Bone
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肌肉骨骼系统 骨 骼 Content 骨骼大体解剖 骨组织学 骨组织新陈代谢 骨组织生物力学 骨折愈合 骨骼疾病 骨折愈合（不愈合） 骨坏死 骨折疏松 器械、生物材料，药物，细胞，因子 骨骼的大体解剖 206 bones make up the adult skeleton (20% of body mass) 80 bones of the axial skeleton 126 bones of the appendicular skeleton The actual number of bones in the human skeleton varies from person to person Human skeleton initially cartilages and fibrous membranes By age 25 the skeleton is completely hardened 4 Functions of Skeletal System Support and Framework Protects Attachment sites Skeletal muscles... Mineral storage Calcium and phosphorus Site of blood cell formation in their marrow SKELETON should be familiar with all major bones Bone Shapes • Long – Upper and lower limbs • Short – Carpals 腕骨、tarsals跗骨 • Flat – Ribs肋骨, sternum胸骨, skull, scapulae肩胛骨 • Irregular – Vertebrae椎骨, facial 6-7 Long Bone Structure • Medullary cavity – Red marrow – Yellow marrow • Periosteum – Outer bone surface • Sharpey’s fibers – Attachment • Endosteum – Lines bone cavities 6-8 Diaphysis Epiphysis Metaphysis Epiphyseal (growth) plate Medullary cavity Flat, Short, Irregular Bones • Flat Bones – diaphyses, epiphyses – Sandwich of cancellous between compact bone • Short and Irregular Bone – Compact bone that surrounds cancellous bone center – No diaphyses and not elongated 6-14 Divisions of the Skeleton Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cranium • Axial Skeleton • Skull • Spine • Rib cage Skull Face Hyoid Clavicle Scapula Sternum Humerus Ribs Vertebral column • Appendicular Vertebral column Hip bone Skeleton • Upper limbs • Lower limbs • Shoulder girdle • Pelvic girdle Carpals Sacrum Radius Coccyx Ulna Femur Metacarpals Phalanges Patella Tibia Fibula Tarsals Metatarsals Phalanges (a) (b) 15 Skull •cranium (brain case) and the facial bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Parietal bone Frontal bone Squamous suture Lambdoid suture Sphenoid bone Ethmoid bone Lacrimal bone Nasal bone Occipital bone Temporal bone External acoustic meatus Zygomatic bone Temporal process of zygomatic bone Mastoid process Maxilla Mandibular condyle Styloid process Zygomatic process of temporal bone Coronoid process Mental foramen Mandible Infantile Skull • Fontanels 囟门– fibrous membranes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal suture (metopic suture) Frontal bone Anterior fontanel Sagittal suture Posterior fontanel (b) 17 Vertebral Column (spinal column) Vertebrae . Intervertebral discs. 18 Vertebral Column Cervical vertebrae (7) Thoracic vertebrae (12) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cervical vertebrae Cervical curvature Vertebra prominens Lumbar vertebrae (5) Rib facet Sacral (4-5 fused segments) Thoracic vertebrae Thoracic curvature •fused bone Intervertebral Coccygeal (3-4 fused segments) Intervertebral foramina Lumbar curvature Lumbar vertebrae •fused bone Sacrum Sacral curvature Coccyx (a) (b) 19 Vertebral Column Cervical curvature Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Thoracic curvature Cervical vertebrae Cervical curvature Lumbar curvature Vertebra prominens Sacral curvature Rib facets Rib facet Thoracic vertebrae Thoracic curvature Vertebral prominens Intervertebral discs (IVD) Intervertebral foramina (IVF) Intervertebral Intervertebral foramina Lumbar curvature Lumbar vertebrae Sacrum Sacral curvature Coccyx (a) (b) 20 Typical Vertebrae Includes the following parts: • Vertebral body • Pedicles椎弓根 • Lamina • Spinous process棘突 • Transverse processes横突 • Vertebral foramen锥孔 • Facets 21 Cervical Vertebrae Atlas寰椎 – 1st; supports Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Posterior Facet that articulates with occipital condyle Vertebral foramen head Axis 枢锥– 2nd; dens pivots to turn head Transverse process Anterior •Transverse foramina •Bifid spinous processes Facet that articulates with dens (odontoid process) of axis Atlas (a) Anterior articular facet for atlas Spinous process Spinous process Dens Superior articular facet Transverse foramen Vertebral prominens 隆锥 – useful landmark Transverse foramen Body Inferior articular process (b) Transverse process (c) Axis Dens (odontoid process) 22 Thoracic Vertebrae • Long spinous processes • Rib facets Superior articular process Transverse process Pedicle Facet for tubercle of rib Superior articular process Body Intervertebral notch Body Spinous process Transverse process Inferior articular process (a) Spinous process Inferior articular process Lamina Intervertebral disc Transverse process Facet for tubercle of rib Superior articular process Vertebral foramen Anterior Spinous process Pedicle Body (b) 23 Posterior (c) Lumbar Vertebrae • Large bodies • Thick, short spinous processes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinous process Lamina Superior articular process Transverse process Pedicle Vertebral foramen Body (c) Lumbar vertebra 24 Sacrum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • 4-5 fused segments Sacral promontory Superior articular process Sacral canal • Median sacral crest 骶正中嵴 • Posterior sacral foramina 骶后孔 • Posterior wall of pelvic cavity 后壁骨盆腔 • Sacral promontory aka base 骶岬 • Area toward coccyx is the apex Auricular surface Tubercle of median sacral crest Sacrum Posterior sacral foramen Sacral hiatus Anterior sacral foramen Coccyx (a) (b) 25 Coccyx •tailbone • 3-4 fused segments Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sacral promontory Superior articular process Sacral canal Auricular surface Tubercle of median sacral crest Sacrum Posterior sacral foramen Sacral hiatus Anterior sacral foramen Coccyx (a) (b) 26 Thoracic Cage The thoracic cage includes the ribs, the thoracic vertebrae, the sternum, and the costal cartilages that attach the ribs to the sternum. 