Skeletal System

1. Skeletal System Introduction to Veterinary Science

2. The Musculoskeletal System The musculoskeletal system consists of two systems that work together to support the body and allow for movement of the animal: the skeletal system = bones, joints, cartilage, and various connective tissues the muscular system = muscles and various connective tissues

3. What is the function of bone? • Bone helps with: • Movement • Support • Protection • Blood cell formation

4. Bones Bones start as cartilage and fibrous membranes that harden into bone before birth. The formation of bone from fibrous tissue is known as ossification. Osteoblasts produce bone tissue Osteocytes maintain bone tissue Osteoclasts break or phagocytize bone tissue Bones build up and break down throughout life and has ability to repair and heal.

5. Important Terms Related to the Skeleton The skeleton can be divided into two parts • Axial Skeleton • Appendicular skeleton

6. Other Important Terms, Con't. • Joints—points where two or more bones meet. • Cartilage • protects the ends of bones • provides a cushion

7. Other Important Terms, Con't. • Ligament—Tough band of connective tissue connecting one bone to another. • Tendon—Thick band of connective tissue that attaches muscle to bone.

8. Types of Bone • Bone is one of the hardest tissues of the body • Connective tissue • Only thing harder-tooth enamel • Compact Bone—layer of protective hard bone tissue surrounding every bone • Cancellous Bone—soft bone filled with many holes and spaces surrounded by hard bone.

9. Combining forms for Bone • Oste/o • Oss/e • Oss/i • Osteoarthritis • Ossification

10. Classification of bones • Long bones • Short bones • Flat bones • Irregular Bones

11. Long Bone Long bones consist of a shaft, two ends, and a marrow cavity. Femur Humerus Tibia Radius

13. Red bone marrow is hematopoietic and is found at the ends of long bones and in flat bones (hemato-blood/ -poietic pertaining to formation) • Red bone marrow produces red blood cells, white blood cells, platelets • Yellow bone marrow replaces red bone marrow (mostly fat cells)

14. Flat bones - thin flat bones: pelvis, ribs, scapula, bones of the skull • Flat bones are made up of a layer of spongy bone between two thin layers of compact bone

15. Short bone- cube shaped, no marrow • Carpal bones • Tarsal Bones

16. Pneumatic bones- sinus containing bones (frontal)

17. Irregular Bones • Vertebrae-make up the spine • Sesamoid bones- small, embedded in a tendon: • Dog: patella, fabellae (2) • Horse: proximal sesamoids (2) and navicular bone

19. FACT: • The average dog has about 320 bones… 134 in the axial skeleton- the skull has 50 flat bones! 186 in the appendicular skeleton The average horse has about 205 bones

20. Bones of the Axial Skeleton The axial skeleton protects the major organs of the nervous, respiratory, and circulatory systems. • Skull • Vertebrae • Ribs • Sternum

21. Cranium Bones and Face Bones Occipital bone • Occipital • Parietal • Frontal • Temporal • Zygomatic Arch • Nasal • Incisive parietal frontal Zygomatic arch nasal incisive

24. Short, Average, Long

28. Vertebral Column The vertebral column supports the head and body and provides protection for the spinal cord. The vertebral column is comprised of individual bones called vertebra. The combining forms for vertebra are spondyl/o and vertebr/o. Vertebrae is the plural form. Horse C7 T18 L6 S5 Cd 15-21 Dog C7 T13 L7 S3 Cd 20 Cat C7 T13 L7 S3 Cd 14-23

29. Parts of a Vertebra Vertebrae are divided into parts: body arch lamina vertebral foramen processes spinous process transverse process articular process

30. Other Axial Skeleton Parts Ribs Combining form is cost/o. Are flat bones Attached by cartilage Purpose to protect Sternum Manubrium, body, xiphoid sternebrae xiphoidprocess (caudal-most sternebra) Flat bones and cartiligenous Make up the boundaries of the thoracic cavity (protects heart and lungs)

31. Bones of the Appendicular Skeleton • The appendicular skeleton includes the bones of the front and hind limbs • Front Limb • Scapula • Humerus • Radius • Ulna • Carpal bones • Metacarpal bones • Phalanges

32. Hind Limb • Pelvis • Femur • Tibia • Fibula • Tarsal bones • Metatarsal bones • Phalanges

33. The Appendicular Skeleton Front limb scapula clavicle humerus radius ulna carpal bones metacarpal bones cannon bone in livestock Phalanges Differ in dog, horse, ungulates (cloven hoof)

34. Forelimb • Scapula (Ball and socket joint) • Humerus • Radius and Ulna • Carpal Bones • Metacarpals • Phalanges

35. Ball and Socket joint Scapula and Humerus – Point of Shoulder

36. “Elbow” joint Hinge joint between Humerus and the Radius/ Ulna AND Pivot Joint

37. The Appendicular Skeleton Phalanx names: Proximal = long pastern bone in livestock Medial = short pastern bone in livestock Distal = coffin bone in livestock Distal in small animals may be called the claw or nail. In cats the claw cannot be separated from the phalanx bone. Combining form for claw or nail is onych/o.

38. Phalanges • Dog: • 3 phalanges • proximal, middle, distal • 5 digits I-V • Start medial to lateral • Medial digit is digit I • (the dewclaw in dogs)

39. Phalanx • Horse • One digit (III) • 3 phalanx bones Fetlock joint

40. Cloven hoof • Cloven hoofed animals • Two digits (III-IV) • Three phalanx bones • Digits II and V are • vestiges • Distal phalanx is • encased in a hoof.

41. The Hind Limb Hind limb pelvis femur patella tibia fibula tarsal bones metatarsal bones cannon bone in livestock phalanges

42. Pelvic Bones The bones of the pelvis: ilium ischium pubis acetabulum—bony part of the socketjoint

43. Cat skeleton: Where is the Clavicle

48. Owl Skeleton