Chapter 8 Lecture Outline See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without no

1. Chapter 8 Lecture Outline See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. The Skeletal System • Overview of the skeleton • The skull • The vertebral column and thoracic cage • The pectoral girdle and upper limb • The pelvic girdle and lower limb

3. Overview of the Skeleton • Regions of the skeleton • axial skeleton = central axis • skull, vertebral column, ribs, sternum and sacrum • appendicular skeleton = limbs and girdles • Number of bones • 206 in typical adult skeleton • varies with development of sesamoid bones (patella) • start at 270 at birth, decreases with fusion • Surface markings defined in Table 8.2

4. Surface Features of Bones

5. Axial and Appendicular Skeleton • Axial skeleton in tan • skull, vertebrae, sternum, ribs, sacrum and hyoid • Appendicular skeleton in green • pectoral girdle • upper extremity • pelvic girdle • lower extremity

6. Major Skull Cavities

7. The Skull • 22 bones joined together by sutures • Cranial bones surround cranial cavity • 8 bones in contact with meninges • frontal, parietal, • calvaria (skullcap) forms roof and walls • Facial bones support teeth and form nasal cavity and orbit • 14 bones with no direct contact with brain or meninges • attachment of facial and jaw muscles

8. Cranial Fossa • 3 basins that comprise the cranial floor or base • anterior fossa holds the frontal lobe of the brain • middle fossa holds the temporal lobes of the brain • posterior fossa contains the cerebellum • Swelling of the brain may force tissue through foramen magnum resulting in death

9. Frontal Bone • Forms forehead and part of the roof of the cranium • Forms roof of the orbit • Contains frontal sinus

10. Parietal Bone • Cranial roof and part of its lateral walls • Bordered by 4 sutures • coronal, sagittal, lambdoid and squamous • Temporal lines of temporalis muscle Temporal lines

11. Temporal Bone • Lateral wall and part of floor of cranial cavity • squamous part • zygomatic process • mandibular fossa and TMJ • tympanic part • external auditory meatus • styloid process • mastoid part • mastoid process • mastoiditis from ear infection • mastoid notch • digastric muscle

12. Petrous Portion of Temporal Bone • Part of cranial floor • separates middle from posterior cranial fossa • Houses middle and inner ear cavities • receptors for hearing and sense of balance • internal auditory meatus = opening for CN VII (vestibulocochlear nerve)

13. Right Temporal Bone

14. Openings in Temporal Bone • Carotid canal • passage for internal carotid artery supplying the brain • Jugular foramen • irregular opening between temporal and occipital bones • passageway for drainage of blood from brain to internal jugular vein

15. Occipital Bone • Rear and base of skull • Foramen magnum holds spinal cord • Skull rests on atlas at occipital condyles • Hypoglossal canal transmits hypoglossal nerve (CN XII) supplying tongue muscles • External occipital protuberance for nuchal ligament • Nuchal lines mark neck muscles

16. Sphenoid Bone • Lesser wing • Greater wing • Body of sphenoid • Medial and lateral pterygoid processes

17. Sphenoid Bone • Body of the sphenoid • sella turcica contains hypophyseal fossa • houses pituitary gland • Lesser wing • optic foramen • Greater wing • foramen rotundum and ovale for brs. trigeminal nerve • foramen spinosum for meningeal artery

18. Sphenoid Bone • Sphenoid sinus

19. Ethmoid Bone • Between the orbital cavities • Lateral walls and roof nasal cavity • Cribriform plate and crista galli • Ethmoid air cells form ethmoid sinus • Perpendicular plate forms part of nasal septum • Concha (turbinates) on lateral wall

20. Ethmoid Bone • Superior and middle concha • Perpendicular plate of nasal septum

21. Maxillary Bones • Forms upper jaw • alveolar processes are bony pointsbetween teeth • alveolar sockets hold teeth • Forms inferomedial wall of orbit • infraorbital foramen • Forms anterior 2/3’sof hard palate • incisive foramen • cleft palate

22. Maxillary sinus fills maxillae bone Other bones containing sinuses are frontal, ethmoid and sphenoid. Locations of Paranasal Sinuses

23. Palatine Bones • L-shaped bone • Posterior 1/3 of the hard palate • Part of lateral nasal wall • Part of the orbital floor

24. Zygomatic Bones • Forms angles of the cheekbones and part of lateral orbital wall • Zygomatic arch is formed from temporal process of zygomatic bone and zygomatic process of temporal bone

25. Lacrimal Bones • Form part of medial wall of each orbit • Lacrimal fossa houses lacrimal sac in life • tears collect in lacrimal sac and drain into nasal cavity

