Skeletal System &Articulations. What Is Osteoporosis? Loss of bone density.Loss of bone density....

Skeletal System

&Articulations

What Is Osteoporosis?

• Loss of bone density.– Due to low hormone levels.

– Occurs prematurely due to extreme weight loss.

– Results in low estrogen levels.

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What Is Osteology?

• Study of bone structure & treatment of bone disorders.

TortoraPages: 114

Dancing Skeleton

Functions of the Skeletal

System• Support• Protection• Assisting in movement

• Mineral homeostasis

• Production of blood

• Triglyceride storage

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Types of Bones

• Long bones– Longer than wide

– Slightly curved

– Compact and spongy bone

– Ex - Radius, ulna, femur.

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Types of Bones

• Flat bones– Thin– Composed of two plates compact bone.

– Spongy bone in between.

• Ex: cranium, ribs, scapula.

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Types of Bones

• Short bones– Cubed shaped– Mostly spongy bone.

– Surface of compact bone

• Ex: wrist (carpals) & ankles (tarsals)

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Types of Bones

• Irregular bones– No consistant shape.

– Varies in compact and spongy bone.

• Ex: Vertebrae

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Types of Bones

• Others• Sutural bones

– Small bones found in joints between bones of skull.

• Sesamoid bones– Bones located in tendons.

– Vary in number.• Ex: Patellas

TortoraPages: 114

Macroscopic Structure of

Bone

• Diaphysis• Epiphysis• Metaphysis• Epiphyseal plate• Articular cartilage• Periosteum• Medullary cavity• Endosteum

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Histology

• Consists of 4 types of connective tissue.– Cartilage– Bone– Bone marrow– periosteum

Histology

• Bone consists of:–loosely spaced cells.

–Matrix• 25% water• 50% mineral salts

• 25% collagenous fibers.

Histology• Bone contains 4 types of cells:– Osteoprogenitor

• Give rise to other cells.

– Osteoblasts• Bone forming cells.

– Osteocytes• Mature bone maintaining cells

– Osteoclasts• Bone breakdown

Pages: 98 - 100

Macroscopic Structure of

Bone

Monday 10/28Pages: 98 - 100

Articular cartilage

Microscopic Structure of

Bone

• Compact bone– Gives strength– Covers spongy bone.– Composed of osteons (Haversian systems)

Monday 10/28Pages: 98 - 100

Exhibit 6.1 Quiz

1. What two of the following minerals make the bone matrix hard?

A) Calcium B) Iron C) Zinc D) ATP E) Phosphorus

2. Which vitamin controls the activity, distribution, and coordination of osteoblasts and osteoclasts?

A) Vitamin E B) Vitamin A C) Vitamin C D) Vitamin D

3. General purpose growth hormone that causes growth in all tissues including bone.

A) HGH B) Estrogens C) Parathyroid hormone

D) Calcitonin E) Thyroxine

Exhibit 6.1 Quiz

4. Which vitamin helps maintain the bone matrix and whose deficiency leads to decrease in collagen?

A) Vitamin E B) Vitamin A C) Vitamin C D) Vitamin D

5. Which hormone promotes bone formation by inhibiting osteoclasts?

B) HGH B) Estrogens C) Parathyroid hormone

D) Calcitonin E) Thyroxine

Exhibit 6.1 Quiz

1) A,E2) B3) A4) C5) D

Macroscopic Structure of

Bone• Spongy bone

– Contains trabeculae

– Formed from collagenous fibers

– Reduces weight

– Maintains strength

TortoraPages: 98 - 100

Ossification

• Process by which bone forms.

• Starts during the 6th or 7th week of life.

TortoraPages: 102-104

Ossification

• Intramembraneous ossification:

• Starts as a membrane shaped like a bone.– Ex: skull, mandible, clavicle

TortoraPages: 102-104

Ossification

• Endochondral ossification:

• Starts with hyaline cartilage.

• Forms most bones.

• Ex: femur, tibia, humerus, etc.

TortoraPages: 102-104

Ossification• Step #1

– Cartilage model of bone develops.

– Surrounded by a perichondrium.

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Ossification

• Step #2– Cartilage model

grows.– Cartilage begins

to calcify.– Cartilage cells

start to die.– Nutrient artery

grows into cartilage model.

– Osteoblasts in perichondrium start ossification

TortoraPages: 102-104

Ossification

• Step #3– Primary

ossification occurs.

– Forms collar around shaft of bone.

– Osteoblasts create new bone.

– Medullary canal created by action of osteoclasts.

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Ossification

• Step #4– Secondary

ossification starts in the ends of the bone.

– Occurs about the time of birth

– Growth is outward from the center of the epiphysis towards the outside of the bone

TortoraPages: 102-104

Ossification

• Cartilage remains at ends of the bone (articular cartilage)

• Epiphyseal plate is last to ossify.

