osteology

Axial skeleton

Composed of bones along central body axis. Skull, vertebral column, thoracic cage

Appendicular skeleton

Bones of upper and lower limbs. Girdles of bones attach limb to axial skeleton

Long bones

Greater in length than width, femur

Short bones

Length nearly equal to width, carpals and tarsals

Flat bones

Flat, thin surface, may be slightly curved, cranial bones

Irregular bones

Elaborate, sometimes complex shapes, vertebrae

Hemopoiesis

Blood cell production

Osteoprogenitor cells

Stem cells that mature to become osteoblasts

Osteoblasts

Immature bone cell that secrete osteoid, the organic component of bone matrix

Osteocytes

Mature bone cell that maintain bone matrix

Osteoclasts

Multinucleated cell that secretes acids and enzymes to dissolve bone matrix

Ossification

Formation and development of bone

Osteon

Basic functional and structural unit of mature compact bone

Trabeculae

Highly porous form of bone tissue that is organized into a network of interconnected rods and plates which surround pores that are filled with bone marrow

Endochondral ossification steps

1. Hyaline cartilage model of bone forms

2. Cartilage calcifies, periosteal bone collar forms

3. Primary ossification center forms in a diaphysis (shaft)

4. Secondary ossification centers form in epiphyses

5. Bone replaces cartilage, except articular cartilage and epiphyseal plates

6. Epiphyseal plates ossify and form epiphyseal lines

Intramembranous ossification Steps

1. Ossification center form within mesenchyme

2. Osteoid undergoes calcification

3. Woven bone and periosteum form

4. Lamellar bone replaces woven bone, compact and spongy bone form

Endochondral ossification forms

Most bones of skeleton such as bones of upper and lower limbs, pelvis and vertebrae

Intramembranous ossification Forms

Produces flat bones of the skull, some facial bones, mandible, central parts of clavicle

Osteon components

1. Central canal

2. Cocentric lamellae

3. Osteocytes

4. Canaliculi

spongy (cancellous) bone composed of

1. Trabeculae

2. Parallel lamellae

Spongy (cancellous) bone found in

Flat bones of the skull, ribs, sternum, mandible and head of long bones

Articulating surface: Condyle

Large, smooth, rounded, oval structure

Articulating surface:Facet

Small, flat shallow surface

Articulating surface:Head

Prominent

M rounded epiphysis

Articulating surface:Trochlea

Smooth, grooved, pulley like process

Depressions: alveolus

Deep pit of socket in the maxillae or mandible

Depressions: Fossa

Flattened or shallow depression

Depressions: Sulcus

Narrow groove

Projections: crest

Narrow, prominent, ridge like projection

Depressions: Epicondyle

Projection adjacent to condyle

Depressions: Line

Low ridge

Depressions: Process

Any marked bony prominence

Depressions: Ramus

Angular extension of bone relative to the rest of the structure

Depressions: Spine

Pointed, slender process

Depressions: Trochanter

Massive, rough projection found only in the femur

Depressions: Tubercle

Small, round projection

Depressions: Tuberosity

Large, rough projection

Openings and spaces: canal

Larger Passageway through bone

Depressions: Fissure

Narrow, slit like opening through a bone

Depressions: Foramen

Rounded passageway through a bone

Depressions: Meatus

Passageway through a bone allows flow of air and fluids

Depressions: Sinus

Cavity or hollow space in a bone

Bone markings

Bumps, holes and ridges on bones where muscles, tendons and ligaments are attached and whew blood vessels and nerves pass through

Articulation

A joint where two bones meet

Fontanels

Spaces between bones in an infant skull

Canaliculi

Tiny canals that radiate outward from the Haversian canal to lacunae to supply the bone cells with nutrients

Diaphysis

Shaft of long bone composed of compact bone

Epiphysis

End of long bone, composed mostly of spongy bone

Epiphyseal line

Marking left on the bone from growth at the epiphyseal plate

Remodeling

Process do breaking down and reforming bone that occurs throughout life to maintain proportion and strength and well as healthy calcium levels

Rickets

Soft bones caused by lack of vitamin D, calcium, or phosphorus

Vertebral body

Thick Anterior weight bearing structure

Vertebral arch

Posterior to body

Vertebral Foramen

Opening enclosed by the body with vertebral arch

Vertebral canal

Formed by stacked vertebral foramina, contains spinal chord

Pedicles

Originate form posterolateral margins of body

Laminae

Extend posteromedially from posterior edge of pedicle

Spinous process

Projects posteriorly from laminae junction

Transverse process

Lateral projections on both sides of vertebral arch

Superior/inferior articular process

Originate at junction between pedicles and laminae, have smooth surface articular facet articulate with vertebra either above or below

Intervertebral discs

Pads of Fibrocartilage separating vertebral bodies, shock absorbers, allows vertebral column to bend

True ribs

Ribs 1-7, connect individually to the sternum by costal cartilages

False ribs

Ribs 8-12, costal cartilages not attached directly to the sternum

How many Cervical vertebrae

7 , c7-c7

Breakfast at 7

How many thoracic vertebrae

12, T1-T12

Lunch at 12

How many lumbar vertebrae

5, L1-L5

Dinner at 5

How many sacrum vertebrae

5, S1-S5

Dessert at 5

How many coccyx vertebrae

4 coccygeal, C1-C4

Midnight snack at 4