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Title:
SYRINGE WITH FLAT INDICIA DISPLAY SURFACE
Document Type and Number:
WIPO Patent Application WO/2019/191285
Kind Code:
A1
Abstract:
A medical syringe having a barrel with a substantially cylindrical, longitudinally extending fluid chamber, a needle retraction cavity substantially coextensive in length with the fluid chamber and disposed adjacent and parallel to the fluid chamber, and at least one substantially flat, outwardly facing display area configured to receive and display an array of volumetric measuring indicia in alignment with and proximal to the fluid chamber.

Inventors:
SHAW, Thomas, J. (5310 Buena Vista, Frisco, TX, 75034, US)
SMALL, Mark (47442 Caughern Lane, Heavener, OK, 74937, US)
ZHU, Ni (4408 Brigade Ct, Plano, TX, 75024, US)
Application Number:
US2019/024361
Publication Date:
October 03, 2019
Filing Date:
March 27, 2019
Export Citation:
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Assignee:
RETRACTABLE TECHNOLOGIES, INC. (511 Lobo Lane, Little Elm, TX, 75068, US)
SHAW, Thomas, J. (5310 Buena Vista, Frisco, TX, 75034, US)
International Classes:
A61M5/32; A61M5/178; A61M5/31; A61M5/50
Foreign References:
US20150196714A12015-07-16
US20080114306A12008-05-15
US20150073303A12015-03-12
US20020082560A12002-06-27
US2117469A1938-05-17
US20120004621A12012-01-05
Attorney, Agent or Firm:
ROSS, Monty, L. (Ross Barnes LLP, 275 W. Campbell Rd. Ste. 21, Richardson TX, 75080, US)
Download PDF:
Claims:
[0031] We claim:

1. A syringe for medical use comprising:

a one-piece barrel further comprising a fluid chamber having at least one substantially flat indicia display surface disposed proximally to the fluid chamber on an outer wall of the barrel.

2. The syringe of claim 1 comprising two oppositely facing, substantially flat indicia display surfaces, with one substantially flat indicia display surface disposed on each of two opposite sides of the barrel..

3. The syringe of claim 1 further comprising a volumetric scale disposed on the at least one substantially flat indicia display surface.

4. The syringe of claim 3 wherein the volumetric scale is longitudinally aligned with a portion of the fluid chamber.

5. A syringe for medical use comprising:

a one-piece barrel further comprising a fluid chamber and a laterally offset needle retraction cavity that are integrally molded and are substantially coextensive longitudinally.

6. The syringe of claim 5 wherein the fluid chamber and needle retraction cavity are separated by a common wall.

7. The syringe of claim 5 further comprising at least one substantially flat display surface disposed proximally to the fluid chamber on an outer wall of the barrel.

8. The syringe of claim 7 comprising two oppositely facing, substantially flat display surfaces.

9. The syringe of claim 7 further comprising a volumetric scale disposed on the at least one substantially flat display surface.

10. The syringe of claim 9 wherein the volumetric scale is longitudinally aligned with a portion of the fluid chamber.

11. The syringe of claim 7 wherein at least a portion of each at least one substantially flat display surface overlies at least part of the needle retraction cavity.

12. The syringe of claim 5 further comprising a plunger slidably engaging a rear portion of the fluid chamber and a frontal attachment slidably engaging a front portion of the barrel in a direction transverse to a longitudinal axis of the plunger.

13. The syringe of claim 12 further comprising a forwardly projecting, rearwardly biased needle seated inside the frontal attachment, the needle being selectively retractable into the needle retraction cavity following use.

14. A syringe for medical use comprising:

a one-piece barrel further comprising a fluid chamber and a laterally offset needle retraction cavity that are integrally molded and longitudinally coextensive, substantially parallel and separated by a common wall.

at least one substantially flat display surface is desirably disposed proximally to the fluid chamber on an outer wall of the barrel.

15. The syringe of claim 14 comprising two oppositely facing, substantially flat display surfaces.

16. The syringe of claim 14 further comprising a volumetric scale disposed on the at least one substantially flat display surface.

