Fundamentals of Anatomy & Physiology Eleventh Edition Chapter 7 The Axial Skeleton Lecture Presentation by Deborah A. Hutchinson Seattle University © 2018 Pearson Education, Inc.

Learning Outcomes 7-1 Identify the bones of the axial skeleton, and specify their functions. 7-2 Identify the bones, foramina, and fissures of the cranium and face, and explain the significance of the markings on the individual bones. 7-3 Describe the structure and functions of the orbital complex, nasal complex, and paranasal sinuses. 7-4 Describe the key structural differences among the skulls of infants, children, and adults. © 2018 Pearson Education, Inc.

Learning Outcomes 7-5 Identify and describe the curves of the spinal column, and indicate the function of each. 7-6 Identify the five vertebral regions, and describe the distinctive structural and functional characteristics of the vertebrae in each region. 7-7 Explain the significance of the joints between the thoracic vertebrae and ribs, and between the ribs and sternum. © 2018 Pearson Education, Inc.

Divisions of the Skeleton Axial skeleton Bones of head and trunk Forms longitudinal axis of body Appendicular skeleton Bones that support the limbs © 2018 Pearson Education, Inc.

Figure 7–1a The Axial Skeleton. SKELETAL SYSTEM 206 AXIAL SKELETON 80 APPENDICULAR SKELETON (see Figure 8-1) Cranium 8 Skull Face 14 Skull and associated bones 29 Auditory ossicles 6 Associated bones Hyoid 1 Sternum 1 Thoracic cage 25 Ribs 24 Vertebrae 24 Vertebral column 26 Sacrum 1 Coccyx 1 ATLAS: Plates 1a,b a An anterior view of the entire skeleton, with the axial components highlighted. The numbers in the boxes indicate the number of bones in the adult skeleton. © 2018 Pearson Education, Inc.

Figure 7–1b The Axial Skeleton. Skull Skull Cervical vertebrae Sternum Thoracic vertebrae Ribs Ribs Costal cartilages Lumbar vertebrae Lumbar vertebrae ATLAS: Plates 1a,b Sacrum Sacrum Coccyx Coccyx b Anterior (top) and posterior (bottom) views of the axial skeleton. The individual bones associated with the skull are not visible. © 2018 Pearson Education, Inc.

The Axial Skeleton Axial skeleton has 80 bones Skull 8 cranial bones and 14 facial bones Bones associated with the skull 6 auditory ossicles and hyoid bone Thoracic cage Sternum and 24 ribs Vertebral column 24 vertebrae, sacrum, and coccyx © 2018 Pearson Education, Inc.

The Axial Skeleton Functions of the axial skeleton Supports and protects organs in body cavities Provides points of attachment for muscles that Adjust positions of head, neck, and trunk Perform breathing movements Stabilize parts of appendicular skeleton © 2018 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 structural characteristics of individual vertebrae. C1 The cervical curve, a secondary curve, develops as the infant learns to balance the weight of its 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, provides room for the thoracic organs. T6 T7 Thoracic (12 vertebrae) T8 T9 T10 T11 T12 ATLAS: Plate 2b L1 The lumbar curve, a second- ary curve, balances the weight of the trunk over the lower limbs. This curve develops with the ability to stand. L2 Lumbar (5 vertebrae) L3 L4 L5 The sacral curve, a primary curve, provides room for various abdominopelvic organs. Sacral Coccygeal © 2018 Pearson Education, Inc.

The Vertebral Column Vertebrae Neck Seven cervical vertebrae Upper back 12 thoracic vertebrae Each articulates with one or more pairs of ribs Lower back Five lumbar vertebrae © 2018 Pearson Education, Inc.

The Vertebral Column Vertebral anatomy Each vertebra consists of three parts Vertebral body Vertebral arch Articular processes © 2018 Pearson Education, Inc.

The Five Vertebral Regions Vertebral anatomy Vertebral body Transfers weight along the spine Forms anterior margin of each vertebral foramen Vertebral arch forms posterior margin of each vertebral foramen Walls are called pedicles Laminae form roof Articular processes Lateral projections between laminae and pedicles © 2018 Pearson Education, Inc.

