Unit 2 - Lecture 5: Articulations

Articulation

Joint, bone to cartilage or bone to bone or bone to teeth

What determines an articulation?

Functionality (type/extent of movement) and joint structure (what tissue binds the structures?)

What is a gliding (transitional) movement?

Articular surfaces slide past each other

Angular

Angle between bones changes (increases or decreases) (ie radius and ulna relative to the humorous)

Rotational

Bone pivots along its own longitudinal axis (rotating femur at hip joint)

Special

Other joint movements not in o the examples

Flexion

Anterior/posterior that decreases angle

Extension

Anterior/posterior that increases angle

Hyperextension

Beyond 180 degrees (neck or wrist)

Lateral flexion

Trunk moves in coronal plane away from midline

Abduction

Lateral movement of body part away from midline

adduction

Lateral movement of body part toward the midline

Circumduction

proximal end of appendage remains stationary, while distal end moves in a circular motion

What are the rotational motions

Lateral and medial rotation, pronation and supination

What is pronation and supination

The rotation of radius around ulna

What is an example of lateral and medial rotation

the neck moving in a no-gesture

Give an example of special movements

depression vs elevation

opposition

dorsiflexion vs plantar flexion

protraction vs retraction

Synarthrosis

Immobile joint, very stable

Amphiarthrosis

Slightly mobile joint

Diarthrosis

Freely mobile joint, highly unstable (ie. Hip, shoulder, knee)

all synovial joints are diarthroses

True

Fibrous Joints

Bones joined by dense regular connective tissue

What are the three subtypes of fibrous joints?

Gomphoses

sutures

syndesmoses

Gomphoses

(Peg in socket) joints between teeth and maxilla,

synarthroses (no movement)

Sutures

Between skull bones

synarthroses

Syndesmoses

joints between parallel bones (radius and ulna; tibia and fibula)

amphiarthroses

how would you refer to a suture joint

Fibrous synarthosis joint

Cartilaginous joints

Bones attached by cartilage, lack fluid filled joint cavity

What are the two subtypes of cartilaginous joints

synchondroses

symphyses

Synchondrosis

bones joined by hyaline cartilage

synarthroses

Symphysis

bones joined by a pad of fibrocartilage

amphiarthroses

What is the structural and functional classification of the epiphysis and diaphysis joint

synchondrosis (hyaline cartilage) synarthroses

What is the structural and functional classification of the pubis and vertebral body joint

symphysis (fibrocartilage) amphiarthrosis

Synovial joints

• freely mobile articulations

• articulations seperated by joint cavity

• ie. elbow, shoulder, knee

General anatomy of synovial joints

• articular capsule

• joint cavity

• synovial fluid

• articular cartilage (hyaline)

• reinforcing ligaments

• nerves and blood vessels

Articuler capsule

• 2 layers

• outer fibrous layer (dense regular tissue → strengthens)

• inner synovial membrane (secretes synovial fluid)

  • reduces friction and shock

Joint cavity

• space between articulating bones

• contains small synovial fluid

• lubricates

• nourishes chondrocytes of articular cartilage

• absorb shock and compression

Ligaments

Connect bone to bone

dense regular connective tissue

strengthen and reinforce capsule

Bursae

Sacs outside most synovial joints where ligaments, muscles, etc rub

contain synovial fluid

can or cannot be connected to joint cavity

Tendon sheaths

Elongated burse around tendons, particularly in confined areas where tendons rub

Fat pads

Packing material and some protection

How are synovial joints classified

Shapes and movement allowed

Movements that describe synovial joints

Uniaxial, biaxial, multiaxial

What are the three types of uniaxial synovial joints

• plane joints

• hinge joints

• pivot joints

What are the two types of biaxial synovial joints

• condylar joints

• saddle joints

What is the one type of multiaxial synovial joints

ball-and-socket

Plane joint

Uniaxial, side to side movement (like plate across table)

Hinge joints

Uniaxial, like door hinge

Pivot joints

Uniaxial, one bone rotates on its longitudinal axis

Condylar joints

Biaxial; oval concave surface of one bone convex to other bone

Saddle joints

biaxial; joint looks like saddle

Ball and socket joints

spherical head in cup-like socket

Example of planar synovial joints

Carpal-carpal and tarsal-tarsal in wrist

What is an example of a planar synovial joint

carpals

what is an example of a synovial hinge joint

elbow joint

what is an example of a synovial pivot joint

atlas

ulna - radius

what is an example of a synovial condylar joint

metacarpals

What is an example of a synovial saddle joint

carpal (scalphoid) - metacarpal 1

what is an example of a synovial ball and socket joint

shoulder and hip joints

When is something more likely to dislocate

when it’s highly mobile and a diarthrodial joint