ST110Concorde Career College, Portland

Objectives

Define the term skeleton. Describe the functions of the skeletal

system. List and identify the structures of the

skeletal system and describe the function of each.

Identify the types of bone.

Objectives

List the types of joints and describe the function of each.

List the classifications of bone and provide examples of each.

Describe the processes of bone formation and bone healing.

Objectives

Describe the mechanism by which the skeletal system helps to maintain homeostasis.

Describe common diseases, disorders, and conditions of the skeletal system including signs and symptoms, diagnosis, and available treatment options.

Demonstrate knowledge of medical terminology related to the skeletal system verbally and in the written form.

Skeleton

Introduction

Includes all bones of the body (206) and includes cartilage, tendons, and ligaments Cartilage – connective tissue that provides a

smooth surface for bone movement (articulation)

Ligaments – connective tissue that attaches bone to bone (ligaments also support abdominal organs)

Tendons – connective tissue that attaches muscle to bone

Serves as a framework for the body Composed of living tissue

Functions

Supports and stabilizes surrounding tissues such as muscles, blood vessels, nerves, fat, and skin

Protects vital body organs such as the brain, spine, heart, and lungs and protects other soft tissues of the body

Assists in body movement by providing attachments for muscles that pull on bones

Matures blood cells Stores mineral salts (e.g., calcium)

Types of Bone Cells

Osteoprogenitor - Stem cell that is destined to become bone

Osteoblast - Bone building cell Osteocyte - Mature bone cell Osteoclast - Resorption

(breakdown)

Osteoprogenitor (osteogenic) Cells: Stem cells of skeletal tissue Composes the Inner layer of periosteum

and the single layer of endosteum Functions: formation of fetal bone and

repair of fractures Differentiate into Osteoblasts (good

blood supply) and Chondroblasts (limited blood supply)

Bone Cells

Osteoblasts: form bone matrix Develop into osteocytes

Osteocytes: responsible for maintaining bone matrix

(develop into osteoblasts) Osteoclasts:

Breakdown and resorption of bone Activated by parathyroid hormone Differentiated from blood monocytes

Bone Cells

Bone Cells

Growth and Development

Osseous tissue Longitudinal growth occurs until the

age of 15-16 Bone maturation occurs around the

age of 21

Skelton is initially composed of cartilage and gradually replaced with bone via two methods

Intramembranous Ossification: Develops flat bones of the cranium, facial bones, Mandible and clavivle

Endochondrial Ossification: long bones, etc. (the rest of the bones) Cartilage > Bone

Embryonic Development of Bone

Embryologic Development

Located at the junction between the diaphysis and each epiphysis

Area of growth (allows bone to lengthen)

Around age 16-25 Epiphyseal plate ossifies marking full maturity (end of growth)

Epiphyseal Plate

Epiphyseal Plate

Epiphyseal Plate

Bones undergo a lifetime of remodeling and adapting to stress

Remodeling maintains bone structure and strength as well as ensures constant supply of calcium to the body

Osteoclasts absorb bone that is then replaced by new compact bone

When low blood calcium levels are detected parathyroid hormone releases and stimulates the osteoclasts. When high blood calcium occurs, calcium is stored in bone.

When normal blood calcium levels are reached the thyroid releases calcitonin. Calcitonin inhibits osteoclasts and stimulates osteoblasts (negative feedback loop)

Bone Remodeling

Hormonal influence

Exercise: weight-bearing exercise is important in maintaining bone strength

Osteoporosis: results when bone matrix is lost faster then replaced

Nutrition: key factor in maintenance of normal bones

Scurvy: results form a deficiency in vitamin C, shaft of long bone becomes thin and fragile predisposing the person to fractures

Rickets: results form vitamin D deficiency, causes poorly calcified, semiriged bones that bend under bodies weight (bowed legs, knock-knees)

