The Skeletal System

1
The Skeletal System

• Allied Health I
• Ms. Campanicki

2
Intro

• Skeletal system includes bones of the skeleton,
  and the cartilage, ligaments, and other
  connective tissues that stabilize and/or connect
  the bones

3
Functions of the Skeletal System

• SUPPORT
• Provides structural support and framework for
  entire body
• STORAGE OF MINERALS AND LIPIDS
• Mainly calcium salts and fats (in yellow marrow)
• BLOOD CELL PRODUCTION
• RBCs, WBCs, and other blood elements are made in
  red marrow

4
Functions of the Skeletal System

• PROTECTION
• Many soft tissues are surrounded by bone
• LEVERAGE
• Bones function as levers that change the
  magnitude and direction of the forces generated
  by skeletal muscles

5
Gross Anatomy of Bones
6
Bone Shapes

• There are 206 bones in the human body, which are
  categorized into 6 shapes
• 1) Long bones
• Long and slender
• Located in arm, thigh, leg, palms, soles, fingers
  and toes.
• The femur (thigh bone) is largest and heaviest
  bone in the body

7
Bone Shapes
8
Bone Shapes

• 2) Flat bones
• Thin, relatively parallel surfaces
• Found in roof of skull, sternum, ribs, scapula
• Provide protection of underlying tissue
• Large surface area for attachment of muscles
• 3) Sutural bones (Wormian bones)
• Small, flat, irregularly shaped
• Found between flat bones of the skull

9
Bone Shapes
10
Bone Shapes

• 4) Irregular bones
• Complex shapes with short, flat, notched or
  ridged surfaces
• Vertebrae, pelvis, some skull bones
• 5) Short bones
• Small and boxy
• Wrist bones and ankle bones
• 6) Sesamoid bones
• Small, flat, shaped like sesame seed
• Kneecaps, some bones in hands and feet

11
Bone Shapes
12
Bone Structure

• There are different parts to bone
• Diaphysis tubular shaft
• Epiphysys expanded area at each end of the
  diaphysis
• Metaphysis thin area that connects the
  epiphysis to the diaphysis

13
(No Transcript)
14
Bone Structure

• There are different parts to bone
• Compact bone outer portion of diaphysis
• Solid, sturdy layer that surrounds the marrow
  cavity
• Spongy bone (cancellous) mainly found in the
  epiphysis
• Open network of struts and plates with a thin
  covering of compact bone
• Marrow is present here, but no marrow cavity

15
(No Transcript)
16
Bone Formation and Growth
17
Bone Formation and Growth

• Skeleton begins to form about 6 weeks after
  fertilization
• Skeleton is cartilage
• Portions of the skeleton dont stop growing until
  the age of 25

18
Bone Formation and Growth

• Ossification - process of replacing other tissues
  with bone
• 2 types
• Endochondral ossification
• Intramembranous ossification
• Calcification deposition of calcium, occurs
  during ossification

19
Endochondral Ossification

• Bones are made of hyaline cartilage in the embryo
• Cartilage gradually converted to bone through
  endochondral ossification

20
Endochondral Ossification

• 6 steps to endochondral ossification
• 1) Chondrocytes increase in size, cartilage is
  reduced to struts that calcify. Chondrocytes
  die and disintegrate
• 2) Blood vessels grow into perichondrium. Cells
  in inner layer become osteoblasts and they
  produce a thin layer of bone along shaft
  (perichondrium become periosteum

21
Endochondral Ossification
22
Endochondral Ossification
23
Endochondral Ossification Animation 1
Endochondral Ossification Animation2
24
Endochondral Ossification

• As long as cartilage is being produced on the
  epiphyseal side, and bone is replacing cartilage
  on the shaft side, the bone will continue to get
  longer.
• At puberty, sex hormones cause dramatic bone
  growth.
• Epiphyseal cartilage starts to disappear and
  become an epiphyseal line

25
Dynamic Nature of Bone
26
The Dynamic Nature of Bone

• The matrix is constantly being recycled
• Process is called remodeling
• Occurs throughout life
• Osteoblasts constantly make matrix
• Osteoclasts constantly dissolve matrix

27
Effects of Exercise on Bone

• Osteoblasts are attracted to minute electrical
  fields, which are created when bone is stressed.
• More matrix is produced where stress is high
• Electrical stimulation is used in fracture
  healing
• Bone that is not stressed will lose matrix
• IF YOU DONT USE IT, YOU WILL LOSE IT!!!!!!!

