Skeletal System-2

1. Skeletal System-2 Honors Anatomy for copy

2. Essential Question What is the main contribution the axial skeleton makes to homeostasis?

3. Divisions of the Skeleton • AXIAL SKELETON • Skull • Cranium • Face • Hyoid • Auditory Ossicles • Vertebral Column • Thorax APPENDICULAR SKELETON: Pectoral Girdle Upper Limbs Pelvic Girdle Lower Limbs

4. Types of Bone • bones fall into 1 of 5 main types based on shape: • Long • Short • Flat • Irregular • Sesamoid

5. Short Bones • somewhat cube-shaped • nearly equal in length as width • consist of: • spongy bone except @ surface

6. Flat Bones • Composed of: • 2 nearly parallel plates of compact bone enclosing spongy bone inside • Function: • give considerable protection • place for muscle attachment

7. Irregular Bones complex shapes (do not fit in other categories) vary in amt spongy bone

8. Sesamoid Bones develop w/in certain tendons where there is considerable friction, tension, & physical stress function: protect tendon from excessive wear & tear vary in # person to person but everyone has 2 patella which develop in quadriceps femoris tendon

9. Sutural Bones classified by location (w/in a suture: a seam between 2 cranial bones) not everyone has them

10. Bone Surface Markings • 2 major types: • depressions & openings • form joints or allow passage of vessels & nerves • processes • projections or outgrowths that either help form joints or serve as attachment points for ligaments & tendons

11. Axial skeleton

12. Skull • 22 bones in 2 categories: • Cranium • 8 bones that form cranial cavity • 1 frontal bone • 2 parietal bones • 2 temporal bones • 1 occipital bone • 1 sphenoid bone • 1 ethmoid bone

13. Skull 2. Facial Bones 14 bones that form the face • 2 nasal bones • 2 maxillae • 1 mandible • 2 zygomatic • 2 lacrimal • 2 palantine • 2 inferior nasal conchae • 1 vomer

14. Skull: Cavities Cranial Cavity Nasal Cavity Orbits Paranasal Sinuses Middle & Inner Ear Cavities

15. Cavities of the Skull

16. Functions of Cranial Bones protecting brain stabilizing position of brain, vessels, & nerves through attachments to the meninges outer surfaces provide large areas of attachment for muscles that move parts of the head & some for facial expression

17. Frontal Bone

18. Parietal Bones form greater portion of sides & roof of cranial cavity

19. Temporal Bones form inferior, lateral aspects of the cranium & part of the cranial floor its zygomatic process forms the lateral half of the zygomatic arch mandibularfossa: where condylar process of mandible forms TMJ (temporal mandibular joint)

20. Temporal Bones external auditory meatus: ear canal mastoid: posterior & inferior to external auditory meatus, contains “air cells” (mastoiditis: inflammation in air cells)

21. Temporal Bone: Petrous Portion base of skull between sphenoid & occipital bones houses middle & inner ear Carotid foramen & Jugular foramen

22. Temporal Bones internal auditory meatus: passage of Cranial nerves VII (facial n.) and VIII (vestibulocochlear n.) styloid process: point of attachment for muscles & ligaments of the tongue & neck

23. Temporal Bone: Internal Surface

24. Occipital Bone forms back of head & most of base of skull foramen magnum: large hole spinal cord passes thru, occipital condyles: articulate with 1st cervical vertebra (atlas)

25. Sphenoid Bone middle base of skull *articulates with all other cranial bones shape resembles a bat

26. Sphenoid Bone sellaturcica: (Turkish saddle) the “seat” of the saddle is the hypophysealfossa: where the pituitary gland sits optic foramen: between body & lesser wings, cranial nerve II (optic n.) and opthlamic artery pass thru

