AP-Ch08

Copyright © 2010 Pearson Education, Inc.

C h a p t e r

8

Articulations

PowerPoint® Lecture Slides prepared by Jason LaPres

Lone Star College - North Harris


An Introduction to Articulations

  Articulations   Body movement occurs at joints

(articulations) where two bones connect

  Joint Structure  Determines direction and distance of

movement (range of motion)

  Joint strength decreases as mobility increases


Classification of Joints

  Two methods of classification

  Functional classification is based on range

of motion of the joint

  Structural classification relies on the

anatomical organization of the joint



  Functional Classifications   Synarthrosis (immovable joint)

  No movement   Fibrous or cartilaginous connections   May fuse over time

  Amphiarthrosis (slightly movable joint)   Little movement   Fibrous or cartilaginous connections

  Diarthrosis (freely movable joint)   More movement   Also called synovial joints   Subdivided by type of motion







  Structural Classifications

  Bony

  Fibrous

 Cartilaginous

  Synovial





  Functional Classifications   Synarthroses (immovable joints)

  Are very strong

  Edges of bones may touch or interlock

  Four types of synarthrotic joints: –  suture

–  gomphosis

–  synchondrosis

–  synostosis



  Synarthrotic Joints

  Suture

  Bones interlocked

  Are bound by dense fibrous connective tissue

  Are found only in skull

  Gomphosis

  Fibrous connection (periodontal ligament)

  Binds teeth to sockets



  Synarthrotic Joints   Synchondrosis

  Is a rigid cartilaginous bridge between two bones: –  epiphyseal cartilage of long bones –  between vertebrosternal ribs and sternum

  Synostosis  Fused bones, immovable:

– metopic suture of skull –  epiphyseal lines of long bones



  Functional Classifications

  Amphiarthroses   More movable than synarthrosis

  Stronger than freely movable joint

  Two types of amphiarthroses

–  syndesmosis:

»  bones connected by ligaments

–  symphysis:

»  bones separated by fibrous cartilage



  Functional Classifications

  Synovial joints (diarthroses)

 Also called movable joints

 At ends of long bones

 Within articular capsules

 Lined with synovial membrane


Synovial Joints

  Components of Synovial Joints

 Articular cartilages

 Pad articulating surfaces within articular

capsules:

–  prevent bones from touching

 Smooth surfaces lubricated by synovial fluid:

–  reduce friction


Synovial Joints

  Components of Synovial Joints   Synovial fluid

  Contains slippery proteoglycans secreted by fibroblasts

  Functions of synovial fluid: –  lubrication

–  nutrient distribution

–  shock absorption


Synovial Joints   Components of Synovial Joints

  Accessory structures  Cartilages:

– cushion the joint: » Fibrous cartilage pad called a meniscus

(articular disc)  Fat pads:

– superficial to the joint capsule – protect articular cartilages

 Ligaments: – support, strengthen joints – sprain: ligaments with torn collagen fibers


Synovial Joints

  Components of Synovial Joints

  Accessory structures

  Tendons:

–  attach to muscles around joint

–  help support joint

  Bursae:

–  pockets of synovial fluid

–  cushion areas where tendons or ligaments rub


Synovial Joints

  Factors That Stabilize Synovial Joints

  Prevent injury by limiting range of motion

 Collagen fibers (joint capsule, ligaments)

 Articulating surfaces and menisci

 Other bones, muscles, or fat pads

 Tendons of articulating bones


Synovial Joints

Figure 8–1a The Structure of a Synovial Joint.


Synovial Joints

Figure 8–1b The Structure of a Synovial Joint.


Synovial Joints

  Injuries

  Dislocation (luxation)

  Articulating surfaces forced out of position

  Damages articular cartilage, ligaments, joint capsule

  Subluxation

  A partial dislocation


Movements

  Types of Dynamic Motion   Linear motion (gliding)

  Angular motion

  Rotation

  Planes (Axes) of Dynamic Motion   Monaxial (1 axis)

  Biaxial (2 axes)

  Triaxial (3 axes)


Movements

Figure 8–2 A Simple Model of Articular Motion.


