The Skeletal System

The Axial Skeleton 5 The Skeletal System . Forms the longitudinal part of the body PART A . Divided into three parts PowerPoint® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University . Skull

ESSENTIALS . Vertebral column OF HUMAN . Bony thorax ANATOMY & PHYSIOLOGY

EIGHTH EDITION

ELAINE N. MARIEB

The Skeletal System The Appendicular Skeleton . Parts of the skeletal system . Limbs (appendages) . Bones (skeleton) . Pectoral girdle . Joints . Pelvic girdle . Cartilages . Ligaments . Divided into two divisions . Axial skeleton . Appendicular skeleton

The Axial Skeleton Functions of Bones 1) Support of the body 2) Protection of soft organs

3) Movement due to attached skeletal muscles

4) Storage of minerals and fats 5) Blood cell formation

1 Bones of the Human Body Classification of Bones . The adult skeleton has 206 bones . Short bones . Two basic types of bone tissue . Generally cube-shape . Compact bone . Contain mostly spongy bone . Solid . Examples: Carpals, tarsals . Spongy bone . Many open spaces

Classification of Bones on the Basis of Classification of Bones Shape . Flat bones . Thin and flattened . Usually curved . Thin layers of compact bone around a layer of spongy bone . Examples: Skull, ribs, sternum

Classification of Bones Classification of Bones . Long bones . Irregular bones . Typically longer than wide . Irregular shape . Have a shaft with heads at both ends . Do not fit into other bone classification categories . Contain mostly compact bone . Example: Vertebrae and hip . Examples: Femur, humerus

2 Gross Anatomy of a Long Bone Structures of a Long Bone . Diaphysis . Medullary cavity . Shaft . Cavity of the shaft . Composed of . Contains yellow compact bone marrow (mostly fat) in adults . Epiphysis . Contains red marrow . Ends of the bone (for blood cell . Composed mostly of formation) in infants spongy bone

Structures of a Long Bone Bone Markings . Periosteum . Surface features of bones . Outside covering of the diaphysis . Sites of attachments for muscles, tendons, and ligaments . Fibrous connective tissue membrane . Passages for nerves and blood vessels . Categories of bone markings . Arteries . Projections and processes – grow out from . Supply bone cells with nutrients the bone surface . Depressions or cavities – indentations

Structures of a Long Bone Microscopic Anatomy of Bone . Articular cartilage . Osteon (Haversian System) . Covers the . A unit of bone external surface of . Central (Haversian) canal the epiphyses . Opening in the center of an osteon . Made of hyaline . Carries blood vessels and nerves cartilage . Perforating (Volkman’s) canal . Decreases friction at joint surfaces . Canal perpendicular to the central canal . Carries blood vessels and nerves

3 Microscopic Anatomy of Bone Changes in the Human Skeleton . In embryos, the skeleton is primarily hyaline cartilage . During development, much of this cartilage is replaced by bone . Cartilage remains in isolated areas . Bridge of the nose . Parts of ribs . Joints

Microscopic Anatomy of Bone Bone Growth . Lacunae . Epiphyseal plates allow for growth of long . Cavities containing bone during childhood bone cells (osteocytes) . New cartilage is continuously formed . Arranged in concentric rings . Older cartilage becomes ossified . Lamellae . Cartilage is broken down . Rings around the . Bone replaces cartilage central canal . Sites of lacunae

Microscopic Anatomy of Bone Bone Growth . Canaliculi . Bones are remodeled and lengthened until growth stops . Tiny canals . Bones change shape somewhat . Radiate from the central canal to . Bones grow in width lacunae . Form a transport system

4 Long Bone Formation and Growth The Skull . Two sets of bones . Cranium . Facial bones . Bones are joined by sutures . Only the mandible is attached by a freely movable joint

Long Bone Formation and Growth The Skull

Types of Bone Cells Bones of the Skull . Osteocytes . Mature bone cells . Osteoblasts . Bone-forming cells . Osteoclasts . Bone-destroying cells . Break down bone matrix for remodeling and release of calcium . Bone remodeling is a process by both osteoblasts and osteoclasts

5 Human Skull, Superior View Common Types of Fractures

Human Skull, Inferior View Repair of Bone Fractures . Hematoma (blood-filled swelling) is formed . Break is splinted by fibrocartilage to form a callus . Fibrocartilage callus is replaced by a bony callus . Bony callus is remodeled to form a permanent patch

Bone Fractures Stages in the Healing of a Bone Fracture . A break in a bone . Types of bone fractures . Closed (simple) fracture – break that does not penetrate the skin . Open (compound) fracture – broken bone penetrates through the skin . Bone fractures are treated by reduction and immobilization . Realignment of the bone

