ARTHROLOGYARTHROLOGY

Where 2 or more bones join.© Robert A. Holmes, DVM, MS, PhD

Compendium joint article

Sweeny (suprascapular n.)

Clinical Importance of Joints Degenerative joint disease

• Trauma – fracture - instability

Developmental• Ununited anconeal process

• Hip dysplasia

Immune• Systemic lupus erythematosis

Metabolic• OCD

Infectious• Polyarthritis

• Lyme disease

Neoplastic• Synovial cell sarcoma

Purposes of Joints

Allow movement.• Directed not random.

Provide stability.Bone growth site.

Joint Nomenclature

Common names, i.e. shoulder, elbow Colloquial names –

femorotibial = stiflecarpus = kneefetlock, pastern, coffin

Scientific, descriptive names. Usually from the bones or region forming the joint.

Categories of Joints

FibrousCartilaginousSynovial

Synarthrodiali.e. rigid

Diarthrodiali.e. moveable

Old Terminology Current Terminology

Category Classification 11. Fibrous joints – joined by dense white

fibrous connective tissue. (syn = union)• Sutures – [L. sutura a seam] narrow strips of CT.

Found mostly in the skull. Allows the growth of bone plates. Stops as ossification occurs.

• Syndesmosis – [Gr. syndesmos band] a type of fibrous joint in which the intervening fibrous connective tissue forms an interosseous membrane or ligament. Between radius and ulna.

• Gomphosis – [Gr. a bolting together] tooth attachments

Category Classification 22. Cartilaginous joints

• Symphysis – divided by a series of tissues, i.e.. cartilage, fibrocartilage, or fibrous tissue in the middle of symmetrical halves. Pubis, mandible.

• Synchondrosis – [Gr. a growing into one cartilage] a union between two bones formed by either hyaline cartilage or fibrocartilage; it is usually temporary, the intervening cartilage being converted into bone before adult life. Skull, hyoid bones.

• Physis – between epiphysis and diaphysis.• Intervertebral disks.

Category Classification 33. Synovial joints [Gr. syn with + oon egg]

• Separated by fluid-filled space.• synovial membrane• fibrous capsule• fibrous bands – ligaments• articular surface

– hyaline cartilage (fibrocartilage).

• synovial fluid– lubrication AND nutrition

• disks or menisci– provide support for bony incongruities– stifle and tmj

Periarticular

Articular

Intraarticular

Synovial Joint Structure 1. Synovial fluid / space

lubrication nutrition clear-yellow, viscous

2. Synovial membrane 3. Articular cartilage

avascular no nerves nutrition by diffusion

synovial fluidvessels – capsule and bone

4. Fibrous joint capsule 5. Periosteum 6. Cortex

2 + 4 = joint capsule

Synovial joint blood and nerve supplies

7. Joint space 8. Synovial fold 9. Synovial villi 10. Artery / vein 11. Efferent to

blood vessels, afferent for pain and proprioception.

Cartilage nutrition 1. synovial fluid 2. blood supply bone, joint capsule

Synovial – Disk and Meniscus

Synovial jointsShoulder Stifle

Return

biceps tendon and retinaculum

Joint Capsule and Ligaments

Shoulder Radiograph and Arthrogram

Contrast media in joint space.

glenoid and humerus en face

Glenoid – scapula Humeral head

Joint Taps - Synovial Fluid Analysis

Joint Tap Approaches

Movements Translation – sliding without changing orientation Rotation

• Inward• Outward

Pendular – angular or swinging about an axis• flexion• extension• adduction• abduction• circumduction

Flexion and Extension

Flexiondecrease joint angle

Extensionincrease joint angle

In saggital plane

Hyper extension / flexion – beyond normal ranges.

Adduction&

Abduction

Midline

Adduction -bring towards median plane.

Add 2 numbers – bring together.

Abduction –move away from median plane.

The child was abducted – taken away.

In transverseplanes.

Circumduction

Flexion+/-

Extension+/-

Adduction+/-

Abduction

Infinitely variablenumber of combinations toform complex actions.

Joint Surfaces

FlexorSurface

Flexion

Angle

Extension

Angle

ExtensorSurface

Mechanics of Joint Movement

Long head triceps:1. flex shoulder2. extend elbow

Other triceps:extend elbow only

Biceps brachii1. extend shoulder2. flex elbow

Triceps:Same insertion

Different origins

What joint surfaces are spanned?

Weightvs

non weight bearing.

What point is consideredfixed or immovable?

1. Standing – leg fixed, head moves.2. Laying – head fixed, leg moves.

Brachiocephalicus m.

Synovial Joints Classified by Geometry

Plane Hinge Pivot Condylar Ellipsoidal Saddle Spheroidal

Plane joint vertebral

articulations

Plane joint2 “flat” planes

Hinge joint(ginglymus =

hinge)Movement in only 1 plane

Pivot joint peg in ring

Atlantoaxial joint

Condylar 2 knuckle condyles

Stifle“Knee”Femorotibial

Ellipsoidal

Oval surfacemovement in 2 planes

Saddle

2 surfacesbiaxial movement

Spheroidal

ball and socketgreatest movement

Slides Section

Mandible slide

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Skull Slides

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Tibia and Fibula

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Humerus

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Nomenclature graphic

Shoulderbounded by:

scapula and humerusscapulohumeral joint

Hipbounded by:

os coxae (pelvis)and femur

coxofemoral joint

Deer skull

Metaphysis

Physis

Epiphysis

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Medial coronoid process DJD

Open vs Closed Physes

Intervertebral Disk

nucleus pulposus anulus fibrosus

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