Arthrology Dr. Archana Rani Associate Professor Department of Anatomy, KGMU UP, Lucknow 16.9.2014

Introduction Arthrology: Study of joints Synonyms: Articulation (Latin) Arthron (Greek) Joint: a junction between two or more bones or cartilages. A device to permit movements

Classification of joints Joints are classified according to structure and function- (A) Functional (based on degree of mobility): 1.Synarthroses: immovable joints (cranial sutures in adults, primary cartilaginous joints in growing children). 2.Amphiarthroses: slightly movable joints (joints between adjacent laminae of vertebrae). 3.Diarthroses: freely movable joints (synovial joints). 3

Functional classification (cont….) Synarthroses Amphiarthroses Diarthroses

(B) Structural classification Based on type of connecting tissue and presence or absence of joint cavity: 1. Fibrous: composed of intervening fibrous tissue with no joint cavity. Immovable or slightly movable. 2. Cartilaginous: articulating bones are united by cartilage (hyaline or fibrocartilage) with no joint cavity. 3. Synovial: articulating bones are separated by a fluid-filled joint cavity.

Structural classification (cont….) Fibrous Cartilaginous Synovial

Fibrous joints 1. Sutures: articular surfaces are connected by a thin layer of connective tissue. They are confined to the skull and are immovable. 2. Syndesmoses: bones are connected by a considerably greater amount of connective tissue than in sutures in the form of interosseous ligaments and membranes. Slight movement is permitted. e.g. interosseous tibiofibular joints, interroseous radioulnar joints. 3. Gomphoses (peg and socket joint): articulation of teeth in alveolar sockets of mandible and maxilla by periodontal ligament. 

Fibrous joints (cont….) Sutures Syndesmoses Gomphoses

Sutures Plane Serrate Denticulate Squamous Schindylesis

Cartilaginous joints 1.Primary (Synchondroses) 2.Secondary (Symphyses)

Synovial joints Most evolved and freely movable joints Have a joint cavity filled with synovial fluid Often termed as diarthrodial joints Components: 1.  Fibrous capsule 2.  Synovial membrane 3.  Ligaments 4.  Articular cartilage 5. Articular disc or meniscus 6. Bursae 7. Fat pads (Haversian glands)

Classification of Synovial joints (A) According to shape of articular surfaces: 1. Plane 2. Hinge 3. Pivot 4. Condylar 5. Ellipsoid 6. Saddle 7. Ball and socket

Plane joints Articular surfaces are nearly flat. Allow gliding movements. e.g. intercarpal and intertarsal joints.

Hinge joints (Ginglymus) Articular surfaces are pulley shaped. Movements are permitted only in one plane (transverse axis). Most common joints. e.g. elbow, knee, ankle and interphalangeal joints.

Pivot joints (Trochoid joints) Rounded end of one bone fits into the concavity of another bone. The rounded part is surrounded by a ligament. Limited rotation around a central axis. e.g. superior radio-ulnar and median atlanto-axial joints.

Condylar joints Round articular surface of one bone fits into a socket-type articular surface of another bone. Permit movements in two directions. e.g. knee and temporo-mandibular joints.

Ellipsoid joints Elliptical convex surface of one bone articulates with elliptical concave surface of another. Permit movements in two directions. Combination of movements cause circumduction. e.g. wrist and atlanto-occipital joints.

Saddle (sellar) joints Articular surfaces are reciprocally saddle shaped i.e. concavo-convex. Allows a wide range of movement. e.g. first carpo-metacarpal, sterno-clavicular, incudo-malleolar joints.

Ball and socket (spheroidal) joints Rounded convex surface of one bone fits into the cup-like socket of another bone. Permits greatest range of movements. e.g. shoulder, hip and incudo-stapedial joints.

(B) According to plane of movements Uniaxial: Hinge and Pivot Biaxial: Condylar, ellipsoid, saddle Multiaxial: Ball and socket Multiaxial Uniaxial Biaxial

(C) According to number of articulating bones Simple (2 bones) Compound (more than 2 bones)

Movements of synovial joints 1. Gliding (slipping) 2. Angular: flexion, extension, abduction, adduction 3. Rotary (circular): rotation (supination, pronation), circumduction

Special movements: 1. Inversion: movement of the foot medially 2 Special movements: 1. Inversion: movement of the foot medially 2. Eversion: movement of the foot laterally 3. Protraction: movement of the mandible forward 4. Retraction: movement of the protracted part back to its starting position 5. Elevation: lifting a body part superiorly 6. Depression: moving the elevated part inferiorly 7. Opposition: touching the thumb to the tips of other fingers

REFERENCES 1. Cunningham’s Manual of Practical Anatomy, Vol.1. 2. Grant’s Method of Anatomy, 11th Edition. 3. Vishram Singh. General Anatomy, 1st Edition.

MCQs 1. All of the following are examples of the fibrous joint except: a) Suture b) Syndesmosis c) Symphysis d) Gomphosis

MCQs 2. All of the following are examples of the synovial joint except: a) Pivot b) Saddle c) Syndesmosis d)Ellipsoid

MCQs 3. Subtype gomphosis is classified under: a) Biaxial synovial joint b) Symphysis c) Fibrous joint d) Synchondrosis

MCQs 4. All of the following are characteristic features of a synovial joint except: a)Articular surfaces are covered by a articular cartilage b) Have a joint cavity filled with synovial fluid c)Mostly are freely movable joints d) Articular cartilage are covered by synovial membrane

MCQs 5. All of the following secondary cartilaginous joints belong to axial skeleton except: a)Manubriosternal joint b) Intervertebral discs c) Symphysis pubis d) Symphysis menti