6 The Vertebral Column Regional Characteristics of Vertebrae . Vertebrae separated by intervertebral discs . The spine has a normal curvature . Each vertebrae is given a name according to its location

Structure of a Typical Vertebrae Development of Spine Curvature

Regional Characteristics of Vertebrae Abnormal Curvatures of the Vertebrae

Kyphosis Exaggerated posterior curvature of the Thoracic Vertebrae (Hunchback

Lordosis Exaggerated anterior curvature of the Lumbar Vertebrae

Scoliosis: Lateral curvature of the spine appearing “S” or “C” shaped Figure 5.17a–b Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

7 The Bony Thorax Bones of the Shoulder Girdle . Made-up of three parts . Sternum . Ribs . Thoracic vertebrae

The Appendicular Skeleton Bones of the Shoulder Girdle . Limbs (appendages) . Pectoral girdle . Pelvic girdle

The Pectoral (Shoulder) Girdle Bones of the Upper Limb . Composed of two bones . The arm is formed by a single bone . Clavicle – collarbone . Humerus . Scapula – shoulder blade . These bones allow the upper limb to have exceptionally free movement

8 Bones of the Upper Limb Bones of the Lower Limbs . The forearm has two . The leg has two bones bones . Tibia . Ulna . Fibula . Radius

Bones of the Upper Limb Bones of the Lower Limbs . The hand . The foot . Carpals – wrist . Tarsus – ankle . Metacarpals – . Metatarsals – sole palm . Phalanges – toes . Phalanges – fingers

Bones of the Lower Limbs Arches of the Foot . The thigh has one . Bones of the foot are bone arranged to form three strong arches . Femur – thigh bone . Two longitudinal . One transverse

9 Bones of the Pelvic Girdle Gender Differences of the Pelvis . Hip bones . Composed of three pair of fused bones . Ilium . Ischium . Pubic bone . The total weight of the upper body rests on the pelvis . Protects several organs . Reproductive organs . Urinary bladder . Part of the large intestine Figure 5.23c Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

The Pelvis Bones of the Lower Limbs . The thigh has one bone . Femur – thigh bone

The Pelvis: Right Coxal Bone Bones of the Lower Limbs . The leg has two bones . Tibia . Fibula

10 Bones of the Lower Limbs Functional Classification of Joints . The foot . Synarthroses – immovable joints . Tarsus – ankle . Amphiarthroses – slightly moveable joints . Metatarsals – sole . Diarthroses – freely moveable joints . Phalanges – toes

Arches of the Foot Structural Classification of Joints . Bones of the foot are . Fibrous joints arranged to form three . Generally immovable strong arches . Cartilaginous joints . Two longitudinal . Immovable or slightly moveable . One transverse . Synovial joints . Freely moveable

Joints Fibrous Joints . Articulations of bones . Bones united by fibrous tissue . Functions of joints . Examples . Hold bones together . Sutures . Allow for mobility . Syndesmoses . Allows more . Ways joints are classified movement than sutures . Functionally . Example: distal . Structurally end of tibia and fibula

11 Cartilaginous Joints Structures Associated with the Synovial . Bones connected by cartilage Joint . Examples . Bursae – flattened fibrous sacs . Pubic . Lined with synovial membranes symphysis . Filled with synovial fluid . Intervertebral . Not actually part of the joint joints . Tendon sheath . Elongated bursa that wraps around a tendon

Synovial Joints The Synovial Joint . Articulating bones are separated by a joint cavity . Synovial fluid is found in the joint cavity

Features of Synovial Joints Types of Synovial Joints Based on Shape . Articular cartilage (hyaline cartilage) covers the ends of bones . Joint surfaces are enclosed by a fibrous articular capsule . Have a joint cavity filled with synovial fluid . Ligaments reinforce the joint

12 Types of Synovial Joints Based on Shape Clinical Forms of Arthritis . Gouty Arthritis . Inflammation of joints is caused by a deposition of urate crystals from the blood . Can usually be controlled with diet

Inflammatory Conditions Associated with Developmental Aspects of the Skeletal Joints System . Bursitis – inflammation of a bursa usually . At birth, the skull bones are incomplete caused by a blow or friction . Bones are joined by fibrous membranes – . Tendonitis – inflammation of tendon sheaths fontanelles . Arthritis – inflammatory or degenerative . Fontanelles are completely replaced with diseases of joints bone within two years after birth . Over 100 different types . The most widespread crippling disease in the United States

Clinical Forms of Arthritis . Osteoarthritis . Most common chronic arthritis . Probably related to normal aging processes . Rheumatoid arthritis . An autoimmune disease – the immune system attacks the joints . Symptoms begin with bilateral inflammation of certain joints . Often leads to deformities