PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PART C 5 The Skeletal System

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Fetal Skull  The fetal skull is large compared to the infant’s total body length  Fontanels—fibrous membranes connecting the cranial bones  Allow the brain to grow  Convert to bone within 24 months after birth

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Fetal Skull Figure 5.13a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Fetal Skull Figure 5.13b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Vertebral Column  Each vertebrae is given a name according to its location  There are 24 single vertebral bones separated by intervertebral discs  Seven cervical vertebrae are in the neck  Twelve thoracic vertebrae are in the chest region  Five lumbar vertebrae are associated with the lower back

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Vertebral Column  Surrounds & protects delicate spinal chord  S-shaped curvature  Nine vertebrae fuse to form two composite bones  Sacrum Coccyx

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Vertebral Column Figure 5.14

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Vertebral Column  The spine has a normal curvature  Primary curvatures are the spinal curvatures of the thoracic and sacral regions  Present from birth  Secondary curvatures are the spinal curvatures of the cervical and lumbar regions  Develop after birth

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Vertebral Column 3 Regions of Vertebral Column 1. Cervical – consist of 7 vertebrae, (C1 to C7) -- forms neck region -- C1 known as atlas; has no body; allows you to nod yes -- C2 known as axis; acts as pivot; allows you to shake no 2. Thoracic – consist of 12 vertebrae -- only vertebrae that articulate with ribs 3. Lumbar – consist of 5 vertebrae -- have massive blocklike bodies -- sturdiest vertebrae cause of stress in this area

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Vertebral Column Figure 5.15

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Back Disorders  Scoliosis – disorder that causes abnormal curvature of the spine/backbone from side to side  Normal look from side  2 to 3 times more common in girls  Hereditary  Kyphosis– curving of the spine causing bowing of the back  Leads to haunchback or humpback  Lordosis– inward curvature of spine  swayback

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Vertebral Column Figure 5.16

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings A Typical Vertebrae, Superior View Figure 5.17

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regional Characteristics of Vertebrae Figure 5.18a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regional Characteristics of Vertebrae Figure 5.18b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regional Characteristics of Vertebrae Figure 5.18c

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regional Characteristics of Vertebrae Figure 5.18d

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Sacrum and Coccyx  Sacrum  Formed by the fusion of five vertebrae -- forms posterior wall of pelvis -- superiorly articulates with L5 -- inferiorly connects to the coccyx  Coccyx  Formed from the fusion of three to five vertebrae  “Tailbone,” or remnant of a tail that other vertebrates have

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Sacrum and Coccyx Figure 5.19

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Bony Thorax  Forms a cage to protect major organs  Consists of three parts  Sternum  Ribs  True ribs (pairs 1–7)‏  False ribs (pairs 8–12)‏  Floating ribs (pairs 11–12)‏  Thoracic vertebrae

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Thoracic Cage  Sternum (breastbone)  Typical flat bone 3 Bony Landmarks 1.Jugular notch 2.Sternal Angle 3.Xiphisternal Joint  Ribs – (12 pairs ) *Contrary to popular opinion Men DO NOT have fewer than women* -- 7 pair connect to sternum; last 2 pair are “free floating”

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Bony Thorax Figure 5.20a