17. The syringe of claim 16 wherein the volumetric scale is longitudinally aligned with a portion of the fluid chamber.

18. The syringe of claim 14 wherein at least a portion of the at least one flat display surface overlies at least part of the needle retraction cavity.

19. The syringe of claim 14 further comprising a plunger slidably engaging the fluid chamber and a frontal attachment slidably engaging a front portion of the barrel in a direction transverse to a longitudinal axis of the plunger.

20. The syringe of claim 19 wherein the frontal attachment further comprises a forwardly projecting, rearwardly biased needle seated inside the frontal attachment, the needle being selectively retractable into the needle retraction cavity following use.

21. A syringe comprising:

a barrel comprising a longitudinally extending, substantially cylindrical fluid chamber and a needle retraction cavity substantially coextensive in length with the fluid chamber and disposed in adjacent and parallel relation to the fluid chamber;

a plunger having a longitudinal axis and slidably engaging an inside wall of the fluid chamber;

a frontal attachment slidably engaging a front portion of the barrel in a direction transverse to the longitudinal axis of the plunger; and

a forwardly projecting, rearwardly biased needle seated inside the frontal attachment, the needle being selectively retractable following use; wherein

the barrel further comprises at least one substantially flat, outwardly facing display surface configured to receive and display volumetric measuring indicia viewable by a user during use of the syringe, said indicia being aligned with and proximal to the fluid chamber.

22. The syringe of claim 21 wherein the syringe barrel comprises two substantially flat, oppositely facing display areas.

23. The syringe of claim 21 in combination with volumetric measuring indicia applied to the at least one display area.

24. The syringe of claim 22 in combination with volumetric measuring indicia applied to each oppositely facing display area.

25. The syringe of claim 21 wherein the volumetric measuring indicia are applied to the display area by at least one of the group consisting of molding, stamping, embossing or printing.

26. The syringe of claim 24 wherein the volumetric measuring indicia applied to one display area are different from the volumetric measuring indicia applied to the oppositely facing display area.

27. The syringe of claim 21 further comprising a removable needle cover.

28. The syringe of claim 27 wherein the removable needle cover further comprises a locking member.

29. The syringe of claim 28 wherein the locking member is a locking arm extending into the needle retraction cavity.

30. The syringe of claim 21 further comprising a selectively removable plunger cap.

31. A medical syringe having a barrel with a substantially cylindrical, longitudinally extending fluid chamber, a needle retraction cavity substantially coextensive in length with the fluid chamber and disposed adjacent and substantially parallel to the fluid chamber, and a substantially flat, outwardly facing display area configured to receive and display an array of volumetric measuring indicia in alignment with and proximal to the fluid chamber.

32. The medical syringe of claim 31 wherein the needle retraction cavity has a non-circular cross-section. and shares a common wall with at least part of the fluid chamber.

Description:
SYRINGE WITH FLAT INDICIA DISPLAY SURFACE

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] This invention relates to a syringe configured for medical use in aspirating or injecting fluids. The syringe desirably includes a barrel, a plunger slidably engaging a portion of the barrel, a forwardly projecting, needle and a substantially flat indicia display surface disposed on the barrel. One aspect of the invention is a barrel having a laterally offset needle retraction cavity that is substantially coextensive with the length of the fluid chamber of the barrel. The substantially full-length, laterally offset needle retraction cavity facilitates the optional use of longer retractable needles than are usable with conventional safety syringes having retractable needles and broadens the range of uses and procedures that are performable with the device without increasing the overall length of the syringe. Depending upon needle length, such uses and procedures can include, for example, performing spinal taps, administering epidural anesthesia, aspirating cysts, and the like, as well as for administering intradermal, subcutaneous or intramuscular injections.

[0002] Another aspect of the invention relates to a syringe having a barrel comprising a substantially cylindrical fluid chamber, a needle retraction cavity disposed in parallel and laterally spaced-apart relation to the fluid chamber, and at least one substantially flat, outwardly facing display surface to which indicia such as dosage scales can be applied using a conventional pad printing process. Still another aspect of the invention relates to a syringe having a barrel with two oppositely facing, substantially flat surfaces on which the same or different indicia can be pad printed without having to rotate the barrel, even when printing on 1 ml_, 0.5 mL or smaller syringes. The substantially flat display surfaces also facilitate the application of indicia to a syringe by other processes such as embossing, injection molding, and the like.

