Spinal Anatomy, Exam 1, P.4-7

Front 1

Diaphysis

Back 1

bone shaft, primary center for ossification

Front 2

Epiphysis

Back 2

• Associated with the the area of articulation with another bone or site of excessive muscle tension

• secondary ossification center

Front 3

Epiphyseal plate/disk

Back 3

• Separates diaphysis and epiphysis

• made of hyaline cartilage (rigid)

Front 4

Periosteum and Endosteum

Back 4

Membranes covering outer and inner bone surfaces

Front 5

Medullary Cavity (marrow cavity)

Back 5

Cavity at the center of a long bone

Front 6

Articular Cartilage

Back 6

• Covers bone where it articulates

• hyaline cartilage

Front 7

What are the 3 types of surface features of bones?

Back 7

1. Elevations

2. Indentations

3. Facets

Front 8

Elevations of bones:

Back 8

• linear (line, ridge, crest)

• rounded (tubercle, protuberance, tuber/tuberosity, trochanter, malleolus

• projection (spine or process)

Front 9

Indentations of bones:

Back 9

• depressions (groove, sulcus, fossa, fovea, cavity)

• passageway (foramen, canal, meatus)

Front 10

Facets of bones:

Back 10

• Flattened smooth surfaces for bone articulation (under the articular cartilage)

Front 11

What are the 3 types of mature bone tissue?

Back 11

1. Spongy (cancellous or trabecular)

2. Compact (cortical)

3. Subchondral

Front 12

Where is spongy bone found?

What is it composed of?

Back 12

• In the interior of a bone

• open latice work that makes it easy for blood to flow (well vascularized)

Front 13

Where is compact found?

What is it composed of?

Back 13

1. Exterior of a bone

2. composed of osteons

Front 14

What five structures make up compact bone?

Back 14

1. Lamellae - concentric layers of bony connective tissue

2. Central Canal - Vascular structure and nerves

3. Lacuna - holes found b/t lamellae

4. Canaliculi - passageways connecting lacunae ot each other and to the central canal

5. Perforating Canals - connecting central canals to each other and blood vessels

Front 15

Where is subchondral bone found?

Back 15

Underlying articular cartilage, making up the facet surface (smooth and glossy)

Front 16

What are the 3 types of bone cells?

Back 16

1. Osteoblasts

2. Osteocytes

3. Osteoclasts

Front 17

Osteoblasts:
1. Function
2. Location
3. Origination

Back 17

1. lay down new bony connective tissue (growth, development, repair)

2. located within the central canal of osteons and beneath periosteum

3. Originate from embryonic cells

Front 18

Osteocytes:
1. Function
2. Location
3. Origination

Back 18

1. Maintain surrounding bone tissue and regulate mineral content
2. Within the lacunae
3. Former osteoblasts

Front 19

Osteoclasts:
1. Function
2. Structure
3. Origination

Back 19

1. Bone destroying cells

2. Large and multinucleated

3. fusion of several monocytes

Front 20

What is Wolff's Law?

Back 20

A bone remodels its shape according to the way force is transmitted through it

Front 21

What are the 3 types of bone (developmentally)?

Back 21

1. Intramembranous (dermal): bones at top of skull and clavicle

2. Endochondral bone (cartilaginous): bones of skull base and all postcranial bones, including part of the clavicle

*Not exclusively one or the other. e.g. The temporal bones can have both.

Front 22

What is the ontogenetic process in endochondral bone? (5)

Back 22

1. Cartilaginous model forms (hyaline cartilage)

2. Cartilage disintegrates and excavates interior of bone; blood vessels invade bringing undifferentiated connective tissue cells

3. Connective tissue cells differentiate into osteoblasts forming spongy bone

4. Periosteum forms; osteoblasts beneath it form compact bone

5. More growth in 2 directions (interstitial and appositional)

Front 23

What is interstitial growth?

Back 23

• Growth b/t diaphysis and epiphysis

1. Blood vessels invade ends of bones forming secondary ossification centers

2. Epiphyseal Plate: site of active growth made up of cartilage b/t primary and secondary ossification centers

3. Growth ceases when plate ossifies (disappears)

Front 24

What is appositional growth?

Back 24

• an increase in over-all size

1. New compact bone from osteoblasts just below periosteum

2. Osteoclasts at inner bone surface destroy bony connective tissue and enlarge the medullary cavity; remodel compact bone/spongy bone interface

Front 25

What is the ontogenetic process in intramembranous bone?

Back 25

1. Membrane forms around blood vessels

2. Undifferentiated connective tissue around BLOOD VESSELS becomes osteoblasts, which start forming spongy bone

3. Periosteum forms and the underlying connective tissue cells differentiate into osteoblasts that form compact bone below the periosteum

4. Remaining growth is the same as endochondral:
• new compact bone
• new spongy bone
• osteoclast destroys inner layer of compact bone
• replaced with spongy bone

Front 26

Clinical considerations: Vitamin C (ascorbic acid)

Back 26

1. proper collagen formation

2. Deficiency leads to scurvy (bone thinning, increase risk of fracture)

Front 27

Clinical considerations: Vitamin D

Back 27

1. Proper bone mineralization

2. deficiency leads to:
• rickets (in children) - demineralization, bones become soft
• osteomalacia (in adults) - fatigue

Front 28

Clinical considerations: Parathyroid Hormone (PTH)

Back 28

1. excess of parathyroid hormone leads to bone thinning:
• osteoclast activity increases (breakdown)
• osteoblast activity decreases (don't make new)