point

1. SYN: punctum. 2. A sharp end or apex. 3. A slight projection. 4. A stage or condition reached, as the boiling p. 5. To become ready to open, said of an abscess or boil the wall of which is becoming thin and about to rupture. 6. In mathematics, a dimensionless geometric element. 7. A location or position on a graph, plot, or diagram. 8. Decimal p.. [Fr.; L. punctum, fr. pungo, pp. punctus, to pierce]

- p. A SYN: subspinale.

- absorbent points cones of paper or paper products used for drying or maintaining medicaments during root canal therapy.

- alveolar p. SYN: prosthion.

- anterior focal p. the p. where parallel rays from the retina are focused.

- apophysary p., apophysial p. 1. SYN: subnasal p.. 2. SYN: Trousseau p..

- auricular p. SYN: auriculare.

- axial p. SYN: nodal p..

- p. B SYN: supramentale.

- boiling p. (b.p.) the temperature at which the vapor pressure of a liquid equals the ambient atmospheric pressure.

- Cannon p. the location in the mid–transverse colon at which innervation by superior and inferior mesenteric plexuses overlaps at the junction of the primitive midgut and hindgut, frequently resulting in narrowing evident on barium enema. See Cannon ring. SYN: Cannon ring.

- Capuron points the iliopubic eminences and the sacroiliac joints, constituting four fixed p. in the pelvic inlet.

- cardinal points 1. the four points in the pelvic inlet toward one of which the occiput of the baby is usually directed in case of head presentation : two sacroiliac articulations and the two iliopectineal eminences corresponding to the acetabula; 2. six points of a compound optical system : the anterior focal p., the posterior focal p., the two principal points, and the two nodal points.

- central-bearing p. the contact p. of a central-bearing device.

- Clado p. a p. at the junction of the interspinous and right semilunar lines, at the lateral border of the rectus abdominis muscle, where marked tenderness on pressure is felt in some cases of appendicitis.

- clinical end p. traditional medical measures of a diagnostic or therapeutic impact that may or may not be perceived by the patient.

- cold-rigor p. the degree of lowered temperature at which the activity of a cell ceases and the cell passes into the narcotic or hibernating state.

- congruent points the p. in each retina referred to the same external stimulus.

- conjugate p. a p. so related to another that an object at one is imaged at the other.

- contact p. SYN: contact area.

- points of convergence convergence.

- craniometric points fixed points on the skull used as landmarks in craniometry.

- critical p. a p. at which two phases become identical; thus, at a given critical temperature and critical pressure, the liquid and gaseous state of a particular substance can no longer be differentiated.

- dew p. the temperature at and below which moisture will condense for a specific humidity.

- p. of elbow SYN: olecranon.

- end p. the completion of a reaction; usually evident by the first perceptible alteration of the color of an added indicator.

- equivalence p. SYN: equivalence zone.

- far p. that p. in conjugate focus with the retina when the eye is not accommodating. SYN: punctum remotum.

- p. of fixation the p. on the retina at which the rays coming from an object regarded directly are focused. SYN: p. of regard.

- flash p. the lowest temperature at which vapors of a liquid may be ignited by a flame.

- focal p. anterior focal p., posterior focal p..

- freezing p. the temperature at which a liquid solidifies.

- fusing p. fusion temperature (wire method).

- Guéneau de Mussy p. a p., painful on pressure, at the junction of a line prolonging the left border of the sternum and a horizontal line at the level of end of the bony portion of the tenth rib; it is present in cases of diaphragmatic pleurisy.

- gutta-percha points cones of a gutta percha compound used for filling root canals in conjunction with a cement, paste, or plastic.

- Hallé p. a p. at the intersection of a horizontal line touching the anterior superior spine of the ilium and a perpendicular line drawn from the spine of the pubis; here the ureter can be most readily palpated.

- heat-rigor p. the degree of elevated temperature at which coagulation of protoplasm occurs with death of the cell.

- incident p. the p. at which a light ray enters an optical system.

- incisal p. the p. located between the incisal edges of the lower central incisors; the graphic projection of the excursions of the incisal p. in certain planes is generally used to illustrate the envelope of motion of mandibular movement.

- isoelectric p. (pI, IEP, I.P., i.p.) the pH at which an amphoteric substance, such as protein or an amino acid, is electrically neutral.

- isoionic p. the pH at which a zwitterion has an equal number of positive and negative charges; in water and in the absence of other solutes, this is the isoelectric p..

- isosbestic p. in applied spectroscopy, a wavelength at which absorbance of two substances, one of which can be converted into the other, is the same.

- J p. the p. marking the end of the QRS complex and the beginning of the S or T wave in the electrocardiogram. SYN: ST junction.

- jugal p. SYN: jugale.

- lower alveolar p. SYN: infradentale.

- malar p. apex of the tuberosity of the zygomatic (malar) bone.

- p. of maximal impulse the p. on the chest wall at which the maximal cardiac impulse is seen and/or felt.

