Transcript olecranon bursitis

Chapter 9: Articulations
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INTRODUCTION
Articulation: point of contact between
bones
Joints are mostly movable, but some are
immovable or allow only limited motion
Movable joints allow complex, highly
coordinated, purposeful movements to be
executed
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CLASSIFICATION OF JOINTS
Joints may be classified by using a
structural or functional scheme (Table 9-1)
Structural classification: joints are named
according to:
Presence of a fluid-filled joint capsule (synovial joint)
Type of connective tissue that joins bones together
(fibrous or cartilaginous joints)
Functional classification: joints are named
according to the degree of movement allowed
Synarthroses: immovable joint
Amphiarthroses: slightly movable
Diarthroses: freely movable
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CLASSIFICATION OF JOINTS (cont.)
 Fibrous joints (synarthroses): bones of joints fit
together closely, thereby allowing little or no
movement (Figure 9-1)
Syndesmoses: joints in which ligaments connect two
bones
Sutures: found only in the skull; teethlike projections
from adjacent bones interlock with each other
Gomphoses: between the root of a tooth and the
alveolar process of the mandible or maxilla
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CLASSIFICATION OF JOINTS (cont.)
Cartilaginous joints (amphiarthroses):
bones of joints are joined together by
hyaline cartilage or fibrocartilage; allow
very little motion (Figure 9-2)
Synchondroses: hyaline cartilage present
between articulating bones
Symphyses: joints in which a pad or disk of
fibrocartilage connects two bones
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CLASSIFICATION OF JOINTS (cont.)
 Synovial joints (diarthroses): freely movable joints (Figure
9-3)
 Structures of synovial joints
 Joint capsule: sleevelike casing of periosteum around the
ends of the bones that binds them together
 Synovial membrane: membrane that lines the joint capsule
and also secretes synovial fluid
 Articular cartilage: hyaline cartilage covering the articular
surfaces of bones
 Joint cavity: small space between the articulating surfaces
of the two bones of the joint
 Menisci (articular disks): pads of fibrocartilage located
between articulating bones
 Ligaments: strong cords of dense, white, fibrous tissue that
hold the bones of a synovial joint more firmly together
 Bursae: synovial membranes filled with synovial fluid;
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cushion joints and facilitate movement of tendons
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CLASSIFICATION OF JOINTS (cont.)
 Synovial joints (cont.)
Types of synovial joints (Figure 9-4)
 Uniaxial joints: synovial joints that permit movement
around only one axis and in only one plane
• Hinge joints: articulating ends of bones form a hingeshaped unity that allows only flexion and extension
• Pivot joints: a projection of one bone articulates with a
ring or notch of another bone
 Biaxial joints: synovial joints that permit movements
around two perpendicular axes in two perpendicular
planes
• Saddle joints: synovial joints in which the articulating
ends of the bones resemble reciprocally shaped
miniature saddles; only example in the body is in the
thumb
• Condyloid (ellipsoidal) joints: synovial joints in which a
condyle fits into an elliptical socket
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CLASSIFICATION OF JOINTS
(cont.)
Types of synovial joints (cont.)
Multiaxial joints: synovial joints that permit
movements around three or more axes in three or
more planes
• Ball-and-socket (spheroid) joints: most movable joints;
the ball-shaped head of one bone fits into a concave
depression
• Gliding joints: relatively flat articulating surfaces that
allow limited gliding movements along various axes
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REPRESENTATIVE SYNOVIAL JOINTS
Humeroscapular joint (Figure 9-5)
Shoulder joint
Most mobile joint because of the shallowness of
the glenoid cavity
Glenoid labrum: narrow rim of fibrocartilage
around the glenoid cavity that lends depth to the
glenoid cavity
Structures that strengthen the shoulder joint are
ligaments, muscles, tendons, and bursae
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
 Elbow joint (Figure 9-6)
 Humeroradial joint: lateral articulation of the capitulum of the
humerus with the head of the radius
 Humeroulnar joint: medial articulation of the trochlea of the
humerus with the trochlear notch of the ulna
 Both components of the elbow joint surrounded by a single joint
capsule and stabilized by collateral ligaments
 Classic hinge joint
 Medial and lateral epicondyles are externally palpable bony
landmarks
 Olecranon bursa independent of elbow joint space; inflammation
called olecranon bursitis
 Trauma to nerve results in unpleasant sensations in the
fingers and part of the hand supplied by the nerve; severe
injury may cause paralysis of hand muscles or reduction in
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wrist movements
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
 Proximal radioulnar joint: between the head of
the radius and the medial notch of the ulna
Stabilized by the annular ligament
Permits rotation of the forearm
Dislocation of the radial head called a pulled elbow
 Distal radioulnar joint: point of articulation
between the ulnar notch of the radius and the
head of the ulna
Acting with the proximal radioulnar joint permits
pronation and supination of the forearm
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
Radiocarpal (wrist) joints (Figure 9-7)
Only the radius articulates directly with the
carpal bones distally (scaphoid and lunate)
Joints are synovial
Scaphoid bone is fractured frequently
Portion of the fractured scaphoid may become
avascular
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
Intercarpal joints
Present between eight carpal bones
Stabilized by numerous ligaments
Joint spaces usually communicate
Movements generally gliding with some
abduction and flexion
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
 Carpometacarpal joints: total of three joints
One joint for the thumb—wide range of movements
Two joints for the fingers—movements largely gliding
type
Thumb carpometacarpal joint is unique and important
functionally
 Loose-fitting joint capsule
 Saddle-shaped articular surface
 Movements: extension, adduction, abduction,
circumduction, and opposition
 Opposition: ability to touch the tip of the thumb to the tip of
other fingers; movement of great functional significance
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
Metacarpophalangeal joints (Figure 9-8)
Rounded heads of metacarpals articulate with
concave bases of the proximal phalanges
Capsule surrounding joints strengthened by
collateral ligaments
Primary movements are flexion and extension
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
Interphalangeal joints
Typical diarthrotic, hinge-type, synovial joints
Exist between heads of phalanges and bases of
more distal phalanges
Two categories:
Proximal interphalangeal joints: between proximal
and middle phalanges
Distal interphalangeal joints: between middle and
distal phalanges
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REPRESENTATIVE SYNOVIAL
JOINTS (cont.)
