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THE SKELETAL SYSTEM 1 BONE FUNCTION • Support • gives shape to head, etc. • supports body’s weight •Leverage • articulation •Bones and muscles interact • Inorganic Salt Storage • calcium • phosphate • magnesium • sodium • potassium • Blood Cell Formation • hematopoiesis • red marrow • Protection • for major organslungs, etc 2 STRUCTURE: OSSEOUS TISSUE •Connective tissue •Specialized cells •Extracellular fibers •Ground substance •Calcium phosphates are 2/3 of bone weight 3 CLASSIFICATION SYSTEM Bone Classification • Long Bones- longer than wide •Femur pg 111 (black book) •Diaphysis – central shaft •Marrow cavity •Epiphysies –ends 4 CLASSIFICATION SYSTEM, CON’T •Short Bones •Equal in dimensions •Ex: carpals/tarsals 5 CLASSIFICATION SYSTEM, CON’T •Flat Bones •Thin and broad •Scapula •these bones protect the internal organs and include the skull (cranium), ribs, scapula (shoulder blade), sternum (breast bone) and the pelvic girdle. 6 CLASSIFICATION SYSTEM, CON’T •Irregular Bones •vertebrae 7 CLASSIFICATION, CON’T •Two types of bone tissue •compact/dense •Spongy - spaces •Outer surfaces of bone: •Periostium – outside layer •Where tendons and ligaments attach •Endosteum – lines the marrow cavity •Active during repair or remodeling, or normal growth 8 PARTS OF A LONG BONE • epiphysis • distal • proximal • diaphysis • compact bone • spongy bone • articular cartilage • periosteum • endosteum • medullary cavity • trabeculae • marrow • red • yellow 9 10 MICROSCOPIC STRUCTURE OF COMPACT AND SPONGY BONE •Histology: •Osteocytes- bone cells •Lacunae – •pockets in spongy bone •Found between lamellae •Lamellae •Calcified matrix •Canaliculi •Channels radiating through the matrix •Link to blood vessels 11 MICROSCOPIC STRUCTURE OF COMPACT BONE • osteon •Functional unit of compact bone •Aka Haversian system (pg 112 in black book) •central canal •Contains blood vessels surrounded by osteocytes •perforating canal •Contains linking blood vessels •Found where bone is stressed 12 MICROSCOPIC FEATURES OF SPONGY BONE •Trabeculae •Lamelle with no osteons •It is rods or plates •Found where there is not much stress •Cells Found in Bone •Osteocytes – •mature bone cells •Osteoclasts – •giant cells that regulate Ca and phosphates in fluids. •Break down bone cells •Osteoblasts – precursor cells Marrow Cavity (Osteoclasts)13 OSTEON 14 BONE DEVELOPMENT Endochondral Ossification • most bones of the skeleton •bones begin as hyaline cartilage •form models for future bones •Begins from center of shaft as early as 6 wks after fertilization •Proceeds to both ends •Epiphyseal plate: cartilage that separates shaft from end •Shaft side – bond keeps advancing •End side – keeps producing cartilage •Hormones during teens speed process up •Epiphysial line – what is left when growth is finished 15 ENDOCHONDRAL OSSIFICATION 16 GROWTH AT THE EPIPHYSEAL PLATE First layer of cells • closest to the end of epiphysis • resting cells • anchors epiphyseal plate to epiphysis Second layer of cells • many rows of young cells • undergoing mitosis 17 GROWTH AT THE EPIPHYSEAL PLATE Third layer of cells • older cells • left behind when new cells appear • cells enlarging and becoming calcified Fourth layer of cells • thin • dead cells • calcified extracellular matrix 18 FACTORS AFFECTING BONE DEVELOPMENT, GROWTH, AND REPAIR • Deficiency of Vitamin A – retards bone development • Deficiency of Vitamin C – results in fragile bones • Deficiency of Vitamin D – rickets, osteomalacia • Insufficient Growth Hormone – dwarfism • Excessive Growth Hormone – gigantism, acromegaly • Insufficient Thyroid Hormone – delays bone growth • Sex Hormones – promote bone formation; stimulate ossification of epiphyseal plates • Physical Stress – stimulates bone growth •Lack of stress causes fast bone loss (3 weeks = 1/3 bone loss 19 HOMEOSTASIS OF BONE TISSUE •Adults – Bone is constantly breaking down and building up 18% of protein and mineral is replaced yearly •Add calcium to body fluids: parathyroid hormone and calcitriol work together •Take calcium out of fluids and into bone: – action of calcitonin 20 HOMEOSTASIS OF BONE TISSUE, CON’T •Calcium: must abundant mineral in body – bones store it •Average human contains 1-2 kg (2.2 – 4.4 lb) of Ca •99% in bones •30 % too much in fluids causes muscles & neurons to be unresponsive •35% too much in fluids causes: muscle and neurons to convolse •50% reduction in fluids may cause death 21 INJURY AND REPAIR •Fracture: cracks and Types of Fractures breaks in bone •Classified by external appearance Pg. 117 black book 22 FRACTURES Open or closed (simple) fractures 23 INJURY AND REPAIR •Sequence of Repair •1st: massive blood clot called a fracture hematoma occurs •2nd Internal and external callus is formed •3rd: external callus replaced by bone Old dead bone has been dissolved •4th Swelling marks new bone. Eventually remodels 24 AGING AND THE SKELETAL SYSTEM • decrease in height at about age 30 • calcium levels fall – NATURALLY: Osteopenia • bones become brittle • osteoclasts outnumber osteoblasts • spongy bone weakens before compact bone • bone loss rapid in menopausal women- 8% per decade. Men 3% per decade as they age • hip fractures common • vertebral compression fractures common Osteoporosis 25 JOINTS Rigid elements of the skeleton meet at joints or articulations Greek root “arthro” means joint Articulations can be: Bone to bone Bone to cartilage Teeth in bony sockets CLASSIFICATIONS OF JOINTS Joints can be classified by function or structure (in this class we will only do the functional classifications) Functional classification – based on amount of movement Synarthroses – immovable – common in axial skeleton Amphiarthroses – slightly movable – common in axial skeleton Diarthroses – freely movable – common in appendicular skeleton SYNARTHROSIS - IMMOVABLE Includes Suture: joint site Tooth to socket Epiphysial plates Coronal suture 28 AMPHIARTHROSIS – SLIGHTLY MOVABLE Ex: between tibia and fibula Symphysis: between two pelvic bones 29 SYMPHYSES Hyaline cartilage – also present as articular cartilage Figure 9.2c DIARTHROSIS -= FREELY MOVABLE Synovial joints – Usually found at the end of the long bones No bone touching bone Encapsulated by cartilages Cushioned by synovial fluid 31 SYNOVIAL JOINTS Most movable type of joint All are diarthroses Each contains a fluid-filled joint cavity Most are “simple” and have just two articulating surfaces Some are “compound” with more than two articulating surfaces Examples include the elbow (humerus, radius and ulna) and knee (femur, tibia, fibula, patella) joints A TYPICAL SYNOVIAL JOINT Figure 9.3a DIARTHROSIS, CONT Kinds of movement Hinge – elbow, knee angle Pivot – atlas and axis rotates the head Saddle joints – at base of thumbs (twiddling) Ball and socket – shoulder and hip joints gliding – ends of clavicle, between carples, at some vertebrae 34 Pivot joint Hinge joint Gliding joint Ball and socket Saddle joint 35 Shoulder Joint • Ball and socket joint synovial and diarthrotic • Glenohumeral joint most movable joint in the body • Shallow glenoid fossa very easily dislocated • Articular cartilage hyaline cartilage at the ends of articulating bones Knee Joint • • • • The largest and most complex joint Synovial and diarthrotic Primarily acts as a hinge joint Two fibrocartilage menisci occur within the joint cavity (absorb stress) SAGITTAL SECTION OF KNEE JOINT Figure 9.12a SUPERIOR VIEW OF KNEE JOINT Figure 9.12b ANTERIOR VIEW OF KNEE Figure 9.12c KNEE JOINT Extracapsular Ligaments Become Provide taut when knee is extended support of sides of the knee Extracapsular Fibular Tibial ligaments: (lateral) collateral ligament (medial) collateral ligament ANTERIOR VIEW OF KNEE ANTERIOR VIEW OF FLEXED KNEE Figure 9.12e KNEE JOINT Cruciate Ligaments Prevent undesirable movements at the knee joint Figure 9.13a Ligaments and Tendons Ligaments – attach bone to bone Tendons – bone to muscle 46 SKELETAL ORGANIZATION Axial Skeleton • head • neck • trunk Appendicular Skeleton • upper limbs • lower limbs • pectoral girdle • pelvic girdle 47 SKELETAL ORGANIZATION 48 CRANIUM Frontal (1) • forehead • roof of nasal cavity • roofs of orbits • frontal sinuses • supraorbital foramen • coronal suture 49 CRANIUM Parietal (2) • side walls of cranium • roof of cranium • sagittal suture 50 CRANIUM Occipital (1) • back of skull • base of cranium • foramen magnum • occipital condyles • lambdoid suture 51 CRANIUM Temporal (2) • side walls of cranium • floor of cranium • floors and sides of orbits • squamous suture • external acoustic meatus • mandibular fossa • mastoid process • styloid process • zygomatic process 52 CRANIUM Sphenoid (1) • base of cranium • sides of skull • floors and sides of orbits • sella turcica • sphenoidal sinuses 53 CRANIUM Ethmoid (1) • roof and walls of nasal cavity • floor of cranium • wall of orbits • cribiform plates • perpendicular plate • superior and middle nasal conchae • ethmoidal sinuses • crista galli 54 FACIAL SKELETON Maxillary (2) • upper jaw • anterior roof