27 Thoracic Cage Ribs (12) Sternum Thoracic vertebrae (12) Costal cartilages • Supports shoulder girdle and upper limbs • Protects viscera • Role in breathing Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Jugular notch (suprasternal notch) Thoracic vertebra Sternal angle Clavicular notch 1 2 Manubrium 3 True ribs (vertebrosternal ribs) 4 5 Body Sternum 6 7 Xiphoid process 8 False ribs Vertebrochondral ribs Ribs 9 Costal cartilage 10 11 Floating ribs (vertebral ribs) 12 (a) 28 (b) b: © Victor B. Eichler, PhD Ribs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Jugular notch (suprasternal notch) 12 pairs of ribs for human: • True ribs (7) • False ribs (5), of which: • Floating (2) Thoracic vertebra Sternal angle Clavicular notch 1 2 Manubrium 3 True ribs (vertebrosternal ribs) 4 5 Body Sternum 6 7 Xiphoid process 8 False ribs Vertebrochondral ribs Ribs 9 Costal cartilage 10 11 Floating ribs (vertebral ribs) 12 (a) • There are some anomalies: • Cervical ribs • Lumbar ribs 29 (b) b: © Victor B. Eichler, PhD Rib Structure Shaft Head – posterior end; articulates with vertebrae Tubercle – articulates with vertebrae Costal cartilage – hyaline cartilage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Neck Head Tubercle Anterior end Shaft Costal groove (a) Spinous process Facet Tubercle Neck Head Facet Shaft (b) Anterior end (sternal end) 30 Sternum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Jugular notch (suprasternal notch) Thoracic vertebra Sternal angle Manubrium 胸骨柄 Clavicular notch 1 2 Manubrium 3 Body True ribs (vertebrosternal ribs) 4 5 Body Sternum 6 7 Xiphoid process 剑突 Xiphoid process 8 False ribs Vertebrochondral ribs Ribs 9 Costal cartilage 10 11 Floating ribs (vertebral ribs) 12 (a) 31 (b) b: © Victor B. Eichler, PhD Pectoral Girdle肩胛带 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Shoulder girdle Clavicles锁骨 Scapulae肩胛骨 • Supports upper limbs • True shoulder joint is simply the articulation of the humerus肱骨 and scapula Acromial end Sternal end Acromion process Clavicle Head of humerus Coracoid process Sternum Scapula Rib Costal cartilage Humerus Ulna Radius (a) 32 Clavicles锁骨 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Articulate with manubrium • Articulate with scapulae (acromion process肩峰) • Acromion-Clavicles joint（A-C joint） Acromial end Sternal end Acromion process Clavicle Head of humerus Coracoid process Sternum Scapula Rib Costal cartilage Humerus Ulna Radius (a) 33 Scapulae Spine肩胛冈 Acromion process肩峰 Supraspinous fossa冈上窝 Coracoid process喙突 Infraspinous fossa冈下窝 Glenoid fossa or cavity关节窝 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior border Coracoid process Suprascapular notch Acromion process Acromion process Coracoid process Supraglenoid tubercle Spine Glenoid cavity Infraglenoid tubercle Supraspinous fossa Infraspinous fossa (a) Glenoid cavity Subscapular fossa Lateral (axillary) border Medial (vertebral) border (b) (c) 34 Upper Limb Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Humerus 肱骨 Radius 桡骨 Ulna 尺骨 (Interosseous membrane骨间膜) Carpals 腕骨 Metacarpals 掌骨 Phalanges 指骨 Humerus Humerus Olecranon process Olecranon fossa Head of radius Neck of radius Ulna (c) Radius Ulna Ulna Carpals Metacarpals Phalanges (a) Hand (palm anterior) (b) Hand (palm posterior) (d) d: © Martin Rotker 35 Humerus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Head Greater tubercle大结节 Lesser tubercle小结节 Anatomical neck解剖颈 Surgical neck外科颈 Deltoid tuberosity三角肌粗隆 Capitulum小头 Trochlea滑车 Coronoid fossa冠突窝 Olecranon fossa鹰嘴窝 Greater tubercle Head Intertubercular groove Anatomical neck Lesser tubercle Surgical neck Greater tubercle Deltoid tuberosity Coronoid fossa Lateral epicondyle Olecranon fossa Lateral epicondyle Medial epicondyle Capitulum Trochlea (a) (b) 36 Radius Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lateral forearm bone Head Radial tuberosity桡骨粗隆 Styloid process茎突 Trochlear notch Olecranon process Coronoid process Head of radius Olecranon process Trochlear notch Radial tuberosity Coronoid process Radial notch Radius (b) Ulna Head of ulna Styloid process (a) Styloid process Ulnar notch of radius 37 Ulna Medial forearm bone Trochlear notch滑车切迹 Olecranon process鹰嘴 Coronoid process冠状突 Styloid process茎突 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Trochlear notch Olecranon process Coronoid process Head of radius Olecranon process Trochlear notch Radial tuberosity Coronoid process Radial notch Radius (b) Ulna Head of ulna Styloid process (a) Styloid process Ulnar notch of radius 38 Wrist and Hand Carpal Bones (16 total bones) • • • • • • • • Scaphoid舟状骨 Lunate月状骨 Triquetral三角骨 Pisiform豌豆骨 Hamate钩骨 Capitate头状骨 Trapezoid小多角骨 Trapezium大多角骨 Radius Ulna Lunate Hamate Triquetrum Pisiform Scaphoid Capitate Trapezoid