Android Makers Encyclopaedia: J

Here are the few specimen entries for the Android Makers Encyclopedia "J" topics:



     Jaw: A bone that is the combined Inferior Maxillary with its two Rami; one for each side that goes up to the pivot points. Both the Superior and Inferior Maxillaries take and seat teeth. The jaw developed as one bone so one hybrid or composite structure may be appropriate.

"...in modern humans, the lower jawbone angles sharply toward the rear of the skull as it ascends to the cheek in nearly all males, but it remains relatively straight in females.

"Hormonally regulated growth of chewing muscles and their associated bones create sex-typical facial traits such as these, ..." [SN, 8 Apr. `95 p.215 cited Susan R. Loth, Florida Atlantic University in Boca Raton.] Perhaps this tidbit will help engineer the three-dimensional facial parameters from a portrait. Admittedly, this is hard to visualize.

     Jig: A special fixture or apparatus to cradle, suspend, prop, etc. parts to an assembly or subassembly to hold alignments. These alignments or adjustments need to be retained throughout some drilling and bolting, gluing, welding, etc. processes.

There are two primary jigs needed for android making. The first in the Steps is a spinal jig. It holds the skull and vertebrae after the spinal cord has been threaded through the spinal foramen of each vertebrae. This allows the alignments of the bones and the intervertebral disks through the ligature laminations. This jig, with the skull and the spinal column with all associated ganglia, is attached to the Main Cradle jig.

This Main Cradle brackets the spinal jig into the android's proper position with respect to remaining body components. The remainder of skeletal frame elements and subassemblies will in their proper turn be located and fixed into their proper position. This jig allows your android in construction to be positioned to facilitate continuing fabrication at any attitude. The android in construction will be in this cradle for many Steps.



     Joint material: There are three primary classifications of joint materials: One is the coating or material at the articulation surface. Second is the synovial fluids. The third makes the ligatures within and encasing the joints.

     ONE: Articulation surfaces must be hard and smooth. See "implant materials" for an excellent candidate.

     TWO: The synovial fluids are lubricants. If the fluid is not a permanent lubricant, then there must be a mechanism to inject fresh synovial fluid and evacuate the old; akin to lachrymal mechanism. This should be developed in its own topic entry.

     THREE: There are a few different types of material used to make ligatures and tendons. The ligatures articulate; i.e. connect the bones together; the skeleton via different types of joints.

Tendons connect muscles to bones. The types of materials used for ligatures and tendons are:

.    TOUGH & ELASTIC FIBRO-CARTILAGE unite osseous surfaces of vertebrae (and the like) where slight movement is required. The "shorthand" used for the androtic equivalent for this is " TEFC." [Gray, p.225]

.    White FIBROUS tissue, PLIANT & FLEXIBLE, STRONG, TOUGH, INEXTENSIBLE connecting medium. The "shorthand" used for the androtic equivalent for this ligature material required some invention, but it is " WhiFt." [Gray, p.217]

.    Yellow ELASTIC Tissues where the elasticity is equivalent to muscle power (like in the adjacent arches of vertebrae). The "shorthand" used for the androtic equivalent for this is " YETS." [Gray, p.217]

See "Joint types." The topics "Ligature Materials" and "Tendon Materials" point back to this entry because the nature of these tissues are similar and defined here.


     Joint modeling [CGW, July`95, pg.17] suggest that a study of human joint mechanics may be instructive. These models are to analyze the impact joint motion has on human body soft tissues primarily for surgical purposes. However, the geometries may influence android engineering. This National Science Foundation Grand Challenge grant study is/has been done at Rensselaer Polytechnic Institute (Troy, NY) in collaboration with Columbia University.

     Joint movement: Joints have methods of movement by types and range of motion (ROM). One tidbit of assorted information: Females have 2 to 14 degrees more joint movement than males. [Farkas]



JOINT TYPES

Connecting the deepest ligatures must be done first. There are successive layers of ligatures over most joints which would prevent access to the joint if the deepest and other deeper articulating strands and layers were not already in place.

Gray describes several types of joint movement (pages 219-223) which have androtic counterparts. Basically, these joint movements and the mechanical movements are:

.    Symphysis.

.    Syndesmosis.

.    Ginglymus.

.    Trochoides.

.    Condyloid.

.    Reciprocal Reception.

.    Enarthrosis.

and
.    Arthrodia.

These are the ways the four kinds; gliding, circumduction, angular, and rotation; of movement are applied in body joints. Connecting the deepest ligatures must consider these movements in the articulations.


It has been decided to retain the previous material because it is basically accurate. However, it is little help with androtics.

