Skeletal System & Bone Anatomy pt 1

• The skeletal system is covered in PSW 1022.

Skeletal System

• The word 'skeleton' is derived from the Greek term meaning "dried up body".
• This system provides the frame that supports the body.
• Bones form the main component of the skeletal system.
• Other structures play roles in the skeletal system in addition to bones.
• Bone is a connective tissue.

Bone Classification

• Bones are classified based on their shape.
• The main classifications are long, short, flat, and irregular bones.

Bone Cells

• Osteocytes are mature bone cells.
• Osteocytes contain calcium and other inorganic mineral salts.
• Osteoblasts are cells responsible for forming bone.
• Bone diameter increases due to osteoblast activity.
• Osteoclasts break down old bone cells.

Basic Bone Anatomy

• Periosteum consists of tough, fibrous connective tissue.
• Periosteum contains blood vessels for nutrient delivery to bone cells.
• It serves as an anchor point for ligaments and tendons.
• The epiphysis is the end of the bone.
• The medullary cavity is the inside of the bone, containing bone marrow.
• Blood cells are created in the bone marrow

Cartilage

• Cartilage is a type of connective tissue, similar to bone.
• It is firm, contains a jelly-like matrix, and is somewhat flexible.
• Cartilage can withstand pressure.
• Flexible cartilage is located in the nose and ears.
• Stronger cartilage can be found in joints and between bones.

Joints

• A joint is where bones meet.
• Ligaments hold most joints together.
• Ligaments connect bone to bone and are very strong.

Types of Joints

• Synovial joints can move a lot and contain synovial fluid.
• Cartilaginous joints allow a little movement, such as where ribs meet the sternum allowing breathing.
• Fibrous joints do not move, such as those where skull bones fit together.

Types of Synovial Joints

• Gliding joints slide back and forth.
• Hinge joints are in elbows and knees.
• Saddle joints are in the thumb.
• Pivot joints allow one bone to rotate along another.
• Ellipsoidal joints are at the wrists, where metacarpals meet the radius and ulna.
• Ball and socket joints are found in the shoulder and hips.

Movements of the Body

• Flexion involves bending a joint, reducing the angle between bones.
• Extension involves straightening a joint, increasing the angle between bones.
• Plantar Flexion involves bending down.
• Dorsiflexion involves bending up.
• Abduction involves moving away from the body's midline.
• Adduction involves moving toward the midline of the body.
• Inversion involves turning inward.
• Eversion involves turning outward.
• Supination involves facing upward.
• Pronation involves facing downward.
• Rotation involves a bone spinning on its axis.