OVRT Resources for the Humanoid Animation Working Group
Useful information
for the Humanoid Animation
Working Group of the VRML Consortium.
Joints
from Biomechanical Basis of Human Movement by Joseph Hamill and
Katheen M. Knutzen, Williams & Wilkins 1995, ISBN: 0-683-03863-X
Types of Diarthrodial Joints
- Simple, Compound, and Complex Joints
- The articulating surfaces found in the different joints in the body
vary in size and shape. There is typically a concave surface on the adjacent
bone, termed female and male surfaces, respectively. Also, there can be
more than two contact points or articulating surfaces. A joint with only
two articulating surfaces is termed a simple joint, while a joint with
three or more articulating surfaces is known as a compound joint. A joint
with more than two articulating surfaces and with a disc or fibrocartilage
is called a complex joint. An example of a simple joint is the hip or the
ankle (talotibial), of a compound joint is the wrist, and of a complex
joint is the knee.
- Close-Packed vs Loose-Packed Positions
- As movement occurs through a range of motion, the actual contact area
varies between the articulating surfaces.
- The Plane or Gliding Joint
- The first type of joint is the plane or gliding joint, found in the
foot between the tarsals and in the hand among the carpals. Movement at
this type of joint does not occur about an axis and is termed non-axial
since it consists of two flat surfaces that slide over each other to allow
movement. In the hand, for example, the carpals will slide over each other
as the hand is moved to positions of flexion, extension, radial deviation,
or ulnar deviation. Likewise, in the foot, the tarsals shift during pronation
and supination, sliding over each other in the process.
- The Hinge Joint
- The hinge (ginglymus) joint allows movement in one plane (flexion,
extension) and is termed uniaxial. Examples of the hunge joint in the body
are the interphalangeal joints of the phalanges in the foot and hand, and
the ulnohumeral articulation at the elbow.
- The Pivot Joint
- The pivot joint also allows movement in one plane (rotation; pronation,
supination) and is uniaxial. Pivot joints are located at the superior and
inferior radioulnar joint and the atlantoaxial articulation at the base
of the skull.
- The Condylar Joint
- The condylar joint is a joint allowing primary movement in one plane
flexion, extension) with small amounts of movement in another plane (rotation).
It is found at the knee joint and the temporomandibular joint.
- The Ellipsoid Joint
- The ellipsoid joint allows movement in two planes (flexion, extension;
abduction, adduction) and is biaxial. Examples of this joint can be found
at the radiocarpal articulation at the wrist and the metacarpophalangeal
articulation in the phalanges.
- The Saddle Joint
- The saddle joint only found at the carpometacarpal articulation of
the thumb, allows two planes of motion (flexion, extension; abduction,
adduction) with a small amount of rotation also allowed. It is similar
to the ellipsoid joint in function.
- The Ball-and-Socket Joint
- The last type of diarthrodial joint, the ball-and-socket joint allows
movement in three planes (flexion, extension; abduction, adduction; rotation)
and is the most mobile of the diarthrodial joint. The hip and shoulder
joints are example of ball-and-socket joints.
Other Types of Joints
- Synarthrodial or Fibrous Joints
- There are other articulations that are limited in movement characteristics
but, nonetheless, play an important role in stabilization of the skeletal
system. Some bones are held together by fibrous articulations, such as
those found in the sutures of the skull. These articulations, referred
to as synarthrodial, allow little or no movement to occur between the bones
and hold the bones firmly together.
- Amphiarthrodial or Cartilaginous Joints
- There are also cartilaginous joint, called amphiarthodial, that are
bones held together by either hyaline cartilage, such as is found at the
epiphyseal plates , or by fibrocartilage, found at the pubic symphysis
and the intervertebral articulations. The movement at these articulations
is also very limited, although not to the degree of the synarthodial joints.
| Major Joints of the Body |
| Joint |
Type |
Degrees of Freedom |
| Vertebrae |
Amphiarthroidial |
3 |
| Hip |
Ball-and-Socket |
3 |
| Shoulder |
Ball-and-Socket |
3 |
| Knee |
Condyloid |
2 |
| Wrist |
Ellipsoid |
2 |
| Metacarpophalangeal (fingers) |
Ellipsoid |
2 |
| Carpometacarpal (thumb) |
Saddle |
2 |
| Elbow |
Hinge |
1 |
| Radioulnar |
Pivot |
1 |
| Atlantoaxial |
Pivot |
1 |
| Ankle |
Hinge |
1 |
| Interphalangeal |
Hinge |
1 |
range tables taken from Human Factors Design Handbook
2nd ed, Woodson, Tillman, Tillman published by McGraw Hill 1992, ISBN:
0-07-071768-0
| Range of Movement at the Joints of the Foot and Leg of Male
Air Force Personel |
| Movement |
Range(deg) Avg. |
Range(deg) S.D. |
| Ankle flexion |
35 |
7 |
| Ankle extension |
38 |
12 |
| Ankle adduction |
24 |
9 |
| Ankle abduction |
23 |
7 |
| Knee flexion |
| Standing |
113 |
13 |
| Kneeling |
159 |
9 |
| Prone |
125 |
10 |
| Knee rotation |
| Medial |
35 |
12 |
| Lateral |
43 |
12 |
| Hip flexion |
113 |
13 |
| Hip adduction |
31 |
12 |
| Hip abduction |
53 |
12 |
| Hip rotation (sitting) |
| Medial |
31 |
9 |
| Lateral |
30 |
9 |
| Hip rotation (prone) |
| Medial |
39 |
10 |
| Lateral |
34 |
10 |
Neck (image) - data in 2nd image
Related OVRT Resources
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