1. Skeletal System 300 baby bones 206 adult bones >1/2 in hands & feet
Humans & giraffes
have same # neck
bones
Longest bone= femur
Smallest bone= inner ear
(hammer, anvil, stirrup)

2. Functions of Skeletal System
Support
Protection
Movement
Hematopoiesis
Reservoir for minerals and adipose tissue

3. 80 bones 126 bones Skull – 22 bones Vertebral Cranium – 8 Column - 32
Facial - 14
Vertebral
Column - 32
Inner
ear - 3
Thorax - 27
Iliac crest
80 bones
Upper limb – 30
Shoulder girdle - 2
Lower limb – 29
Pelvic girdle – 6
126 bones

4. Thoracic Cage 27 bones

5. Vertebral Column 32 bones

6. Abnormal Spinal Curvatures
Lordosis Kyphosis Scoliosis

7. The Hand 27 bones

8. The Foot 26 bones

9. Arches of the Foot

10. The Skull 22 bones Foramen – For nerves “keystone of cranium”
and vessels
Ethmoid
Ethmoid

12. Suture - Fibrous joint
Process - projection that contacts
adjacent bone

14. Infant Skull closes at 8 wks closes at 9-18 mths
Fontanel – space between infant skull bones

15. Sinus Cavities
Sinus: air-filled space

16. Compact & Spongy Bone

17. Compact Bone
canaliculi

18. Bone Classification Flat Long Short Irregular Scapula Arms Sternum
Ribs
Skull
Arms
Legs
Phalanges
Short
Irregular
Wrist
Ankle
Vertebrate
Hip
Patella

19. Anatomy of Long Bones

20. Anatomy of Short, Flat & Irregular Bones

21. Osteon Structural and functional unit of bone
Haversion Canal
Allows passage of blood vessels, lymphatic vessels, and nerve fibers
Lamella
Concentric rings of collagen fibers around haversion canal
Allows bone to withstand force
Lacunae
Small cavities occupied by osteocytes that join lamella
Canaliculi
Hairlike canals that join lacunae to each other and the central canal
Allow osteocytes to exchange nutrients, wastes, and chemical signals via gap junctions

22. Type of Cells in Bone Osteoblast Osteocytes Osteoclasts
Build bone cells
Synthesize and secrete organic components of bone matrix
Initiate calcification
Found in periosteum and endosteum
Osteocytes
Mature bone cells
Formed when osteoblasts get trapped in matrix
Do not secrete matrix
Maintain bone tissue
Osteoclasts
Bone resorption (digest/break down matrix): part of normal bone growth, development, maintenance and repair
Found in endosteum

23. Bone Matrix Organic components (1/3) Inorganic components (2/3)
Collagen fibers
Provide resilience against stretching and twisting
Inorganic components (2/3)
Mg, F, Na
Salts that interact to form hydroxyapatite
Calcium phosphate
Calcium hydroxide
Provide hardness and resist compression

24. Types of Tissue in Bone Connective Nervous Osseous Dense fibrous
Adipose
Vascular
Lymphatic
Nervous

25. Hyoid Bone
A single bone in the neck. It is U shaped and can be felt just above the larynx.
The tongue muscle & certain muscles on the floor of the mouth attach to the hyoid bone.
This is the only bone in the body that doesn’t attach to any other bones.

26. Appendicular Skeleton
Pelvic Girdle- Stable, circular base that supports the trunk and the lower extremities are connected to it.
Early in life it is made up of three separate bones. Later they fuse into a single, massive irregular bone that is broader than any other bone in the body.
Ilium
Ischium
Pubis

27. Appendicular Skeleton
Pelvic Outlet- The digestive tract empties.
The female reproductive tract passes here.
During delivery the baby will pass through the pelvic outlet so the baby’s head must be positioned correctly.
Prior to delivery the symphysis pubis softens to expand for the baby’s head.
Sometimes the coccyx bone breaks during labor.

28. Appendicular Skeleton
Femur- Thigh bone. Longest and heaviest bones in the body.
Patella- kneecap. When the knee joint is extended, you can see the patella through the skin, but as the knee flexes, it sinks and can’t be distinguished.
Tibia- larger, stronger bone in front
Fibula- smaller and deeper into leg

29. Appendicular Skeleton
Foot-Bones form springy lengthwise & crosswise arches that give it more strength.
Strong ligaments and tendons hold the arches in position. If they weaken, the arches can flatten causing fallen arches or flat feet.
High heels are bad for these arches.

30. Skeletal Differences in Men & Women
Male skeletons are larger & heavier.
The pelvic bones are shaped differently It is wider in women.

31. Bone Fractures
Open Fracture- (compound) broken bone projects through the surrounding tissue and skin.
Closed Fracture- (simple) doesn’t break the skin & no immediate danger of infection.

32. Bone Fractures
Incomplete Fracture- partial break in which bone fragments are still partially joined.
Complete Fracture- breaks across the entire section of bone.

33. Bone Fractures
Greenstick fracture- bone is bent on one side and the other side is broken. Usually seen in kids because their bones are less brittle.
Denate fracture- fragmented ends of the bone being jagged, fitting together like teeth on a gear.

34. Bone Fractures
Linear fracture- fracture line is parallel to the bone’s long axis.
Transverse fracture- fracture is at a right angle to the bones axis.
Oblique- fracture is slanted, or diagonal

35. Skeletal Disorders Osteomalacia “soft bones”
Lacking minerals (ie. Calcium, vit D)
Rickets
Child form of osteomalacia
More detrimental since bones are still growing
Signs: bowed legs; deformities of pelvis, ribs and skull
Osteomyelitis
“bone marrow inflammation”
Caused by pus-forming bacteria that enter via wound or nearby infection
Osteoporosis
Bone degradation occurs faster than bone can be deposited
Decrease in bone mass
Porous bones
Fractures in the vertebrate and femur are common
Most common postmenopause: rapid decline in estrogen (stimulates osteoblasts and inhibits osteoclasts

36. Skeletal Disorders Giantism Acromegaly Pituitary Dwarfism
Childhood hypersecretion of GH
Excessive growth
Acromegaly
Adult hypersecretion of GH
Overgrowth of face, feet, hands
Pituitary Dwarfism
Childhood deficiency of GH
Short long bones; max height is 4 ft.
Paget’s Neoplasms
Bone remodeling process disturbed
Bones are abnormal, enlarged, not as dense, brittle, and prone to fracture
Affects older adults