Trapezium Scaphoid Capitate Trapezoid Trapezium Carpals (carpus) 1 1 Metacarpals (metacarpus) Metacarpal Bones (10) Phalangeal Bones (28) Phalanges • • • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Proximal phalanx Middle phalanx Distal phalanx 2 5 5 3 4 4 3 2 Proximal phalanx Middle phalanx Distal phalanx (a) (b) 39 Pelvic Girdle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coxal Bones (2)坐骨 • Supports trunk of body • Protects viscera • Forms pelvic cavity Sacral canal Ilium Sacrum Sacral hiatus Coccyx Ischium (b) Pubis Obturator foramen Sacroiliac joint Ilium Sacral promontory Sacrum Acetabulum Pubis Symphysis pubis Pubic tubercle Ischium Pubic arch (a) 40 c: © Martin Rotker (c) Hip Bones 髋骨 Also known as the coxae: • Acetabulum 髋臼 • There are three (3) bones: Iliac crest 1. Ilium髂骨 Iliac fossa Anterior • Iliac crest髂嵴 superior iliac spine • Iliac spines髂棘 • Greater sciatic notchAnterior inferior iliac spine 坐骨大切迹 Obturator foramen 2. Ischium坐骨 • Ischial spines坐骨棘 Pubis • Lesser sciatic notch 坐骨小切迹 • Ischial tuberosity坐骨结节 (a) 3. Pubis耻骨 • Obturator foramen闭孔 • Symphysis pubis耻骨联合 • Pubic arch耻骨弓 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Iliac crest Posterior superior iliac spine Ilium Ilium Posterior inferior iliac spine Greater sciatic notch Acetabulum Obturator foramen Ischium Ischial spine Lesser sciatic notch Pubic crest Ischium Pubis Pubic tubercle Ischial tuberosity (b) 41 Greater and Lesser Pelvis Greater Pelvis • Lumbar vertebrae posteriorly • Iliac bones laterally • Abdominal wall anteriorly Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Flared ilium Sacral promontory Pelvic brim Symphysis pubis (a) Female pelvis Pubic arch Lesser Pelvis • Sacrum and coccyx posteriorly • Lower ilium, ischium, and pubic bones laterally and anteriorly Sacral promontory Sacral curvature (b) Male pelvis Pubic arch 42 Differences Between Male Female Pelves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Female VS Male • Iliac bones more flared • Broader hips • Pubic arch angle greater • More distance between ischial spines and ischial tuberosities • Sacral curvature shorter and flatter • Lighter bones Flared ilium Sacral promontory Pelvic brim Symphysis pubis (a) Female pelvis Pubic arch Sacral promontory Sacral curvature (b) Male pelvis Pubic arch 43 Lower Limb Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Femur股骨 Femur • Patella髌骨 Patella Femur Fibula • Tibia胫骨 Tibia (c) Lateral view • Fibula腓骨 Patella • Tarsals跗骨 Fibula Femur Tibia • Metatarsals跖骨 Lateral condyle Medial condyle Fibula Tibia • Phalanges趾骨 Tarsals Metatarsals Phalanges (b) (d) Posterior view 44 Femur Fovea capitis Longest bone of body Head Fovea capitis股骨头凹 Neck Greater trochanter大转子 Lesser trochanter小转子 Linea aspera股骨嵴 Condyles髁 Epicondyles上髁 Neck Head Greater trochanter Gluteal tuberosity Lesser trochanter Linea aspera Lateral epicondyle (a) Patellar surface Medial epicondyle Medial Lateral condyle condyle Intercondylar fossa (b) Patella Femur kneecap • Anterior surface of the knee joint • Flat sesamoid bone(子骨) located in the quadriceps tendon(股四头肌腱) Patella Femur Fibula Tibia (c) Lateral view Patella Fibula Femur Tibia Lateral condyle Medial condyle Fibula Tibia Tarsals Metatarsals (d) Posterior view Phalanges (b) 46 Tibia Lateral condyle Aka shin bone • Medial to fibula • Condyles • Tibial tuberosity • Anterior crest • Makes the medial malleolus Head of fibula Intercondylar eminence Medial condyle Tibial tuberosity Anterior crest Fibula Tibia Lateral malleolus Medial malleolus Fibula Lateral condyle • Lateral to tibia • Long, slender • Head • Makes the lateral malleolus • Non-weight bearing Head of fibula Intercondylar eminence Medial condyle Tibial tuberosity Anterior crest Fibula Tibia Lateral malleolus Medial malleolus Foot Tarsal Bones (14) • Calcaneus跟骨 • Talus距骨 • Navicular舟骨 • Cuboid • Lateral (3rd) cuneiform(楔状骨) • Intermediate (2nd) cuneiform • Medial (1st) cuneiform Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fibula Tibia Talus Medial cuneiformNavicular Metatarsals (metatarsus) Metatarsal Bones 跖骨(10) Phalanges趾骨 (28) • Proximal • Middle • Distal Calcaneus Phalanges Calcaneal tuberosity (b) Tarsals (tarsus) 49 Foot Calcaneus Talus Tarsals (tarsus) Navicular Cuboid Lateral cuneiform Intermediate cuneiform Medial cuneiform 5 4 3 2 1 Metatarsals (metatarsus) Proximal phalanx Middle phalanx Distal phalanx (a) Phalanges 50 骨骼的组织学 Long bone Diaphysis: long shaft of bone Epiphysis: ends of bone Epiphyseal plate: growth plate Metaphysis: b/w epiphysis and diaphysis Articular cartilage: covers epiphysis Periosteum: bone covering (pain sensitive) Sharpey’s fibers: periosteum attaches to underlying bone Medullary cavity: Hollow chamber in bone - red marrow produces blood cells - yellow marrow is adipose. Endosteum: thin layer lining the medullary cavity Blood and nerve supply to bone Abundant supply of blood May have several nutrient arteries Nerves accompany blood vessels Periosteum (review) Outer layer : protective, fibrous dense irregular connective tissue Inner layer: osteogenic stem cells that differentiate (specialize) into bone cells like osteoblasts (bone forming) or osteoclasts (bone dissolving) cells. Periosteum: double-layered membrane on external surface of bones Woven and Lamellar Bone Woven bone – Formed • During fetal development • During fracture repair Remodeling – Removing old bone and adding new Lamellar bone – Mature bone in sheets called lamellae 6-56 Histology of bone tissue Cells are surrounded by matrix. - 25% water - 25% protein - 50% mineral salts Abundant inorganic mineral salts: •Tricalcium phosphate in crystalline form -- hydroxyapatite Ca3(PO4)2(OH)2 •Calcium Carbonate: CaCO3 •Magnesium Hydroxide: Mg(OH)2 •Fluoride (氟化物)and Sulfate(硫酸盐) These salts are deposited on the collagen fiber framework (tensile strength) and crystallization occurs.