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 – 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