Figure 6-1 A Classification of Bones by Shape Sutural Bones Flat Bones Sutures Parietal bone External table Sutural bone Internal table Diploë (spongy bone) Irregular Bones Long Bones Vertebra Humerus Short Bones Sesamoid Bones Carpal bones Patella p. 180 © 2015 Pearson Education, Inc. 1

Table 6-1 An Introduction to Bone Markings © 2012 Pearson Education, Inc. 2

Figure 6-2 An Introduction to Bone Markings (Part 1 of 2). Openings Sinus: Chamber within a bone, normally filled with air Elevations and Projections Foramen: Rounded passageway for blood vessels and/or nerves Process: Projection or bump Fissure: Deep furrow, cleft, or slit Ramus: Extension of a bone that forms an angle with the rest of the structure Meatus: Passage or channel, especially the opening of a canal Skull, anterior view Canal: Duct or channel Skull, lateral view p. 181 © 2015 Pearson Education, Inc.

Figure 6-2 An Introduction to Bone Markings (Part 2 of 2). Processes formed where tendons or ligaments attach Processes formed where joints (articulations) occur between adjacent bones Trochanter: Large, rough projection Head: Expanded articular end of an epiphysis, often separated from the shaft by a narrower neck (see Figure 6–3a) Crest: Prominent ridge Spine: Pointed process Neck: Narrow connection between the epiphysis And diaphysis (see Figure 6–3a) Head Line: Low ridge Femur Tubercle: Small, rounded projection Pelvis Neck Depressions Facet: Small, flat articular surface Sulcus: Narrow groove Tuberosity: Rough projection Fossa: Shallow depression Humerus Condyle: Smooth, rounded articular process Trochlea: Smooth, grooved articular process shaped like a pulley Condyle p. 181 © 2015 Pearson Education, Inc.

Table 6-1 An Introduction to Bone Markings Trochanter Sinus Head Neck Tubercle Head Crest Sulcus Neck Fossa Foramen Fissure Process Tuberosity Spine Ramus Line Facet Fossa Foramen Tubercle Ramus Trochlea Skull Pelvis Condyle Condyle Femur Humerus © 2012 Pearson Education, Inc. 5

Figure 6-6a The Structure of Compact Bone (Part 1 of 2). Venule Circumferential lamellae Capillary Osteons Periosteum Perforating fibers Interstitial lamellae Concentric lamellae Trabeculae of spongy bone (see Fig. 6–7) Vein Artery Arteriole Central canal Perforating canal a The organization of osteons and lamellae in compact bone p. 186 © 2015 Pearson Education, Inc.

Figure 6-6b The Structure of Compact Bone Endosteum Central canal Concentric lamellae The organization of osteons and lamellae in compact bone The orientation of collagen fibers in adjacent lamellae Collagen fiber orientation p. 186 © 2015 Pearson Education, Inc. 7

Figure 6-8 The Distribution of Forces on a Long Bone Body weight (applied force) Tension on lateral side of shaft Compression on medial side of shaft p. 187 © 2015 Pearson Education, Inc. 8

Figure 6-7 The Structure of Spongy Bone Trabeculae of spongy bone Canaliculi opening on surface Endosteum Lamellae p. 186 © 2015 Pearson Education, Inc. 9

Figure 6-9a The Periosteum and Endosteum Circumferential lamellae Fibrous layer of periosteum Cellular layer of periosteum Canaliculi Osteocyte in lacuna Perforating fibers The periosteum contains outer (fibrous) and inner (cellular) layers. Collagen fibers of the periosteum are continuous with those of the bone, adjacent joint capsules, and attached tendons and ligaments. p. 188 © 2015 Pearson Education, Inc. 10

Figure 6-9b The Periosteum and Endosteum Osteoclast Bone matrix Osteocyte Osteoprogenitor cell Osteoid Osteoblast The endosteum is an incomplete cellular layer containing osteoblasts, osteoprogenitor cells, and osteoclasts. p. 188 © 2015 Pearson Education, Inc. 11

Figure 6-7 The Structure of Spongy Bone Trabeculae of spongy bone Canaliculi opening on surface Endosteum Lamellae p. 186 © 2015 Pearson Education, Inc. 12