Movements

Figure 8–2 A Simple Model of Articular Motion.


Movements

  Types of Movements at Synovial Joints

  Terms describe

 Plane or direction of motion

 Relationship between structures


Movements


  Linear motion

 Also called gliding

 Two surfaces slide past each other:

–  between carpal or tarsal bones


Movements

  Angular Motion   Flexion

  Angular motion   Anterior–posterior plane   Reduces angle between elements

  Extension   Angular motion   Anterior–posterior plane   Increases angle between elements


Movements

  Angular Motion  Hyperextension

 Angular motion

 Extension past anatomical position

Angular Movements


Movements

Figure 8–3a Angular Movements.


Movements

  Angular Motion   Abduction

  Angular motion   Frontal plane   Moves away from longitudinal axis

  Adduction   Angular motion   Frontal plane   Moves toward longitudinal axis


Movements

Figure 8–3 Angular Movements.


Movements



Movements

  Angular Motion

 Circumduction

 Circular motion without rotation

 Angular motion


Movements



Movements

  Types of Movement at Synovial Joints  Rotation

 Direction of rotation from anatomical position

 Relative to longitudinal axis of body

 Left or right rotation

 Medial rotation (inward rotation): –  rotates toward axis

 Lateral rotation (outward rotation): –  rotates away from axis


Movements

Figure 8–4a Rotational Movements.


Movements


 Rotation

 Pronation:

–  rotates forearm, radius over ulna

 Supination:

–  forearm in anatomical position


Movements

Figure 8–4b Rotational Movements.


Movements

  Types of Movements at Synovial Joints   Special movements

  Inversion: –  twists sole of foot medially

  Eversion: –  twists sole of foot laterally

  Dorsiflexion: –  flexion at ankle (lifting toes)

  Plantar flexion: –  extension at ankle (pointing toes)


Movements

  Special Movements at Synovial Joints   Opposition

 Thumb movement toward fingers or palm (grasping)

  Protraction   Moves anteriorly

  In the horizontal plane (pushing forward)

  Retraction   Opposite of protraction   Moving anteriorly (pulling back)


Movements

  Special Movements at Synovial Joints   Elevation

 Moves in superior direction (up)

 Depression  Moves in inferior direction (down)

  Lateral flexion  Bends vertebral column from side to side


Movements

Figure 8–5 Special Movements.


Movements

Figure 8–5 Special Movements.


Movements

  Classification of Synovial Joints by Shape  Gliding  Hinge   Pivot   Ellipsoid   Saddle   Ball-and-socket

A Functional Classification of Synovial Joints


Movements

  Gliding Joints

  Flattened or slightly curved faces

  Limited motion (nonaxial)

  Hinge Joints

  Angular motion in a single plane (monaxial)

  Pivot Joints

  Rotation only (monaxial)


Movements

Figure 8–6 Movements at Synovial Joints.


Movements

  Ellipsoid Joints   Oval articular face within a depression

  Motion in two planes (biaxial)

  Saddle Joints   Two concave, straddled (biaxial)

  Ball-and-Socket Joints   Round articular face in a depression (triaxial)


Movements

Figure 8–6 Movements at Synovial Joints.


Movements

  A joint cannot be both mobile and strong

  The greater the mobility, the weaker the joint

  Mobile joints are supported by muscles and ligaments, not bone-to-bone connections


Intervertebral Articulations

  Intervertebral Articulations

 C2 to L5 spinal vertebrae articulate

 At inferior and superior articular processes (gliding

joints)

 Between adjacent vertebral bodies (symphyseal

joints)



  Intervertebral Articulations   C2 to L5 spinal vertebrae articulate

  Intervertebral discs: –  pads of fibrous cartilage –  separate vertebral bodies –  anulus fibrosus:

»  tough outer layer »  attaches disc to vertebrae

–  nucleus pulposus: »  elastic, gelatinous core »  absorbs shocks



Figure 8–7 Intervertebral Articulations.



