7-5 The Vertebral Column The Vertebral Column (Spine) Protects the spinal cord Supports the head and body 26 bones 24 vertebrae, the sacrum, and the coccyx © 2015 Pearson Education Inc.

Figure 7-17 The Vertebral Column. Spinal Curves Vertebral Regions Primary curves develop before birth, and secondary curves after birth. Regions are defined by anatomical characteristics of individual vertebrae. C1 The cervical curve, a secondary curve, develops as the infant learns to balance the weight of the head on the vertebrae of the neck. C2 C3 C4 Cervical (7 vertebrae) C5 C6 C7 T1 T2 T3 T4 T5 The thoracic curve, a primary curve, accommo- dates the thoracic organs. T6 T7 Thoracic (12 vertebrae) T8 T9 T10 T11 T12 L1 The lumbar curve, a secondary curve, balances the weight of the trunk over the lower limbs; it develops with the ability to stand. L2 L3 Lumbar (5 vertebrae) L4 L5 The sacral curve, a primary curve, accommodates the abdominopelvic organs. Sacral Coccygeal

7-5 The Vertebral Column Vertebrae The neck The upper back Seven The upper back 12 Each articulates with one or more pair of ribs The lower back Five © 2015 Pearson Education Inc.

7-5 The Vertebral Column The Sacrum and Coccyx The fifth lumbar vertebra articulates with the The sacrum articulates with the © 2015 Pearson Education Inc.

7-5 The Vertebral Column Four Spinal Curves curve Thoracic curve Sacral curve © 2015 Pearson Education Inc.

7-5 The Vertebral Column Thoracic and Sacral Curves Are called (present during fetal development) Lumbar and Cervical Curves Are called (appear after birth) © 2015 Pearson Education Inc.

Figure 7-18a Vertebral Anatomy. Vertebral arch Articular processes Pedicle Vertebral body a The major components of a typical vertebra

7-5 The Vertebral Column Vertebral Anatomy The vertebral arch Pedicles Walls of the vertebral arch Laminae Roof of the vertebral arch © 2015 Pearson Education Inc.

7-5 The Vertebral Column Vertebral Anatomy The vertebral arch Spinous process Projection where vertebral laminae fuse Transverse process Projection where laminae join pedicles © 2015 Pearson Education Inc.

7-5 The Vertebral Column Vertebral Anatomy The articular processes Superior articular process Inferior articular process Have articular facets on articular faces © 2015 Pearson Education Inc.

Figure 7-18b Vertebral Anatomy. Superior articular process Pedicle Transverse process Vertebral body Spinous process Inferior articular facet Arrow passing through vertebral foramen Inferior articular process b A lateral and slightly inferior view of a vertebra

Figure 7-18c Vertebral Anatomy. Spinous process Superior articular process Inferior articular process Transverse process Inferior articular facet Pedicle Vertebral foramen Vertebral body c An inferior view of a vertebra

7-5 The Vertebral Column Vertebral Foramina Intervertebral foramina Gaps between pedicles of adjacent vertebrae For nerve connections to spinal cord Vertebral canal Formed by vertebral foramina Encloses the spinal cord © 2015 Pearson Education Inc.

7-5 The Vertebral Column Intervertebral Are pads of fibrocartilage Separate the vertebral bodies Absorb © 2015 Pearson Education Inc.

Figure 7-18d Vertebral Anatomy. Superior articular facets Superior articular process Lamina of vertebral arch Spinous process Intervertebral disc Transverse process Vertebral body Inferior articular process d A posterior view of three articulated vertebrae

Figure 7-18e Vertebral Anatomy. Superior articular facets Lamina of vertebral arch Intervertebral foramen Intervertebral disc Spinous process Transverse process Vertebral body Inferior articular facet Arrow passing through vertebral canal e A lateral and sectional view of three articulated vertebrae

7-6 Vertebral Regions Vertebral Regions Vertebrae are numbered By region, from top ( ) to bottom ( ) articulates with skull, with sacrum Vertebrae of each region Have characteristics determined by functions © 2015 Pearson Education Inc.

7-6 Vertebral Regions Regions of the Vertebral Column Cervical (C) (T) Lumbar (L) (S) Coccygeal (Co) © 2015 Pearson Education Inc.

7-6 Vertebral Regions The Cervical Vertebrae Small body (support only head) Large vertebral foramen (largest part of spinal cord) C1 (atlas) has no spinous process © 2015 Pearson Education Inc.