Factors that Affect Bone Maintinance

Scurvy

Rickets

Two Types of Bone

1. Cortical - Hard compact bone found in the shaft of long bones and makes up the outer layer of all other bones.

2. Cancellous (trabecular) - Soft spongy bone found at the ends of long bones and at the center of all other bones.

Compact Bone 75%

Spongy Bone 25%

Bone Types

Cortical Bone

Dense and strong Osteon (Haversian System)

Rings of mineral salts that allow bone cell metabolism

Central Canals Small canals that contain blood vessels

Lamella-surrounds central canals Lacunae-tiny cavities in between lamella

that contain osteocytes

Cortical Bone

Canaliculi-connect the lacunae and central canals

Haversian (perforating) canals-run horizontally and contain blood vessels

Haversian System

Cancellous Bone

Spongy bone Located at the ends of long bones

and forms the center of all other bones

Trabeculae Meshwork of interconnecting bone

secretions Gives strength to bone Filled with lamellae and osteocytes

Skeletal System

Bone Membranes

Periosteum - Covers the outside of the bone with the exception of the articulating surface and contains osteoblasts for bone growth and repair.

Endosteum - Lines the marrow cavity and also contains growth and repair cells.

Layer of fibrous tissue that surrounds bone

Functions: Layer of defense to protect from infection Forms new bone cells Full of nerves and blood vessels to aid in

nourishment of bone Attachment for tendons and ligaments

**Due to these various functions the orthopedic surgeon will approximate the periosteal layer when incised

Periosteum

Periosteum

Canal that runs down the middle of bone Contains semisolid tissue Red Bone

Marrow Located in the spaces of spongy bone found in the

ends of long bones, sternum, vertebrae, and ribs In adults RBM is replaced with yellow bone

marrow Functions: production of erythrocytes, leukocytes,

and platelets Endosteum: fibrous layer of tissue that lines

medullary cavity

Medullary Canal

Bone Marrow

Red Bone Marrow

Fills in spaces in cancellous bone Richly supplied with blood Hematopoiesis

Blood cells in all stages of development Gradually decreases with age

Bone Marrow

Yellow Bone Marrow

Contains fat cells Found in the medullary cavity (canal)

Bone Identification

Shapes Long Short Flat Irregular Sesamoid

Markings Projections Depressions

Bone Shapes

Long Bones

Length exceeds width Diaphysis-shaft of mainly compact

bone Thickness Curvature Medullary cavity Femur, radius, humerus

Structure of a Long Bone

Long Bones

Metaphysis-flared portion on each end consisting of spongy bone

Epiphysis-on the end out from the metaphysis consisting of spongy bone Epiphyseal line (plate - growth)

Short Bones

No long axis Irregular shaped Thin layer of compact tissue over

cancellous Carpal bones

Flat Bones

Very thin bones that attach to muscle and/or protect vital areas

Sternum, bones of the skull

Flat Bones

Irregular Bones

Very strange shape Layers of Compact bone over spongy

bone Ossicles, vertebrae

Irregular Bones

Sesamoid Bone

Small, round Enclosed in a tendon Adjacent to joints Kneecap, patella

Sesamoid Bone

Bone Markings-Processes (projections) Obvious bony prominence Types

Spine-sharp, slender projection Condyle-rounded or knuckle-like

prominence Tubercle-small round process Trochlea-process shaped like a pulley Trochanter-very large projection

Bone Markings-Processes

Crest - narrow ridge of bone Line - a little less prominent ridge of

bone Head - an enlargement at the end of

the terminal Neck - part of a bone that connects

the head or terminal enlargement to the rest of the bone

Bone Marking-Fossae (depression) Any depression or cavity in or on a

bone Types

Suture-narrow junction many times found between two bones

Foramen-an opening in which blood vessels, nerves and ligaments pass

Meatus (canal)-long, tube-like passage Sinus (antum)-cavity within a bone Sulcus-furrow or groove

Divisions of the Skeleton

Axial - Head and trunk (80 Bones)

Appendicular - Extremities and their attachments (shoulder and pelvic girdles) (126 Bones)

