1. Skeletal System: Bones and Bone Tissue
Unit 3
Skeletal System: Bones and Bone Tissue

2. Skeletal System Functions
Support - provides hard framework for soft tissue
Protection - Encloses underlying organs
Movement – transmission of forces generated by contracting muscles
Storage – of minerals such as Calcium and Phosphorous
Blood cell production (Hematopoiesis) - Bone marrow produces blood cells and platelets

3. Bone Shapes Long- Longer than they are wide
Short- vary in shape but typically have cuboid or trapezoid shape
Ex. Carpals and tarsals
Flat- Cancellous/Spongy bone sandwiched between compact bone
Irregular- complex bones that do not fit in the other categories

4. Classification of Joints
Gliding- ankle, wrist, carpals, and tarsals
Hinge – Knee, elbow
Pivot – atlas to the skull
Condylar –Mandible (jawbone)
Ellipsoid- base of fingers
Saddle- base of thumb
Ball and Socket-hip, shoulder
Gliding-Flat or slightly flat surfaces move against each other allowing sliding or twisting without any circular movement
Hinge -A convex projection on one bone fits into a concave depression in another permitting only flexion and extension
Pivot -a bony ring rotates round the pivot (axis) of another bone
Condylar -two bones fit together with an odd shape (e.g. an ellipse), and one bone is concave, the other convex
Ellopsoid
Saddle- touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement
Ball and Socket-The ball-shaped end of one bone fits into a cup shaped socket on the other bone allowing the widest range of motion including rotation.

5. Bone Architecture- Bone Cells
Osteoblasts
Active in bone formation, a process known as ossification or osteogenesis. Bone-making.
Osteocytes
Essentially osteoblasts that have been trapped in the matrix
Trapped Bone-making
Osteoclasts.
Very large cells used to breakdown bone - Bone Reabsorption
Bone Architecture- Bone Cells

6. Bone Structure-Compact Bone
Dense, solid bone
Contain Haversian Systems with Osteocytes=bone making cells

7. Microscopic Structure of Compact Bones
Figure 6.6

8. Cancellous (Spongy) Bone
Located beneath compact bone along stress lines, made of a network of connecting bone spicules called trabeculae.

9. Components of Bone Diaphysis Cylindrical Shaft
Thick wall of compact bone
Epiphysis
End of the bone
Epiphyseal plate - responsible for growth in length of bone
Medullary cavity - central, hollow cavity

10. Components of Bone Periosteum - membrane surrounding diaphysis
Composed of 2 layers
Fibrous Periosteum: the outer layer
Osteogenic Layer- bone forming layer
A single layer of bone cells including osteoblasts, osteoclasts and osteochondral progenitor cells
Sharpey’s fibers - periosteal fibers that penetrate into the bone matrix and firmly anchor the periosteum to compact bone
Endosteum- Lines all internal spaces including spaces in cancellous bone. Internal lining of bone

11. Components of Bone
Endosteum- Lines all internal spaces including spaces in cancellous bone. Internal lining of bone

12. Structure of a Long Bone
Figure 6.3a-c

13. Bone Development: Osteogenesis
Bone formation occurs in 2 different ways
Intramembranous ossification
Occurs in connective tissue membrane
Endochondral ossification
Occurs in cartilage

14. Intramembranous Ossification
Typical in the flat bones of the skull, parts of the clavicle, and mandible
The process: Think Baby’s Skull
Vascularized connective tissue forms collagen
Mesenchymal cells of collagen slowly turn to osteoblasts
Bone cells fill in the collagen matrix on the edge of the bone and slowly begin to ossify and weave together at joints called sutures.

15. Baby’s Fontanelles (Soft Spots)

16. Intramembranous cont’d
Summary: Occurs in the skull and allows for the individual bones to fill in completely.
No more “soft spots”
The coming together/stitching of the bones are called sutures

17. Endochondral Ossification
All bones except some bones of the skull and clavicles
This process continues until a persons mid twenties

18. Endochondral Ossification-simplified
Cartilage model is formed
Ossification begins in the middle of the diaphysis
Formation of periosteum: Periosteum forms around bone and gives rise to osteoblasts (early form of osteocytes)
Formation of bone collar: Osteoblasts secrete osteoid against the shaft of the cartilage model. This serves as support for the new bone.
Calcification of cartilage:. This can create cavities within the bone. (This would be spongy bone.)

19. Endochondral Ossification
Invasion of periosteal bud: a periosteal bud, which consists of blood vessels, lymph vessels, and nerves invades the cavity, the center of the bone.
Formation of Medullary Cavity: Osteoclasts break down spongy bone for the medullary cavity.
Cartilage remain at epiphyseal plates of bones: the plates are where growth can continue to lengthen bones

20. Stages in Endochondral Ossification
Figure 6.10

21. Bones • Children have more flexible bones than adults.
• Your body has 206 bones.
• Children have more flexible bones than adults.
•Ligaments are bands of strong tissue that connect bones to other bones. Help with joints exist.

