KNEE

The knee joints [Gray, p.274] are separated from the hip joints by the shaft of the Femurs above and apart from the feet below by the shafts of the Tibia and Fibula. This defines another area topic for the innermost joint ligatures.

The salient points of knee construction are the:

.    Knee joint ligatures at the inner layer are as illustrated in Gray's Figures 185 and 186.

.    Knee joint is really much more complex than a hinge!

Notes From Prosthetics:

Once again the medical discipline of prosthetics provides some information usable in androtics. Certain aspects of a knee joint replacement for a flesh and blood human would be consistent with an HTA of the same physiognomy. That is the:

    . Same size condyle (other head of the Femur from the hip) and its location, the

    . same length and angle of the Femur's shaft and lower head, the

    . same axial angle toward the hip and geometries of the shafts of the Femur and Tibia,

etc. of a replacement knee joint for a young female of a certain race; e.g. early twenties caucasoid; would be the same for such an android.

It is conceivable that production prosthesis can be used as a part to make the skeleton of an HTA. However, a make/buy decision would be to determine if it is worth the cost because the shaft and hip would still need fabrication for your android. Also, the prosthetic would need to be securely seated or implanted into the shaft of the femur.

The gluing technique described in [NTB, Sept.`95, p.121] may not apply. Replacement knee joints do not seem to have the same problem with unmodified prosthetics that artificial hips have. The lower replacement condyle is pinned and secured with a screw to the upper head of the Tibia. The Femur's condyle seems to be glued into the remainder of its lower head.

Designing/Engineering Notes:

[    Knee geometry]
There are few detailed engineering notes to the knee as of August 28, 1999. However, there are meaningful, applicable concepts. There are certain geometric aspects that are apparent in the "Knee geometry" figure:

     One: The axis of the shafts of the Femur and Tibia and the angle between them. These are coincident with their component of the Articulation Diagram.

     Two: The articulation at the condyles are not flat or level.

     Three: The knee joint is not very hinge-like even though it may be a "hinge" type of joint. There is no fixed pivot axis. A knee works more like a cam and follower.

Most of the engineering of the knee geometry can not be done best with such a small scope as this topic. It would be better with a view of the lower extremities; up to the Dorsal vertebrae; or even the entire articulation diagram.

The knee geometry makes it possible for humans to stand and walk on two legs. Locking the knee in extension (see "screw home" in anatomical or kinesiological texts) aids balance for standing.

Frame Elements:

The frame element classifications of the knee joints are incorporated within the "Leg(s)" topic. That is because this topic is a joint and that the legs are made of the Femur, Tibia, Fibula, and the Patella.

Articulations:

It is assumed that the bones have the proper surface treatment already accomplished. It is also assumed that the synovial membranous parts are ready for installation. However, not all joints may need most of this particular process step because of the nature of the most internal mechanics of that joint.

The most internal ligatures of the knee joints are the two Crucia te ligatures; the Anterior and the Posterior, and the Ligamentum Mucosum. The Crucia tes actually cross each other deep internally between the inner and outer condyles of the Femur and Tibia. Together they form and limit the nature of the knee joint's articulation and motion. See the respective entries for more details about these three deepest ligatures.

Clearly, there is more than one layer of ligaments, cartilages, bursa, and other tissues of the knee joint. Layers of ligatures going outward include the:

.    Anterior, or Ligamentum Patella,

.    Posterior, Ligamentum Posticum Winslowii,

.    Internal Lateral,

.    two External Lateral,

and
.    the Capsular ligaments.

The procedures and order of making the innermost layers of ligatures of the knees follow:

[1]    Use WhiFt to make the Anterior Crucial Ligament [Gray, p. 276] which starts at the front of the tibia, goes through the joint itself upwardly and to the rear, and to attach to the back part of the femur. See [Gray, p.276] for more specific information.

    Alternatively, this may be made from a cable assembly in a manner like the Ligamentum Teres of the hip joint. These would be a lot more mechanical and highly likely to be made this way. A mechanical cable assembly may have a threaded adjustment for perfect tension upon installation. However, that would require knowledge of how to compensate for pre-stress cable.

