The Skeletal System
! Two subdivisions of the skeleton
1. Axial skeleton
2. Appendicular skeleton
! Parts of the skeletal system
o Bones (skeleton)
o Joints
o Cartilages
o Ligaments
Functions of Bones
! Support the body
! Protect soft organs
o Skull and vertebrae protect brain and spinal cord
o Rib cage protects thoracic cavity organs
! Attached skeletal muscles allow movement
! Store minerals and fats
o Calcium and phosphorus
o Fat in the internal marrow cavity
! Blood cell formation (hematopoiesis)
Bones of the Human Body
! The adult skeleton has 206 bones
! Two basic types of bone tissue
1. Compact bone
! Dense, smooth, and homogeneous
2. Spongy bone
! Small needle-like pieces of bone
! Many open spaces
Classification of Bones
Bones are classified on the basis of shape, as:
o Long
o Short
o Flat
o Irregular
Classification of Bones
! Long bones
o Typically longer than they are wide
o Shaft with heads situated at both ends
© 2015 Pearson Education, Inc.
, o Contain mostly compact bone
o All of the bones of the limbs (except wrist, ankle, and kneecap bones) are long
bones
o Examples:
! Femur
! Humerus
Classification of Bones
! Short bones
o Generally cube-shaped
o Contain mostly spongy bone
o Include bones of the wrist and ankle
o Sesamoid bones are a type of short bone that form within tendons (patella)
o Examples:
! Carpals
! Tarsals
Classification of Bones
! Flat bones
o Thin, flattened, and usually curved
o Two thin layers of compact bone surround a layer of spongy bone
o Examples:
! Skull
! Ribs
! Sternum
Classification of Bones
! Irregular bones
o Irregular shape
o Do not fit into other bone classification categories
o Examples:
! Vertebrae
! Hip bones
Anatomy of a Long Bone
! Diaphysis
o Shaft
o Makes up most of bone’s length
o Composed of compact bone
! Periosteum
o Outside covering of the diaphysis
o Fibrous connective tissue membrane
o Perforating (Sharpey’s) fibers secure periosteum to underlying bone
© 2015 Pearson Education, Inc.
! Two subdivisions of the skeleton
1. Axial skeleton
2. Appendicular skeleton
! Parts of the skeletal system
o Bones (skeleton)
o Joints
o Cartilages
o Ligaments
Functions of Bones
! Support the body
! Protect soft organs
o Skull and vertebrae protect brain and spinal cord
o Rib cage protects thoracic cavity organs
! Attached skeletal muscles allow movement
! Store minerals and fats
o Calcium and phosphorus
o Fat in the internal marrow cavity
! Blood cell formation (hematopoiesis)
Bones of the Human Body
! The adult skeleton has 206 bones
! Two basic types of bone tissue
1. Compact bone
! Dense, smooth, and homogeneous
2. Spongy bone
! Small needle-like pieces of bone
! Many open spaces
Classification of Bones
Bones are classified on the basis of shape, as:
o Long
o Short
o Flat
o Irregular
Classification of Bones
! Long bones
o Typically longer than they are wide
o Shaft with heads situated at both ends
© 2015 Pearson Education, Inc.
, o Contain mostly compact bone
o All of the bones of the limbs (except wrist, ankle, and kneecap bones) are long
bones
o Examples:
! Femur
! Humerus
Classification of Bones
! Short bones
o Generally cube-shaped
o Contain mostly spongy bone
o Include bones of the wrist and ankle
o Sesamoid bones are a type of short bone that form within tendons (patella)
o Examples:
! Carpals
! Tarsals
Classification of Bones
! Flat bones
o Thin, flattened, and usually curved
o Two thin layers of compact bone surround a layer of spongy bone
o Examples:
! Skull
! Ribs
! Sternum
Classification of Bones
! Irregular bones
o Irregular shape
o Do not fit into other bone classification categories
o Examples:
! Vertebrae
! Hip bones
Anatomy of a Long Bone
! Diaphysis
o Shaft
o Makes up most of bone’s length
o Composed of compact bone
! Periosteum
o Outside covering of the diaphysis
o Fibrous connective tissue membrane
o Perforating (Sharpey’s) fibers secure periosteum to underlying bone
© 2015 Pearson Education, Inc.