22. Muscles
• Muscles are soft tissues. • Your body has over 600 different muscles. • Most muscles are attached to bones by strong tissues called tendons.

23. Joints
• Joints= two or more bones coming together at one place. • Joints are held together by bands of fibers called ligaments. • When joints are moved beyond their normal range of motion/movement, ligaments stretch and tear.

25. Types of Injuries
The four basic types of injuries to muscles, bones and joints are: •Fractures •Dislocations •Strains •Sprains

26. X-Rays X-rays are a form of radiation that can penetrate the body
to form an image on film.
Structures that are dense
(such as bone) will appear
white, air will be black

27. Fractures A fracture is a complete break, chip or crack in a bone.
Treated by:
Closed Reduction-
Open Reduction-
Traction-

28. Closed Fracture
Closed fracture
right wrist.
(Radius & ulna)

29. Closed Fracture Posterior x-ray, closed fracture right lower leg.
(Fibula)

30. Open Fracture Open fracture left collarbone. (Clavicle) More dangerous
because of the
risk of infection

33. Comminuted Fracture Comminuted-a fracture with many relatively
small fragments.
(right thigh/femur)

34. Ski Accident – Broken Fibula
Spiral type fracture
Dislocated
Sprained

35. Ski Accident – Broken Fibula
Spiral type fracture
Dislocated
Sprained

36. Dislocation A dislocation is the movement of a bone at
a joint away from its
normal position.
The joint no longer
functions properly.

37. Sprain
• A sprain is the tearing of ligaments at a joint. • Mild sprains swell and usually heal quickly. • Do not ignore the signals of pain & swelling. If you become active too soon there is the chance the joint could be hurt again.

38. Type I Sprain
The most common way the ankle can be injured is by an ankle sprain. Type I ankle sprain is mild. It occurs when the ligaments have been stretched or torn minimally.

39. Type II Sprain
Type II ankle sprain is a moderate level of sprain. It occurs when some of the fibers of the ligaments are torn completely.

40. Type III Sprain
Type III ankle sprain is the most severe. It occurs when the entire ligament is torn and there is instability of the ankle joint.

41. Knee and Shoulder Ligaments

42. General Care for Muscle, Bone or Joint Injuries
The acronym RICE is helpful in remembering how to treat minor injuries: • "R" stands for rest. • "I" is for ice. • "C" is for compression. • "E" is for elevation.

43. Bursitis
Inflammation of the Bursa (fluid filled sac surrounding the joint).
Bursitis is typically identified by localized pain or swelling, tenderness, and pain with motion of the tissues in the affected area.

45. Carpal Tunnel Syndrome
Any condition that causes swelling or a change in position of the tissue within the carpal tunnel can squeeze and irritate the median nerve. Irritation of the median nerve in this manner causes tingling and numbness of the thumb, index, and the middle fingers, a condition known as "carpal tunnel syndrome."

49. Osteoporosis
Osteoporosis is a term that means "porous bones." It is a skeletal disease affecting women and men. Osteoporosis is a condition in which bones have lost minerals especially calcium-making them weaker, more brittle, and susceptible to fractures (broken bones). Any bone in the body can be affected by osteoporosis, but the most common places where fractures occur are the back (spine), hips, and wrists. **Ladies especially** Why???

52. Rheumatoid arthritis Systemic chronic inflammatory disease
Autoimmune disease
Joints become swollen and painful
More common in women 3:1
Remissions and exacerbations 52

53. Osteoarthritis Most common joint disease, 80% of Americans
Slow progressive degeneration of articular cartilage
Weight bearing joints
Fingers
Primary: defect in cartilage, not an inflammatory disease
Secondary: trauma, crystal deposits, infection
Interphalangeal joints, knees, hips, cervical and lumbar spine 53

54. HERNIATED DISC
Disc ruptures
or protrudes.

55. Scoliosis
Scoliosis is an abnormal curvature of the spine. If your child has scoliosis, the view from behind may reveal one or more abnormal curves. Scoliosis runs in families, but doctors often don't know the cause. More girls than boys have severe scoliosis.

58. Kyphosis
With kyphosis, your spine may look normal or you may develop a hump. Kyphosis can occur as a result of developmental problems; degenerative diseases, such as arthritis of the spine; osteoporosis with compression fractures of the vertebrae; or trauma to the spine. It can affect children, adolescents and adults.

61. Lordosis
A normal spine, when viewed from behind appears straight. However, a spine affected by lordosis shows evidence of a curvature of the back bones (vertebrae) in the lower back area, giving the child a "swayback" appearance.

63. Osteomyelitis Inflammation of bone caused by an infectious organism
Staphylococcus, streptococcus, neisseria gonorrhea,…..
Direct penetration
Wounds, fractures, surgery
Hematogenous
Bloodstream, teeth; metaphyses
Knee, ankle, hip

64. Bone Marrow Aspiration