Divisions of the Skeleton

AxialAppendicular

Axial Skeleton

Axial Skeleton

Skull, Facial

Axial Skeleton

Axial Skeleton

Hyoid Bone

Hyoid Bone

Axial Skeleton

Axial Skeleton

Vertebral Column

Axial Skeleton

Atlas

Axis

Vertebral Types

Axial Skeleton

Vertebra

Axial Skeleton

Sternum

Appendicular Skeleton

Appendicular Skeleton

Appendicular Skeleton

Appendicular Skeleton

Appendicular Skeleton

Appendicular Skeleton

Appendicular Skeleton

Knee Joint

Knee Joint

Arthroscopy- visual examination of the internal structure of a joint.

LIGAMENTS

Ligaments- A white band of fibrous connectivetissue. Connects Bone to Bone

TENDONS

Tendons- Bands or cords of fibrous connective tissue that connect muscle to bone

Appendicular Skeleton

Appendicular Skeleton

Articulation

Articulation - Place of union (joint) between two or more bones, regardless of movement

Types of Joints

Synarthroses

Joints between bones that do not allow movement Suture-bones united by a thin layer of

fibrous tissue Syndesmosis-joints are connected by

ligaments between the bones Gomphosis-a conical process fits into a

socket and is held by ligaments

Amphiarthroses

Joints that allow only slight movement Symphysis-joints where the bones are

connected by a disk of fibrocartilage Synchondrosis-two bony surfaces are

connected by hyaline cartilage Replaced by permanent bone later in life

Synovial Joints (Diarthroses) Freely moving joints

Contain a cavity enclosed by a capsule reinforced by ligaments Synovial fluid

Provides a smooth gliding surface Nourishes the articular cartilage

Synovial Joints (Diarthroses) Ball and socket joint

Ball shaped head fits into a concave socket Multiaxial joint-Movement can occur in all

planes and directions Hinge joint

Uniaxial joint-Movement is limited to flexing and extending

Pivot Joint Uniaxial joint Limited to rotation in a single plane

Synovial Joints (Diarthroses) Condyloid joint

Biaxial joint-motion is possible in two planes at right angles to each other

Oval-shaped condyle fits into a cavity Saddle Joint

Biaxial One articular surface is concave in one

direction and convex in the other, the other articular surface is reciprocally convex and concave

Two bones fit together

Synovial Joints (Diarthroses) Gliding joint

Multiaxial Only allows gliding movement

Synovial Joint Movement

Flexion-bending or decreasing the angle between bones

Extension-increasing the angle between bones-opposite of flexion

Hyperextension-increases the joint angle beyond the anatomic position

Synovial Joint Movement

Abduction-moving the bones or limbs away from the midline

Adduction-moving the bones or limbs toward the midline

Rotation-moving the bone around a central axis-rotating your head

Circumduction-moving a bone or limb so that it describes a circle in the air

Synovial Joint Movement

Supination-movement of forearm and hand so that the radius and ulna are parallel

Pronation-movement of the forearm and hand so that the radius and ulna are not parallel

Eversion-moving the sole of the foot outward at the ankle

Inversion-moving the sole of the foot inward at the ankle

Synovial Joint Movement

Protraction-moving part of the body forward on a plane parallel to the ground

Retraction-moving a part of the body backward on a plane parallel to the ground

Elevation-raising a part of the body Depression-lowering a part of the

body

Synovial Joint Movement

Opposition-when the tip of the thumb and fingers are brought together

Reposition-when the fingers return to their normal position

Dorsiflexion-raising the foot up at the ankle

Plantar flexion-pushing the foot down at the ankle

Bursae

Closed sacs with a synovial membrane lining

Found in spaces between tendons, ligaments and bones

Facilitate the gliding of muscle over muscle or tendons over bony ligament surfaces

Joint Disorders

Bursitis Inflammation of the synovial bursae Caused from excessive stress or tension Eventual degeneration

