LECT 8
• JOINTS
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INTRODUCTION
• JOINTS
• TYPES OF JOINTS
• SYNOVIAL JOINT
• TYPES/VARIETY OF SYNOVIAL JOINT
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JOINTS
BY
DR TAMKNAT
Allah has bestowed human beings with a
wide variety of joints.
`A'ishah (R.A) narrated that the Prophet
(S.A.W) said: "Everyone has been created
with three hundred and sixty joints.
DEFINITION
• The point where two or more bones meet is called a
joint.
• The other name of joints is arthroses.
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MEANING
• Arthrology: Study of joints
• Synonyms: Articulation (Latin)
Arthron (Greek)
• Joint: a junction between two or more bones
or cartilages.
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FUNCTIONS
• Give the skeleton
mobility.
• Hold the skeleton
together.
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Classification of joints
1) On the basis of structure
2) On the basis of function
3) On the basis of movement
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1)Classification on the basis of structure:
I. Solid joints: the joints without a cavity .
II. Synovial joints: the joints with a cavity
between them.
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Types of solid joints
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I. Solid joints
1) Fibrous joints: the bones are held together by fibrous
connective tissue that is rich in collagen fibers. No
synovial cavity
a. Sutures
– Skull only
– Bony fusion
– Bound by dense fibrous connective tissue
– TYPES:
• Serrate edges are saw-like
• Denticulate: tooth like processes
• Squamous suture: bone margins overlap
• Plane suture: apposition of flat surfaces
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Fibrous joints……………continued
b.Gomphosis
– Teeth to gums
– Peg and socket
joint
c.Syndesmoses
– bones
connected by
ligaments
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Types of solid joints....continued
2)Cartilaginous joints:
The bones are held together by
cartilage.
a. Synchondroses/primary
cartilaginous joints
– On completion of
growth hyaline
cartilage is replaced by
bone
e.g
– epiphyseal cartilage of
long bones
– between
vertebrosternal ribs
and sternum
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Types of cartilagenous joints…continued
b. Symphyses/ secondary
cartilaginous joints
– bones separated by fibro
cartilage
– Mostly permanent
e.g.
– pubic symphysis
– Intervertebral discs
– Some joints e.g.
between sacrum and
coccyx undergo partial
or complete synostosis
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II. Synovial joints
– more movement
– within articular capsules
• lined with synovial
membrane
• where synovial fluid is
found
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Accessory structures of synovial joint…continued
• Articular/Hyaline Cartilage
Smooth cartilage at the end of bones at joint
• Two-Layered Joint Capsule
Outer Layer – Tough fibrous capsule
Inner Layer – Synovial Membrane
• Synovial Fluid
Slippery fluid in joint capsule
• Ligament
A band of strong fibrous tissue
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Accessory structures of synovial joint…continued
• Articular/Hyaline Cartilage
Prevent friction between articulating bones
• Two-Layered Joint Capsule
Outer Layer – Strengthen joint
Inner Layer – To secrete synovial fluid
• Synovial Fluid
Reduce friction between articular cartilages
Nourish articular cartilage
• Ligament
To connect one bone to another
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Accessory structures of synovial joint…continued
• Tendons–
Strong connective tissue that attaches muscle to bone.
Connect muscle to muscle.
• Bursa
Fluid filled sacs
Cushion the joint and act as shock absorbers
• Meniscus
White fibrocartilage
Improves the fit between bone ends
Increases joint stability
Reduces wear and tear at joint •21
SYNOVIAL JOINT
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Types of synovial joints
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Types of synovial joints…continued
• Plane joints :the articulating
surfaces are flat or slightly
curved.
• e.g are intercarpal joints,
intertarsal joints,
sternoclavicular joints,
acromioclavicular joints,
sternocostal joints,
vertebrocostal joints.etc.
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Examples of plane joint
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Types of synovial joints…continued
• Hinge Joints-the
convex surface of
one fits into the
concave surface of
another.
• e.g. elbow joint,
ankle joint,
interphalangeal
joints,etc.
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Types of synovial joints…continued
• Pivot Joints-here the
rounded or pointed
surface of one bone
articulates with a ring
formed partly by
another bone and
partly by a ligament.
