Articular system

Specific readings:
Behnke: 8-10, 19, 28-30
Thompson and Floyd: 9-19

Synarthroses

1.      Fibrous joints

-    Suture Syndesmoses

-      Gomphosis

-       Membranous Syndesmoses

2.      Cartilagenous joints

-      Symphysis

-      Synchondrosis

Synovial joint(Greek, meaning a joint in which there is a separation or articular cavity)

- Characteristics

1)     Articular cavity

2)     Joint encased within a fibrous capsule

a)     Stratum fibrosum

i)         

ii)       

b)     Stratum Synovium

i)         

ii)      Synoviocytes

iii)     

iv)     

3)     Smooth articular surfaces

4)     cartilage (hyaline), fibrocartilage.

5)     fibrocartilagenous disks, menisci, labrums, fat pads, ligaments, tendons.

a)     Menisci composed of fibrocartilage. 

6)     Menisci, synovial fluid, and disks

7)     Ligaments and tendons.

8)     Seperation of joint surfaces

9)     Joint Stability

• Structure of the joint, joint capsule
• Tendons and ligaments around the joint
• Gravity
• Vacuum

Joint Function.

-         structure reflects function t

-         synarthrodial joints

-         diarthrodial joints

4)     Joint Motion

a.       

b.      Roll –

c.      Sliding

d.      Spin

e.      Type of motion

f.         

g.      Locked or Close packed position

h.      Unlocked or Loose Packed Position

2)     Degrees of Freedom

a)     6 degrees of freedom

b)     Angular movements of Synovial Joints include:

i)        Flexion and Extension

ii)      Ab/adduction

iii)    Axial rotation (internal and external rotation)

iv)    Circumduction

3)     Classification

a)     Uniaxial joints

i)        Hinge (ginglymus).

ii)      Pivot (trochoid; screw).

b)     Biaxial joints

i)        Condyloid (ovoid; ellipsoidal).

ii)      Saddle (sellar).

c)      Triaxial joint

i)        Plane (Arthrodial) joint

ii)      Ball-and-Socket (Enarthrodial) joints

4)     Flexibility and Stability

i.        Flexibility

j.         Flexibility is determined by:

                                                  i.       

                                                ii.       

                                              iii.       

                                               iv.       

k.      Stability

l.         Laxity

m.    Stability determined by:

                                                  i.       

                                                ii.       

                                              iii.       

n.      Hyperflexibility

5)     Kinematic Chains

o.      Kinematic chains are the relationship between multiple joints in a system. 

p.      Closed kinematic chain

q.      Open kinematic chain

r.        Joints are interdependent. 

Connective Tissue

Ligaments

-         Non-contractile links between bones

-         Capsular Ligaments

-         Non-Capsular ligament

o       Extracapsular

o       Intracapsular

Tendons and Aponeuroses

Retinacula

General Structure of connective tissue

-         Parallel-fibered collagenous tissue

-         collagen, elastin, and ground substance (matrix composed of fluid and (glycoproteins and proteoglycans).

-         Actual arrangement in tissue:

o       Bundles – fibers – fibrils – microfibrils – collagen molecule

o       Many bundles together form connective tissue.

o        

-         Most connective tissue is fairly pliant and flexible, until loaded.

-         In an unloaded state, bundles of collagen are fairly relaxed. 

-         Tendon and Ligament Extensibility. 

-         Both tendons and ligaments (as with bones) weaken with disuse.