Skeletal System: Day Two

1. Skeletal System: Day Two Long Bone Anatomy, Microscopic Anatomy, Bone Composition, and Joint Anatomy

2. Structure of Long Bone – Gross Anatomy • Diaphysis (shaft) • Epiphyses • Epiphyseal Line • Medullary Cavity • Bone Markings

3. Long Bone • Diaphysis • Shaft • Makes up most of the bones length • Composed of compact bone • Covered and protected by a connective tissue membrane, the periosteum • Sharpey’s fibers secure the periosteum to the bone

4. Long Bone • Epiphyses • Ends of long bone • Thin layer of compact enclosing an area filled with spongy bone • Articular cartilage • instead of periosteum, covers its external surface • a glassy hyaline cartilage • Provides a smooth, slippery surface that decreases friction at joint surfaces

5. Long Bone • Epiphyseal Line • Thin line of bony tissue spanning the epiphysis that looks different from the rest of the bone in that area • Remnant (what’s left …) of the epiphyseal plate seen in young growing bone. • Epiphyseal plates cause the length wise growth of a long bone.

6. Long Bone • Medullary Cavity • In adults, the cavity is primarily for storage of adipose tissue (yellow marrow) • In infants, the cavity is used to form blood cells (red marrow) • In adults, red marrow is in the cavities of spongy bone located in the flat bone and the epiphysis (ends) of long bone ONLY.

7. Long Bone • Bone Markings • Reveal were muscles, tendons, and ligaments were attached and where blood vessels and nerves passed • Two categories: • Projections – grow out from bone • Depressions – indentations in the bone

8. CENTRAL CANAL CENTRAL CANAL VOLKMANN’S CANAL Structure of Long Bone – Microscopic Anatomy • Osteocytes • Lacunae • Lamellae • Central canals • Osteon • Canaliculi • Volkmann’s canals

9. Microscopic Anatomy of Long Bones • Osteocytes – mature bone cells • Found in lacunae (spaces) • Arranged in circles called lamellae • Lamellae circle around the Central Canal

11. Microscopic AnatomyOsteon • Osteon • Central canal plus the lamellae • Central Canal • runs lengthwise through bone carrying blood vessels and nerves to all parts of the bone. • Canaliculi • Tiny canals that extend out from the central canal to the lacunae. • Form a transportation system that connects all osteocytes (bone cells) to the nutrient supply • Volkmann’s canals • Communicate from outside of bone to the central canal • Run at right angles

12. CENTRAL CANAL CENTRAL CANAL VOLKMANN’S CANAL

13. Bone Composition Calcium Salts give bone its hardness Organic parts (collagen) give bone flexibility and tensile strength

14. Joints • With the exception of the hyoid bone, every bone in the body forms a joint with at least one other bone • Joints serve two functions • Hold the bones securely together • Give the rigid skeleton flexibility

15. Joint Classification • Functional: depends on the amount of movement allowed by the joint • Structural: depends on whether fibrous tissue, cartilage, or a joint cavity separates the bony regions at the joint

16. Three Types of Joints • Synarthrosis Joints – held together by collagenous fibers. The bones closely contact each other. Ex. Skull sutures, distal end of fibula and tibia • Amphiarthosis Joints – hyaline cartilage or fibrocartilage connect the bones. Ex. Vertebrae, pubis bone • Diarthrosis (Synovial Joint) – Most common joint and most complex

17. Synovial Joint

18. Types of Synovial Joints

19. Ball and Socket Joint • Hip and shoulder are examples • Egg shaped head with a cup shaped cavity

20. Condyloid Joint • Metacarpals and phalanges

21. Gliding Joint • Joints of the wrist and ankle • Back and forth movement

22. Hinge Joint • Elbow • Concave and convex surfaces fit together

23. Pivot Joint • Rotation around a central axis • Radius and ulna, neck turning

24. Saddle Joint • Carpal and metacarpal of the thumb

25. Inflammatory Disorders of the Joints • Bursitis: inflammation of bursa (synovial membrane); water on the knee

26. Inflammatory Disorders of the Joints • Sprain • Ligaments or tendons reinforcing joint are damaged by excessive stretching or are torn away from bone • Slow to heal because of poor blood supply • Dislocation • When a bone is forced out of normal position in the joint cavity

27. Inflammatory Disorders of the Joints • Arthritis • Most widespread, crippling disease in the U.S. • 1 in 7 Americans suffer with it • Initial symptoms: Pain, stiffness, and swelling of the joint • Acute and Chronic Forms of Arthritis

28. Inflammatory Disorders of the Joints • Acute Arthritis • Result from bacterial invasion • Treated with antibiotic • Synovial membrane thickens and fluid production decreases, leading to increased friction and pain

29. Inflammatory Disorders of the Joints • Chronic Arthritis • Osteoarthritis • Most common form • Degenerative condition usu. affects the aged • Wear and tear affects • Can cause bone spurs which restrict joint movement • Rheumatoid arthritis • Occurs between 40-50 years old, but can occur at any age • Affects more women than men • Many joints affected at the same time and usu. in symmetrical manner (left elbow than right elbow) • Marked by remission (goes away) and flare ups (comes back) • Autoimmune disease – body attacks its own tissues • Gouty arthritis

30. Inflammatory Disorders of the Joints