- calcification or mineralization Bone cells 4 types make up osseous tissue Osteoclasts Osteoprogenitor cells Osteoblasts Osteocytes Bone Matrix 6-59 Osteoprogenitor cells or mesenchymal stem cells(MSCs): • derived from mesenchyme -all connective tissue is derived • unspecialized stem cells • undergo mitosis and develop into osteoblasts • found on inner surface of periosteum and endosteum. Osteoblasts: • • • • bone forming cells found on surface of bone no ability to mitotically divide collagen secretors Osteocytes: • • • • mature bone cells derived form osteoblasts do not secrete matrix material cellular duties include exchange of nutrients and waste with blood. Osteoclasts • bone resorbing cells • bone surface • growth, maintenance and bone repair Structure of Bone Tissue Compact bone Spongy bone 19 Sept. 2012 Bone_tissue.ppt 63 Structure of Bone Tissue Compact bone – Hard, densely calcified “typical bone” – Living tissue with blood supply, nerves – Organized of osteons 19 Sept. 2012 Bone_tissue.ppt 64 Structure of Bone Tissue Compact bone – Osteon • Central (Haversian) canal at center • Osteocytes in lacunae surrounding Haversian canal • Lamellae of bone matrix between rings of osteocytes 19 Sept. 2012 Bone_tissue.ppt 65 Structure of Compact Bone Osteons can’t fit together • Interstitial lamellae fill space to make solid structure • Circumferential lamellae fill space to shape outer surface of bone 19 Sept. 2012 Bone_tissue.ppt 66 Cancellous Bone Consists of trabeculae – Oriented along lines of stress 6-69 Structure of Spongy Bone Spongy bone – Trabeculae • Irregular thin plates & struts of hydroxyapatite with osteocytes – Spaces between filled with marrow (yellow or red) 19 Sept. 2012 Bone_tissue.ppt 70 Compact VS Spongy bone Compact bone – External layer – Arranged in osteons – Lamellae are found around periphery and between osteons – Central canals connected to each other by perforating canals Spongy bone – No osteons – Arranged in trabeculae – Major type of tisse in short, flat, irregular bones – Much lighter than compact bone – Supports red bone marrow 骨骼的发育 Formation of Bone: Ossification Two mechanisms – Intramembranous ossification(膜内成骨） – Endochondral ossification No difference in final result. 73 Intramembranous ossification Begins in embryonic mesenchyme membranes Mesenchyme cells become osteoblasts Begin laying down matrix (osteoid) 74 Intramembranous ossification Layer of “woven bone” and periosteum(骨膜) Remodeling to form compact bone on surfaces Cranial(颅骨) & facial bones, mandible(下颌骨), clavicles. 75 Endochondral ossification Embryonic mesenchyme differentiates to cartilage – Chondrocytes – Perichondrium(软骨膜) “Cartilage model” is starting point for endochondral ossification(软骨内成骨) – (endo- = within, chondr- = cartilage) 76 Endochondral ossification Perichondrium becomes periosteum Mesenchyme cells become osteoblasts Form primary ossification center Cartilage under bone collar calcifies & dies (软骨钙化及凋亡) 77 Endochondral ossification Invasion of nutrient blood vessel Continued deterioration of cartilage (软骨进一步退化) Formation of spongy bone 78 Endochondral ossification Elongation of primary ossification center Formation of marrow cavity Formation of secondary ossification centers at ends Ossification of epiphyses(骨骺) 79 Postnatal bone growth Growth in length at epiphyseal plates – Growth of cartilage – Bone tissue “races” to keep up Growth in width at periosteum – Dismantling and remodeling(分解及重塑) 80 Growth in Bone Length Appositional growth – New bone on old bone or cartilage surface Epiphyseal plate zones – – – – ①Resting cartilage ②Proliferation ③Hypertrophy ④Calcification Physiology of bone growth Four zones of bone growth under hGH ① Zone of resting cartilage - no bone growth - located near the epiphyseal plate - scattered chondrocytes - anchors plate to bone ② Zone of proliferating cartilage - chondrocytes stacked like coins - chondrocytes divide Physiology of bone growth ③ Zone of hypertrophic (maturing)cartilage - large chondrocytes arranged in columns - lengthwise expansion of epiphyseal plate ④ Zone of calcified cartilage - few cell layers thick - occupied by osteoblasts and osteoclasts and capillaries from the diaphysis - cells lay down bone - dead chondrocytes surrounded by a calcified matrix. Growth in Bone Length Growth in Bone Width When does lengthening stop? Age 18-21: Longitudinal bone growth ends when epiphysis fuses with the diaphysis – epiphyseal plate closure – epiphyseal line is remnant last bone to stop growing: clavicle When does lengthening stop? Lengthening stops at the end of adolescence – Chondrocytes stop mitosis(分裂) – Plate