[2]    What are the condyloid ligatures since the Tibia and Femurs both have inner and outer condyles? The tissues that prevent bone-to-bone contact within the knee are:
[2.1]    The Internal and

[2.2]    External Semilunar Fibro-cartilages

[2.3]    "The Synovial Membrane of the knee-joint is the largest and most extensive in the [human] body." [Gray, p.277] Is a good beginning description. This is composed of several parts:
[2.3.1]    The cul-de-sac from the upper edge of the knee cap has been described by Gray on page 277. Clearly this is a ligature that pertains outer of this most inner layer.

[2.3.2]    Ligamentum mucosum is a fold of a few fibers between the front of the intercondyloid notch of the Femur to the front of the knee joint below the knee cap.

    This is a very extensive, complex structure. In fact, Gray devotes an entire page with a compound structure to this topic. Clearly and admittedly, more investigation and development work is needed within this topic.

[2.4]    Transverse Ligament [Gray, p.277] is wrapped around the semilunar fibro-cartilages. This means that it could be associated with a middle layer ligature. However, because of the containment action on the lubricating tissues, this ligature is applied at this innermost layer.

    This discussion is located between the crucial ligaments because these tissue equivalents must be made in one step. It is expected that fabricating this joint can be very difficult because of managing and manipulating many components.

[3]    Posterior Crucial Ligament

Remember to apply the innermost layer of ligatures for Gray's "Articulations between the Tibia and Fibula" [p.282] topic because there is a relationship; especially the "Superior Tibio-Fibular Articulation."

[4]    Incorporate the Superior Tibio-Fibular Articulation [Gray, p.282] ligatures in the following order:
[4.1]    Synovial Membrane is upper and posterior of the joint. Sometimes these fibers merge with the knee.

[4.2]    Posterior Superior Ligament.

[4.3]    Anterior Superior Ligament. See [Gray, Fig. 185] for human application.

[4.4]    The Capsular ligament could be applied in a subsequent layer. It can be applied with these or installing it can be deferred. This is listed here so that if it is inadvertently omitted in later discussions for outer layers, this matter may not be lost.

The Tibia and Fibula articulations need to be researched and developed. There is an interosseus ligament ("Middle" [Gray, p.282] between the Tibia and Fibula that is clearly separate from that of the knee.

Locating the Patella has not been presented in any great detail because it fixed primarily by tendons and the Ligamentum Patella. The ligature is affixed to the tubercle of the Tibia. In humans the Patella is easily separated from the Ligamentum mucosum. And yet, that will need to be applied early within the ligature applications. The Ligamentum Patella and the Patella itself will be attached last of the knee components to the skeleton presentation.

Layers of Muscles and Other Tissues:

The layers of tissues and fascia could be almost an extension of the "Articulations" topic. See the "Leg(s)" topics for any dissertations about the various layer's muscles.

There are ligatures applied on top of those [Gray, p.274] already applied initially addressed in the "Articulations" subsection. The ligatures applied later going outward defines an areal topic for middle and outermost layer joint ligatures. The salient point of knee joint construction is the knee joint ligatures at this level are as illustrated in Gray's Figures 183 and 184. Clearly, this adds more layers of ligatures of the knee joint.

Internal Components:

There are no known respective internal components to be installed in the knees or legs yet. These are not of the normal muscle controls and other thews and sinews.

Final Layers and Artifacts:

Certain subcutaneous fat is used to protect the skin from articulation abrading. A little more in femdroids with their substantially smoother limbs adds to the feminine softness and curviness desired. See the "Leg(s)" topics for any other possible particulars.

Inspection Criteria:

The knee must extend to where the shaft axis are straight and stable. Also, it must be able to easily flex to the extent of its range of motion. Furthermore, the encasing ligatures must be smooth and secure.

In order to have the desired final likeness, the knee as assembled should be small enough to allow application of the remaining muscle, fascia, and skin. The final inspection values for the knee are girth measurements:
    . At the hock, which at the milepost "completed skeleton" is the largest of these. Strangely,k when your android is complete this measurement should be the smallest of these (unless a table leg taper is desired ... but why?).

    . At a certain distance above the knee at completion of the skin application to help prescribe the taper of the thigh.

And:
    . At a certain distance below the knee after skin applied to help form the shape of the calf.

These measurements assume a suitable cross section shape. This shape is basically circular or a bit elliptical. However, the Femoral Biceps tendons to the Fibula may have a squarish aspect.

Trivia:

"No noted trivia, yet. Still another stub.

INDEX:    See "Hip" and "Leg" for more information.