Figure 7-19a The Cervical Vertebrae. Spinous process of vertebra prominens C7 A lateral view of the cervical vertebrae, C1–C7. a

Figure 7-19b The Cervical Vertebrae. Vertebral arch Spinous process Lamina Vertebral foramen Superior articular process Pedicle Vertebral body Transverse process Superior articular facet Transverse foramen Costal process b A superior view of a representative cervical vertebra showing characteristics of C3–C6. Notice the typical features listed in Table 7–1.

Figure 7-19c The Cervical Vertebrae. Superior articular process Transverse process Inferior articular process Spinous process Bifid tip of spinous process Location of transverse foramen Inferior articular facet Vertebral body c A lateral view of the same vertebra as in b.

7-6 Vertebral Regions The Cervical Vertebrae Transverse processes Are fused to costal processes Which encircle transverse foramina (protect arteries and veins) Atlas (C1) Articulates with occipital condyles of skull Has no body or spinous process Has a large, round foramen within anterior and posterior arches © 2015 Pearson Education Inc.

7-6 Vertebral Regions The Cervical Vertebrae Axis (C2) Supports the atlas Has heavy spinous process To attach muscles of head and neck Axis and atlas bodies fuse during development to form the dens © 2015 Pearson Education Inc.

Figure 7-19d The Cervical Vertebrae. Dens of axis Anterior arch Transverse ligament Atlas (C1) Posterior arch Axis (C2) d The atlas (C1) and axis (C2) in posterolateral view.

7-6 Vertebral Regions Thoracic Vertebrae (T1–T12) Have heart-shaped bodies Larger bodies than in C1–C7 Smaller vertebral foramen than in C1–C7 Long, slender spinous processes Dorsolateral surfaces of body have costal facets Which articulate with heads of ribs © 2015 Pearson Education Inc.

7-6 Vertebral Regions Thoracic Vertebrae (T1–T12) T1–T10 Have transverse costal facets On thick transverse processes for rib articulation Ribs at T1–T10 Contact costal and transverse costal facets T1–T8 articulate with two pairs of ribs At superior and inferior costal facets T9–T11 articulate with one pair of ribs T10–T12 transition to lumbar vertebrae © 2015 Pearson Education Inc.

Figure 7-20a The Thoracic Vertebrae. Vertebra prominens C7 T1 T2 Intervertebral foramen T3 T4 T5 T6 T7 Thoracic vertebrae (T1–T12) T8 T9 T10 T11 T12 L1 a A lateral view of the thoracic region of the vertebral column. The vertebra prominens (C7) resembles T1, but lacks facets for rib articulation. Vertebra T12 resembles the first lumbar vertebra (L1) but has a fact for rib articulation.

Figure 7-20b The Thoracic Vertebrae. Spinous process Transverse process Lamina Transverse costal facet Superior articular facet Vertebral foramen Superior costal facet Vertebral body b Thoracic vertebra, superior view.

Figure 7-20c The Thoracic Vertebrae. Superior costal facet for head of superior rib Transverse costal facet for tubercle of superior rib Transverse process Vertebral body Spinous process Inferior costal facet for head of inferior rib c Thoracic vertebra, lateral view.

7-6 Vertebral Regions Lumbar Vertebrae (L1–L5) Largest vertebrae Oval-shaped bodies Thicker bodies than T1–T12 No costal or transverse costal facets Triangular vertebral foramen Superior articular processes Face up and in Inferior articular processes Face down and out © 2015 Pearson Education Inc.

7-6 Vertebral Regions Lumbar Vertebrae (L1–L5) Transverse processes Slender Project dorsolaterally Spinous processes Short, heavy For attachment of lower back muscles © 2015 Pearson Education Inc.

Figure 7-21a The Lumbar Vertebrae. Sacrum Coccyx A lateral view of the lumbar vertebrae, sacrum, and coccyx a

Figure 7-21b The Lumbar Vertebrae. Superior articular process Pedicle Transverse process Vertebral body Spinous process Inferior articular process Inferior articular facet b A lateral view of a typical lumbar vertebra

Figure 7-21c The Lumbar Vertebrae. Spinous process Superior articular facet Lamina Superior articular process Transverse process Transverse process Vertebral foramen Pedicle Vertebral body c A superior view of the same vertebra shown in part b

Table 7-1 Regional Differences in Vertebral Structure and Function (Part 1 of 2).