Figure 7–18a Vertebral Anatomy. Vertebral arch Articular processes Pedicle Laminae Vertebral body a The major parts of a typical vertebra © 2018 Pearson Education, Inc.

The Five Vertebral Regions Vertebral anatomy Spinous process Posterior projection from where vertebral laminae fuse Transverse processes Projections from where laminae join pedicles Superior and inferior articular processes Have articular facets For articulations with neighboring vertebrae © 2018 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 © 2018 Pearson Education, Inc.

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 © 2018 Pearson Education, Inc.

The Five Vertebral Regions Vertebrae are numbered By region, from top (superior) to bottom (inferior) C1 articulates with skull, L5 with sacrum Vertebrae of each region Have characteristics determined by functions © 2018 Pearson Education, Inc.

The Five Vertebral Regions Regions of the vertebral column Cervical (C) Thoracic (T) Lumbar (L) Sacral (S) Coccygeal (Co) © 2018 Pearson Education, Inc.

The Five Vertebral Regions Cervical vertebrae C1 to C7 Small body (support only head) Large vertebral foramen (largest part of spinal cord) Concave superior surface Anterior edge is inferior to posterior edge © 2018 Pearson Education, Inc.

The Five Vertebral Regions Cervical vertebrae Transverse processes are fused to costal processes Encircle transverse foramina for vertebral arteries and vertebral veins All except C1 have spinous processes Tips of most spinous processes are notched (bifid) Whiplash—partial or complete dislocation of cervical vertebrae © 2018 Pearson Education, Inc.

Figure 7–19a The Cervical Vertebrae. Spinous process of vertebra prominens ATLAS: Plates 20b; 21a–e C7 a A lateral view of the cervical vertebrae, C1–C7. © 2018 Pearson Education, Inc.

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 (C3–C6). Note the typical features listed in Table 7–1. © 2018 Pearson Education, Inc.

The Five Vertebral Regions: The Atlas Cervical vertebrae The atlas (C1) Articulates with occipital condyles of skull Has no body or spinous process Has a large, round vertebral foramen within anterior and posterior arches © 2018 Pearson Education, Inc.

The Five Vertebral Regions: The Atlas © 2018 Pearson Education, Inc.

The Five Vertebral Regions: The Axis Cervical vertebrae The axis (C2) Articulates with the atlas Has heavy spinous process to attach muscles of head and neck Bodies of axis and atlas fuse during development to form the dens © 2018 Pearson Education, Inc.

The Five Vertebral Regions: The Axis © 2018 Pearson Education, Inc.

© 2018 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. © 2018 Pearson Education, Inc.

The Five Vertebral Regions Thoracic vertebrae (T1–T12) Have heart-shaped bodies Larger bodies and relatively smaller vertebral foramina than those in cervical vertebrae Long, slender spinous process Dorsolateral surfaces of body have costal facets Articulate with heads of ribs © 2018 Pearson Education, Inc.

The Five Vertebral Regions Thoracic vertebrae T1–T8 each articulate with two pairs of ribs At superior and inferior costal facets T9–T11 articulate with one pair of ribs T1–T10 Have thick transverse processes With transverse costal facets for rib articulation Ribs pairs 1–10 Contact costal and transverse costal facets T10–T12 transition to lumbar vertebrae © 2018 Pearson Education, Inc.

Figure 7–20a The Thoracic Vertebrae. prominens C7 T1 T2 Intervertebral foramen T3 T4 T5 T6 T7 Thoracic vertebrae (T1–T12) T8 T9 T10 ATLAS: Plates 22a–c 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 facet for rib articulation. © 2018 Pearson Education, Inc.

Figure 7–20b The Thoracic Vertebrae. Spinous process Transverse process Lamina Transverse costal facet Superior articular facet Vertebral foramen Superior costal facet ATLAS: Plates 22a–c Vertebral body b Thoracic vertebra, superior view. © 2018 Pearson Education, Inc.

