SKELETAL SYSTEM Chapter 7 7-1

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

Bone Function Support and Protection gives shape to head, etc. supports body’s weight protects lungs, etc. Body Movement interacts with muscles bones act as rigid bar of a lever Blood Cell Formation hematopoiesis red marrow Inorganic Salt Storage calcium phosphate magnesium sodium potassium 7-12

Parts of a Long Bone epiphysis (end) distal proximal diaphysis (shaft) compact bone spongy bone 7-3 medullary cavity (central space) marrow red (hematopoiesis, make RBC’s) yellow (fat storage) articular cartilage periosteum (outer covering) endosteum (inner covering)

Compact and Spongy Bone 7-4

Microscopic Structure of Compact Bone osteon (cells grow in circle) osteonic canal (canal for bv) perforating canal (for bv) osteocyte (bone cell) lacuna (space) bone matrix (collagen, salt) canaliculus (connects cells) 7-5

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

Terms Used to Describe Skeletal Structures See table 7.4 on page 202 These terms will be used to describe specific parts of a bone. You will need to understand what many of them mean.

Hyoid (1) 7-16 Supports tongue

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

Skull Parietal (2) (blue) side walls of cranium roof of cranium sagittal suture between 2 parietal bones 7-18

Skull Temporal (2) (red) 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) (blue) back of skull base of cranium foramen magnum occipital condyles lambdoidal suture 7-20

Skull Sphenoid (1) (purple) 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 Support mucous membranes moisten and warm air ethmoidal sinuses crista gallis 7-22

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

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

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

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

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

Infantile Skull Fontanels – fibrous membranes (soft spot) 7-30 Fontanels close by: Posterior – 2 mo sphenoid – 3 mo Mastoid – end 1 st yr Anterior – end 2 nd yr

Vertebral Column cervical vertebrae (7) thoracic vertebrae (12) lumbar vertebrae (5) sacrum (1; 5 fused ) coccyx (1; 4 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 (7) Atlas – 1 st ; supports head Axis – 2 nd ; dens pivots to turn head transverse foramina bifid spinous processes vertebral prominens – useful landmark on 7 th 7-33

Thoracic Vertebrae (12) long spinous processes rib facets 7-34

Lumbar Vertebrae (5) large bodies thick, short spinous processes 7-35

Sacrum (1) five fused vertebrae (between 18 – 30 yrs) median sacral crest dorsal sacral foramina posterior wall of pelvic girdle sacral promontory 7-36

Coccyx (1) tailbone four fused vertebrae (by 25 yrs) 7-37

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

Ribs (24) True ribs (7)[on each side] False ribs (5)[on each side] floating (inferior 2) [on each side] 7-39

Rib Structure Shaft Head – posterior end; articulates with vertebrae Tubercle – articulates with vertebrae Costal cartilage – hyaline cartilage, connect rib to sternum 7-40

Sternum (1) Manubrium Body Xiphoid process 7-41

Pectoral Girdle shoulder girdle clavicles (2) scapulae (2) supports upper limbs 7-42

Clavicles (2) articulate with manubrium articulate with scapulae (acromion process) 7-43

Scapulae (2) spine supraspinous fossa infraspinous fossa acromion process coracoid process glenoid cavity 7-44

Upper Limb Humerus Radius Ulna Carpals Metacarpals Phalanges 7-45

Humerus (2) bone in upper arm head greater tubercle lesser tubercle anatomical neck surgical neck deltoid tuberosity capitulum (w/ radius) trochlea (w/ ulna) coronoid fossa olecranon fossa 7-46

Radius (2) lateral forearm bone head allows rotation crosses over ulna radial tuberosity styloid process 7-47

Ulna (2) medial forearm bone trochlear notch olecranon process coronoid process styloid process 7-48

Wrist and Hand Carpals (16) [8 in each] trapezium trapezoid capitate scaphoid pisiform triquetrum hamate lunate So Long Top Part (Lat to Med) Here Comes The Thumb (Med to Lat) Metacarpals (10) [5 in each] # 1-5 Lateral to Medial Phalanges (28) [14 in each] proximal phalanx middle phalanx distal phalanx 7-49

Pelvic Girdle Coxae (2) supports trunk of body protects viscera Sacrum and Coccyx sometimes considered part of girdle 7-50

Coxae (2) hip bones ilium iliac crest iliac spines greater sciatic notch ischium ischial spines lesser sciatic notch ischial tuberosity pubis obturator foramen acetabulum 7-51

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

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

Femur (2) longest/strongest bone head fovea capitis neck greater trochanter lesser trochanter linea aspera condyles epicondyles 7-55

Patella (2) kneecap anterior surface of knee flat sesmoid bone located in a tendon 7-56

Tibia (2) shin bone weight bearing bone medial to fibula condyles tibial tuberosity anterior crest medial malleolus 7-57

Fibula (2) Insert figure 7.54 lateral to tibia long, slender head lateral malleolus does not bear any body weight 7-58

Ankle and Foot Tarsals (14) [7 in each] calcaneus talus navicular cuboid lateral cuneiform intermediate cuneiform medial cuneiform Metatarsals (10) [5 in each] Phalanges (28) [14 in each] proximal middle distal 7-59

Ankle and Foot 7-60

Life-Span Changes decrease in height beginning about age 30 calcium levels fall osteoclasts outnumber osteoblasts bones become brittle spongy bone weakens before compact bone bone loss rapid in menopausal women ‘hip’ fractures common vertebral compression fractures common 7-61

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