• Ends growth.• Remodeling is

only change possible afterwards.

TortoraPages: 102-104

Homeostasis

• Bone replaces itself throughout life.

• Referred to as remodeling.

TortoraPages: 104-106

Bone Surface Markings

• Depressions and openings– Foramen– Fossa

TortoraPages: 107-108

Bone Surface Markings

• Processes that form joints– Condyle

• Knuckle-like process

– Head• Rounded

projection, supported by constricted portion of bone.

– Facet• Smooth, flat

surface

TortoraPages: 104-106

Bone Surface Markings

• Processes that connect to ligaments and other connective tissue.– Tuberosity

• Large rouned area.

– Spinous process• Slender

projection– Trochanter

• Large blunt projection

– Crest• ridge

TortoraPages: 104-106

Male/female Differences

1. General Structure– Male:

Heavy/thick– Female:

Light/thin

2. Pubic Arch– Male: Less

than 90– Female:

Greater than 90

3. Obturator Foramen– Male: Round– Female: Oval

TortoraPages: 132-133

Articulations

• Gravity mandates a stiff and rigid skeleton.

• Movement requires flexibility.

• Flexibility created by articulations (joints)

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Articulations

• Structure determines function.

• Movement is determined by– Structure of bones

forming the joint.– The flexibility of

connective tissue connecting the bones.

– Position of ligaments, tendons, and muscles.

– Hormones

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Structural Classificati

on• Fibrous: bones

connected with fibrous connective tissue.

• EX: tibia - fibula

• Cartilaginous: Bones connected by cartilage.

• EX: Ribs - sternum• Synovial: Joint

surrounded by synovial membrane.

• EX: knee, elbow, hip.

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Classification of Synovial

Joints• Gliding Joints

– Surfaces are flat

– Side to side motion

– Ex; Between carpals, tarsals.

• Hinge Joint– Convex surface -

concave surface.– Single plane

movement– EX: knee

TortoraPages: 160-163

Classification of Synovial

Joints• Pivot Joint

– Rounded or pointed with ring-like structure.

– Rotation movement– EX: atlas - axis,

radius ulna.• Condyle Joint

– Oval shaped - depression

– Side to side movement, back and forth movement.

– Radius - carpals

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Classification of Synovial

Joints• Saddle Joint

– Metacarpaland carpal of thumb.

• Ball and Socket Joint– Rounded end - cup

like depression.– Movement in three

planes.– EX: Hip and

shoulder.

• Condyloid– Ex: radius and wrist

bones.

TortoraPages: 160-163

Structures of a Synovial

Joint

Saddle

• Synovial cavity• Articular

cartilage• Articular capsule

– Fibrous capsule (outer)

– Ligaments– Synovial membrane

(inner)– Synovial fluid

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ATC Animati

on

ATC Surgery

Meniscus Repair Surgery

Structures of a Synovial

Joint

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Saddle

• Accessory ligaments– Lie outside the

articular capsule.

• Articular discs (menisci)

• BursaeKnee Structure

MOVEMENT AT

SYNOVIAL JOINTS

Classification of Joints

• Structural classification– Fibrous– Cartilaginous– Synovial

• Functional Classification– Synarthrosis– Amphiarthrosis– Diarthrosis

TortoraPages: 157-160

Osteoarthritis

Basic Anatomical Position

• Standing erect– Toes forward– Head facing forward.

– Hands at side.– Palms facing forward.

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Basic Anatomical Position

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• Structural classification– Fibrous– Cartilaginous– Synovial

• Functional Classification– Synarthrosis– Amphiarthrosis– Diarthrosis

Categories of Movement

• Gliding– Flat bones form joint• Back and forth• Side to side

• Angular – Increase or decrease in angle of bones.

• Rotation– A bone rotates on long axis

• Special Movewment

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Angular Movements

• Flexion–Reducing angle of joint

–Extension • Increasing angle of joint

–Hyperextension• Beyond basic anatomical position

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Angular Movements

• Abduction–Movement away from midline of body.

• Adduction–Movement towards midline of body.

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Angular Movements

• Circumduction– Moving distal end of arm or leg in a circle.• Ex: shoulder

– hip

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Special Movements

• Inversion– Lifting of medial side of foot so that soles face each other.

• Eversion– Lifting of lateral side of foot so that sole faces outward.

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Special Movements

• Pronation– Movement of hand such that palm faces backward.

• Supination– Movement of palm such that it faces forward.

TortoraPages 160-163

Special Movements

• Dorsiflexion– Bending foot in the superior direction

Plantar FlexionBending of foot in the inferior direction

TortoraPages 160-163

Synovial Joint

Movements

TortoraPages: 160-163

• Flexion Vs Extension• Abduction Vs Adduction• Circumduction• Elevation Vs Depression• Supination Vs Pronation