WEEK 3 joint dr Muddther.ppt

8/10/2019 WEEK 3 joint dr Muddther.ppt

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JOINTS

Definition:

Joint is :

Place of articulation

Place of union

Place of Junction betweentwo or more bones or

cartilages or parts of bones

of the skeleton.

Place of movementFulcurum


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CLASSIFICATION

3 classes

Structural Classification

Functional Classification

(according to the degree of

mobility)

Regional Classification


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According to the manner or type of

material by which the articular bone are

united.

A)Fibrous joints: Are united by fibrous

tissue.

B)Cartilaginous joints: are united by

hyaline or fibro-cartilage

C)Synovial joints : having joint orsynovial cavity.


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According to the manner or type of material by which

the articular bone are united.

A)Fibrous joints: Are united by fibrous tissue.

1-Gomphosis 2-Sutures 3-SyndesmosisTooth in its socket. The bones are

connected byinterosseous ligament.


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According to the manner or type of material by which the articular bone are

united.

B) Cartilaginous joints: are united by hyaline or fibro-cartilage

1.Primary or synchondrosis 2- Secondary or symphysisPrimary or synchondrosis

Secondary or symphysis


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Structural ClassificationSynovial Joint

1. Most common in the body.

2. Most mobile type of joints.

3. The articular surfaces are covered with

hyaline (articular) cartilage.

4. Joint cavity filled with synovial fluid. The

cavity may be partially or completely

subdivided by an articular disc or

meniscus.5. The joint is surrounded by an articular

capsule.

6. Synovial membrane line whole of the

interior of the joint except for the

articular surfaces.7. Synovial fluid or synovia secreted by the

cells of the synovial membrane.

8. Capsular or true ligaments representing

thickenings of the fibrous capsule.

9. Accessory ligaments which may be intraor extra-capsular.


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Synovial joints : having

joint or synovial cavity.

1.Ball-and-socket orspheroidal joints.

2.Saddle or sellar joint

3.Ellipsoid Joint

4.Hinge Joint

5.Pivot joint

6.Plane Joint


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Synovial joints

1- Ball-and-socket or spheroidal

joints2- Saddle or sellar

joint

3- Ellipsoid joints

Ellipsoid


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Synovial jo ints

4-Pivot

joint

5-Hinge

Joint6- Plane

Joint


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Functional Classification (according to the degree of mobility)

A)Synarthrosis(Immovable) like fibrous joints

B)Amphiarthrosis(slight movement) like cartilaginous joints

C)Diarthrosis(freely movable) like synovial joints


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Regional Classification

A)Skull type: Immovable

B)Vertebral type : Slightly movable

C)Limb type: Freely movable


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Articulation:

The form of the articulating surfaces

controls the type of movement which

takes place at any joint. The movementspossible at synovial joint are:

Angular e.g. Flexion, extension,

abduction, adduction.

Rotary : Rotation; turning upon an axis,circumduction, the whole part inscribes a

cone.

Gliding: one part slides on another.


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Limitation of Movement:

Factors

Reflex contraction of antagonistic muscles.

Due to stimulation of mechanoreceptors in articular

tissue.

Ligaments tension.

Approximation of soft part.


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Factors maintaining stability at a joint

Muscles.The tone of different groups of muscles acting on the joint is

the most important and indispensable factor e.g. Knee, shoulder, joint.

Ligaments are important in preventing any over-movement, and in

guarding against sudden accidental stresses.

Bones. Help in maintaining stability only in firm type of joint like the

hip and ankle.


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Blood supply of synovial

joint:

The articular and

epiphysial branches given off

the neighbouring arteries

form a periarticular arterialplexus in the deeper parts of

synovial membrane.

(Arterial articular networks).

Articular veins are communi-cating veins.


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Nerve supply of synovial joint:

The capsule and ligaments

possess a rich nerve supply which

makes them acutely sensitive to pain.Articular nerves contain sensory and

autonomic fibres. Some of the

sensory fibres are proprioceptive in

nature. These are sensitive toposition and movement, and are

concerned with the reflex control of

posture and locomotion. Hilton's Law

states that a motor nerve to the

muscle acting on joint tends to give a

branch to that joint (capsule) and

another branch to the skin covering

the joint.

WEEK 3 joint dr Muddther.ppt

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