Figure 6-4 Types of Bone Cells Canaliculi Osteocyte Matrix Matrix Osteoid Osteoblast Osteocyte: Mature bone cell that maintains the bone matrix Osteoblast: Immature bone cell that secretes organic components of matrix Osteoprogenitor cell Osteoclast Matrix Medullary cavity Medullary cavity Endosteum Osteoprogenitor cell: Stem cell whose divisions produce osteoblasts Osteoclast: Multinucleate cell that secretes acids and enzymes to dissolve bone matrix p. 183 © 2015 Pearson Education, Inc. 13

Figure 6-3a Bone Structure Epiphysis Spongy bone Metaphysis Compact bone Diaphysis (shaft) Medullary cavity Metaphysis Epiphysis The structure of a representative long bone (the femur) in longitudinal section p. 182 © 2015 Pearson Education, Inc. 14

Figure 6-3b Bone Structure Cortex (compact bone) Diploë (spongy bone) The structure of a flat bone (the parietal bone) p. 182 © 2015 Pearson Education, Inc. 15

Figure 6-6a The Structure of Compact Bone (Part 1 of 2). Venule Circumferential lamellae Capillary Osteons Periosteum Perforating fibers Interstitial lamellae Concentric lamellae Trabeculae of spongy bone (see Fig. 6–7) Vein Artery Arteriole Central canal Perforating canal a The organization of osteons and lamellae in compact bone p. 186 © 2015 Pearson Education, Inc.

Figure 6-5a The Histology of Compact Bone Canaliculi Concentric lamellae Central canal Osteon Lacunae Osteon LM  343 A thin section through compact bone. By this procedure the intact matrix making up the lamellae appear white, and the central canal, lacunae, and canaliculi appear black due to the presence of bone dust. p. 185 © 2015 Pearson Education, Inc. 17

Figure 6-5b The Histology of Compact Bone Osteon Lacunae Central canals Lamellae Osteons SEM  182 Several osteons in compact bone. p. 185 © 2015 Pearson Education, Inc. 18

Figure 6-4 Types of Bone Cells Canaliculi Osteocyte Matrix Matrix Osteoid Osteoblast Osteocyte: Mature bone cell that maintains the bone matrix Osteoblast: Immature bone cell that secretes organic components of matrix Osteoprogenitor cell Osteoclast Matrix Medullary cavity Medullary cavity Endosteum Osteoprogenitor cell: Stem cell whose divisions produce osteoblasts Osteoclast: Multinucleate cell that secretes acids and enzymes to dissolve bone matrix p. 183 © 2015 Pearson Education, Inc. 19

Enlarging chondrocytes within calcifying matrix Hyaline cartilage pp. 190-191 © 2015 Pearson Education, Inc. 20

pp. 190-191 21 Epiphysis Diaphysis Bone formation © 2015 Pearson Education, Inc. 21

pp. 190-191 22 Medullary cavity Blood Primary vessel ossification center Superficial bone Spongy bone pp. 190-191 © 2015 Pearson Education, Inc. 22

pp. 190-191 23 Medullary cavity Metaphysis © 2015 Pearson Education, Inc. 23

pp. 190-191 24 Hyaline cartilage Epiphysis Metaphysis Periosteum Compact bone Secondary ossification center pp. 190-191 © 2015 Pearson Education, Inc. 24

Figure 6-11 Endochondral Ossification (Part 10 of 11). Articular cartilage Spongy bone Epiphyseal cartilage Diaphysis pp. 190-191 © 2015 Pearson Education, Inc.

pp. 190-191 7 At puberty, the rate of epiphyseal cartilage production slows and the rate of osteoblast activity accelerates. As a result, the epiphyseal cartilage gets narrower and narrower, until it ultimately disappears. This event is called epiphyseal closure. The former location of the epiphyseal cartilage becomes a distinct epiphy- seal line that remains after epiphy- seal growth has ended. Articular cartilage Epiphyseal line Spongy bone Medullary cavity A thin cap of the original cartilage model remains exposed to the joint cavity as the articular cartilage. This cartilage prevents damaging the joint from bone-to-bone contact. pp. 190-191 © 2015 Pearson Education, Inc.