28
Effects of Hormones and Nutrition on Bone

• YOU NEED CALCIUM AND PHOSPHATE SALTS!!!!!!!
• Vitamin D - helps make calcitrol, which helps
  body absorb calcium
• Vitamin C helps with collagen synthesis and
  with osteoblast differentiation
• Vitamin A osteoblast activity
• Vitamins K, B12 protein fiber production

29
Effects of Hormones and Nutrition on Bone

• Growth hormone (in pituitary gland) stimulates
  bone growth
• Sex hormones stimulate osteoblasts
• Estrogen causes faster epiphyseal closure than
  testosterone, which is why women are shorter than
  men

30
Fracture Repair

• Damage to bone tissue is known as a fracture
• 4 steps to repair
• 1) Extensive bleeding occurs and a fracture
  hematoma forms
• 2) An external callus forms
• Enlarged collar of cartilage and bone on surface
  of bone
• An internal callus forms in the marrow cavity

31
Fracture Repair
32
Fracture Repair

• 3) Osteoblasts replace the cartilage with spongy
  bone in external and internal callus
• Broken ends of bone are united
• 4) Continued remodeling of bone by osteoblasts
  and osteoclasts.
• Lasts from 4 months to over a year
• Bone is thicker and stronger than original

33
Fracture Repair
Fracture Repair Animation
34
Types of Fractures

• Fractures can be open (compound) or closed
  (simple)

35
(No Transcript)
36
Types of Fractures
37
Types of Fractures
38
Skeletal System

• Axial Skeleton

39
(No Transcript)
40
Introduction

• Skull, vertebral column, thoracic cage (ribs
  sternum)

41

• Function
• 1. framework that supports organs
• 2. surface area for muscle attachment

42
Skull

• Protects the brain and guards the entrance to the
  digestive and respiratory tract
• Cranial Bones occipital, parietal (2), frontal,
  temporal (2), sphenoid ethmoid bones
• Cranial bones protect the brain

43
Skull

• Facial bones
• Function protect and support entrances to
  digestive respiratory tracts
• Superficial bones maxillary, nasal, zygomatic,
  Mandible. Allow for attachment of muscles that
  control facial expressions and help in
  manipulation of food

44
(No Transcript)
45
(No Transcript)
46
(No Transcript)
47
(No Transcript)
48
(No Transcript)
49
(No Transcript)
50
(No Transcript)
51
Skull

• Facial bones (cont)
• Deeper facial bones palatine vomer (separates
  oral and nasal cavities)
• Several bones of skull have sinuses
• Air filled chambers
• Function
• 1. helps to make bones lighter
• 2. has a mucus membrane that helps moisten and
  clean air

52

• Sutures immoveable joints that are connections
  b/n skull bones
• 4 major sutures
• 1. lamboidal suture across posterior surface
  of skull. Separates occipital bone from the 2
  parietal bones.
• 2. coronal suture attaches frontal bone to
  parietal bones on either side
• 3. saggital suture from lamboidal suture to
  coronal suture b/n the 2 parietals
• 4. squamosal suture on each side of the skull
  boundary b/n temporal and parietal bones
• Cranial and Facial Bones see handout

53

• Orbital and nasal complexes
• 1. Orbital complex formed form cranial and
  facial bones which surround each eye
• 2. Nasal complex surrounds nasal cavity

54
(No Transcript)
55
(No Transcript)
56

• Skulls of Infants and Children
• Right before birth, brain enlarges and bones
  cannot keep up. So at birth some bones are
  connected by fibrous connective tissue. Flexible
  so brain is not damaged.
• Fontanels fibrous areas b/n cranial bones
• Also called the SOFT SPOT

57
Vertebral Column

• Adult vertebral column 26 bones 24 vertebrae,
  sacrum coccyx
• Function
• 1. support
• 2. bears weight of head, neck and trunk
• 3. transfers weight to appendicular skeleton
• 4. protects spinal cord
• 5. maintains upright position

58

• Divided into
• 7 cervical
• 12 thoracic (articulates with ribs)
• 5 lumbar
• 1 sacrum
• 1 coccyx
• With development, sacrum is made up of 5
  vertebrae until 25 than 1

59
(No Transcript)
60
(No Transcript)
61

• Cervical vertebrae
• 7 of them
• C1 atlas nod head yes
• C2 axis rotation to say no

62
(No Transcript)
63

• Throracic
• 12 of them
• Contain facets for rib articulation
• Lumbar
• 5 largest
• Bear most weight
• Sacrum
• Fused components of 5 sacral vertebrae
• Coccyx
• tailbone

