Anatomy and Physiology

Types of Joint Movements A. The following terms describe movements at joints (p. 165): There will be a quiz on these! 1. Flexion 10. Pronation 2. Extension11. Supination 3. Dorsiflexion12. Eversion 4. Plantar flexion13. Inversion 5. Hyperextension14. Retraction 6. Abduction15. Protraction 7. Adduction16. Elevation 8. Rotation17. Depression 9. Circumduction

A. Bone is an active, living tissue. B. Composed of: 1. Bone tissue, cartilage, dense connective tissue, blood, and nervous tissue. 7.1 Introduction

A. Supports and gives shape to the body. B. Protects internal organs. 1. Skull, rib cage and shoulder girdle, pelvic girdle. C. Helps make movements possible. 1. Bones and muscles form levers. D. Hematopoiesis or blood cell formation (red bone marrow). 1. Begins in yolk sac, later in liver and spleen, and still later in bone marrow. E. Passageway for blood vessels and nerves. 7.1 Introduction (and 7.4 Bone Function)

F. Stores inorganic salts. 1. Bone stores calcium in the form of calcium phosphate. 2. Blood calcium is low, parathyroid hormone stimulates osteoclasts to break down tissue and release calcium. 3. Blood calcium is high, osteoclasts are inhibited and osteoblasts form bone tissue (stores extra calcium). 4. Calcium is needed for muscle contraction, nerve impulse conduction, and blood clotting. 7.1 Introduction (and 7.4 Bone Function)

A. Long: humerus (upper arm), femur (upper leg) B. Short: carpals (wrist) C. Flat: frontal (skull), scapula (shoulder) D. Irregular: vertebrae (spine) E. Sesamoid (round): patella (knee) 7.2 Bone Structure

F. Parts of a Long Bone 1. Epiphyses or ends of the bone; spongy bone contains red bone marrow. 2. Articular cartilage: Covers epiphyses as a cushion. 3. Diaphysis or shaft. 4. Medullary cavity containing yellow marrow. 5. Endosteum: Lines medullary cavity. 6. Periosteum: Tough, vascular covering of fibrous tissue. 7.2 Bone Structure

G. Microscopic Structure 1. Spongy a. Also called cancellous bone. b. Texture results from needlelike threads of bone called trabeculae surrounded by a network of open spaces. c. Found in epiphyses of bones. d. Spaces contain red bone marrow. 7.2 Bone Structure

Red and Yellow Bone Marrow Section through femoral head

2. Compact a. Structural unit is an osteon (Haversian system) composed of concentric lamella, lacunae containing osteocytes, and canaliculi, all covered by periosteum.

A. Intramembranous Bones 1. Broad, flat bones of the skull. 2. Form by replacing unspecialized connective tissue. 3. Osteoblasts become active and deposit bony matrix in the form of spongy bone. 4. Once completely surrounded by matrix they are termed osteocytes. 5. The periosteum develops and osteoblasts form compact bone over spongy bone – this is termed ossification. Bone remodeling video 7.3 Bone Development and Growth

B. Endochondral Bones 1. Most bones are this type. 2. Formed from hyaline cartilage “models” that are gradually replaced with harder tissue of bone. 3. Primary ossification begins in center of diaphysis and secondary ossification at the epiphyses. 4. Epiphyseal plate (metaphysis) remains between the primary and secondary centers. 5. Epiphyseal plates are cartilaginous tissue and where bone lengthens (until they ossify). 6. Long bones thicken as compact bone is formed under the periosteum. 7.3 Bone Development and Growth

Bone Growth and Development

Epiphyseal Plate

C. Homeostasis of Bone Tissue % of bone calcium is exchanged each year. 2. Osteoclasts break down calcified matrix by secreting an acid. 3. Osteoblasts invade the region and deposit new bone tissue. 4. This occurs through life and hormones that regulate blood calcium control this process. 7.3 Bone Development and Growth

D. A number of factors influence bone development, growth, and repair. 1. Vitamin D is necessary for absorption of calcium in the small intestine. a. Without it the matrix of bone lacks calcium causing softening and deformity. 2. Growth hormone secreted by the anterior pituitary stimulates cartilage in epiphyseal plate. 3. Sex hormones stimulate ossification of epiphyseal plate. 4. Physical exercise stimulates bone to thicken and strengthen. 7.3 Bone Development and Growth

VI. Divisions of the Skeleton A. Skeleton composed of the following divisions and subdivisions: 1. Axial skeleton a. Skull b. Spine (vertebrae) c. Thorax (ribs and sternum) d. Hyoid Bone 2. Appendicular skeleton a. Upper extremities, including shoulder girdle (clavicle & scapula). b. Lower extremities, including hip girdle (hip bones).

