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Articulations
BIO 238
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2. Joint Classification A joint is where two bones meet*
Joints may be classified by structure or by function
The structural classification of joints:
Fibrous joints (bones held together by dense collagen fibers)
Cartilaginous joints (bones held together by cartilage)
Synovial joints (bones held together by ligaments)

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Joint Classification
The functional classification of joints:
Synarthrosis (an immovable joint)
Amphiarthrosis (a slightly movable joint)
Diarthrosis (a freely movable joint)
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4. Joints (Fibrous Joints)
Lack a synovial cavity
The articulating bones are held very closely together by dense irregular connective tissue
Fibrous joints permit little or no movement
3 types of fibrous joints:
Sutures
Syndesmoses
Gomphoses
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5. Joints (Fibrous Joints)
Sutures
Immovable joint
Occur only between the skull bones
Syndesmoses
Permits slight movement
Interosseous membrane
Between the tibia and fibula in the leg
Gomphoses
Joint in which a cone-shaped peg fits into a cup shaped socket
Articulations of the teeth with the sockets of the maxillae and mandible

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Syndesmoses
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7. Joints (Cartilaginous Joints)
Lack a synovial cavity
Allow little or no movement
The joint is tightly connected by cartilage
2 types of cartilaginous joints:
Synchondroses
Symphyses

8. Cartilaginous Joints Synchondroses Symphyses
The Connecting tissue is hyaline cartilage
Found in Epiphyseal (growth) plate in bones
Symphyses
Slightly movable joint
Ends of the articulating bones are covered with hyaline cartilage, but a disc of fibrocartilage connects the bones
Pubic Symphysis is between the anterior surfaces of the hip bones
Also found in the intervertebral joints between the vertebrae

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Synchondrosis
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Symphysis
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11. Synovial Joints Components of a synovial joint:
Ligaments hold bones together for extra support
Synovial cavity a space allowing a joint to be freely movable
Articular Capsule
A sleeve-like capsule enclosing the synovial cavity
The articular capsule is composed of 2 layers:
an outer fibrous capsule
an inner synovial membrane

12. Synovial Fluid Secreted by the synovial membrane lining the capsule
Functions to reduce friction by:
lubricating the joint
absorbing shock
supplying oxygen and nutrients to the cartilage
removing carbon dioxide and metabolic wastes from the cartilage

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Synovial Joints
Accessory Ligaments and Articular Discs
May be present in some joints for example the knee joint
Collateral ligaments of the knee joint (Medial and Lateral)
Cruciate ligaments of the knee joint (Anterior and Posterior)
Menisci ( C shaped and O shaped)
Pads of cartilage lie between the articular surfaces of the bones
Allows bones of different shapes to fit together more tightly
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16. Nerve and Blood Supply Nerve and Blood Supply
Nerve endings convey information about pain from the joint to the spinal cord and brain
Nerve endings respond to the degree of movement and stretch at a joint
Arterial branches from several different arteries merge around a joint before penetrating the articular capsule

