The concave-convex rule states that if a concave surface moves on a convex surface, roll and slide must occur in the same direction , and if a convex surface moves on a concave surface, roll and slide occurs in opposite directions.
Who proposed concave-convex rule?
Note the shift of axis of motion (after Jordan 1963: 22). The convex–concave rule, introduced by Kaltenborn into manual therapy, is a didactic simplification of the lever law, during rotatory movements of the joints.
Is the knee convex on concave?
The knee is referred to as a condyloid joint. However, that tells you nothing about the surfaces of the joint. In this case, the femur is the convex surface and the tibia is the concave surface .
How do you remember convex and concave rules?
Finding a mnemonic device for concave is easy enough. There’s a “cave” in concave , and caves are inward curvatures. That doesn’t work as well for convex, but if you can recall what we said for concave, all you need to do is remember that convex is the exact opposite.
Is the talus concave or convex?
Head. The talus bone of the ankle joint connects the leg to the foot. The head of talus looks forward and medialward; its anterior articular or navicular surface is large, oval, and convex .
What is Concavo convex rule?
The concave-convex rule states that if a concave surface moves on a convex surface, roll and slide must occur in the same direction , and if a convex surface moves on a concave surface, roll and slide occurs in opposite directions.
What is a convex and concave?
Concave means “hollowed out or rounded inward” and is easily remembered because these surfaces “cave” in. The opposite is convex meaning “curved or rounded outward.” Both words have been around for centuries but are often mixed up.
What is Jointplay?
Joint play is defined by Mennell as small movements within a synovial joint that are independent of voluntary muscle contraction (1). These movements measure not more than 1/8 inch in any plane and follow the contour of the opposing joint surfaces.
Why is there a convex concave joint?
Why is there a convex-concave rule? Its all about which bone contains the axis of rotation . In a convex bone (humeral head) it rotates around the axis which is WITHIN its head. In a concave bone the axis is inside the other ‘fixated’ bone.
Is the hip joint concave on convex?
joint surfaces and is the motion occurring between the femoral head and acetabulum in the case of the hip joint. The arthrokinematics of the hip joint abide by the principles of the convex on concave and concave on convex rules [23].
How do you distinguish between concave and convex?
| Convex Lens Concave Lens | A convex lens is thicker at the centre and thinner at the edges. A concave lens is thicker at the edges and thinner at the centre. | Due to the converging rays, it is called a converging lens. Due to the diverging rays, it is called a diverging lens. |
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Does convex make things look bigger?
A convex lens makes objects look larger and farther away . ... A concave lens makes objects look smaller and closer.
Which is the concave side?
Concave describes an inward curve ; its opposite, convex, describes a curve that bulges outward. They are used to describe gentle, subtle curves, like the kinds found in mirrors or lenses.
Is talus a weight bearing?
Talus fracture causes significant ankle pain, difficulty bearing weight on the ankle , and swelling around the ankle joint. 3 These symptoms warrant going to the healthcare provider right away. Expect to have an X-ray and ankle exam to determine whether it’s a fracture or other type of injury.
What is the purpose of talus?
Where the talus meets the foot bones, it forms the subtler joint. This joint is important for walking on uneven ground. Besides connecting the foot to the leg and body, the talus helps transfer weight and pressure across the ankle joint .
What connects to the talus?
The talus is connected to the tibia at the top (superior), the calcaneus to both the back (posterior) and below (inferior), the navicular to the front (anterior), and the cuboid below (inferior). Blood is supplied to the talus through the posterior tibial, anterior tibial, and peroneal arteries.