thins out and replaced by bone – Diaphysis and epiphysis fuse to be one bone • Epiphyseal plate closure (18 yr old females, 21 yr old males) Thickening of bone continuous throughout life Factors Affecting Bone Growth Nutrition – Vitamin D • Necessary for absorption of calcium from intestines • Insufficient causes rickets and osteomalacia – Vitamin C • Necessary for collagen synthesis by osteoblasts • Deficiency results in scurvy Hormones – Growth hormone from anterior pituitary – Thyroid hormone required for growth of all tissues – Sex hormones as estrogen and testosterone 6-91 骨骼的维持 Bone Remodeling Bone Remodeling Bone structural integrity is continually maintained by remodeling • Osteoclasts and osteoblasts assemble into Basic Multicellular Units (BMUs) 骨骼基本多细胞单位 • Bone is completely remodeled in approximately 3 years Amount of old bone removed equals new bone formed Biomechanical Characteristics of Bone Wolff’s Law bone is laid down where needed and resorbed where not needed shape of bone reflects its function – tennis arm of pro tennis players have cortical thicknesses 35% greater than contralateral arm (Keller & Spengler, 1989) osteoclasts resorb or take-up bone osteoblasts lay down new bone Bone is Dynamic! Bone is constantly remodeling and recycling Coupled process between 1. Bone deposition (by osteoblasts)成骨细胞 2. Bone destruction/resorption (by osteoclasts)破骨细胞 5-7% of bone mass recycled weekly All spongy bone replaced every 3-4 years All compact bone replaced every 10 years Prevents mineral salts from crystallizing; protecting against brittle bones and fractures Bone Resorption骨的再吸收 Osteoclasts are related to macrophages • Secrete lysosomal enzymes and HCl acid(溶酶体酶) • Move along surface of bone, dissolving grooves into bone with acid and enzymes • Dissolved material passed through osteoclasts and into bloodstream for reuse by the body Bone Deposition • Thin band of osteoid (unmineralized bone) laid down by osteoblasts, located on inner surface of periosteum and endosteum. • Mineral salts (Ca2+ and Pi) are precipitated out of blood plasma and deposited amongst the osteoid fibers – Requires proper Ca2+ and Phosphate ion concentration – Vitamin D, C, A, and protein from diet (Poor nutrition will negatively affect bone health) Bone Remodeling Sequence Osteocytes Activation Quiescence Resorption Formation & Mineralization Reversal Bone is a reservoir for Calcium Constant supply of Ca2+ in the blood stream is needed for – Transmission of nerve impulses – Muscle contraction – Blood coagulation – Cell division A narrow range of 9-11 mg Ca/100 ml blood maintained at all times Bone remodeling = key in maintaining proper blood calcium levels Calcium Homeostasis Bone is the major storage site for calcium in the body – Calcium moves into bone as osteoblasts build new bone – Calcium moves out of bone as osteoclasts break down bone – When osteoclast and osteoblast activity is balanced, the movement of calcium in and out is equal 6-101 Calcium Homeostasis 6-102 Bone growth regulated by hormones Human Growth Hormone (HGH): from pituitary gland in brain promotes epiphyseal plate activity Thyroid hormones: regulate HGH for proper bone proportions Excesses in any hormones can cause abnormal skeletal growth Ex. gigantism or dwarfism Yao Defen, gigantess currently in treatment for pituitary tumor in China 7 ft 7 inches 396 lbs Effects of Aging on Skeletal System Bone Matrix decreases Bone Mass decreases Increased bone fractures Bone loss causes deformity, loss of height, pain, stiffness – Stooped posture – Loss of teeth 6-104 Bone Mass (g of Ca) Age, Bone Mass and Gender 1000 500 0 25 50 Age (yr) 75 From: Biomechanics of Musculoskeletal Injury, Whiting and Zernicke 100 Changes in bone over time Early Years Osgood-Schlatter’s disease • development of inflammation, bony deposits, or an avulsion fracture of the tibial tuberosity muscle-bone strength imbalance • “growth factor” between bone length and muscle tendon unit (e.g., rapid growth of femur and tibia places large strain on patellar tendon and tibial tuberosity) • during puberty muscle development (testosterone) may outpace bone development allowing muscle to pull away from bone Changes in bone over time Early Years overuse injuries – repeated stresses mold skeletal structures specifically for that activity – Little Leaguer’s Elbow • premature closure of epiphyseal disc – Gymnasts • 4X greater occurrence of low back pathology in young female gymnasts than in general population (Jackson, 1976) Changes in bone over time Adult Years little change in length most change in density – lack of use decreases density • DECREASE STRENGTH OF BONE activity – increased activity leads to increased diameter, density, cortical width and Ca Changes in bone over time Adult Years hormonal influence – estrogen to maintain bone minerals – previously only consider after menopause – now see link between amenorrhea and decreased estrogen - Female Athlete Triad disordered eating amenorrhea low body fat excessive training osteoporosis low estrogen levels Changes in Bone Over Time Older Years 30 yrs males and 40 yrs females – BMD peaks (Frost, 1985; Oyster et al., 1984) – decrease BMD, diameter and mineralization after this activity slows aging