27. Ethmoid Bone “like a sieve” midline of anterior part of cranial floor, anterior to sphenoid, posterior to nasal bones cribiforme plate: forms roof of nasal cavity, the holes of the sieve where olfactory nerves pass from roof of nasal cavity to brain cristagalla: triangular process which serves as pt of attachment for meninges of brain

28. Ethmoid Bone

29. Facial Bones • shape of face changes dramatically during 1st 2 yrs of life: • brain & cranial bones expand • 1st set of teeth erupt • paranasal sinuses enlarge • growth of face stops ~16 years old

30. Facial Bones 14 facial bones: 2 nasal bones 2 maxillae 2 zygomatic bones 1 mandible 2 lacrimal bones 2 palatine bones 2 inferior nasal conchae 1 vomer

31. Nasal Bones form part of the bridge of the nose (rest is cartilage)

32. Maxillae = upper jaws *articulate with every bone in face except the mandible form part of floor of orbits, parts of nasal cavity, & most of the hard palate (bony roof of mouth) each one has large maxillary sinus alveolar process is small arch that contains the alveolar sockets for upper set of teeth

33. Maxillae

34. Cleft Palate & Cleft Lip • 10-12 wks gestation the palatine processes of maxillae typically join • not doing so  cleft palate +/- cleft lip • speech & swallowing can be affected • many ear infections • reparative surgery recommended 1st few wks of life / surgery needs to be completed by 12 – 18 mos b/4 speech: speech therapy & orthodontic care frequently necessary

35. Zygomatic Bones “cheekbones”: the temporal process of the zygomatic bone articulates with the zygomatic process of the temporal bone also part of floor of orbit

36. Inferior Nasal Conchae inferior to the middle nasal conchae of the ethmoid bone forming part of lateral wall of nasal cavity same function as superior & middle conchae: swirling inhaled air to deposit particulates but not involved in sense of smell

37. Vomer Δ shaped bone on the floor of nasal cavity forming inferior portion of nasal septum

38. Mandible largest & strongest facial bone (lower jaw) alveolar processes hold lower teeth sockets mental foramen: dentist numb mental nerve

39. Sutures an immovable joint in an adult found only between skull bones & holds most skull bones together name generally reflects bones they unite

40. Newborn Skull

41. Hyoid Bone “U-shaped “ *does not articulate with any other bone in skeleton suspended by ligaments from styloid process of temporal bone in anterior neck between mandible & larynx function: supports tongue *frequently fractured during strangulation

42. Hyoid Bone

43. Vertebral Column Fetus has anteriorly concave curve 3 mos old when holds head cervical curve develops lumbar curve develops as infant sits up, stands, walks

44. Intervertebral Discs • between bodies of consecutive vertebra • under compression they flatten & broaden • harden, less elastic w/aging & narrow  loss of height • annulus fibrosus: outer fibrous ring • nucleus pulposus: inner soft, highly elastic

45. Parts of a Vertebra • Body • thicker, anterior portion, weight bearing portion • Vertebral Foramina • contains spinal cord, adipose, areolar CT, blood vessels • Spinous Process • 1 of 7 processes, posterior, palpable on back of body Transverse Processes: on each side, extending laterally

46. Vertebrae: 1st & 2nd Cervical • Atlas • ring-shaped • articulates with condyles of occipital bone • allows you to nod head “yes” • Axis • 2nd cervical v. • allows you to shake head “no”

47. Typical Thoracic Vertebrae T-1 to T-12 larger & stronger than cervical v. distinguishing feature: articulate with ribs (facets on transverse processes of T-1 to T-10

48. Typical Lumbar Vertebrae L-1 to L-5 largest & strongest of the vertebrae processes are short & thick

49. Sacrum triangular bone formed by union of S-1 to S-5 fusion begins ~16, complete by age 30 female: shorter, wider, more curved S-2 to S-3

50. Coccyx small triangle formed by fusion of 4 coccygeal v. (Co-1 to Co-4), start between 20 & 30 females points inferiorly; males it points anteriorly