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Synovial Joints
Bursae and Tendon Sheaths
Bursae
Sac-like structures containing fluid similar to synovial fluid
Located between tendons, ligaments and bones
Cushion the movement of these body parts
Tendon sheaths
Wrap around tendons
Reduce friction at joints
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Types of Movements at Synovial Joints
Specific terminology is used to designate the movements that occur at joints
Movements are grouped into four main categories:
1) Gliding
2) Angular movements
3) Rotation
4) Special movements
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Types of Movements at Synovial Joints
Gliding
Simple movement back-and-forth and from side-to-side
There is no significant alteration of the angle between the bones
Limited in range
Intercarpal joints
Angular Movements
Increase or a decrease the angle between articulating bones
Angular movements include:
Flexion
Extension
Lateral flexion (side bending)
Hyperextension
Abduction
Adduction
Circumduction
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Types of Movements at Synovial Joints
Flexion
Decreases the angle between articulating bones
Bending the trunk forward
Extension
Increases the angle between articulating bones
Flexion and extension are opposite movements
Lateral flexion
Movement of the trunk sideways to the right or left at the waist
Hyperextension
Continuation of extension beyond the normal extension
Bending the trunk backward
Abduction
Movement of a bone away from the midline
Moving the humerus laterally at the shoulder joint
Adduction
Movement of a bone toward the midline
Movement that returns body parts to normal position from abduction
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Types of Movements at Synovial Joints
Circumduction
Movement of a body part in a circle
Moving the humerus in a circle at the shoulder joint
Rotation
A bone revolves around its own longitudinal axis
Turning the head from side to side as when you shake your head “no”
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Types of Movements at Synovial Joints
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Types of Movements at Synovial Joints
Special Movements
Elevation
Depression
Protraction
Retraction
Inversion
Eversion
Dorsiflexion
Plantar flexion
Supination
Pronation
Opposition
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24. Types of Synovial Joints
Synovial joints are classified based on type of movement
Planar (Plane Joints)
Hinge
Pivot
Condyloid
Saddle
Ball-and-socket
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25. Types of Synovial Joints
Planar Joints
Primarily permit back-and-forth and side-to-side movements
Intercarpal joints
Pivot Joints
Allow for rotation
Found in the radioulnar and alanto-axial joints
Hinge Joints
Produce an opening and closing motion like that of a hinged door
Permit only flexion and extension
Knee and elbow
Condyloid
Oval-shaped condyle fits into an ellipsoidal socket
Joint between carpals and wrist
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26. Types of Synovial Joints
Saddle
Two saddle shaped bones fitting together
Found in joint between thumb metacarpal and wrist carpal.
Ball and socket
Provides the greatest ROM
Found in the hip and shoulder joints
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33. Temporomandibular Joint
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34. Temporomandibular Joint
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Shoulder Joint
Ball-and-socket joint formed by the head of the humerus and the scapula
More freedom of movement than any other joint of the body
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Elbow Joint
Hinge joint formed by the humerus, the ulna, and the radius
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Hip Joint
Ball-and-socket joint formed by the femur and the hip bone
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Knee Joint
Largest and most complex joint of the body
Modified hinge joint
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Range of Motion (ROM)
Refers to the range, measured in degrees of a circle, through which the bones of a joint can be moved
Measured in a scale up to 360 degrees
Measured using a goniometer
Range of motion allows us to measure a persons movements and compare them to an average person’s range to determine if they have an injury or impairment
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Factors that contribute to keeping the articular surfaces in contact and affect range of motion
Structure or shape of the articulating bones
Strength and tension of the joint ligaments
Arrangement and tension of the muscles
Contact of soft parts
Hormones
Disuse
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Aging and Joints
May result in decreased production of synovial fluid
The articular cartilage becomes thinner
Discs and muscle may have decrease in water content
Ligaments shorten and lose some of their flexibility
Osteoarthritis increases with age
Stretching, aerobic exercises and strength training has shown to be helpful in minimizing the effects of aging
Exercise helps to maintain the effective functioning of ligaments, tendons, muscles, synovial fluid, and articular cartilage by increasing nutrition to the joint
Furthermore weight bearing stimulates the joint to produce more bone which prevents osteoarthritis
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Joint Diseases
Osteoarthritis
The most common type of arthritis
A degenerative disease that results from aging and wear.
The articular cartilages gradually disintegrate, which causes pain and restricts movement.
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Joint Diseases
Rheumatoid Arthritis
A chronic autoimmune condition
Often the most painful and crippling type of arthritis
The synovial membrane thickens, synovial fluid accumulates causing swelling, and articular cartilages are destroyed.
The joint is invaded by fibrous connective tissue that ultimately ossifies, making the joint immovable.
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Joint Diseases
Dislocation- the displacement of bones forming a joint.
Subluxation- a slight dislocation
Sprains result from tearing or excessive stretching of the ligaments and tendons at a joint without a dislocation.
Bursitis- the inflammation of a bursa. It may be caused by excessive use or injury
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Joint Diseases
Herniated disc is a condition in which the nucleus pulposis of an intervertebral disc protrudes beyond the edge of a vertebra. The protruding disk may place pressure on a spinal nerve and cause considerable pain.
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46. Arthrocentesis

47. Treatment for Damaged Joints
Arthroplasty
Joints may be replaced surgically with artificial joints
Most commonly replaced are the hips, knees, and shoulders
Hip Replacements
Partial hip replacements involve only the femur
Total hip replacements involve both the acetabulum and head of the femur
Knee Replacements
Actually a resurfacing of cartilage and may be partial or total
Potential complications of arthroplasty include infection, blood clots, loosening or dislocation of the replacement components, and nerve injury
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Hip Joint Replacement
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49. Healthcare Applications:
For therapists range of motion (ROM) will be an important tool to determine a clients limitations and a motivating factor for improvement in musculoskeletal injuries.
During the acute stages of many of these conditions, massage is contraindicated. However it can be used in later stages to ease muscle tension, reduce pain, and maintain flexibility.