Do now activity #4 Describe the types of bone marrow. What are the 4 categories of bone fracture classification? Describe all types. What are the different types of fractures? Describe each. How do doctors treat bone fractures? Why do they choose to use this type of treatment? Describe the steps of bone fracture healing. What is the difference between lacunae and lamellae?

chapter 6-4: Bone fractures Essential Question: List the stages of bone fracture healing in order. chapter 6-4: Bone fractures Learning Targets List the types and characteristics of bone fractures. Describe the common disorders of the bone. Identify the effects of aging on bone.

announcements Chapter Test Retake (>70%) Completed stamp sheet assignments Retake score will be permanent No retakes on Chapter 7 Bone Practical Class website will be updated today Check your Stamp Sheet to submit assignments on a timely basis Quiz 2 scheduled for: Wednesday, 10/24/18 Quiz 2 scheduled for: Thursday, 10/25/18 Chapter 6 Test scheduled for: Tuesday, 10/30/18 Last Day to Stamp Chapter 6: Monday, 10/29/18

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Bone Fractures (Broken bones) Bone fractures are classified by: The position of the bone ends after fracture Nondisplaced– bone ends retain their normal position Displaced– bone ends are out of normal alignment The completeness of the break Complete – bone is broken all the way through Incomplete – bone is not broken all the way through

Bone Fractures (Broken bones)—continued 3. The orientation of the bone to the long axis Linear– the fracture is parallel to the long axis of the bone Transverse– the fracture is perpendicular to the long axis of the bone 4. Whether or not the bone penetrate the skin Compound (open)– bone ends penetrate the skin Simple (closed) – bone ends do not penetrate the skin

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Common Types of Fractures Comminuted – bone fragments into three or more pieces; common in the elderly Spiral – ragged break when bone is excessively twisted; common sports injury Depressed – broken bone portion pressed inward; typical skull fracture

Common Types of Fractures—continued Compression – bone is crushed; common in porous bones Epiphyseal – epiphysis separates from diaphysis along epiphyseal line; occurs where cartilage cells are dying Greenstick – incomplete fracture where one side of the bone breaks and the other side bends; common in children

Common Types of Fractures Table 6.2.1

Common Types of Fractures Table 6.2.2

Common Types of Fractures Table 6.2.3

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Bone fracture treatments Bone are put back into position/realigned reduction Bone are immobilized by casts, braces or splints Not allowed to move

Stages in the Healing of a Bone Fracture 1. Hematoma formation Torn blood vessels hemorrhage A mass of clotted blood (hematoma) forms at the fracture site Site becomes swollen, painful, and inflamed Figure 6.13.1

Stages in the Healing of a Bone Fracture Fibrocartilaginous callus forms Granulation tissue (soft callus) forms a few days after the fracture Capillaries grow into the tissue and phagocytic cells begin cleaning debris Continued on next slide Figure 6.13.2

Stages in the Healing of a Bone Fracture Osteoblasts and fibroblasts begin reconstructing the bone Fibroblasts secrete collagen fibers that connect broken bone ends Osteoblasts begin forming spongy bone Osteoblasts secrete a bulging cartilaginous matrix that later calcifies

Stages in the Healing of a Bone Fracture 3. Bony callus formation New bone trabeculae appear in the fibrocartilaginous callus Fibrocartilaginous callus converts into a bony (hard) callus Bone callus begins 3-4 weeks after injury, and continues until firm union is formed 2-3 months later Figure 6.13.3

Stages in the Healing of a Bone Fracture 4. Bone remodeling Excess material on the bone shaft exterior and in the medullary canal is removed Compact bone is laid down to reconstruct shaft walls Figure 6.13.4

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Homeostatic Imbalances Osteomalacia Bones are inadequately mineralized causing softened, weakened bones Main symptom is pain when weight is put on the affected bone Caused by insufficient calcium in the diet, or by vitamin D deficiency Treated with calcium and vitamin D supplements

Homeostatic Imbalances Rickets Osteomalacia in children Bones are inadequately mineralized causing softened, weakened bones Bowed legs and deformities of the pelvis, skull, and rib cage are common Caused by insufficient calcium in the diet, or by vitamin D deficiency Treated with calcium and vitamin D supplements Mostly milk fortified with vitamin D

Homeostatic Imbalances Osteoporosis Group of diseases in which bone resorption outpaces bone deposit Spongy bone of the spine is most vulnerable Occurs most often in postmenopausal women Bones become so fragile that sneezing or stepping off a curb can cause fractures

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Osteoporosis: Treatment Calcium and vitamin D supplements Increased weight-bearing exercise Hormone (estrogen) replacement therapy (HRT) slows bone loss Natural progesterone cream prompts new bone growth Statins (drugs used to lower cholesterol) increase bone mineral density

Developmental Aspects of Bones By age 25, nearly all bones are completely ossified In old age, bone resorption outpaces bone deposition A single gene that codes for vitamin D docking determines both the tendency to accumulate bone mass early in life, and the risk for osteoporosis later in life

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