1. Chapter 5 – Vertebrate Anatomy
BONES
Chapter 5 – Vertebrate Anatomy

2. Major Functions of Bone
Support
Backbone, etc.
Protection
Skull, ribs
Movement
Levers against which muscles work
Mineral storage
Blood cell formation

3. Two Major Types of Bone
Compact Bone
Spongy Bone

4. Compact Bone
Dense
Smooth and solid in appearance

5. Spongy Bone
Honeycombed
Contains marrow in spaces

6. Bones are Classified by Shape
Long Bones
Short Bones
Flat Bones
Irregular Bones

7. Long Bones Bones that are longer than they are wide.
Shaft with two ends
Primarily compact bone
Spongy bone at interior
All bones of the limbs are long bones

9. Short Bones Roughly cubelike in shape Contain mostly spongy bone
Bones of the wrist and ankle

10. Flat Bones Thin, flattened and usually a bit curved
Two roughly parallel compact bone surfaces with spongy bone within
Skull bones; scapulae (shoulder blades)

11. Irregular Bones Bones that fit none of the other classes
Vertebrae
Hip bones (pelvic bones)
These bones have complex shapes
Consist mainly of spongy bone

12. Bones are Organs
Bones are supplied and associated with many other tissues, thus they are organs
Supplied with nerves, blood vessels, lymph vessels
Covered with membranes (epithelial tissues)

13. Structure of a Typical Long Bone
Diaphysis – shaft of the long bone
Thick collar of compact bone surrounds a central marrow cavity
Epiphysis – ends of a long bone
Exterior of epiphyses are formed by compact bone
interior contains spongy bone
Joint surface of each epiphysis is covered with articular cartilage
Epiphyseal line
Remnant of a structure called the epiphyseal PLATE
Epiphyseal plate is the disk-like plate which allows for growth of the long bone during childhood
Cushions opposing bone ends during movement

15. Epiphysis detail
Click here for a detailed view of the epiphysis

16. Structure of Long Bone, cont.
Both internal and external surfaces are covered with membranes
Outer membrane – periosteum
Covers shaft
Richly supplied with blood vessels, nerves, etc.
Vessels enter through holes in the bone called nutrient foramen
Membrane also is anchoring point for tendons and ligaments
Inner membrane - endosteum

17. Structure of Short, Irregular and Flat bones
Simple design
Outside – compact bone
Inside – spongy bone

18. Blood forming tissue in bones
Red marrow
Typically found in cavities of spongy bone in long bones and flat bones
In adults, most blood formation occurs in
Head of femur/humerus
Sternum
Hip bones
In adults, the marrow cavity containing yellow marrow (fat) extends well into the epiphyses of most long bones

19. Chemical Composition of Bone
Both inorganic and organic compounds make up bone
Proper combination of organic and inorganic components allows bones to be durable without being brittle
Organic components
Composed of
Cells
Organic portion of matrix
Provide flexibility and tensile strength (strength under tension)
Inorganic components
Mineral salts
Calcium phosphate is the main mineral salt
Provide hardness

20. Bone Markings Bones have many bumps, bulges, depressions, holes, etc.
“Bumps” are typically are points for muscle attachment
Holes are typically points for blood vessels or nerves to pass through

21. Terms for Bone Markings
Condyle – smooth rounded projection that allows for articulation
Articulation – usually a place where two bones meet and move against each other, but sometimes no movement occurs.
The image shows the occipital condyles at the base of the skull. These articulate with the first vertebra.

22. Terms for Bone Markings
Crest
A narrow ridge of bone
The images show the sagittal crest of a badger

23. Terms for Bone Markings
Foramen
A hole
Usually for passage of blood vessels and/or nerves

24. Terms for Bone Markings
Process
Any bony prominence or projection
To the right is the mastoid process
Also visible is the styloid process
Both are sites of muscle attachment to the skull

25. Terms for Bone Markings
Spine
A sharp slender process or projection
This photo shows the neural spines on vertebrae of a dinosaur

26. Terms for Bone Markings
Suture
A seam
Irregular lines produced by interlocking bones
An immovable joint
The photo shows sutures of the skull

27. Terms for Bone Markings
Fossa
A depression
Often an articulating surface
May meet with a condyle on another bone

28. Types of Fractures Simple –
only bone damage – little or no tissue damage
Complete break

29. Types of Fractures
Compound – bone breaks through the soft tissue to the outside
High risk of infection

30. Types of Fractures Compression
This type of bone fracture generally occurs after a fall where the vertebral column is compressed and then under the extreme pressure cracks or breaks.
Crushing of bone

31. Types of Fractures
Comminuted – more than two fragments of bone broken off.

32. Types of Fractures
Impacted
Ends of bone become wedged together

33. Types of Fractures Spiral
Fracture caused by twisting force that creates an oblique fracture around and through the bone

34. Types of Fractures Greenstick
incomplete fracture in which only one side of the bone has been broken.

35. Types of Fractures
Depression

36. Homeostatic Imbalances of Bone
Osteoporosis
Diseases in which bone resorption outpaces bone replacement
Bone marrow becomes porous and lighter
Spine is most vulnerable; also neck of femur
Estrogen and testosterone are important in maintaining normal bone density
After menopause, estrogen secretion in women diminishes and contributes to bone loss
Other causes of bone loss
Lack of exercise
smoking

37. Preventing Osteoporosis
Take calcium beginning at age 35-40
Drink flouridated water
Do weight bearing exercise

38. Other diseases of bone Osteomalacia Rickets
Bones inadequately mineralized
Rickets
Bones bend/deform
Children mostly affected
Caused by low calcium; vitamin D