8. Sternum or breast bone. 9. Ribs. 10. Scapula or shoulder blade. 11. Humerus or shoulder bone. 12. Radius or bone of the fore-arm. 13. Ulna or bone of the fore-arm. 14. Carpus or bones of the knee. 15. Os Melacarpi Magnus, metacarpal, or cannon bone. 16. Ossa Melacarpi Parva, or splint bones. 17. Proximal Phalanx, os suffraginis, or large pastern bone. 18. Great Sesamoid Bones. 19. Medium Phalanx, os coronæ, or small pastern bone. 20. Distal Phalanx, os pedis, or coffin bone. 21. Os Naviculare, small sesamoid, or shuttle bone. (This bone can be plainly seen Plate VII). 22. Femur, or thigh bone. 23. Patella, or stifle bone. 24. Tibia, or leg bone. 25. Fibula. (This bone is little developed in the horse.) 26. Tarsus or hock bones. 27. Metatarsus, or os metatarsi magnus. 28. Ossa Metatarsi Parva, or splint bones of the hind leg.
Names of joints placed according to numbers.
I. Shoulder Joint. II. Elbow Joint. III. Carpus or knee joint. IV. Fetlock Joint. V. Pastern Joint. VI. Coffin Joint. VII. Hip Joint. VIII. Stifle Joint. IX. Tarsus or hock joint.