The Android Maker passed an Anatomical Kinesiology course taken winter quarter, 2001. Borrowing heavily from that textbook [Luttgens] and hopefully avoiding plagiarism, compare and contrast:

[1]    Diarthrotic joints have an articular cavity. There must be some separation in order to have movement, even though such gap may be in microns.
[1.1]    Salient characteristics;
[1.1.1]    A sleeve-like ligamentous capsule encloses the joint.

[1.1.2]    The joint is lubricated by a synovial fluid secreted by the membrane liner of the capsule.

[1.1.3]    The articular surfaces are smooth and hard.

[1.1.4]    These articular surfaces are covered with hyaline, but some by fibrocartilage.

[1.2]    Classes:
[1.2.1]    Irregular joints are flat to slightly curved. Gliding is the movement which is nonaxial. Examples are carpals, tarsals, and vertebral arch articulations.

[1.2.2]    Hinge, "ginglymus" see previous text, does not have a pivot or a shaft like a mechanical device. One part of the joint has a concave surface and the mating part of the joint on the other bone is convex. The uniaxial motion is about one axis through one plane so the movements are flexion and extension. The examples are elbows and knees.

[1.2.3]    Pivot joints have a peg, a bit like the pintle as used to hang rudders. The uniaxial motion, alike the hinge type, is in the atlantoaxial and the radioulnar joints.

[1.2.4]    Condyloid joints have oval or elliptical shaped surfaces that mate concave or convex to its other parts. The forward and backward (flexion and extension) and side to side (abduction and adduction) movements are biaxial. Circumduction is done with a sinusoidal sequence between these four movements of the wrist and metacarpophalangeal joints (and equivalent of the feet).

[1.2.5]    Saddle joints are modified condyloids and are thus biaxial. They are such that the movement is much greater such as the carpometacarpal thumb joint.
    There was a temptation to combine the saddle type into the condyloid type for androtics. However, the opposable thumb is so uniquely human and useful, that it was deemed best to retain this classification and to be more conformable to anatomy and kinesiology disciplines.

[1.2.6]    Ball and socket joints are of the shoulders and the hips. The type is triaxial because movement can be done about three axis. Note the spherical head is on the limb and the socket is of the trunk. The socket could be on the limb of a mechanical contrivance, but bodies grow round things well at the end of a long bone and sockets, acetabulums, are formed by the construction of more than one bone.

[1.3]    For android makers: All biological joints with movement are made of surfaces with more than one concave or convex shape. Usually, only the ball-and-sockets; as in tie rod ends and ball joints; have such dual (or compound) shape. Cams' shapes form around only one axis; disregarding the shapes of hypoid gears for this study.

    Bone grows round, and the dual axis shape of the articular surfaces may allow some lateral motion to protect the joint. However primarily, the compound shape helps retain the articular capsules and other tissues, especially the medial and lateral meniscus of the knee, which helps cushion shock through the joint.

    Androids will have an equivalence of the meniscus in their knees. It may not be advantageous to put something like that in an androtic doll at the scale of 1cm:1" (or smaller) unless for the sake of type retention.

[2]    Syntharthrotic joints do not have such cavity. Any movement is done with flexibility of the associated material. This is a second part of an outline to properly discriminate the primary first part.
[2.1]    Salient characteristics;
[2.1.1]    Bones of cartilaginous and fibrous are conjoined by tissue attached to the joints' surface.

[2.1.2]    The ligamentous type is not a true joint, but it explains another connection (or relationship) of bones.

[2.2]    Classes:
[2.2.1]    Cartilaginous joints, adhered to with a fibrocartilage, allow bending and twisting. Intervertebral joints are the prime example of this type.
    The text cites a hyaline epiphyseal union as another example, but that is the apparent mechanism of growth. By its presence, it is an indicator of lack of growth completion and is representative of the subject's age. Androids will not likely "grow" as such, and if they ever do, are they still androids?

[2.2.2]    There is no movement in this "fibrous" type because such examples are the skull's sutures. Again, this is for biological growth.

[2.2.3]    Ligamentous joints; e.g. coracoacromial and radio-ulnar unions; surfaces may be widely separated. These are tied together by some ligaments which may require anatomical androids' and dolls' maker's attention.

[2.3]    For android makers: Thickness of the intervertebral disks allow for some triaxial movement; akin to ball-and-sockets. According to an article in the 18 December issue of "Design News" starting on page 64, Mattel used a ball-and-socket in the armature of the "twisty-tummy" Barbie dolls (this feature may not be used in their collectors' editions).




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as of July 4, 2001 ... Back to the Android Making Encyclopedia Page of/or to The Android Maker site's home page.


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R. Elaine Hatfield