VII. Differences Between a Man’s and Woman’s Skeleton A. Size: Male skeleton generally larger. B. Shape of pelvis: Male pelvis deep and narrow; female pelvis broad and shallow. C. Size of pelvic inlet: Female pelvic inlet generally wider, normally large enough for baby’s head to pass through. D. Pubic angle: Angle between pubic bones of female generally wider.

Female and Male Pelvis

VIII. Joints (Articulations) A. Kinds of Joints 1. Functional junctions between bones. 2. Classified by type of movement made: a. Synarthroses (no movement) b. Amphiarthroses (slight movement) c. Diarthrotic (freely moveable) B. Fibrous Joints 1. Between bones that closely contact each other. 2. Sutures of the skull – no movement – synarthroses C. Cartilaginous Joints 1. Vertebrae of vertebral column, symphysis pubis, 1 st rib and sternum 2. Limited movement - amphiarthroses

Synarthroses

Amphiarthroses

D. Synovial Joints 1. Allow free movement – diarthroses 2. Structures of freely moveable joints – joint capsule and ligament hold adjoining bones together. a. Articular cartilage: Covers joint ends of bones and absorbs jolts. b. Synovial membrane: Lines joint capsule and secretes lubricating fluid. c. Joint cavity space between joint ends of bones. 3. Some have fibrocartilage called menisci 4. Others have bursae. Common between tendons and underlying bones

E. Types of freely moveable joints: 1. Ball and socket – Shoulder, hip 2. Hinge – Elbow, knee 3. Pivot – Radius and humerus 4. Saddle - Thumb 5. Gliding – Carpal, tarsal 6. Condyloid – Hand (Metacarpal and Phalange)

Ball and Socket

Hinge

Pivot

Saddle Joint

Gliding

Disorders of the Skeletal System A. Bone tumors and cancers: Benign and malignant neoplasms of bone, cartilage, and fibrous tissue. B. Metabolic bone diseases 1. Osteoporosis: Excessive loss of bone matrix (mineral and collagen). 2. Osteomalacia: Softening of bone from loss of mineral (but not volume) in bone matrix; called rickets in children. Due to lack of Vitamin D. 3. Paget Disease: Osteitis deformans; abnormal remodeling in which spongy bone is replaced by disorganized, excessive bone matrix.

Rickets

Osteoporosis

Paget Disease This is an advanced case of Paget's disease in the tibia. The bone has become very large in comparison to the fibula and the trabeculae have become very coarse.

Osteomalacia

Paget Disease

C. Bone Infection 1. Osteomyelitis: General term for bacterial (usually staphylococcal) infection of bone. 2. Bone infections may also be caused by virus, fungi, and other pathogens. D. Bone Fractures 1. Open (Compound) fractures: Pierce the skin. 2. Closed (Simple): Do not pierce skin. 3. Complete fractures involve total separation of bone fragments. 4. Incomplete (Greenstick, fissure): Involve partially separated fragments. 5. Comminuted: Involve many fragments. 6. Fracture lines can be spiral, transverse, or oblique.

Osteomyelitis of Big Toe

Closed Fracture

Comminuted Fracture

A transverse fracture of the tibial shaft.

Oblique Fracture

Patient with an anterior dislocation of the right shoulder.

E. Joint Disorders 1. Noninflammatory joint disease does not usually involve inflammation of the synovial membrane. a. Osteoarthritis: Degenerative joint disease; degeneration of articular cartilage. b. Traumatic Injuries: i. Subluxation: Dislocation of articular surfaces. ii. Sprain: Damage involving ligaments. Osteoarthritis

Ankle Sprain

2. Inflammatory joint disease (arthritis): Inflammation of synovial membrane with systemic signs or symptoms. a. Rheumatoid arthritis: Autoimmune inflammation of synovial membrane and other structures; juvenile form especially severe. b. Gouty arthritis: Synovial inflammation caused by gout, a condition in which sodium urate crystals form in joints and other tissues. c. Infectious arthritis: Arthritis resulting from infection by a pathogen, as in Lyme Disease.

Joints typically affected by rheumatoid arthritis

Rheumatoid Arthritis

Gouty Arthritis