- maximum occipital p. the p. on the squama of the occipital bone farthest from the glabella.

- Mayo-Robson p. a p. just above and to the right of the umbilicus, where tenderness on pressure exists in disease of the pancreas.

- McBurney p. a p. between 112 and 2 inches superomedial to the anterior superior spine of the ilium, on a line joining that process and the umbilicus, where pressure elicits tenderness in acute appendicitis.

- median mandibular p. a p. on the anteroposterior center of the mandibular ridge in the median sagittal plane.

- melting p. (m.p., T_m) 1. the temperature at which a solid becomes a liquid; 2. the temperature at which 50% of a macromolecule becomes denatured.

- mental p. SYN: pogonion.

- metopic p. SYN: metopion.

- motor p. a p. on the skin overlying the endplates of an underlying muscle; the application of an electrical stimulus, via an electrode, will cause contraction of the muscle.

- Munro p. a p. at the right edge of the rectus abdominis muscle, between the umbilicus and the anterior superior spine of the ilium, where pressure elicits tenderness in appendicitis.

- nasal p. SYN: nasion.

- near p. that p. in conjugate focus with the retina when the eye exerts maximal accommodation. SYN: punctum proximum.

- neutral p. the p. at which a solution is neither acid nor alkaline (pH 7 at 22°C for aqueous solutions).

- nodal p. one of two points in a compound optical system so related that a ray directed toward the first p. will appear to have passed through the second p. parallel to its original direction. SYN: axial p..

- occipital p. the most prominent posterior p. on the occipital bone above the inion.

- p. of ossification SYN: ossification center.

- painful p. Valleix points.

- posterior focal p. the p. of a compound optical system where parallel rays entering the system are focused.

- power p. in dentistry, the vertical dimension at which the greatest masticatory force may be registered.

- preauricular p. a p. of the posterior root of the zygomatic arch lying immediately in front of the upper end of the tragus.

- pressure p. a cutaneous locus having pressure-sensitive elements that, when compressed, yield a sensation of pressure.

- primary p. of ossification SYN: primary ossification center.

- principal p. one of two points on an optic axis so related that an object at one is exactly imaged at the other without magnification, minification, or inversion.

- p. of proximal contact SYN: contact area.

- p. of regard SYN: p. of fixation.

- retention p. a provision made within a cavity preparation of a tooth to hold in place the first pieces of gold when placing a direct gold restoration.

- secondary p. of ossification SYN: secondary ossification center.

- silver p. a solid core cone of silver used in filling root canals in conjunction with a cement or paste.

- spinal p. SYN: subnasal p..

- subnasal p. the center of the root of the anterior nasal spine. SYN: apophysary p. (1), apophysial p., spinal p..

- Sudeck critical p. region in the colon between the supply of the sigmoid arteries and that of the superior rectal artery.

- supra- auricular p. a craniometric p. on the posterior root of the zygomatic process of the temporal bone directly above the auricular p..

- supranasal p. SYN: ophryon.

- supraorbital p. SYN: ophryon.

- sylvian p. the nearest p. on the skull to the lateral (sylvian) fissure, about 30 mm behind the zygomatic process of the frontal bone.

- tender points SYN: Valleix points.

- trigger p. a specific p. or area where stimulation by touch, pain, or pressure induces a painful response. SYN: dolorogenic zone, trigger area, trigger zone.

- triple p. the temperature at which all three phases ( I.E., solid, liquid, and gas) are in equilibrium; the triple p. of water (273.16 K) is a fundamental fixed p. in temperature scales.

- Trousseau p. a painful p., in neuralgia, at the spinous process of the vertebra below which arises the offending nerve. SYN: apophysary p. (2), apophysial p..

- Valleix points various points in the course of a nerve, pressure upon which is painful in cases of neuralgia; these points are: 1) where the nerve emerges from the bony canal; 2) where it pierces a muscle or aponeurosis to reach the skin; 3) where a superficial nerve rests upon a resisting surface where compression is easily made; 4) where the nerve gives off one or more branches; and 5) where the nerve terminates in the skin. SYN: tender points.

- Weber p. a p. situated 1 cm below the promontory of the sacrum; believed by Weber to represent the center of gravity of the body.

- zygomaxillary p. SYN: zygomaxillare.

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point 'pȯint n

1) a narrowly localized place or area

2) the terminal usu. sharp or narrowly rounded part of something

3) a definite measurable position in a scale see BOILING POINT, FREEZING POINT

point vi of an abscess to become distended with pus prior to breaking

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(point) [L. punctum] 1. a small area or spot; the sharp end of an object. 2. to approach the surface, like the pus of an abscess, at a definite spot or place. 3. a tapered, pointed endodontic instrument used for exploring the depth of the root canal in root canal therapy; called also root canal p. 3. an anthropometric landmark from which measurements are made. 4. an elongated silver or gutta-percha cone used in root canal obturation.