Joints Lecture

Just Powerpoint

How are Joints classified?

By function or structure

How is functional classification of joints determined?

It’s based on amount of movement

Description of Synarthroses classification

Immovable; common in axial skeleton

Description of Amphiarthroses classification

Slightly movable; common in axial skeleton

Description of Diarthroses classification

Freely movable; common in appendicular skeleton (all synovial joints)

Structural classification is based on

Material that binds bones together & Presence or absence of a joint cavity

First Structural Classification

Fibrous

Second Structural Classification

Cartilaginous

Third Structural Classification

Synovial

Structural Characteristics of Fibrous joint class

Adjoining bones united by collagenic fibers

Structural Characteristics of Cartilaginous joint class

Adjoining bones united by cartilage

Structural Characteristics of Synovial joint class

Adjoining bones separated by a joint cavity, covered with articular cartilage, and enclosed within an articular capsule lined with synovial membrane

First type and its mobility of Fibrous joint class

Suture (short fibers) ~ Immobile

Second type and its mobility of Fibrous joint class

Syndesmosis (longer fibers) ~ Slightly mobile and immobile

Third type and its mobility of Fibrous joint class

Gomphosis (periodontal ligament) ~ Immobile

First type and its mobility of Cartilaginous joint class

Synchondrosis (hyaline cartilage) ~ Immobile

Second type and its mobility of Cartilaginous joint class

Symphysis (fibrocartilage) ~ Slightly movable

First type of Synovial joint

Plane

Second type of Synovial joint

Hinge

Third type of Synovial joint

Pivot

Fourth type of Synovial joint

Condylar

Fifth type of Synovial joint

Saddle

Sixth type of Synovial joint

Ball-and-Socket

Movement of Synovial joints

Feely moveable; movements depend on design of joint

Where are Sutures found?

Only between the bones of the skull

How do Sutures hold bones together

They’re tightly bound by a minimal amount of fibrous tissue

How do Syndesmoses hold bones together?

They’re connected exclusively by ligaments

Where are Syndesmoses found?

Tibiofibular joint & Interosseous membrane between radius and ulna

How do Gomphoses hold bones together?

With a connecting ligament, peg-in-socket

Where are Gomphoses found?

Tooth in socket

How do Synchondroses hold bones together?

Hyaline cartilage unites bones

Where are Synchondroses found?

Epiphyseal plates & Joint between first rib and manubrium

How do Symphyses hold bones together?

Fibrocartilage unites bones; resists tension and compression

Where are Symphyses found?

Intervertebral discs & Pubic symphysis

First trait of all Synovial Joints

Articular Cartilage

Second trait of all Synovial Joints

Joint (Articular) Cavity

Third trait of all Synovial Joints

Articular Capsule

Fourth trait of all Synovial Joints

Synovial Fluid

Fifth trait of all Synovial Joints

Reinforcing Ligaments

Traits of Articular Cartilage

Ends of opposing bones covered with hyaline cartilage & absorbs compression

Traits of Joint (articular) Cavity

Unique to synovial joints & Cavity is a potential space that holds a small amount of synovial fluid

Traits of Articular Capsule

Joint cavity is enclosed in a two-layered capsule

First layer of Articular Capsule

Fibrous layer—dense irregular connective tissue, which strengthens joint

Second layer of Articular Capsule

Synovial membrane—loose connective tissue, Lines joint capsule and covers internal joint surfaces, Functions to make synovial fluid

Traits of Synovial Fluid

A viscous fluid similar to raw egg white

A filtrate of blood

Arises from capillaries in synovial membrane

Contains glycoprotein molecules secreted by fibroblasts

Traits of Reinforcing Ligaments

Often are thickened parts of the fibrous layer

What are Synovial joints supplied with?

Richly supplied with sensory nerves and blood supply

Which Synovial joints contain an articular disk?

Temporomandibular joint and knee joint

Why do some Synovial joints contain an articular disk?

For joints whose articulating bones have somewhat different shapes (allows separate movement for each shape)

What does it mean for a joint to Glide?

One bone across the surface of another

Gliding occurs between

Carpals

Articular processes of vertebrae

Tarsals

What does it mean for a joint to do Angular Movement?

Movements change the angle between bones

Angular Movements involve

Flexion and extension

Abduction and adduction

Circumduction

What does it mean for a joint to do Rotation?

Movement around a bone's long axis

Rotation occurs between

Only movement allowed between atlas and axis, occurs at the hip and shoulder joints

First Special Movement and description

Elevation—lifting a body part superiorly

Second Special Movement and description

Depression—moving the elevated part inferiorly

Third Special Movement and description

Protraction—nonangular movement anteriorly

Fourth Special Movement and description

Retraction—nonangular movement posteriorly

Fifth Special Movement and description

Supination—forearm rotates laterally, palm faces anteriorly

Sixth Special Movement and description

Pronation—forearm rotates medially, palm faces posteriorly

Seventh Special Movement and description

Opposition—thumb moves across the palm to touch the tips of other fingers

Eighth Special Movement and description

Inversion—turns sole medially

Ninth Special Movement and description

Eversion—turns sole laterally

Tenth Special Movement and description

Dorsiflexion—lifting the foot so its superior surface approaches the shin

Eleventh Special Movement and description

Plantar flexion—depressing the foot, elevating the heel

What happens when knee is fully extended?

Both cruciate ligaments are taut and the knee is locked