Figure 6-11a Bone Growth at an Epiphyseal Cartilage An x-ray of growing epiphyseal cartilages (arrows) p. 189 © 2015 Pearson Education, Inc. 27

Figure 6-11b Bone Growth at an Epiphyseal Cartilage Epiphyseal lines in an adult (arrows) p. 189 © 2015 Pearson Education, Inc. 28

Figure 6-12 Intramembranous Ossification (Part 1 of 5). Parietal bone 1 Mesenchymal cells cluster together, differentiate into osteoblasts, and start to secrete the organic components of the matrix. The resulting osteoid then becomes mineralized with calcium salts forming bone matrix. Frontal bone Bone matrix Osteoid Occipital bone Mesenchymal cell Ossification center Blood vessel Osteoblast Mandible Intramembranous ossification starts about the eighth week of embryonic development. This type of ossification occurs in the deeper layers of the dermis, forming dermal bones. p. 193 © 2015 Pearson Education, Inc.

Figure 6-12 Intramembranous Ossification (Part 2 of 5). As ossification proceeds, some osteoblasts are trapped inside bony pockets where they differentiate into osteo- cytes. The developing bone grows outward from the ossification center in small struts called spicules. Spicules Osteocyte p. 193 © 2015 Pearson Education, Inc.

Figure 6-12 Intramembranous Ossification (Part 3 of 5). Blood vessels begin to branch within the region and grow between the spicules. The rate of bone growth accelerates with oxygen and a reliable supply of nutrients. As spicules interconnect, they trap blood vessels within the bone. Blood vessel trapped within bone matrix p. 193 © 2015 Pearson Education, Inc.

Figure 6-12 Intramembranous Ossification (Part 4 of 5). Continued deposition of bone by osteoblasts located close to blood vessels results in a plate of spongy bone with blood vessels weaving throughout. p. 193 © 2015 Pearson Education, Inc.

Figure 6-12 Intramembranous Ossification (Part 5 of 5). Subsequent remodeling around blood vessels produces osteons typical of compact bone. Osteoblasts on the bone surface along with connective tissue around the bone become the periosteum. Fibrous periosteum Blood vessels trapped within bone matrix Areas of spongy bone are remodeled forming the diploë and a thin covering of compact (cortical) bone. Cellular periosteum p. 193 © 2015 Pearson Education, Inc.

Figure 6-13 The Blood Supply to a Mature Bone Articular cartilage Branches of nutrient artery and vein Epiphyseal artery and vein Metaphyseal artery and vein Periosteum Periosteum Compact bone Periosteal arteries and veins Connections to superficial osteons Medullary cavity Nutrient artery and vein Nutrient foramen Metaphyseal artery and vein Metaphysis Epiphyseal line p. 194 © 2015 Pearson Education, Inc. 34

Figure 6-16 Types of Fractures and Steps in Repair REPAIR OF A FRACTURE Fracture hematoma Dead bone Bone fragments Spongy bone of external callus Periosteum Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops. An internal callus forms as a network of spongy bone unites the inner edges, and an external callus of cartilage and bone stabilizes the outer edges. pp. 200-201 © 2015 Pearson Education, Inc. 35

Figure 6-16 Types of Fractures and Steps in Repair External callus Internal callus External callus The cartilage of the external callus has been replaced by bone, and struts of spongy bone now united the broken ends. Fragments of dead bone and the areas of bone closest to the break have been removed and replaced. A swelling initially marks the location of the fracture. Over time, this region will be remodeled, and little evidence of the fracture will remain. pp. 200-201 © 2015 Pearson Education, Inc. 36

Figure 6-16 Types of Fractures and Steps in Repair Transverse fracture Displaced fracture pp. 200-201 © 2015 Pearson Education, Inc. 37

Figure 6-16 Types of Fractures and Steps in Repair Compression fracture Spiral fracture pp. 200-201 © 2015 Pearson Education, Inc. 38

Figure 6-16 Types of Fractures and Steps in Repair Epiphyseal fracture Comminuated fracture pp. 200-201 © 2015 Pearson Education, Inc. 39

Figure 6-16 Types of Fractures and Steps in Repair Colles fracture Greenstick fracture Pott’s fracture pp. 200-201 © 2015 Pearson Education, Inc. 40

Figure 6-17 The Effects of Osteoporosis on Spongy Bone Normal spongy bone SEM  25 Spongy bone in osteoporosis SEM  21 p. 202 © 2015 Pearson Education, Inc. 42

Osteopenia p. 202 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings