Chapter 7 Skeletal System Bone Classification Long Bones Short Bones Flat Bones Irregular Bones Sesamoid Bones 7-2

Parts of a Long Bone red epiphysis- expanded end of long bone distal proximal diaphysis-shaft compact bone-outer surface spongy bone- cancellous bone, which contain bony plates called trabeculae. Found at the epiphysis of long bone. medullary cavity -hollow space found in the diaphysis and spaces of spongy bone endosteum - thin membrane lining the cavity-contains bone forming cell. periosteum-tough, vascular membrane covering the outer surface. marrow- red yellow 7-3

Major parts of long bone

Compact and Spongy Bone 7-4

Spongy bone Location: Flat bones, irregular bones, and end of long bones Osteocytes- lie within the bony plates No central canal A layer of spongy sandwiched between plates of compact bone In an adult, red marrow, is found in the spongy bone of all flat bones. In an infant, red marrow occupies the cavities of long bone. Yellow marrow stores fat and fills the cavity in an adult.

Compact bone In compact bone, the osteocyte's lie concentrically around a central canal. Each unit forms an osteon cemented together to form compact bone. Central canals - contains blood vessels and nerve fibers, which provide nutrients for bone cells. Transverse canals interconnect with the central canals, allowing communication between each osteon and the surface of bone. Collagen gives bone strength and inorganic salts make it hard and resistant.

Microscopic Structure of Compact Bone osteon central canal perforating canal osteocyte lacuna bone matrix canaliculus 7-5

Bone Development Intramembranous Ossification bones originate within sheetlike layers of connective tissues broad, flat bones skull bones (except mandible) intramembranous bones Endochondral Ossification bones begin as hyaline cartilage most bones of the skeleton endochondral bones 7-6

Endochondral Ossification hyaline cartilage model primary ossification center secondary ossification centers epiphyseal plate osteoblasts vs. osteoclasts 7-7

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 7-8

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 intercellular substance 7-9

Homeostasis of Bone Tissue Bone Resorption – action of osteoclasts and parathyroid hormone Bone Deposition – action of osteoblasts and calcitonin 7-10

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 7-11

Levers and Movement 7-14

Skeletal Organization Axial Skeleton head neck trunk Appendicular Skeleton upper limbs lower limbs pectoral girdle pelvic girdle 7-15

Skeletal Organization 7-16

Skull Frontal (1) forehead roof of nasal cavity roofs of orbits frontal sinuses supraorbital foramen coronal suture 7-17

Skull Parietal (2) side walls of cranium roof of cranium sagittal suture 7-18

Skull Temporal (2) wall of cranium floor of cranium floors and sides of orbits squamosal suture external acoustic meatus mandibular fossa mastoid process styloid process zygomatic process 7-19

Skull Occipital (1) back of skull base of cranium foramen magnum occipital condyles lambdoidal suture 7-20

Skull Sphenoid (1) base of cranium sides of skull floors and sides of orbits sella turcica sphenoidal sinuses 7-21

Skull 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 gallis 7-22

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 7-23

Facial Skeleton Palatine (2) posterior roof of mouth floor of nasal cavity lateral walls of nasal cavity 7-24

Facial Skeleton Zygomatic (2) prominences of cheeks lateral walls of orbits floors of orbits temporal process 7-25

Facial Skeleton Lacrimal (2) Nasal (2) medial walls of orbits groove from orbit to nasal cavity Nasal (2) bridge of nose 7-26

Facial Skeleton Vomer (1) inferior portion of nasal septum 7-27

Facial Skeleton Inferior Nasal Conchae (2) extend from lateral walls of nasal cavity 7-28

Facial Skeleton Mandible (1) lower jaw body ramus mandibular condyle coronoid process alveolar process mandibular foramen mental foramen 7-29

Vertebral Column cervical vertebrae C1—c7 thoracic vertebrae T1-T12 lumbar vertebrae L1-L5 sacrum S1-S5 coccyx 5-fused 7-31

Vertebral Column cervical curvature thoracic curvature lumbar curvature pelvic curvature rib facets vertebra prominens intervertebral discs intervertebral foramina 7-32

Cervical Vertebrae Atlas – 1st; supports head Axis – 2nd; dens pivots to turn head transverse foramina bifid spinous processes vertebral prominens – useful landmark 7-33

Thoracic Vertebrae long spinous processes rib facets 7-34

Lumbar Vertebrae large bodies thick, short spinous processes 7-35

Sacrum five fused vertebrae median sacral crest dorsal sacral foramina posterior wall of pelvic cavity sacral promontory 7-36

Coccyx tailbone four fused vertebrae 7-37

Thoracic Cage Ribs Sternum Thoracic vertebrae Costal cartilages Supports shoulder girdle Protects viscera Role in breathing 7-38

Ribs True ribs (7) False ribs (5) floating (2) 7-39

Rib Structure Shaft Head – posterior end; articulates with vertebrae Tubercle – articulates with vertebrae Costal cartilage – hyaline cartilage 7-40

Sternum Manubrium Body Xiphoid process 7-41

Pectoral Girdle shoulder girdle clavicles scapulae supports upper limbs 7-42

Clavicles articulate with manubrium articulate with scapulae (acromion process) 7-43

Scapulae spine supraspinous fossa infraspinous fossa acromion process coracoid process glenoid cavity 7-44

Upper Limb Humerus Radius Ulna Carpals Metacarpals Phalanges 7-45

Humerus head greater tubercle lesser tubercle anatomical neck surgical neck deltoid tuberosity capitulum trochlea coronoid fossa olecranon fossa 7-46

Radius lateral forearm bone head radial tuberosity styloid process 7-47

Ulna medial forearm bone trochlear notch olecranon process coronoid process styloid process 7-48

Wrist and Hand Carpals (16) Metacarpals (10) Phalanges (28) trapezium trapezoid capitate scaphoid pisiform triquetrum hamate lunate Metacarpals (10) Phalanges (28) proximal phalanx middle phalanx distal phalanx 7-49

Pelvic Girdle Coxae (2) supports trunk of body protects viscera 7-50

Coxae hip bones ilium ischium pubis obturator foramen acetabulum iliac crest iliac spines greater sciatic notch ischium ischial spines lesser sciatic notch ischial tuberosity pubis obturator foramen acetabulum 7-51

Greater and Lesser Pelvis 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 7-52

Male and Female Pelvis Female iliac bones more flared broader hips pubic arch angle greater more distance between ischial spine and ischial tuberosity sacral curvature shorter and flatter lighter bones 7-53

Lower Limb Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges 7-54

Femur longest bone of body head fovea capitis neck greater trochanter lesser trochanter linea aspera condyles epicondyles 7-55

Patella kneecap anterior surface of knee flat sesmoid bone located in a tendon 7-56

Tibia shin bone medial to fibula condyles tibial tuberosity anterior crest medial malleolus 7-57

Fibula Insert figure 7.54 lateral to tibia long, slender head lateral malleolus does not bear any body weight Insert figure 7.54 7-58

Ankle and Foot Tarsals (14) Metatarsals (10) Phalanges (28) calcaneus talus navicular cuboid lateral cuneiform intermediate cuneiform medial cuneiform Metatarsals (10) Phalanges (28) proximal middle distal 7-59

Ankle and Foot 7-60

Clinical Application Types of Fractures green stick fissured comminuted transverse oblique spiral 7-62

Bone-Fractures Classification-type-location-direction of the fracture Open/compound- broken through the skin Complication-infection-osteomyelitis-delayed union Closed-not open to the outside of the skin Degree of the fracture-partial or complete break- eg. Greenstick, seen in children, until age 10. Comminuted has more than two pieces and compression fracture, involves two bones compressed together. Impacted-fragments are wedged together-often breaks of the humerus

Bone Fractures Pattern-The direction of the injury produces a pattern of fracture. Transverse- angular forces Spiral- results from a twisting motion Location- Long bones, neck or head, proximal/distal Grouped according to their etiology sudden trauma- most common stress trauma- wear and tear on a bone pathologic fractures- weakened by disease

Bone Healing Hematoma- Clot forms during the first 48/72 hrs after a fracture Cellular proliferation- Involves all three layers- Granulation tissue replace the clot New capillary buds and fibroblast Fibrocartilaginous callus forms distal to fracture- forming a bridge between the fragments

Bone healing Callus formation- cartilage forms at the site 3/4 weeks mineral salts are deposited Ossification Mature bone cells replace the callus, osteoclast resorb the callus-cast removed at this point Remodeling- resorbition of excess callus fracture site becomes thicker and stronger in relation to function