| axial skeleton | Articulated bones of head and vertebral column, i.e., head and trunk, as opposed to the appendicular skeleton, the articulated bones of the upper and lower limbs. Synonym: skeleton axiale. (05 Mar 2000) |
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| axial surface | The surface of a tooth parallel with its long axis; the axial surface's are the vestibular (labial or buccal), lingual, and contact (mesial or distal). (05 Mar 2000) |
| axial view | Radiographic projection devised to obtain direct visualization of the base of the skull. Synonym: axial view, base projection, submental vertex projection, submentovertical projection, verticosubmental view. (05 Mar 2000) |
| axial walls of the pulp chambers | The wall's parallel with the long axis of a tooth: the mesial, distal, buccal, and lingual wall's. (05 Mar 2000) |
| computerised axial tomography | Cat scanning adds X-ray images with the aid of a computer to generate cross-sectional views anatomy. It can identify normal and abnormal structures and be used to guide procedures. CAT scanning is painless. Iodine-containing contrast material is sometimes used in CAT scanning. If you are having a CAT scan and are allergic to iodine or contrast materials, you should notify your physicians and radiology staff. (12 Dec 1998) |
| half-axial projection | Reverse tilted AP radiographic projection devised to permit demonstration of the entire occipital bone, foramen magnum, and dorsum sellae, as well as the petrous ridges. Synonym: half axial view, half-axial projection, Towne view. (05 Mar 2000) |
| half axial view | Reverse tilted AP radiographic projection devised to permit demonstration of the entire occipital bone, foramen magnum, and dorsum sellae, as well as the petrous ridges. Synonym: half axial view, half-axial projection, Towne view. (05 Mar 2000) |
| extra-axial | Off the axis; applied to intracerebral lesions that do not arise from the brain itself. (05 Mar 2000) |
| action current | An electrical current induced in muscle fibres when they are effectively stimulated; normally it is followed by contraction. (05 Mar 2000) |
| alternating current | Electrical current which alternates direction periodically. (For instance, household electric current is AC alternating at 60 oscillations/sec (60 Hertz) in the United States, and 50 Hertz in many other countries.) Acronym: AC (09 Oct 1997) |
| anodal current | A current produced in tissues under the anode when the circuit is closed. (05 Mar 2000) |
| ascending current | The direction of current flow in a nerve when the anode is placed peripheral to the cathode, in contrast to descending current; the convention used is that current flows from positive to negative. Synonym: centripetal current. (05 Mar 2000) |
| bootstrap current | <radiobiology> Currents driven in toroidal devices by neo-classical diffusion. They may amount to a substantial fraction of the net current in a tokamak reactor, thus lengthening the pulse time or decreasing the power needed for current drive. (09 Oct 1997) |
| calcium current | Inflow of calcium ions through specific calcium channels. Critically important in release of transmitter substance from presynaptic terminals. (18 Nov 1997) |
| galvanic current | See: direct current, galvanism. (05 Mar 2000) |