| radial head | The name applied to a head of origin of a muscle arising from the radius. Nomina Anatomica no longer lists any muscles as having radial heads, although formerly a radial head was listed for the flexor digitorum superficialis muscle Synonym: caput radiale. (05 Mar 2000) |
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| radial head subluxation | Subluxation of the radial head within the elbow joint is also referred to as nursemaid's elbow. This orthopaedic condition is seen commonly in toddlers who may be lifted up by outstretched arms. Instability of the radial head leads to subluxation. The child with nursemaid's usually has their arm in hanging in extension at their side and any attempted movement of the elbow joint is met with pain. (27 Sep 1997) |
| radial immunodiffusion | <technique> A quantitative variation of immunodiffusion in which the agar gel contains evenly distributed antigen (or antibody) and its counterpart from the test sample diffuses into the gel from a single well resulting in a circular precipitin line around the sample well. The diameter of the precipitin ring is proportional to the concentration of the antibody (or antigen) present in the test sample. By comparing the diameter of the test specimen precipitin ring to known standards, a relatively insensitive estimation of the concentration of specific antibody or antigen can be achieved. (01 Dec 1998) |
| radial index artery | <anatomy, artery> Origin, radial; distribution, radial side of index finger. Synonym: arteria radialis indicis, arteria volaris indicis radialis, radial index artery. (05 Mar 2000) |
| radial keratotomy | A keratotomywith radial incisions around a clear central zone. A form of refractive keratoplasty used in the treatment of myopia. (05 Mar 2000) |
| radial nerve | <anatomy, nerve> A major nerve of the upper extremity. In humans the fibres of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually c5 to t1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibres to extensor regions of the arm and hand. (12 Dec 1998) |
| radial notch | The concavity on the lateral aspect of the coronoid process of the ulna that articulates with the head of the radius. Synonym: incisura radialis. (05 Mar 2000) |
| radial phenomenon | Dorsal flexion of the hand occurring involuntarily with palmar flexion of the fingers. (05 Mar 2000) |
| radial ponderomotive force stabilisation | <radiobiology> In magnetic mirror devices, use of rf waves in the neighborhood of the ion cyclotron frequency to stabilise interchange modes. The radial ponderomotive force produced by a radial gradient in the applied rf electric field opposes the destabilising centrifugal force resulting from bad magnetic field curvature. The net particle current is in the direction that would result from field lines with good curvature, eliminating the drive for the interchange instability. (09 Oct 1997) |
| radial pulse | The pulse as appreciated at the radial artery usually in the wrist. (05 Mar 2000) |
| radial recurrent artery | <anatomy, artery> Origin, radial; distribution, ascends around lateral side of elbow joint; anastomoses, radial collateral, interosseous recurrent. Synonym: arteria recurrens radialis, recurrent radial artery. (05 Mar 2000) |
| radial reflex | On tapping the lower end of the radius, flexion of the forearm occurs, and sometimes, on strong percussion, flexion of the fingers. See: inverted radial reflex. (05 Mar 2000) |
| radial scar | A variant of sclerosing adenosis of the breast with central scar formation and radiating hyperplastic ducts. Synonym: radial scar. (05 Mar 2000) |
| radial sclerosing lesion | A variant of sclerosing adenosis of the breast with central scar formation and radiating hyperplastic ducts. Synonym: radial scar. (05 Mar 2000) |
| radial spoke | The structure that links the outer microtubule doublet of the ciliary axoneme with the sheath that surrounds the central pair of microtubules. The spokes are arranged periodically along the axoneme every 29nm, have a stalk about 32nm long and a bulbous region adjacent to the sheath. at least 17 different polypeptides are associated with the spokes. Spokes are thought to restrict the sliding of doublets relative to one another, digestion of the radial spokes will allow sliding apart of the doublets. (18 Nov 1997) |