 Hip joint (Figure 9-9)
Stable joint because of the shape of the head of the
femur and the acetabulum
A joint capsule and ligaments contribute to the joint’s
stability
 Knee joint (Figures 9-10 and 9-11)
Largest and one of the most complex and most
frequently injured joints
Tibiofemoral joint is supported by a joint capsule,
cartilage, and numerous ligaments and muscle tendons
Permits flexion, extension and, with the knee flexed,
some internal and external rotation
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
 Ankle joint (Figure 9-12)
 Synovial-type hinge joint
 Articulation between the lower ends of the tibia and fibula and
the upper part of the talus
 Joint is mortise, or wedge, shaped
 Lateral malleolus lower than medial malleolus
 Internal rotation injury results in common “sprained ankle”
 Involves anterior talofibular ligament
 Other ankle ligaments also may be involved in sprain injuries
(e.g., deltoid ligament)
 External ankle rotation injuries generally involve bone fractures
rather than ligament tears
 First-degree ankle injury: lateral malleolus fractured
 Second-degree ankle injury: both malleoli fractured
 Third-degree ankle injury: fracture of both malleoli and
articular surface of tibia
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REPRESENTATIVE SYNOVIAL JOINTS
(cont.)
Vertebral joints (Figures 9-13 and 9-14)
Vertebrae are connected to one another by
several joints to form a strong flexible column
Bodies of adjacent vertebrae are connected by
intervertebral disks and ligaments
Intervertebral disks are composed of two parts
Annulus fibrosus: disk’s outer rim, made of fibrous
tissue and fibrocartilage
Nucleus pulposus: disk’s central core, made of a
pulpy, elastic substance
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TYPES AND RANGE OF MOVEMENT
AT SYNOVIAL JOINTS
 Measuring range of motion (Figure 9-15)
 Range of motion (ROM) assessment used to determine extent of
joint injury
 ROM can be measured actively or passively; both are generally
equal
 ROM measured by instrument called a goniometer
 Angular movements change the size of the angle
between articulating bones
 Flexion: decreases the angle between bones; bends or folds one
part on another (Figures 9-16, 9-18, and 9-19)
 Extension and hyperextension
 Extension: increases the angle between bones; returns a
part from its flexed position to its anatomical position
 Hyperextension: stretching or extending part beyond its
anatomical position (Figures 9-19, 9-21, and 9-23)
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TYPES AND RANGE OF MOVEMENT
AT SYNOVIAL JOINTS (cont.)
Plantar flexion and dorsiflexion (Figure 9-25)
Plantar flexion increases the angle between the top
of the foot and the front of the leg
Dorsiflexion decreases the angle between the top of
the foot and the front of the leg
Abduction and adduction (Figures 9-19 and 923)
Abduction moves a part away from the median plane
of the body
Adduction moves a part toward the median plane of
the body
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TYPES AND RANGE OF MOVEMENT
AT SYNOVIAL JOINTS (cont.)
 Circular movements
Rotation and circumduction
 Rotation: pivoting a bone on its own axis (Figure 9-16, D)
 Circumduction: moves a part so that its distal end moves
in a circle
Supination and pronation (Figure 9-20, B)
 Supination turns the hand palm side up
 Pronation turns the hand palm side down
 Gliding movements: simplest of all movements;
articular surface of one bone moves over the
articular surface of another without any angular
or circular movement
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TYPES AND RANGE OF MOVEMENT
AT SYNOVIAL JOINTS (cont.)
Special movements
Inversion and eversion (Figure 9-25, B)
Inversion: turning the sole of the foot inward
Eversion: turning the sole of the foot outward
Protraction and retraction (Figure 9-17, A)
Protraction moves a part forward
Retraction moves a part backward
Elevation and depression (Figure 9-17, B)
Elevation moves a part up
Depression lowers a part
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