The Skeleton: Bones & Joints

1. The Skeleton: Bones & Joints Chapter 7 Anatomy & Physiology I

2. Outline • BONES • Main functions • Bone structure • Bone growth and repair • Bone markings • BONES OF THE AXIAL SKELETON • Framework of the skull • Framework of the trunk • BONES OF THE APPENDICULAR SKELETON • Upper division • Lower division • DISORDERS OF BONE • Metabolic—osteoporosis, osteopenia, osteitisdeformans, osteomalacia, rickets • Tumors • Infection—osteomyelitis, tuberculosis (in spine is called Pott disease) • Structural disorders—curvature of the spine, cleft palate, flat foot • Fractures—closed, open, greenstick, impacted, comminuted, spiral, transverse, oblique • Changes in aging—loss of calcium salts, decreased collagen production, thinning of intervertebral disks, loss of flexibility • THE JOINTS (ARTICULATIONS) • Kinds of joints • More about synovial joints • Disorders of Joints • Joint repair

3. Skeleton • Skeletal system is made up of bones, joints, and supporting connective tissue • Framework on which the body is constructed • Must be strong enough to support & protect all body structures • Most dense form of connective tissue in the body • Consists of 206 bones, joints & supporting connective tissue

4. Bone Functions • Framework for entire body • Protection of delicate structures like brain & spinal cord • Levers to assist muscles in providing movement • Storehouse for Ca++ salts • Produce blood cells in red marrow

5. II. Bone Structure • 206 bones • Axial skeleton – 80 bones -skull, facial bones, spine, ribcage • Appendicular skeleton – 126 bones - pelvic bones, collarbones, extremity bones

6. a. Long Bones • Long bones • Diaphysis – long narrow shaft • Medullary cavity – middle of diaphysis, contains marrow • Epiphysis – ends of long bone

7. b. Bone Tissue – Osseus Tissue • Bones are alive. Bones are organs, with their own system of blood vessels, lymphatic vessels, and nerves. • 2 types of bone • Compact • Spongy, aka Cancellous

8. Compact Bone • Makes up main shaft in long bones & outer layer in other bones • Haversian System – ring of bone tissue surrounding a canal for nerves blood vessels • Haversian canals – canal through which nerves & blood vessels travel in bone • Lacunae – space in which bones cells (osteocytes) live • Volkmann canals – tunnels for nerves and vessels that lead to the outside of the bone

9. Compact Bone

10. Cancellous (Spongy) Bone • Spongy appearance because it has more spaces than compact bone • Filled with red bone marrow • Found at the epiphyses (ends) of long bones & at the center of other bones

11. Checkpoint 7-1:A long bone has a long narrow shaft and two irregular ends. What are the scientific names for the shaft and the ends of a long bone? Checkpoint 7-2:What are the two types of osseus (bone) tissue and where is each type found?

12. c. Bone Marrow • Red marrow – in epiphyses of long bones & center of other bones • Red bone marrow manufactures blood cells. • Yellow marrow – in central cavities of the long bones • Composed mainly of fat

13. d. Bone Membranes • Periosteum– Covering on the outside of bones • Inner layer made of osteoblasts (bone producing cells) • Rich blood and nerve supply to nourish bone • Endosteum – very thin covering that lines the marrow cavity in a bone

14. e. Bone Growth & Repair • Embryonic skeleton is mainly cartilaginous (parts of skull fibrous CT) • Osteoblasts – bone producing cells • Become active between 8 &12 weeks • From stem cells in endosteum & periosteum • Ossification – conversion of cartilage to bone • Osteoblasts form a matrix (the material between cells) mainly of collagen • Enzymes help deposit Ca++ in the matrix • Osteoblasts remain enclosed in lacunae and are now called osteocytes • Osteocytes – mature bone cells that do not produce new bone

15. Bone Growth & Repair • Osteoclasts – responsible for breakdown or resorption of bone tissue • Develop from monocytes (WBC) • Necessary for remodeling and repair of bone during growth & development, & after injury • Bone tissue formation & resorption regulated by hormones • Bone formation & resorptioncontinues throughout life

16. Checkpoint 7-3:What are the three types of cells found in bone and what is the role of each? Which of these is a bone-building cell? a. osteoblastb. osteoclastc. osteocyte

17. Formation of Long Bones • Ossification begins at the center of the diaphysis during fetal development • Epiphysial plates – bone forming centers at the ends of long bones that appear around birth • Long bones grow in length from the epiphyseal plates throughout childhood • Long bones grow wider in diaphysis as medullary cavity grows • Calcification ends in late teens, early 20s and epiphyseal plate hardens

18. Ossification

19. Checkpoint 7-4:As the embryonic skeleton is converted from cartilage to bone, the intercellular matrix becomes hardened. What compounds are deposited in the matrix to harden it? Checkpoint 7-5:After birth, long bones continue to grow in length at secondary centers. What are these centers called?