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 ATLAS: Plates 22a–c c Thoracic vertebra, lateral view. © 2018 Pearson Education, Inc.

The Five Vertebral Regions Lumbar vertebrae (L1–L5) Largest vertebrae Thick, oval-shaped bodies No costal facets or transverse costal facets Triangular vertebral foramen Superior articular processes face medially Inferior articular processes face laterally Slender transverse processes project dorsolaterally Massive spinous processes For attachment of lower back muscles © 2018 Pearson Education, Inc.

Figure 7–21a The Lumbar Vertebrae. ATLAS: Plates 23a–c Sacrum Coccyx a A lateral view of the lumbar vertebrae, sacrum, and coccyx © 2018 Pearson Education, Inc.

Figure 7–21b The Lumbar Vertebrae. Spinous process Superior articular facet Lamina Superior articular process Transverse process Transverse process Vertebral foramen Pedicle ATLAS: Plates 23a–c Vertebral body b Superior view of typical lumbar vertebra © 2018 Pearson Education, Inc.

Figure 7–21c The Lumbar Vertebrae. Superior articular process Pedicle Transverse process Vertebral body Spinous process Inferior articular process ATLAS: Plates 23a–c Inferior articular facet c Lateral view of a typical lumbar vertebra © 2018 Pearson Education, Inc.

Table 7–1 Regional Differences in Vertebral Structure and Function (Part 2 of 2) © 2018 Pearson Education, Inc.

The Five Vertebral Regions Sacrum and coccyx L5 articulates with the sacrum Sacrum articulates with the coccyx © 2018 Pearson Education, Inc.

The Five Vertebral Regions Sacrum Curved, more so in males than in females Protects reproductive, urinary, and digestive organs Attaches Axial skeleton to pelvic girdle Broad muscles that move the thigh © 2018 Pearson Education, Inc.

The Five Vertebral Regions Sacrum The adult sacrum Consists of five fused sacral vertebrae Fusion occurs between puberty and ages 25–30 Leaving transverse lines Sacral canal Passageway that extends the length of the sacrum Contains nerves and membranes © 2018 Pearson Education, Inc.

7-6 The Five Vertebral Regions Sacrum Median sacral crest Ridge formed from fused spinous processes Four pairs of sacral foramina open to either side Lateral sacral crest Ridge formed from fused transverse processes Attaches to muscles of lower back and hip © 2018 Pearson Education, Inc.

7-6 The Five Vertebral Regions Sacrum Sacral cornua Ridges formed from laminae of fifth sacral vertebra Laminae do not meet at midline Sacral hiatus Opening at inferior end of sacral canal Bordered by sacral cornua Covered by connective tissues © 2018 Pearson Education, Inc.

Figure 7–22a The Sacrum and Coccyx. Articular process Entrance to sacral canal Sacral tuberosity Lateral sacral crest Sacral foramina Median sacral crest Sacral cornu Sacral hiatus Coccygeal cornu Coccyx a A posterior view © 2018 Pearson Education, Inc.

7-6 The Five Vertebral Regions Sacrum Apex Narrow inferior portion Articulates with the coccyx Base Broad superior surface Sacral promontory Prominent bulge at anterior tip of base Ala A wing on either side of the base To attach muscles © 2018 Pearson Education, Inc.

Figure 7–22c The Sacrum and Coccyx. Base Sacral promontory Ala Ala Sacral foramina Transverse lines Apex Coccyx c An anterior view © 2018 Pearson Education, Inc.

The Five Vertebral Regions Coccyx Mature coccyx Consists of three to five fused coccygeal vertebrae Attaches ligaments and a constricting muscle of the anus First two coccygeal vertebrae have transverse processes And unfused vertebral arches Coccygeal cornu Prominent lamina of first coccygeal vertebra © 2018 Pearson Education, Inc.

Figure 7–22b The Sacrum and Coccyx. Sacral promontory Auricular surface Lateral sacral crest Median sacral crest Sacral curve Sacral cornu Coccygeal cornu Coccyx b A lateral view from the right side © 2018 Pearson Education, Inc.