26. Nasal Bones • Forms bridge of nose and supports cartilages of nose • Often fractured by blow to the nose

27. Inferior Nasal Conchae • A separate bone • Not part of ethmoid like the superior and middle concha or turbinates

28. Vomer • Inferior half of the nasal septum • Supports cartilage of nasal septum

29. Mandible • Only movable bone • jaw joint between mandibular fossaand condyloid process • Holds the lower teeth • Attachment of muscles of mastication • temporalis muscle onto coronoid process • masseter muscle onto angle of mandible • Mandibular foramen • Mental foramen

30. Ramus, Angle and Body of Mandible

31. Bones Associated With Skull • Auditory ossicles • malleus, incus, and stapes • Hyoid bone • suspended from styloid process of skull by muscle and ligament • greater and lesser cornua

32. Skull in Infancy and Childhood • Spaces between unfused bones called fontanels • filled with fibrous membrane • allow shifting of bones during birth and growth of brain • 2 frontal bones fuse by age six (metopic suture) • Skull reaches adult size by 8 or 9

33. The Vertebral Column • 33 vertebrae and intervertebral discs of fibrocartilage • Five vertebral groups • 7 cervical in the neck • 12 thoracic in the chest • 5 lumbar in lower back • 5 fused sacral • 4 fused coccygeal • Variations in number of lumbar and sacral vertebrae

34. Newborn Spinal Curvature • Spine exhibits one continuous C-shaped curve • Known as primary curvature

35. Adult Spinal Curvatures • S-shaped vertebral column with 4 curvatures • Secondary curvatures develop after birth • lifting head as it begins to crawl develops cervical curvature • walking upright develops lumbar curvature

36. Abnormal Spinal Curvatures • From disease, posture, paralysis or congenital defect • Scoliosis from lack of proper development of one vertebrae • Kyphosis is from osteoporosis • Lordosis is from weak abdominal muscles

37. General Structure of Vertebra • Body • Vertebral foramen form vertebral canal • Neural arch • 2 lamina • 2 pedicles • Processes • spinous, transverse and articular

38. Intervertebral Foramen and Discs • Intervertebral foramen • Notches between adjacent vertebrae • passageway for nerves • Intervertebral discs • bind vertebrae together • absorb shock • gelatinous nucleus pulposus surrounded by anulus fibrosus (ring of fibrocartilage) • herniated disc pressures spinal nerve or cord

39. Typical Cervical Vertebrae • Small body and larger vertebral foramen • Transverse process short with transverse foramen for protection of vertebral arteries • Bifid or forked spinous process in C2 to C6 • C7 vertebra prominens

40. The Unique Atlas and Axis • Atlas (C1) supports the skull • concave superior articular facet • nod your head in “yes” movement • ring surrounding large vertebral foramen • anterior and posterior arch • no vertebral body • Axis (C2) • dens or odontoid process is held in place inside the vertebral foramen of the atlas by ligaments • allows rotation of head -- “no”

41. Atlas and Axis Articulation

42. Typical Thoracic Vertebrae • Larger body than cervical but smaller than lumbar • Spinous processes pointed and angled downward • Superior articular facets face posteriorly permitting some rotation between adjacent vertebrae • Rib attachment • costal facets on vertebral body and at ends of transverse processes for articulation of ribs

43. Lumbar Vertebrae • Thick, stout body and blunt, squarish spinous process • Superior articular processes face medially • lumbar region resistant to twisting movements

44. Sacrum (Anterior View) • 5 sacral vertebrae fuse by age 26 • Anterior surface • smooth and concave • sacral foramina were intervertebral foramen • nerves and blood vessels • 4 transverse lines indicate line of fusion of vertebrae

45. Sacrum (Posterior View) • Median sacral crest • Lateral sacral crest • Posterior sacral foramina • Sacral canal ends as sacral hiatus • Auricular surface is part of sacroiliac joint

46. Coccyx • Single, small bone • 4 vertebrae fused by 30 • Co1 to Co4 • Attachment site for muscles of pelvic floor • Cornua • hornlike projections on Co1 for ligaments attach coccyx to sacrum • Fractured by fall or during childbirth

47. Thoracic Cage • Consists of thoracic vertebrae, sternum and ribs • Attachment site for pectoral girdle and many limb muscles • Protects many organs • Rhythmically expanded by respiratory muscles to draw air into the lungs

48. Rib Structure Tubercle Head • Flat blade called a shaft • inferior margin has costal groove for nerves and vessels • Proximal head and tubercle are connected by neck • Articulation • head with body of vertebrae • tubercle with transverse process

49. Numbered Rib Articulations

50. True and False Ribs • True ribs (1 to 7) attach to sternum with hyaline cartilage • False ribs (8-12) • 11-12 are floating and not attached to sternum • 12 pairs of ribs in both sexes