  Vertebral Joints   Also called symphyseal joints

  As vertebral column moves   Nucleus pulposus shifts

  Disc shape conforms to motion

  Intervertebral Ligaments   Bind vertebrae together

  Stabilize the vertebral column



  Six Intervertebral Ligaments  Anterior longitudinal ligament

 Connects anterior bodies

  Posterior longitudinal ligament  Connects posterior bodies

  Ligamentum flavum  Connects laminae



  Six 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

  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   Turning


Articulations of the Axial Skeleton






The Shoulder Joint

  Also called the glenohumeral joint

  Allows more motion than any other joint

  Is the least stable

  Supported by skeletal muscles, tendons, ligaments

  Ball-and-socket diarthrosis

  Between head of humerus and glenoid cavity of

scapula


The Shoulder Joint

  Socket of the Shoulder Joint   Glenoid labrum

  Deepens socket of glenoid cavity

  Fibrous cartilage lining

  Extends past the bone

  Processes of the Shoulder Joint   Acromion (clavicle) and coracoid process (scapula)

  Project laterally, superior to the humerus

  Help stabilize the joint


The Shoulder Joint

  Shoulder Ligaments   Glenohumeral

  Coracohumeral

  Coraco-acromial

  Coracoclavicular

  Acromioclavicular

  Shoulder Separation   Dislocation of the shoulder joint


The Shoulder Joint

  Shoulder Muscles (also called rotator cuff)   Supraspinatus   Infraspinatus   Subscapularis   Teres minor

  Shoulder Bursae   Subacromial   Subcoracoid   Subdeltoid   Subscapular


The Shoulder Joint

Figure 8–8a The Shoulder Joint.


The Shoulder Joint

Figure 8–8b The Shoulder Joint.


The Elbow Joint

  A stable hinge joint

  With articulations involving humerus,

radius, and ulna


The Elbow Joint

  Articulations of the Elbow

  Humero-ulnar joint

  Largest articulation

  Trochlea of humerus and trochlear notch of ulna

  Limited movement

  Humeroradial joint:

  Smaller articulation

  Capitulum of humerus and head of radius


The Elbow Joint

Figure 8–9a The Elbow Joint.


The Elbow Joint

  Supporting Structures of the Elbow   Biceps brachii muscle

  Attached to radial tuberosity

  Controls elbow motion

  Elbow Ligaments   Radial collateral

  Annular

  Ulnar collateral


The Elbow Joint

Figure 8–9b The Elbow Joint.


The Hip Joint

  Also called coxal joint

  Strong ball-and-socket diarthrosis

  Wide range of motion


The Hip Joint   Structures of the Hip Joint

  Head of femur fits into it   Socket of acetabulum   Which is extended by fibrocartilaginous acetabular

labrum

  Ligaments of the Hip Joint   Iliofemoral   Pubofemoral   Ischiofemoral   Transverse acetabular   Ligamentum teres


The Hip Joint

Figure 8–10a The Hip Joint.


The Hip Joint

Figure 8–10b The Hip Joint.


The Hip Joint

Figure 8–10c The Hip Joint.


The Knee Joint

  A complicated hinge joint

  Transfers weight from femur to tibia

  Articulations of the knee joint

  Two femur–tibia articulations

 At medial and lateral condyles

 One between patella and patellar surface of femur


The Knee Joint

  Menisci of the Knee  Medial and lateral menisci

 Fibrous cartilage pads  At femur–tibia articulations  Cushion and stabilize joint  Give lateral support

  Locking knees  Standing with legs straight:

–  “locks” knees by jamming lateral meniscus between tibia and femur


The Knee Joint

  Seven Ligaments of the Knee Joint

  Patellar ligament (anterior)

  Two popliteal ligaments (posterior)

  Anterior and posterior cruciate ligaments (inside joint

capsule)

  Tibial collateral ligament (medial)

  Fibular collateral ligament (lateral)


The Knee Joint

Figure 8–11a The Knee Joint.


The Knee Joint

Figure 8–11b The Knee Joint.


The Knee Joint

Figure 8–11c The Knee Joint.


The Knee Joint

Figure 8–11d The Knee Joint.


The Knee Joint


The Knee Joint

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AP-Ch08