• e.g atlanto-axial joint,
radioulnar joint etc.
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Types of synovial joints…continued
• Condyloid Joints-also
called ellipsoidal joint.
The convex oval-shaped
projection of one fits
into the oval-shaped
depression of another
• e.g
metacarpophalangeal
joints.
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Types of synovial joints…continued
• Saddle Joints-here the
articular surface of one
bone is saddle-shaped
and the articular
surface of the other fits
into the “saddle”.
• e.g. Carpometacarpal
joint.
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Types of synovial joints…continued
• Ball-and-Socket
Joints- this consists
of the ball-like
surface of one bone
fitting into a cuplike
depression of
another bone
• e.g Shoulder and hip
joints.
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2)Classification on the basis of
function
• Functionally, joints are classified
as one of the following:
– Synarthrosis: an immovable joint.
– Amphiarthrosis: a slightly movable
joint. Most amphiarthrosis joints are
cartilaginous.
– Diarthrosis: a freely movable joint.
All diarthroses are synovial joints.
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3)CLASSIFICATION ON THE BASIS OF
MOVEMENT
• Uniaxial joints e.g.
the elbow joint
• Biaxial joints e.g.
the wrist joint
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CLASSIFICATION ON THE BASIS OF MOVEMENT…
continued
• Multiaxial joints: e.g. shoulder joint
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(B) According to plane of movements
• Uniaxial: Hinge and Pivot
• Biaxial: Condylar, ellipsoid, saddle
• Multiaxial: Ball and socket
•Uniaxial •Biaxial •Multiaxial
(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
Factors affecting ROM at Synovial
Joints
• Structure or shape of
the articulating bones
• Strength and tension of
ligaments.
• Arrangement and
tension of muscles
• Apposition of soft parts
• Hormones
• use
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Vasculature of joints
• Articular arteries from vessels
around joints
• Often these arteries form
anastamoses around joints
• Articular veins accompany
arteries
• Articular veins like articular
arteries, are located inside a
joint capsule, mostly in the
synovial membranes
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Innervation
• Rich nerve supply
• Most articular nerves are
branches of cutaneous nerves
supplying the muscles that
cross and move the joint( obey
Hiltons law)
• In distal parts of limbs( hands
and feet) articular nerves are
branches of cutaneous nerves
supplying the overlying skin
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Innervation ……………continued
• Joints transmit a sensation called proprioception
• Synovial membrane is relatively insensitive
• Pain fibers are numerous in fibrous layer and
associated ligaments causing pain when joints are
injured
• Sensory nerve endings respond to twisting and
stretching that occur during sport activities
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Joints of new born
• The bones of the
calvarium (skullcap)
of a new born infant
do not make full
contact with each
other
• At these sites, the
sutures form wide
areas of fibrous
tissue called
fontanelles
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DEGENERATIVE JOINT DISEASES
• Risk factors include age ,heredity,
injury and obesity
• Particularly those of hip, knee,
vertebral column and hands
• Some destruction is inevitable
during such activities as jogging,
which wears away the articular
cartilages and sometimes erodes the
underlying articular surfaces
• Trauma to a joint may be followed
by arthritis ,inflammation of joint
and septicemia
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Degenerative joint
diseases………..continued
Most common is
osteoarthritis,
which is often
accompanied by
stiffness, discomfort
and pain.
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Degenerative joint
diseases………..continued
• Rheumatoid
arthritis
– Chronic
inflammatory
disorder
– Marked by flare-ups
– Autoimmune
disease.
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Degenerative joint diseases………..continued
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Examination of joint
1. Clinical examination
2. Imaging( MRI/CT)
3. Arthroscopy
• A cannula and
arthroscope is inserted
in joint cavity
• For abnormalities such
as torn articular discs
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• https://www.youtube.com/watch?
v=0cYal_hitz4
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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
Tell the type of joint?
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Tell the type of joint?
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Tell the type of joint?
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Tell the type of joint?
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Tell the type of joint?
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Tell the type of joint?
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Summary
• Joints definition and meaning
• Types of joints
• Fibrous joint
• Cartilaginous joint
• Synovial joint
• Types of synovial joint
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• JAZAKALLAH
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