of mouth • floors of orbits • sides of nasal cavity • floors of nasal cavity • alveolar processes • maxillary sinuses • palatine process 55 FACIAL SKELETON 56 FACIAL SKELETON Palatine (2) • L shaped bones located behind the maxillae • posterior section of hard palate • floor of nasal cavity • lateral walls of nasal cavity 57 FACIAL SKELETON Zygomatic (2) • prominences of cheeks • lateral walls of orbits • floors of orbits • temporal process 58 FACIAL SKELETON Lacrimal (2) • medial walls of orbits • groove from orbit to nasal cavity Nasal (2) • bridge of nose 59 FACIAL SKELETON Vomer (1) • inferior portion of nasal septum 60 FACIAL SKELETON Inferior Nasal Conchae (2) • extend from lateral walls of nasal cavity 61 FACIAL SKELETON Mandible (1) • lower jaw • body • ramus • mandibular condyle • coronoid process • alveolar process • mandibular foramen • mental foramen 62 INFANTILE SKULL Fontanels – fibrous membranes 63 VERTEBRAL COLUMN • cervical vertebrae (7) • thoracic vertebrae (12) • lumbar vertebrae (5) • sacrum • coccyx 64 VERTEBRAL COLUMN • cervical curvature • thoracic curvature • lumbar curvature • sacral curvature • rib facets • vertebra prominens • intervertebral discs • intervertebral foramina 65 CERVICAL VERTEBRAE • Atlas – 1st; supports head • Axis – 2nd; dens pivots to turn head • transverse foramina • bifid spinous processes • vertebral prominens – useful landmark 66 THORACIC VERTEBRAE • long spinous processes • rib facets 67 LUMBAR VERTEBRAE • large bodies • thick, short spinous processes 68 SACRUM • five fused vertebrae • median sacral crest • posterior sacral foramina • posterior wall of pelvic cavity • sacral promontory 69 COCCYX • tailbone • four fused vertebrae 70 THORACIC CAGE • Ribs • Sternum • Thoracic vertebrae • Costal cartilages • Supports shoulder girdle and upper limbs • Protects viscera • Role in breathing 71 RIBS • True ribs (7) • False ribs (5) • floating (2) 72 RIB STRUCTURE • Shaft • Head – posterior end; articulates with vertebrae • Tubercle – articulates with vertebrae • Costal cartilage – hyaline cartilage 73 STERNUM • Manubrium • Body • Xiphoid process 74 PECTORAL GIRDLE • shoulder girdle • clavicles • scapulae • supports upper limbs 75 CLAVICLES • articulate with manubrium • articulate with scapulae (acromion process) 76 SCAPULAE • spine • supraspinous fossa • infraspinous fossa • acromion process • coracoid process • glenoid cavity 77 UPPER LIMB • Humerus • Radius • Ulna • Carpals • Metacarpals • Phalanges 78 HUMERUS • head • greater tubercle • lesser tubercle • anatomical neck • surgical neck • deltoid tuberosity • capitulum • trochlea • coronoid fossa • olecranon fossa 79 RADIUS • lateral forearm bone • head • radial tuberosity • styloid process 80 ULNA • medial forearm bone • trochlear notch • olecranon process • coronoid process • styloid process 81 WRIST AND HAND • Carpals (16) • trapezium • trapezoid • capitate • scaphoid • pisiform • triquetrum • hamate • lunate • Metacarpals (10) • Phalanges (28) • proximal phalanx • middle phalanx • distal phalanx 82 PELVIC GIRDLE • Coxae (2) • supports trunk of body • protects viscera 83 COXAE • hip bones •acetabulum • ilium • iliac crest • iliac spines • greater sciatic notch • ischium • ischial spines • lesser sciatic notch • ischial tuberosity • pubis • obturator foramen • symphysis pubis • pubic arch 84 GREATER AND LESSER PELVES Greater Pelvis • lumbar vertebrae posteriorly • iliac bones laterally • abdominal wall anteriorly Lesser Pelvis • sacrum and coccyx posteriorly • lower ilium, ischium, and pubis bones laterally and anteriorly 85 MALE AND FEMALE PELVES Female • 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 86 LOWER LIMB • Femur • Patella • Tibia • Fibula • Tarsals • Metatarsals • Phalanges 87 FEMUR • longest bone of body • head • fovea capitis • neck • greater trochanter • lesser trochanter • linea aspera • condyles • epicondyles 88 PATELLA • kneecap • anterior surface of knee • flat sesamoid bone located in a tendon 89 TIBIA • shin bone • medial to fibula • condyles • tibial tuberosity • anterior crest • medial malleolus 90 FIBULA • lateral to tibia • long, slender • head • lateral malleolus • does not bear any body weight 91 ANKLE AND FOOT • Tarsals (14) • calcaneus • talus • navicular • cuboid • lateral cuneiform • intermediate cuneiform • medial cuneiform • Metatarsals (10) • Phalanges (28) • proximal • middle • distal 92 ANKLE AND FOOT 93 MAKE YOUR OWN SKELETON SIGNATURE Make your own skeletal signature at: http://www.signgenerator.org /logos/skeleton/ 94