dr. anand srinivasan for mbbs 2013 on 10/10/2013

JOINTS

Dr. Anand Srinivasan for MBBS 2013 on 10/10/2013

OBJECTIVES

Classify and describe the characteristic features of fibrous, cartilaginous and synovial joints.

Describe the parts and clinical importance of structures forming synovial joint.

What is a joint?

Site where 2 or more bone come together, whether or not movements occurs between them.

CLASSIFICATION

FUNCTIONAL Synarthoses = immovable joint Amphiarthroses = slightly movable Diarthroses = freely movable

Based on the tissues that lie between them : Fibrous Cartilaginous Synovial

FIBROUS JOINT

Articulating surfaces joined by fibrous tissue

No joint cavity

Very little / no movement

TYPES : Suture Syndesmosis Gomphosis

FIBROUS JOINT – Suture

FIBROUS JOINT – Syndesmosis

Inferior tibio-fibular joint Interosseous membrane of radio

ulnar joint

FIBROUS JOINT – Gomphosis

Peg in socket type

CARTILAGINOUS JOINTS

CARTILAGINOUS JOINT - Synchondrosis

Joint between Epiphysis and Diaphysis

1st rib and sternum

CARTILAGINOUS JOINT - Symphyses

Intervertebral disc

Pubic symphysis

SYNOVIAL JOINT

Freely movable.

Presence of joint cavity (synovial cavity)

Articulating surface – lined by hyaline cartilage

Presence of synovial membrane – secreting synovial fluid – reduces friction

Synovial membrane protected by “Capsule”

ARTICULAR DISC Wedges of fibrocartilage interposed

between articular surfaces.

FATTY PADS Found between synovial membrane &

capsule / bone

SYNOVIAL JOINT : Types

Arrangement of articular surfaces & type of movements

PLANE / GLIDING JOINTS Articular surface – flat Type of movement – sliding E.g. : Sternoclavicular,

Acromioclavicular

SYNOVIAL JOINT : Types

HINGE JOINTS E.g. : Elbow, Knee & Ankle joints

PIVOT JOINTS E.g. Atlanto-axial,

Radio-ulnar

SYNOVIAL JOINT : Types

CONDYLOID JOINT : Has 2 convex surfaces which articulate

with concave surfaces E.g. Metacarpophalangeal joint

ELLIPSOID JOINT : E.g. Wrist joint

SYNOVIAL JOINT : Types

SADDLE JOINT Reciprocally concavoconvex E.g.1st Carpometacarpal joint

BALL & SOCKET JOINT E.g. Shoulder joint,

Hip joint

JOINT STABILITY Shape, size and arrangement of articular

surfaces Ligaments Muscle tone

HILTON’S LAW Sensory nerve supplying a joint also

supplied the muscles moving the joint and the overlying skin

LIGAMENTS : Bands of connective tissue that connect bones to other

bones. TYPES:▪ Intrinsic or Capsular▪ Extracapsular▪ Intracapsular

▪ Fibrous ▪ Elastic

TENDONS: Bands of connective tissue that connect muscles to the

bones

BURSAE Closed space containing synovial fluid

Lined by synovial membrane on the inside and a fibrous membrane on the outside.

Found where tendons rub against bones, ligaments or other tendons.

Close to joints where skin rubs against underlying structures e.g. Prepatellar bursa

Occassionaly may communicate with cavity of synovial joint e.g. suprapatellar bursa

Synovial sheath

Synovial sheaths tubular bursa surrounding a tendon.

Recommended Reading

Clinical Anatomy by Regions – Snell 9th edition – Chapter 1 : Introduction Pg : 11 – 16.

Acknowledgement :

Pictures – from Google images

http://www.dummies.com/how-to/content/articulating-the-importance-of-joints-in-anatomy.html

http://www.zoology.ubc.ca/~biomania/tutorial/bonejt/anc07.htm