20. f. Bone Markings • Projections – “sticky-outy things” • Head • Process • Condyle • Crest • Spine • Depressions – dents or holes • Foramen • Sinus • Fossa • Meatus

21. Bony Projections • Head – large knobby end attached to a bony neck (femur) • Process – large projection of bone (styloid process radius & ulna) – for muscle attachment • Condyle – rounded projection of bone – (humerus at elbow) • Crest – distinct border or ridge – (pelvic bone has a crest) • Spine – sharp projection from the surface of bone (spinous)

22. Bony Depressions • Foramen – hole that acts as a tunnel for nerves, vessels • Foramena - holes • Sinus – air space found in some skull bones • Fossa – depression on a bone surface • Fossae - depressions • Meatus – short channel or passage, like ear canal

23. III. Bones of the Axial Skeleton • 80 bones of the head & trunk • Skull 28 bones • Cranium – 8 bones • Facial bones – 14 bones • Ear bones (ossicles)- 6 (3 in each ear) • Trunk – 52 bones • Hyoid – in throat, for muscle attachment • 26 vertebrae • 12 pair ribs (24 total) • Sternum

24. Cranium • Encloses the brain • 8 bones • Frontal bone • 2 parietal bones • 2 temporal bones • Ethmoid bone • Sphenoid bone • Occipital bone

25. Cranium Continued • Frontal bone – forehead bone • Frontal sinuses over eyes • Parietal bones – top of the head & top sides of the head • Temporal bones – sides of head around ears • Mastoid sinuses • Ear canal, eardrum • Mastoid process – behind external ear

26. Cranium Continued • Ethmoid – between the eyes • Contains paranasal sinuses • Forms nasal septum • Superior & middle conchae – along walls of nasal cavity • Sphenoid – forms part of eye socket, inside head • Sellaturcica – depression that holds & protects pituitary gland • Occiput – base of skull • Foramen magnum – large hole for spinal cord to connect to brain

28. Cranial Sutures • Suture – flat, immovable joint that unites cranial bones • Coronal suture –joins frontal bone with parietal bones • Squamous suture – joins temporal bones with parietal bones (on flat part of skull) • Lamboid suture – joins occipital bones with parietal bones • Sagittal suture – joins the parietal bones

30. 14 Facial Bones • Mandible • 2 Maxillae • 2 Zygomatic bones • 2 Nasal bones • 2 Lacrimal bones • Vomer • 2 Palatine bones • 2 Inferior nasal conchae

32. Facial Bones • Mandible – lower jaw bone; only moveable bone of the skull • 2 maxillae – fuse to each other to form upper jaw bone, front of hard palate • Maxillary sinuses • 2 zygomatic bones – cheek bones • 2 nasal bones –bridge of nose

33. Facial Bones • 2 Lacrimal bones – corners of the eyes, size of fingernail • Vomer – lower part of nasal septum • 2 Palatine bones – back of hard palate • 2 Inferior nasal conchae – along the lower sides of the nasal cavity

35. Infant Skull

36. Vertebral Column • 26 bones in vertebral column • 7 cervical • 12 thoracic • 5 lumbar • 1 sacrum • 1 coccyx

37. Vertebrae • Body – weight bearing • discs of cartilage that act as shock absorbers between them • Spinous process – projects posteriorly • Transverse process – projects laterally • Bony arch which forms a foramen for spinal cord • Intervertebral foramina – between the vertebrae for spinal nerves to pass through

39. Spinal Column • Cervical – 7 neck bones • Atlas – first neck bone; to support head • Axis – second neck bone; to move head • Only 2 spinal bones without a body • Thoracic – 12 bones • Ribs attach to these vertebrae

40. Atlas & Axis

41. Spinal Column • Lumbar – 5 lower back bones • Large & heavy • Sacrum – form part of pelvic girdle • Coccyx –tailbone

42. Spinal Column • Has 4 curves corresponding to groups of vertebrae which develop through childhood • Fetus – curled up & this is first curve • Infant – lifts head, develops 2nd curve • Toddler – develops 3rd & 4th curve as learns to walk

43. Development of Spinal Curves

44. Thorax • Sternum – aka breastbone • Manubrium – superior aspect, joins with collarbone • Sternal angle – where manubrium joins body • Body – long & bladelike & joins with rib pairs 2-7 • Xiphoid process – tip at inferior aspect • Ribs – 12 pair attached to thoracic spine posteriorly • Rib pairs 1-7 – “true ribs” – attach to sternum • Rib pairs 8-12 – “false ribs” • 8-10 attach to cartilage • 11-12 – floating ribs with no anterior attachment

46. IV. Bones of the Appendicular Skeleton • 126 bones of the shoulders, hips & extremities • Upper division of appendicular skeleton • Shoulder girdle • Upper extremity • Lower division of appendicular skeleton • Pelvis • Lower extremity

47. Shoulder Girdle • Clavicle aka collarbone • Most frequently fractured bone in body • Connects to sternum & scapula • Scapula aka shoulder blade • Spine – posterior ridge • Supraspinousfossa – above spine • Infraspionousfossa – below spine • Acromian – attaches to clavicle • Glenoid cavity – forms arm socket • Coracoid process – for muscle attachment

48. Shoulder Girdle Anterior & Posterior

49. Scapular Anatomy