1. Skeletal System

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

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

4. 80 bones 126 bones Skull – 25 bones Vertebral Cranium – 8 Column - 33
Facial - 14
Vertebral
Column - 33
Inner
ear - 3
Thorax - 27
Iliac crest
80 bones
Upper limb – 30
Shoulder girdle - 2
Lower limb – 29
Pelvic girdle – 6
126 bones

6. Thoracic Cage 27 bones

7. Vertebral Column 33 bones
5 fused
4 fused

8. Abnormal Spinal Curvatures
Lordosis Kyphosis Scoliosis

9. The Hand 27 bones

10. The Foot 26 bones

11. Arches of the Foot

12. The Skull 25 bones Foramen – For nerves “keystone of cranium”
and vessels
Ethmoid
Ethmoid

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

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

17. Sinus Cavities
Sinus: air-filled space

18. Compact & Spongy Bone

19. Compact Bone
canaliculi

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

22. Anatomy of Long Bones

23. Anatomy of Short, Flat & Irregular Bones

24. 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

25. 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

26. 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

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

28. Bone Marrow Red = hematopoietic tissue Yellow = fatty tissue
Bone cell forming tissue
Everywhere in infant
Yellow = fatty tissue
Young to middle age develop in shafts
Does NOT produce blood

29. I love anatomy!!!!!

30. Bone Development Osteogenesis (ossification) – bone tissue formation
Embryo: leads to skeleton
Intramembranous ossification
Fibrous membrane replaced with bone
Endochondral ossification
Hyaline cartilage replaced with bone
Most bones develop this way
More complicated (hyaline cartilage broken down first)
Children: leads to bone growth
Adults: leads to bone remodeling and repair

31. Intramembranous Ossification
Osteoblasts permit calcification
Some osteoblasts trapped in ossification center (now considered osteocytes)
Growth is outward from ossification center
Osteoblasts require oxygen and nutrients, so blood vessels are trapped in bone
Fibrous membranes→spongy bone→compact bone
Outer fibrous membrane becomes periosteum

32. Endochondrial Ossification
Chondrocytes in center of shaft increase in size and calcify
Deprived of nutrients and die
Vessels grow into perichondrium
Inner layer turns to osteoblasts
Perichondrium now periosteum
Thin layer of bone formed around shaft
Bone collar provides support
Calcified cartilage breaks down
Osteoblasts replace with spongy bone
1° oss. center- bone dev and spreads toward epiphysis

33. Endochondrial Ossification
1° oss. center enlarges
Osteoclasts break down spongy bone
Medullary cavity now open
Osteoblasts move to epiphysis

35. Bone Growth Length Thickness Primary ossification center
center of diaphysis
Thickness
Secondary ossification center
center of epiphysis

36. Hormonal Effects on Bone Growth
Growth Hormone (GH)
Produced by pituitary gland
Stimulates protein synthesis and cell growth
Thyroxine
Produced by thyroid gland
Stimulates cell metabolism and increases osteoblast activity
Sex Hormones at Puberty
Cause osteoblasts to produce bone faster than epiphyseal cartilage can divide
Growth spurt
Epipyseal plate closure
Estrogens (female)
Cause faster closure of plate than androgens
Androgens (male)
Parathyroid Hormone
Increases blood calcium level (decreases bone calcium)
Inhibits osteoblast; Stimulates osteoclast
Calcitonin
“tones down” blood calcium level (increases bone calcium)
Inhibits osteoclast; stimulates osteoblast

37. Nutrients and Bone Growth
Calcium and phosphate salts
Hormone calcitriol and Vit D allow absorption
Vitamins A, C, K, B12

38. Categories of Fractures
Simple vs. Compound
Simple (Closed) - the bone is broken, but the skin is not lacerated
Compound (Open) - skin is pierced by the bone or by a blow that breaks the skin at the time of the fracture
Stable vs Displaced
Stable - fracture is barely out of place; broken ends are still aligned and stay in place while healing
Displaced – broken ends are separated and do not line up; often requires surgery
Displaced

39. Types of Fractures
Spiral – fracture wraps around bound in spiral manner
Comminuted - results in three or more bone fragments.
Transverse - fracture is at right angles to the diaphysis
Oblique – slanted fracture along the diaphysis

40. Types of Fractures cont.
Greenstick - fracture on one side of the bone, causing a bend on the other side of the bone.
Compression – occurs in vertebrate
Lisfranc - one or all of the metatarsal bones are displaced from the tarsus
Stress/Hairline - an overuse injury; the fatigued muscle transfers the overload of stress to the bone causing a tiny crack
Impacted - one fragment is firmly driven into the other
Compression
Lisfranc

41. Fracture Repair
Bony
(Fracture
Hematoma)

42. Skeletal Disorders Osteomalacia Osteomyelitis Osteoporosis
“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

43. 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