Equine Skeletal System

1. Equine Skeletal System By Jess and Keara

2. What bones are made of?

3. Periosteum • fibrous membrane rich in blood vessels that envelopes the bone, except at the articular surfaces; it contributes especially to the bone’s growth in thickness. *(articular surface= the surface of a joint at which the ends of the joint meet)

4. Compact Bone • dense bone tissue composed of osteons, which resist pressure and shocks and protect the spongy tissue; it forms especially the diaphysis of the long bones.

5. Haversian Canal Osteon • Elementary cylindrical structure of the compact bone made up of four to 20 concentric bone plates that surround the Haversian canal. • Lengthwise central canal of the osteon. It encloses blood vessels and nerves.

6. Spongy Bone • Tissue made of bony compartments separated by cavities filled with bone marrow, blood vessels and nerves • This structure gives bones their lightness.

7. Medullary Cavity • Cylindrical central cavity of the bone containing the bone marrow • Encloses lipid-rich yellow bone marrow • Soft substance contained in bone cavities, • producing blood cells; • marrow is yellow in the long bones of adults. Bone Marrow

8. Volkmann’s Canal • Transverse canals of the compact bone enclosing blood vessels and nerves; • Connect the Haversian canals with each other and with the medullary cavity and the periosteum Blood Vessel • Channel in the bone through which the blood circulates, carrying the nutrients and mineral salts the bone requires

9. Articular Cartilage • Smooth resistant elastic tissue covering the terminal part of the bone where it articulates with another bone • it facilitates movement and absorbs shocks

10. Connective Tissue

11. Ligaments • Link bones • Sheets of strong, fibrous connective tissue • Identical to tendons in muscular system • Only difference is there function • Ligaments attach bone to boneand tendons attach muscleto bone

12. Cushioning… • Cartilage • Smooth resistant elastic tissue covering the terminal part of the bone where it articulates with another bone • it facilitates movement and absorbs shocks • Synovial Fluid • Small membranous sacks that contain fluid and rest between bones of a joint, i.e., above coffin bone • Helps to cushion and absorb shock

13. Joints

14. Types • Fibrous • Cartilagenous • Synovial

15. Fibrous • Immoveable! • Ex, plates in skull

16. Cartilagenous • Partially moveable • Connected by cartilage • Ex, joints between vertebrae

17. Synovial • Completely moveable • Hinge • Joint between 3rd metacarpal and long pastern • Ball and Socket • Joint between ilium and femur (hip joint)

18. Can you name the bones? We’ll see…

19. Skull

20. What makes up the mouth… • Premaxilla (incisive bone) • Holds alveoli for upper incisive teeth • Maxilla • Holds alveoli for molar and premolar teeth • Mandible (lower jaw) • Holds alveoli for all teeth of lower jaw

21. And all the rest….

22. Bones of the Middle Ear • Malleus~ Hammer • Incus~ Anvil • Stapes ~Stirrup

23. Spine • Cervical vertebrae • Thoracic vertebrae • Lumbar vertebrae • Sacrum • Coccygeal/ caudal vertebrae

24. Cervical Vertebrae • Make up the neck of the horse • 1st cervical vertebrae = Atlas • 2nd cervical vertebrae = Axis • Allows neck to flex and rotate

25. Thoracic Vertebrae • 18 • Characteristically have high spines • 3rd and 4th form the withers

26. Lumbar Vertebrae • 6 • Characteristically long and flat

27. SacrumCoccyx • Made up of 6 sacral vertebrae fused together (*not mentioned in video but comes right after lumbar vertebrae and before the caudal) • Made up of 15-21 coccygeal Vertebrae. (More commonly known as the Caudal Vertebrae.)

28. Ribs and Sternum • 18 pairs of ribs • First 8 pairs connect to the sternum • Sternum ~ breast bone • Made up of 6-8 sternebrae and cartilage

29. Foreleg

30. Shoulder bones connected to the…. • Scapula • Humerus • Radius • Ulna (not functional in a horse)

31. From the wrist distally… • Carpus • Forms what is commonly called the knee in a horse • Metacarpus • 3rd metacarpal, or cannon bone, is the only functional metacarpal • Splint bones – 2nd and 4th metacarpal • Small bones running parallel to the cannon bone on either side *** splints is a condition when a splint bone sustains a fraction

32. Fingers??? • Technically referred to as phalanges • 1st Phalange ~ Proximal Phalanx ~ Long Pastern • 2nd Phalange ~ Middle Phalanx ~ Short Pastern • 3rd Phalange ~ Distal Phalanx ~ Coffin Bone

33. Can you name them?

34. Hind Leg

35. Pelvic Girdle • Os Coxae ~ half of the pelvic girdle • 3 bones • Ilium • Ischium • Pubis

36. Hip bone’s connected to the … • Femur • Patella ~ knee cap • Crus = Fibula + Tibia • Fibula isn’t functional; fuses along the length of the tibia

37. Now you know the bones……Can you name all 205-210 of them?

38. While you were learning all about the bones of a horse, did you notice any similarities between a horse’s skeleton and a humans?

39. Here are just a few… • We have almost the exact number of bones as horses • Horses’ forelegs are almost identical to our arms in position, the only real difference being the elongation of the bones that make up our wrist, hand and fingers in the horses’ knee, lower leg (cannon), ankle and hoof

40. Differences • The main differences between a horse’s skeleton and a human’s skeleton come from a horse being a quadraped while humans are bipeds • This changes the angle of the limbs in relation to the spine, the length of the neck, and the shape of the head • Horses’ being prey animals and humans predators also affects the skull; a horse’s orbits are laterally positioned because they are monocular, and their jaw is longer to provide for the powerful molars they use to chew their fibrous diet

41. the end Oh my bones!!!!!!!!!! ………xd

42. Sources • http://visual.merriam-webster.com/human-being/anatomy/skeleton/structure-long-bone.php • http://www.besthealth.com/besthealth/bodyguide/reftext/html/skel_sys_fin.html#joints • http://www.teachpe.com/anatomy/joints.php • http://www.yourveterinaryclinic.com/page7/page8/skeleton-horse.html