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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
B. Vertebral Column (spine)5. Cervical vertebrae—7
-form the neck region of spine
-the first 2 (atlas & axis) are unique in their structure & function
a. atlas (C1): first cervical vertebra
-contains no body
-occipital condyles of skull articulate with atlas
-the bone responsible for allowing you to nod head “yes” (atlas = the “yes” bone)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
ATLAS: Has superior surfaces of transverse processes have depressions that articulate with occipital condyles of skull
ATLAS: Has no body
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
B. Vertebral Column (Spine)b. axis (C2): acts as a pivot for rotation of the
atlas & skull above it
i. dens (odontoid) process—acts as the pivot point
-the joint between atlas & axis allows you to shake head “no”
-axis= the “no” bone
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
B. Vertebral Column (spine)c. typical cervical vertebrae
(C3-C7):
-smallest, lightest vertebrae
-usually have short spinous processes that are often divided into 2 branches
-transverse processes contain foramina (openings/holes) that arteries pass through
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Characteristics of Cervical Vertebrae
Figure 5.17a–b
CERVICAL
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
B. Vertebral Column (Spine)6. Thoracic vertebrae—12
-labeled T1-T12
-larger than cervical vertebrae
-body is somewhat heart-shaped
-extra set of facets for ribs
-long, thin spinous process
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
B. Vertebral Column (Spine)7. Lumbar vertebrae—5
-labeled L1-L5
-have massive, blocklike bodies
-short, hatchet-shaped spinous processes
-the sturdiest of the vertebrae since most of stress on vertebral column occurs here
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Characteristics of Thoracic & Lumbar Vertebrae
Figure 5.17c–dTHORACICLUMBAR
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
B. Vertebral Column (Spine)8. Saccrum—1
-formed by the fusion of 5 vertebrae
-connects superiorly to L5 and inferiorly to coccyx
-joins to hip bones at sacroiliac joints
EXTRA CREDIT
* median sacral crest: the fused spinous processes of sacral vertebrae; found on midline of sacrum
*sacral canal: continuation of vertebral canal
* sacral hiatus: large inferior opening; termination of sacral canal