THE SKELETAL SYSTEM1 PARTS OF THE SKELETAL SYSTEM

THE SKELETAL SYSTEM-1

PARTS OF THE SKELETAL SYSTEM • Bones (skeleton) • Joints • Cartilages • Ligaments

TWO SUBDIVISIONS OF THE SKELETON • Axial skeleton • Appendicular skeleton

• Adult skeleton approximately 206 bones • Axial: 80 bones • Appendicular: 126 bones

FUNCTIONS OF BONES

TWO BASIC TYPES OF BONE TISSUE • Compact bone • Spongy bone

CLASSIFICATION OF BONES BASED ON SHAPE

CLASSIFICATION OF BONES BASED ON SHAPE

CLASSIFICATION OF BONES BASED ON SHAPE

CLASSIFICATION OF BONES BASED ON SHAPE

CLASSIFICATION OF BONES BASED ON SHAPE

ANATOMY OF A LONG BONE • Epiphysis

ANATOMY OF A LONG BONE

ANATOMY OF A LONG BONE • Diaphysis

ANATOMY OF A LONG BONE • Periosteum • Sharpey’s (Perforating) fibers • Arteries

ANATOMY OF A LONG BONE

ANATOMY OF A LONG BONE

ANATOMY OF A LONG BONE • Articular cartilage • Hyaline cartilage found on articular surfaces of bone

ANATOMY OF A LONG BONE • Epiphyseal plate • Epiphyseal line

ANATOMY OF A LONG BONE

ANATOMY OF A LONG BONE • Medullary cavity • Cavity inside of the shaft

ANATOMY OF A LONG BONE • Endosteum:

BONE MARKINGS • Are bones smooth surfaces? • Femur

• Are bones smooth surfaces? • Tibia

BONE MARKINGS • Are bones smooth surfaces? • Mandible

BONE MARKINGS • Are bones smooth surfaces? • Optical canal

COMPACT VS. SPONGY BONE

MICROSCOPIC ANATOMY OF COMPACT BONE • Osteocytes: mature bone cells • Lacunae:

MICROSCOPIC ANATOMY OF COMPACT BONE • Lamella:

MICROSCOPIC ANATOMY OF COMPACT BONE • Lamella: concentric circles

MICROSCOPIC ANATOMY OF COMPACT BONE • Central (Haverersian) Canals:

MICROSCOPIC ANATOMY OF COMPACT BONE • Osteon (Haversian System):

MICROSCOPIC ANATOMY OF COMPACT BONE

MICROSCOPIC ANATOMY OF COMPACT BONE • Canaliculi: • Hint: which way do central canals run?

MICROSCOPIC ANATOMY OF COMPACT BONE • Canaliculi:

MICROSCOPIC ANATOMY OF COMPACT BONE

MICROSCOPIC ANATOMY OF COMPACT BONE • This eleaborate network of canals ensures bone cells are well nourished • What significance does this have?

MICROSCOPIC ANATOMY OF COMPACT BONE • Perforating (Volkmann’s) canals: • Run through compact bone at right angles to the shaft

MICROSCOPIC ANATOMY OF COMPACT BONE

BONE FORMATION, GROWTH, & REMODELING • Mostly hyaline cartilage • Replaced by bone

BONE FORMATION, GROWTH, & REMODELING Articular cartilage Hyaline cartilage Spongy bone New center of bone growth New bone forming Epiphyseal plate cartilage Growth in bone width Medullary cavity Bone starting to replace cartilage Growth in bone length Bone collar (a) New bone forming Epiphyseal plate cartilage Hyaline cartilage model In an embryo Blood vessels In a fetus In a child

BONE FORMATION, GROWTH, & REMODELING • Osteocytes— • Osteoblasts— • Osteoclasts—

GROWTH & REMODELING • New cartilage is continuously formed • Older cartilage becomes ossified • Cartilage is broken down by osteoclasts • Buit by osteoblasts

GROWTH & REMODELING • Osteocytes can sense areas of stress • Enhances the process • Balance of calcium levels

FRACTURES

FRACTURES

FRACTURES

FRACTURES

FRACTURES

FRACTURES

FRACTURES • Treated by Reduction: • Closed • Open