Table 7-1 Regional Differences in Vertebral Structure and Function (Part 2 of 2).

7-6 Vertebral Regions The Sacrum Is curved, more in males than in females Protects reproductive, urinary, and digestive organs Attaches: The axial skeleton to pelvic girdle of appendicular skeleton Broad muscles that move the thigh © 2015 Pearson Education Inc.

7-6 Vertebral Regions The Sacrum The adult sacrum Sacral canal Consists of five fused sacral vertebrae Fuses between puberty and ages 25–30 Leaving transverse lines Sacral canal Replaces the vertebral canal © 2015 Pearson Education Inc.

7-6 Vertebral Regions The Coccyx Mature coccyx Consists of three to five fused coccygeal vertebrae © 2015 Pearson Education Inc.

Figure 7-22a The Sacrum and Coccyx. Articular process Entrance to sacral canal Sacral tuberosity Lateral sacral crest Median sacral crest Sacral hiatus Sacral cornu Coccygeal cornu A posterior view a

Figure 7-22b The Sacrum and Coccyx. Sacral promontory Auricular surface Lateral sacral crest Median sacral crest Sacral curve Sacral cornu Coccygeal cornu Coccyx A lateral view from the right side b

Figure 7-22c The Sacrum and Coccyx. Base Sacral promontory Ala Ala Sacral foramina Transverse lines Apex Coccyx An anterior view c

7-7 The Thoracic Cage The Thoracic Cage The Rib Cage The skeleton of the chest Supports the thoracic cavity Consists of: Thoracic vertebrae Ribs Sternum (breastbone) The Rib Cage Formed of ribs and sternum © 2015 Pearson Education Inc.

Figure 7-23a The Thoracic Cage. Jugular notch T1 Clavicular articulation 1 Sternum Manubrium 2 3 Body True ribs (ribs 1–7) 4 Xiphoid process 5 Costal cartilages 6 10 T11 7 T12 11 Vertebrochondral ribs (ribs 8–10) 12 8 9 False ribs (ribs 8–12) Floating ribs (ribs 11–12) a An anterior view, showing the costal cartilages and the sternum

Figure 7-23b The Thoracic Cage. 1 T2 1 2 T3 2 3 3 T4 4 4 T5 5 T6 5 True ribs (ribs 1–7) 6 T7 6 7 T8 7 8 T9 8 T10 9 9 T11 10 T12 10 11 False ribs (ribs 8–12) L1 11 12 12 A posterior view, showing the articulations of the ribs and vertebrae b

7-7 The Thoracic Cage Functions of the Thoracic Cage Protects organs of the thoracic cavity Heart, lungs, and thymus Attaches muscles For respiration Of the vertebral column Of the pectoral girdle and the upper limbs © 2015 Pearson Education Inc.

7-7 The Thoracic Cage Ribs (Costae) Are of long, curved, flat bones Extending from the thoracic vertebrae Ribs are divided into two types True ribs False ribs © 2015 Pearson Education Inc.

7-7 The Thoracic Cage Ribs 1–7 ( ) Vertebrosternal ribs Connected to the sternum by costal cartilages © 2015 Pearson Education Inc.

7-7 The Thoracic Cage Ribs 8–12 ( ) Do not attach directly to the sternum Vertebrochondral ribs (ribs 8–10) Fuse together Merge with cartilage before reaching the sternum Floating or vertebral ribs (ribs 11–12) Connect only to the vertebrae and back muscles Have no connection with the sternum © 2015 Pearson Education Inc.

7-7 The Thoracic Cage The Sternum A flat bone In the midline of the thoracic wall Three parts of the sternum The © 2015 Pearson Education Inc.

7-7 The Thoracic Cage Manubrium The superior portion of sternum Broad, triangular shape Articulates with (collarbones) Articulates with cartilages of first rib pair Has , a shallow indentation between clavicular articulations © 2015 Pearson Education Inc.

7-7 The Thoracic Cage The Sternal Body The Xiphoid Process Is tongue-shaped Attaches to the manubrium Attaches to of ribs 2–7 The Xiphoid Process Is the smallest part of the sternum Attaches to the sternal body Attaches to and rectus abdominis muscles © 2015 Pearson Education Inc.

7-7 The Thoracic Cage Development of the Sternum The developing sternal body Consists of four unfused bones about age 25 Leaving transverse lines The Is the last part of sternum to fuse Can easily be broken away © 2015 Pearson Education Inc.