process Osteopenia Reduced BMD slightly elevated risk of fracture Osteoporosis Hormonal Factors Nutritional Factors 28 million Americans affected – 80% of these are women 10 million suffer from osteoporosis 18 million have low bone mass Severe BMD reduction very high risk of fracture (hip, wrist, spine, ribs) Physical Activity Osteoporosis age – women lose 0.5-1% of their bone mass each year until age 50 or menopause – after menopause rate of bone loss increases (as high as 6.5%) Do you get shorter with age? Osteoporosis compromises structural integrity of vertebrae(椎体) – weakened trabecular bone – vertebrae are “crushed” • actually lose height • more weight anterior to spine so the compressive load on spine creates wedgeshaped vertebrae – create a kyphotic curve known as Dowager’s Hump • for some reason men’s vertebrae increase in diameter so these effects are minimized Preventing Osteoporosis $13.8 billion in 1995 (~$38 million/day) Lifestyle Choices – proper diet • sufficient calcium, vitamin D, • dietary protein and phosphorous (too much?) • tobacco, alcohol, and caffeine – EXERCISE, EXERCISE, EXERCISE • 47% incidence of osteoporosis in sedentary population compared to 23% in hard physical labor occupations (Brewer et al., 1983) Osteoporosis, Activity and the Elderly Rate of bone loss (50-72 yr olds, Lane et al., 1990) – 4% over 2 years for runners – 6-7% over 2 years for controls However rate of loss jumped to 10-13% after stopped running suggest substitute activities should provide high intensity loads, low repetitions (e.g. weight lifting) Response to Mechanical /Gravitational Forces Wolff’s Law: – Bones respond to muscles pulling on them (mechanical stress) and to gravity by keeping the bones strong where they are being stressed. • weight bearing activities stronger projections where muscles/ligaments attach and thicker bones where there is compression. • High rate of bone deposition in specific areas. Bone Deposits A response to regular activity – regular exercise provides stimulation to maintain bone throughout the body tennis players and baseball pitchers develop larger and more dense bones in dominant arm male and female runners have higher than average bone density in both upper and lower extremities non-weightbearing exercise (swimming, cycling) can have positive effects on BMD Bone Resorption lack of mechanical stress – Calcium (Ca) levels decrease – Ca removed through blood via kidneys • increases the chance of kidney stones(肾结石) weightless effects (hypogravity)低重 – astronauts use exercise routines to provide stimulus from muscle tension • these are only tensile forces - gravity is compressive Disuse Immobilization, bed rest, space flight Space flight: lack of loads – deposition – resorption – affect more weight bearing trabercular bones Mostly reversible process: recovery is much slower Early mobilization – fracture braces etc. 骨骼的生物力学 Biomechanical Characteristics of Bone - Bone Tissue Organic Components (e.g. collagen) Inorganic Components (e.g., calcium and phosphate) 65-70% (dry wt) H2O (25-30%) 25-30% (dry wt) ductile one of the body’s hardest structures brittle viscoelastic Mechanical Loading of Bone Compression Tension Shear剪切力 Torsion Bending Compressive Loading Vertebral fractures cervical fractures spine loaded through head e.g., football, diving, gymnastics once “spearing” was outlawed in football the number of cervical injuries declined dramatically lumbar fractures weight lifters, linemen, or gymnasts spine is loaded in hyperlordotic (aka swayback) position Tensile Loading Main source of tensile load is muscle tension can stimulate tissue growth fracture due to tensile loading is usually an avulsion other injuries include sprains, strains, inflammation, bony deposits when the tibial tuberosity experiences excessive loads from quadriceps muscle group develop condition known as Osgood-Schlatter’s disease Shear Forces created by the application of compressive, tensile or a combination of these loads Bone Compressive Strength Material Femur (cortical) Compressive Strength (MPa) 131-224 Tibia (cortical) 106-200 Wood (oak) 40-80 Steel 370 From: Biomechanics of the Musculo-skeletal System, Nigg and Herzog Relative Strength of Bone Bending Forces Usually a 3- or 4-point force application Torsional Forces •Caused by a twisting force produces shear, tensile, and compressive loads •tensile and compressive loads are at an angle •often see a spiral fracture develop from this load Testing Procedures • Same testing principles used for testing materials • Materials can be tested under: – – – – – compression tension torsion bending shear • Sample of material of known dimension is tested Geometry几何学 A Moment of Inertia – I=mr2 Example A: • smaller moment of inertia, bending will occur Example B: • larger (I) greater cross-sectional more stiffness B Structural vs. material properties Material properties are the characteristics of the material regardless of size, density etc. The femur and phalange can have the same material properties but different structural properties (maximal load, bending stiffness) Bone geometry I Exam I Periostial Endosteal Bone area Area I Force Stress 2 0.5 2.95 0.78 20 256 Exam II 2 0 3.14 0.79 20 253 Exam III 2.5 2d= 2.0 1.77 1.13 20 