64
Thoracic Cage

• Ribs
• 12 pairs
• First 7 true. Connected to sternum
• Ribs 8-12 false b/c do not attach directly to
  sternum
• Ribs 11 12 floating. Attach to vertebrae
• Sternum (breast bone) flat
• Manubrium articulates with clavicles first
  pair of ribs
• Body ribs 2-7
• Xiphoid process smallest part

65
(No Transcript)
66
The Skeleton

• Appendicular Skeleton

67
Appendicular Skeleton

• Allows us to move and manipulate objects
• Includes all bones besides axial skeleton
• the limbs
• the supportive girdles

68
Appendicular Skeleton

• Pectoral Girdle

69
Pectoral Girdle

• Also called the shoulder girdle
• Connects the arms to the body
• Positions the shoulders
• Provides a base for arm movement
• Consists of the scapula (shoulder blade) and the
  clavicle (collarbone)

70
Appendicular Skeleton

• Upper Limb

71
Upper Limb

• Consists of arms, forearms, wrists, and hands
• Note arm (brachium) 1 bone, the humerus

72
Upper Limb

• Humerus
• Also called the arm
• The long, upper arm bone
• Articulates with the pectoral girdle and forearm

73
Upper Limb

• Humerus
• Features
• Head articulates with glenoid fossa
• Medial and lateral epicondyles
• Olecranon fossa

74
(No Transcript)
75
Upper Limb

• Forearm
• Consists of 2 long bones
• ulna (medial)
• Olecranon process
• radius (lateral)

76
(No Transcript)
77
Upper Limb

• Wrist
• 8 carpal bones
• 4 proximal carpal bones (starting Laterally)
• Scaphoid bone
• Lunate bone
• Triquetrum
• Pisiform bone
• 4 distal carpal bones (starting Laterally)
• Trapezium
• Trapezoid bone
• Capitate bone
• Hamate bone

78
(No Transcript)
79
Upper Limb

• Hand (Metacarpals)
• 5 long bones of the hand
• Numbered IV from lateral (thumb) to medial
• Fingers/Thumb
• Pollex (thumb)
• 2 phalanges (proximal, distal)
• Fingers
• 3 phalanges (proximal, middle, distal)

80
(No Transcript)
81
Appendicular Skeleton

• Pelvic Girdle

82
Pelvic Girdle

• Also known as the hip
• Made up of 3 fused bones
• ilium
• ischium
• pubis

83
(No Transcript)
84
Pelvic Girdle

• Acetabulum
• Also called the hip socket
• Is the meeting point of the ilium, ischium, and
  pubis
• Articulates with head of the femur

85
Pelvic Girdle

• Ilium
• Iliac crest
• Anterior superior iliac spine (ASIS)
• Ischium
• Pubis
• Pubic symphysis

86
(No Transcript)
87
Pelvic Girdle

• Differences between male and female pelvic
  girdles.
• Female pelvis
• smoother
• lighter
• less prominent muscle and ligament attachments
• Modifications for Childbearing
• Enlarged pelvic outlet
• Broad pubic angle (gt 100)
• Less curvature of sacrum and coccyx
• Wide, circular pelvic inlet
• Broad, low pelvis
• Ilia project laterally, not upwards

88
(No Transcript)
89
Appendicular Skeleton

• Lower Limb

90
Lower Limb

• Consists of
• Femur (thigh)
• Patella (kneecap)
• Tibia and fibula (leg)
• Tarsals (ankle)
• Metatarsals (foot)
• Phalanges (toes)

91
Lower Limb

• Femur
• Largest, heaviest bone
• Features
• Head articulates with acetabulum

92
(No Transcript)
93
Lower Limb

• Patella (knee cap)
• A sesamoid bone
• Formed within tendon of quadriceps muscles

94
Lower Limb

• Tibia (shin bone)
• Medial bone in lower leg
• Supports body weight
• Features
• Tibial tuberosity
• Medial Malleolus medial ankle bone

95
(No Transcript)
96
Lower Limb

• Fibula
• Lateral bone in lower leg
• Does not support body weight
• Features
• Head
• Lateral Malleolus lateral ankle bone

97
(No Transcript)
98
Lower Limb

• Ankle (Tarsus)
• Consists of 7 tarsal bones
• Talus
• Calcaneus (heel bone)
• Cuboid bone
• Navicular bone
• Medial cuneiform
• Intermediate cuneiform
• Lateral cuneiform

99
Lower Limb

• Feet (Metatarsals)
• 5 long bones of foot
• Numbered IV, medial to lateral
• Toes (phalanges)
• Hallux
• big toe, 2 phalanges (distal, proximal)
• Other 4 toes
• 3 phalanges (distal, middle, proximal)