Arthritis Inflammation of the whole joint Affects all tissues of a joint with over 100

varieties

Joint Disorders

Rheumatoid Arthritis CT disorder resulting in severe inflammation

of small joints A layer forms from abnormal growth of the

synovial membrane and the surrounding CT that destroys cartilage and starts to fuse the bones of the joint

Joint Disorders

Osteoarthritis Affects weight bearing joints Degenerative joint disease

Gout Accumulation of uric acid crystals in the

base of the large toe and other joints of the feet and legs

Types of Fractures

Compound (Open Fracture): fractured bone pierces the skin

Simple (Closed Fracture): fracture that does not pierce the skin

Complete: fracture line continuous through bone

Incomplete (Partial): may bend on one side and break on the other (ex. Greenstick fracture)

Classification of Fractures

Linear: fracture runs parallel to the axis of the bone

Spiral: fracture line curves around the bone

Transverse: fracture line is across the bone

Pott’s Fracture: break of the lower fibula

Classification of Fractures

COLLES

A fracture of the distal endof the radius in which the distal fragment is displacedposterioraly

Classification of Fractures

COMPRESSION

Aka-vertebral crush fracture.

Bone is pressed together or compressed on itself

Classification of Fractures

Avulsion: Bone and other tissues are pulled from normal attachments

Types of Fractures

Bucket Handle: Dual vertical fractures on the same side of the pelvis

Comminuted: Fracture with more than two pieces of bone fragment Butterfly: butterfly-shaped

pieces of fractured bone

Compound (open): broken end of bone has penetrated skin exposing bone

Depressed: occurs when bone is driven inward

Displaced: bone ends are out of alignment

Types of Fractures

Greenstick: bone splits longitudinally and is not a complete break

Types of Fractures

Impacted: broken ends of bone are forced into eachother

Intra-articular: bones inside a joint are fractured

Types of Fractures

Oblique: occurs at an oblique angle across bone

Spiral: fracture that curves around bone

Types of Fractures

Simple: fracture is in normal anatomic position and the skin is not borken

Spontaneous: occurs without trauma

Stellate: fracture occurs at central point in which additional breaks in bone radiate form the central point

Types of Fractures

Transverse: horizontal fracture through the bone

Types of Fractures

Heals in approx. 8-12 weeks Bone ends must be aligned Site of injury must be completely immobilized (case,

external or internal fixation)

Inflammatory Stage: Begins when fracture occurs & lasts approx. 2 days Hematoma forms

Cellular proliferation stage: Begins approx. 3rd day Macrophages: debridement Fibrin mesh forms (seals the approximated edges) Ingrowth of capillaries and fibroblasts begins

Normal Bone Healing

Callus formation: Lasts 3-4 weeks Cartilage, immature bone, and fibrous tissue

provide stabilization to the fracture site

Ossification Stage: Lasts 3-4 months Bone calcifies completing union of bone ends

Remodeling: return of homeostasis Bone is mature and resumes all normal

functions

Normal Bone Healing

Normal Bone Healing

Abnormal Curvatures of the Spine

A. KyphosisB. LordosisC. Scoliosis

Diseases of the Skeletal System Rickets

Deficiencies in Vitamin D

Fracture Breaking bone and harming surrounding

tissue

Scoliosis Curving of the spine Abnormal vertebral structure, muscle

paralysis

Diseases of the Skeletal System Osteoporosis

Decrease in bone mass Increased susceptibility for fractures Decrease in estrogen

Stimulate osteoblasts

Diseases of the Skeletal System Paget’s Disease

Irregular thickening and softening of bone

Gigantism Abnormal endochondral ossification at

the epiphyseal plates on long bones-abnormally large limbs

Dwarfism Inadequate ossification

Diseases of the Skeletal System Spina bifida

Herniated Disk Rupture of fibrocartilage around

intervertebral disk Severe pain

Normal Disc

Herniated Disc

Ruptured Disc

Bone Scan

Radiograph

Fractured Femur

Total Joint Replacement