221 Increase in stiffness without adding mass Why not solid bones? II III d = 2.5 Material Properties Comparison* Material Compressive Strength (MPa) Modulus (GPa) Cortical 10-160 4-27 Trabelcular 7-180 1-11 Concrete ~4 30 Steel 400-1500 200 Wood 100 13 Strength and Stiffness of Bone Tissue evaluated using relationship between applied load and amount of deformation LOAD - DEFORMATION CURVE Bone Tissue Characteristics Anisotropic非匀质 Viscoelastic Elastic Plastic可塑 Load-deformation curve • Elastic region • Proportional limit (yield point) • Elastic limit • Plastic region • Ultimate strength • Energy stored Stress = Force/Area Strain = Change in Length/Angle Note: Stress-Strain curve is a normalized Load-Deformation Curve Elastic & Plastic responses plastic region fracture/failure Stress (Load) elastic region •elastic thru 3%deformation •plastic response leads to fracturing Dstress •Strength defined by failure point Dstrain •Stiffness defined as the slope of the •elastic portion of the curve Strain (Deformation) Anisotropic response behavior of bone is dependent on direction of applied load Bone is strongest along long axis - Why? Elastic Biomaterials (Bone) Elastic/Plastic characteristics Brittle material fails before permanent deformation Ductile material deforms greatly before failure Load/deformation curves elastic limit ductile material 韧性材料 brittle material 刚性材料 Bone exhibits both properties bone deformation (length) Bone Anisotropy trabecular tension compression cortical shear tension compression 0 50 100 150 Maximum Stress (MPa) From: Biomechanics of the Musculo-skeletal System, Nigg and Herzog 200 Viscoelastic Response behavior of bone dependent on rate load is applied Bone will fracture sooner when load applied slowly Load fracture fracture deformation Mechanical properties of cortical bone • Anisotropic • Stiffness: calcium/porosity • Poisson ratio() – High: < 0.6 • Absorbs ME before fracture • Ductile: Allows deformation Cortical Bone Properties Viscolelastic • Strain-rate sensitive rate ultimate strength also • Fatigue: cyclic loads • Remodeling outpaced by damage microcracks develop, stress fractures • Microcracks(微裂隙): most likely to occur in the highly mineralized part of the bone Trabercular Bone Mesh network: different densities and patterns Nonlinear elastic modulus and strength Marrow: Enhances Load bearing effect Fatigue of Bone Microstructural damage due to repeated loads below the bone’s ultimate strength – Occurs when muscles become fatigued and less able to counter-act loads during continuous strenuous physical activity – Results in Progressive loss of strength and stiffness Cracks begin at discontinuities within the bone (e.g. haversian canals, lacunae) – Affected by the magnitude of the load, number of cycles, and frequency of loading Fatigue of Bone 3 Stages of fatigue fracture – Crack Initiation • Discontinuities result in points of increased local stress where micro cracks form – Often bone remodeling repairs these cracks – Crack Growth (Propagation) • If micro cracks are not repaired they grow until they encounter a weaker material surface and change direction – Often transverse growth is stopped when the crack turns from perpendicular to parallel to the load – Final Fracture • Occurs only when the fatigue process progresses faster than the rate of remodeling http://www.orthoteers.co.uk/Nrujp~ij33lm/Orthbonemech.htm Simon, SR. Orthopaedic Basic Science. Ohio: American Academy of Orthopaedic Surgeons; 1994. Fatigue Fracture A fatigue fracture may be caused by: – Abnormal muscle stress • Loss of shock absorption • Strenuous or repeated activity –Torque 力矩 • bone with normal elastic resistance – Associated with new or different activity • Abnormal loading • Abnormal stress distribution Process to Fatigue Failure Road to Failure: Region 1 1. Crack initiation起始 2. Accumulation 3. Growth Characteristics: – Matrix damage in regions of • • High stress concentration Low strength Causes of Stress Fractures There are two theories about the origin of stress fractures: 1. Fatigue theory 2. Overload theory Fatigue Theory During repeated efforts (as in running) • Muscles become unable to support during impact • Muscles do not absorb the shock • Load is transferred to the bone • As the loading surpasses the capacity of the bone to adapt • A fracture develops Overload Theory Certain muscle groups contract Cause the attached bones to bend After repeated contractions and bending Bone finally breaks 骨折愈合 Fractures: Any bone break. Blood clot will form around break Fracture hematoma Inflammatory process begins Blood capillaries grow into clot Phagocytes and osteoclasts remove damaged tissue Procallus forms and is invaded by osteoprogenitor cells and fibroblasts Collagen and fibrocartilage turns procallus to fibrocartilagenous (soft) callus Broken ends of bone are bridged by callus Osteoprogenitor cells are replaced by osteoblasts and spongy bone is formed Bony (hard) callus is formed Callus is resorbed by osteoclasts and compact bone replaces spongy bone. Remodeling : the shaft is reconstructed to resemble original unbroken bone. Bone Repair 6-160 Fractures MUST Have A Blood Supply to Heal Bone Blood Supply Endosteal Inner 2/3rds Periosteal Outer 1/3rd Disrupted