Articulations
Chapter 9
Classification
Table 9–1
Functional Classification of Joints
• Synarthroses (singular = synarthrosis)
– Immovable joints
• Amphiarthroses (singular = amphiarthrosis)
– Slightly movable joints
• Diarthroses (singular = diarthrosis)
– Freely movable joints
Structural Classification of Joints
• Fibrous
• no joint cavity, bones held together with
collagen fibers
• Cartilagnous
• no joint cavity, bones held together with
cartilage
• Synovial
• have a “synovial” cavity, bones held together
with an enclosed capsule & ligaments
•Synostosis
• Conversion of other joints to solid bone mass
Structural Classification
Table 9–2
Suture: a fibrous synarthrosis
Gomphosis
Syndesmosis: a fibrous amphiarthrosis
An amphiarthrotic synchondrosis
Symphysis
Synovial Joints
The shoulder joint
Types of
Synovial
Joints
• Pencil maintains
vertical orientation, but
changes position
Linear (non-axial) Motion
Figure 9–2a, b
Angular Motion
(non-axial)
• Pencil maintains position,
but changes orientation
Figure 9–2c
Circumduction
(Multiaxial)
• Circular angular motion
Figure 9–2d
Rotation
(Uniaxial)
• Pencil maintains position and
orientation, but spins
Figure 9–2e
Planes (Axes) of Dynamic
Motion
• Monaxial or uniaxial (1 axis)
• Biaxial (2 axes)
• Triaxial or multiaxial (3 axes)
Types of Movements Possible at
Synovial Joints
Gliding
Flexion
Figure 9–3a
Flexion
• Angular motion
• Anterior–posterior plane
• Reduces angle between elements
• Bends vertebral
column from
side to side
Lateral Flexion
Figure 9–5f
Extension
• Angular motion
• Anterior–posterior plane
• Increases angle between elements
Hyperextension
• Angular motion
• Extension past anatomical position
Abduction & Adduction
Figure 9–3b, c
Abduction
• Angular motion
• Frontal plane
• Moves away from longitudinal axis
Adduction
• Angular motion
• Frontal plane
• Moves toward longitudinal axis
Circumduction
• Circular motion
without rotation
• Angular motion
Figure 9–3d
Abduction,
Adduction
&
Circumduction
Rotation
Figure 9–4
Rotation
• Direction of rotation from anatomical position
• Relative to longitudinal axis of bodyLeft or
right rotation
• Medial rotation (inward rotation):
– rotates toward axis
• Lateral rotation (outward rotation):
– rotates away from axis
Pronation and Supination
• Pronation:
– rotates forearm, radius over ulna
• Supination:
– forearm in anatomical position
Special movements of the antebrachium
Inversion
and
Eversion
Figure 9–5a
Special movements of the foot
Inversion and Eversion
• Inversion:
– twists sole of foot medially
• Eversion:
– twists sole of foot laterally
Special movement of the ankle
Dorsiflexion and Plantar Flexion
• Dorsiflexion:
– flexion at ankle (lifting toes)
• Plantar flexion:
– extension at ankle (pointing toes)
Opposition
• Thumb movement
toward fingers or
palm (grasping)
Figure 9–5c
Protraction and Retraction
• Protraction:
– moves anteriorly
– in the horizontal plane (pushing forward)
• Retraction:
– opposite of protraction
– moving anteriorly (pulling back)
Elevation and Depression
Figure 9–5e
Elevation and Depression
• Elevation:
– moves in superior direction (up)
• Depression:
– moves in inferior direction (down)
Types
synovial
joints
Gliding Joints
• Flattened or slightly curved faces
• Limited motion (nonaxial)
Hinge Joints
• Angular motion in a single plane (monaxial)
Figure 9–6 (2 of 6)
Pivot Joints
• Rotation only (monaxial)
Figure 9–6 (3 of 6)
Ellipsoidal Joints
(sometimes called “condylar” joints)
• Oval articular face within a depression
• Motion in 2 planes (biaxial)
Figure 9–6 (4 of 6)
Saddle Joints
• 2 concave faces, straddled (biaxial)
Figure 9–6 (5 of 6)
Ball-and-Socket Joints
• Round articular face in a depression
(triaxial)
Figure 9–6 (6 of 6)
Structural Details of Some
Synovial Joints
Intervertebral
Articulations
Figure 9–7
Intervertebral Articulations
• C2 to L5 spinal vertebrae articulate:
– at inferior and superior articular processes
(gliding joints)
– between adjacent vertebral bodies (symphyseal
joints)
Disc Structure
• Anulus fibrosus:
– tough outer layer
– attaches disc to vertebrae
• Nucleus pulposus:
– elastic, gelatinous core
– absorbs shocks
Verterbral Joints
• Also called symphyseal joints
• As vertebral column moves:
– nucleus pulposus shifts
– disc shape conforms to motion
6 Intervertebral Ligaments
• Anterior longitudinal ligament:
– connects anterior bodies
• Posterior longitudinal ligament:
– connects posterior bodies
• Ligamentum flavum:
– connects laminae
6 Intervertebral Ligaments
• Interspinous ligament:
– connects spinous processes
• Supraspinous ligament:
– connects tips of spinous processes (C7 to
sacrum)
• Ligamentum nuchae:
– continues supraspinous ligament (C7 to skull)
Damage to Intervertebral Discs
Figure 9–8
Damage to Intervertebral Discs
• Slipped disc:
– bulge in anulus fibrosus
– invades vertebral canal
• Herniated disc:
– nucleus pulposus breaks through anulus
fibrosus
– presses on spinal cord or nerves
Movements of the
Vertebral Column
• Flexion:
– bends anteriorly
• Extension:
– bends posteriorly
• Lateral flexion:
– bends laterally
• Rotation
Articulations and Movements of the Axial Skeleton
Articulations and Movements of the Axial Skeleton
The
Shoulder
Joint
Figure 9–9a
The Shoulder
Joint
Figure 9–9b
The Elbow Joint
Figure 9–10
The elbow: medial
Fig. 09.12b
The elbow: lateral
The Hip Joint
Figure 9–11a
The Hip Joint
The Knee Joint
Figure 9–12a, b
The Knee Joint
Figure 9–12c, d
Common
knee
injury
ACL replacement
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Articulations of the Appendicular Skeleton
Articulations of the Appendicular Skeleton
Rheumatism
• A pain and stiffness of skeletal and
muscular systems
Arthritis
• All forms of rheumatism that damage
articular cartilages of synovial joints
Osteoarthritis
• Caused by wear and tear of joint surfaces,
or genetic factors affecting collagen
formation
• Generally in people over age 60
Rheumatoid Arthritis
• An inflammatory condition
• Caused by infection, allergy, or autoimmune
disease
• Involves the immune system
Gouty Arthritis
• Occurs when crystals (uric acid or calcium
salts):
– form within synovial fluid
– due to metabolic disorders
Joint Immobilization
• Reduces flow of synovial fluid
• Can cause arthritis symptoms
• Treated by continuous passive motion
(therapy)
Bones and Aging
• Bone mass decreases
• Bones weaken
• Increases risk of hip fracture, hip
dislocation, or pelvic fracture
No Mas