Anatomy of Bones: Functions, Types, Structure, and Markings, Slides of Anatomy

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Bones

Vertebrate Anatomy

Major Functions of Bone

• Support
  • Backbone, etc.
• Protection
  • Skull, ribs
• Movement
  • Levers against which muscles work
• Mineral storage
• Blood cell formation

Two Major Types of Bone

• Compact Bone
• Spongy Bone

Compact Bone

• Dense
• Smooth and solid in appearance

Spongy Bone

• Honeycombed
• Contains marrow in spaces

Bones are Classified by Shape

• Long Bones
• Short Bones
• Flat Bones
• Irregular Bones

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

Short Bones

• Roughly cubelike in shape
• Contain mostly spongy bone
• Bones of the wrist and ankle

Flat Bones

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

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

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)

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 Docsity.com

Epiphysis detail

• Click here for a detailed view of the epiphysis

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

Structure of Short, Irregular and

Flat bones

• Simple design
• Outside – compact bone
• Inside – spongy bone

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 Docsity.com

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

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

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.

Terms for Bone Markings

• Crest
  • A narrow ridge of bone
  • The images show the sagittal crest of a badger

Terms for Bone Markings

• Foramen
  • A hole
  • Usually for passage of blood vessels and/or nerves

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

Terms for Bone Markings

• Spine
  • A sharp slender process or projection
  • This photo shows the neural spines on vertebrae of a dinosaur