by a fracture Further damaged by surgery Bone Blood Supply Reaming Damages endosteal blood supply Blood flow reverses BUT Stimulates callus Bone blood supply Plates Damage periosteal blood supply Causes underlying necrosis Bone blood supply - plates • Can be reduced by – LCDCP – Locking plate Augmentation of Fracture Healing Bone Grafts Bone Graft Substitutes Osteo-inductive agents Mechanical methods Ultrasound Electromagnetic fields Bone Graft Properties Osteoconduction 3D scaffold Osteo-induction Biological stimulus Mesenchymal cells Osteoprogenitor cells Osteogenic Contains living cells that can differentiate to from bone Structural Osteo-inductive Agents Transforming growth factor Superfamily BMPs GDFs (growth differentiation factors) Possibly TGF-β 1, 2, and 3. Demineralized Bone Matrix • Acid extraction of allograft – type-1 collagen – non-collagenous proteins – osteoinductive growth factors: BMP, GDFs, TGF1,2 + 3 Different companies , processing different ALLOGRAFT, no reported infection transmission BMP 7 (OP-1) Tibial non-unions RCT OP1 v autogenous graft No difference in union rate Less infections Friedlaender et al J Bone Joint Surg Am. 2001;83 Suppl 1(Pt 2):S151-8. Open Tibia OP1 v control Less secondary interventions McKee et al Proceedings of the 18th Annual Meeting of the Orthopaedic Trauma Association; 2002 Oct 11-13 OP 1 653 cases, overall success rate 82% Injury, Int. J. Care Injured (2005) 36S, S47—S50 BMP £ 3000 per vial Mean number of operations Pre BMP 4.16 Post BMP 1.2 Hospital stay and cost Pre BMP 26.84 days and £ 13,844.68 Post BMP 7.8 days and £ 7338.40 Overall cost using BMP-7 - 47.0% less. Injury, Int. J. Care Injured (2007) 38, 371—377 BMP 2 BESTT Open tibial fractures Control v 6mg v 12mg Higher dose Fewer secondary procedures accelerated time to union improved wound-healing Reduced infection rate Govender et al Recombinant human bone morphogenetic protein-2 for treatment of open tibial fractures: a prospective, controlled, randomized study of four hundred and fifty patients. J Bone Joint Surg Am. 2002;84:2123-34. Osteoconductive Making the break. Karin Hing's fellowship has brought independence to pursue her work on bone graft substitutes. Osteoconductive RCT’s osteoconductive materials Vs autograft encouraging. Calcium sulfate Predictable resorption Resorbs a little too fast Calcium phosphates Tricalcium phosphate TCP Hydroxyapatite TCP is more rapidly absorbed than hydroxyapatite, TCP inadequate when structural support is desired Injectable osteoconductive cements Several variations Concentrated Bone Marrow Aspirate Non union – 75-95% success Aseptic non-unions Only works if adequate cell concentration Hernigou Pet al Influence of the number and concentration of progenitor cells. J Bone Joint Surg Am. 2005;87:1430 -7 Concentrated BM aspirate Ongoing multicentre RCT in France Open tibial fractures Composite Synthetic Graft Prospective multicenter RCT 249 long-bone #, min two years FU Bone graft v biphasic calcium phosphate mixed with bovine collagen + autogenous bone marrow No sig. diff. More infections with bone graft (22 v 9 p=0.008) Chapman MW et al. Treatment of acute fractures with a collagen-calcium phosphate graft material. A randomized clinical trial. J Bone Joint Surg Am. 1997;79:495-502. Mechanics Controlled axial micromotion Compression Distraction LIPUS Electromagnetic Controlled axial micromotion Prospective RCT 102 tibial fractures 1.0 mm at 0.5 Hz /30 minutes per day Sig. reduction Time to union Secondary surgery Kenwright J, Goodship AE. Controlled mechanical stimulation in the treatment of tibial fractures. Clin Orthop 1988;241:36-47. Low Intensity Ultrasound Several RCTs Reduced time to union Non-op tibia (No benefit in nailed #) Scaphoids Impacted distal radius Jones May reduce time to healing JW Busse et al. The effect of low-intensity pulsed ultrasound therapy on time to fracture healing: a meta-analysis. Canadian Medical Association Journal 2002 166: 437-441 Sonic Accelerated Fracture Healing System (SAFHS®) Exogen 2000® Acute fractures with ultrasound Inconsistency in evidence ? Type II failure Available evidence supports the use of ultrasound in the treatment of acute fractures of tibia and radius treated with plaster immobilization. (non op) No benefit of LIPUS in the treatment of fractures of the tibia managed with intramedullary fixation. J Trauma. 2008 Dec;65(6):1446-52 Current evidence on the efficacy of low-intensity pulsed ultrasound to promote fracture healing is adequate to show that this procedure can reduce fracture healing time and gives clinical benefit, particularly in circumstances of delayed healing and fracture non-union. There are no major safety concerns. Therefore this procedure may be used with normal arrangements for clinical governance, consent and audit Electromagnetic Devices In vivo Osteoblasts BMP,TGFs, IGF Small RCT 66% vs 0 healing of tibial non-union Scott G, King JB. A prospective double blind trial of electrical capacitive coupling in the treatment of nonunion of long bones. J Bone Joint Surg [Am] 1994;76-A:820-6. Several series 64-87% union of tibial non-union 知识要点 主要骨骼结构（脊柱，骨盆，肱骨，尺骨，桡骨 ，股骨，胫骨，腓骨，跟骨等） 骨组织的结构，骨单位结构 骨组织的细胞和细胞外基质成分和作用 骨组织发育过程主要事件 骨组织代谢平衡主要过程 骨组织生物力学特性 骨愈合主要过程和要素 谢 谢！
