25-1 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Skeletal System Mrs. Northeim Part 1 of 2 Anatomy & Physiology

25-2 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Skeletal/Bone Introduction Classification by shape Classification by division 3 main components of axial division Diagram bones

25-3 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Introduction Bones provide the body with structure and support 206 bones with joints and connective tissue

25-4 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Bone Structure Classification by shape Long bones – located primarily in the arms and legs Femur (thigh bone) Humerus (upper arm bone) Short bones – small bones located in the wrists and ankles Carpals (wrist bones) Tarsals (ankle bones)

25-5 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Bone Structure (cont.) Flat bones – located in the skull and rib cage Ribs Frontal bone Irregular bones Vertebrae Bones of the pelvic girdle

25-6 © 2009 The McGraw-Hill Companies, Inc. All rights reserved How we will study the bones. Divisions Axial – 80 bones Skull Vertebral column Rib cage Appendicular – 126 bones Arms and legs Pectoral girdle Pelvic girdle

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25-8 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Main parts of axial skeleton Skull Vertebral column Thoracic cage

25-9 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Cranium - Skull 1. Cranial bones Frontal bone – forehead Parietal bone – top sides Temporal bones – hence the name “temples” Occipital bone – back of head Sphenoid bone – resembles a bat with wings. Anchors the frontal, parietal, occipital and ethmoid bones Ethmoid bone – medial walls of eye orbit.

25-10 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Facial bones Maxillae – upper jaw Mandible – lower jaw Zygomatic bones – cheek bone Nasal bones – upper nose between eye orbits, “bridge of nose” Lacrimal bone – fingernail shaped bones by tear ducts (nasal lacrimal ducts) Palatine bones – forms hard (anterior) portion of palate Vomer – inside bone of nose

25-11 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Bony Structures (cont.) TermDefinition CondyleA rounded process that usually articulates with another bone CrestA narrow, ridge-like projection EpicondyleA projection situated above a condyle ForamenAn opening through a bone that is usually a passageway for blood vessels, nerves, or ligaments FossaA relatively deep pit or depression

25-12 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Bony Structures (cont.) TermDefinition HeadAn enlargement on the end of a bone ProcessA prominent projection on a bone SutureAn interlocking line of union between bones TrochanterA relatively large process TubercleA small, knoblike process TuberosityA knoblike process, usually larger than a tubercle

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25-14 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Hyoid Bone U shaped bone in the neck below the mandible and above the larnyx “Adam’s apple”…..more defined in men – determines the tone of the larynx

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25-16 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Vertebral column 24 vertebrae + sacrum + coccyx It is flexible because it is segmented Vertebral anatomy encases the spinal cord balances the head on top Serves as point of attachment for ribs and lower extremities

25-17 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Vertebral column Cervical vertebra 7 in the neck. Called C1-C7. Top one holds the head on – called the atlas. The second one allows the head to “swivel” – called the axis Thoracic vertebra 12 of them, called T1-T12 Lumbar vertebra 5 of them, called L1-L5

25-18 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Vertebral column Sacral vertebrae “sacrum” A fusion of 5 bones, S1-S5 Coccyx – “tail bone” A single bone. Fusion of 4 or 5.

25-19 © 2009 The McGraw-Hill Companies, Inc. All rights reserved The Spinal Column 7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae Sacrum Coccyx

© 2009 The McGraw-Hill Companies, Inc. All rights reserved Vertebrae Compared Superior View of Cervical, Thoracic & Lumbar Vertebrae Posterior View of the Sacrum 1. Body 2. Vertebral foramen 3. Anterior tubercle 4. Posterior tubercle 5. Foramen transversarium or transverse foramen 6. Demifacet for head of rib 7. Superior articular process 8. Pedicle 9. Lamina 10. Transverse process 11. Spinous process or spine 12. Lateral mass 13. Posterior sacral foramina 14. Coccyx 15. Sacral hiatus

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25-22 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Sternum Dagger shaped bone, called “breastbone” Manubrium Top part of sternum Body Mid part of sternum bone below Manubrium and above Xiphoid process. Xiphoid process Little point at the end of the sternum. Often breaks during CPR if hands are not positioned correctly.

25-23 © 2009 The McGraw-Hill Companies, Inc. All rights reserved The Rib Cage (cont.) 12 pairs of ribs All are attached posteriorly to thoracic vertebrae True First seven pairs of ribs Attach to sternum by costal cartilage False Rib pairs 8, 9, and 10 Attach to the costal cartilage of rib pair 7 Floating Rib pairs 11 and 12 Do not attach anteriorly to any structure

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