[0003] Another aspect of the invention relates to a medical syringe comprising a barrel and plunger as disclosed above in combination with a frontal attachment having a forwardly projecting, rearwardly biased needle. The frontal attachment and barrel are desirably cooperatively configured so that the frontal attachment slidably engages a front portion of the barrel along an axis that is transverse to the longitudinal axis through the needle.

2. Description of Related Art

[0004] Syringes intended for medical use typically have barrels comprising substantially cylindrical inside and outside walls, meaning that volumetric dosage indicia or other markings are applied to an arcuate outer surface during manufacture. This can be difficult, and especially so when the diameter of the barrel and radius of curvature of the outside wall are small (as with 1 mL, 0.5 mL and smaller syringes) and where the available outside surface area is extremely limited, or on syringes where different dosing scales or other indicia are applied to opposite sides of the barrel. In such instances it is often necessary to spin or rotate the barrel while printing, and it is also often difficult to read indicia such as dose measuring lines and the related numeric values or other markings because they wrap so far around the circumference of the barrel and because indicia or markings on one side are often viewable through the syringe and can confuse the user, sometimes leading to the commission of medical errors. For at least these reasons, syringes having substantially flat surfaces for use in applying dosage markings and other indicia are needed.

[0005] Medical syringes having rearwardly biased needles that retract into coaxially aligned retraction cavities disposed inside the plunger are known, having previously been disclosed, for example, in United States Patent Nos. 5,049,133; 5,053,010; 5,084,018 and 6,090,077. More recently, medical syringes having frontal attachments containing rearwardly biased needles that retract into needle retraction cavities that are part of the frontal attachment have been disclosed, for example, in U.S. 9,381 ,309.

[0006] Even more recently, medical syringes with frontal attachments have been disclosed that slidably engage barrels having needle retraction cavities unitarily molded together with the barrel and disposed parallel to the fluid chamber. In U.S. 9,814,841 (FIGS. 37-42), for example, the length of the needle retraction cavity is substantially shorter than the length of the fluid chamber inside the barrel and the needle retraction cavity does not cooperate with an outer wall of the barrel to form substantially flat outside surfaces that are adjacent to and substantially coextensive with the fluid chamber.

SUMMARY OF THE INVENTION

[0007] A syringe for medical use is disclosed that comprises a one-piece barrel having a fluid chamber and a laterally offset needle retraction cavity that are substantially parallel and separated by a common wall. The needle retraction cavity can have a non-circular cross-section and is desirably substantially coextensive in length with the fluid chamber, thereby facilitating the use of longer needles without increasing the overall length of the barrel in order to accommodate retraction of the longer needles as is the case with safety syringes that retract the needle into the barrel following use. The barrel further comprises an outer wall having at least one substantially flat, outwardly facing display surface upon which indicia such as a volumetric dosage scale, for example, can be applied using conventional pad printing technology or another similarly effective alternative means. The at least one substantially flat display surface is desirably disposed proximally to the fluid chamber and also desirably comprises a measurement scale that is longitudinally aligned with at least that portion of the fluid chamber that is useful for injecting or aspirating a fluid. According to one preferred embodiment of the invention, two oppositely facing, longitudinally coextensive, substantially flat surfaces are provided, with each surface spanning at least a portion of an external wall of the fluid chamber and at least a portion of the external wall of the needle retraction cavity.

[0008] The subject invention is particularly useful with syringes having usable volumes of 1 ml_ or less, which syringes typically have smaller barrel diameters that cause the volumetric dosage indicia applied to the outside surface to wrap around a greater portion of the circumference of the barrel. According to another preferred embodiment of the invention, pad printing technology (sometimes referred to as“tampography”) is used to apply volumetric dosage indicia or other markings to the substantially flat display surface of the syringe. The needle retraction cavity can be made (preferably molded from a suitable polymeric material) with a non-circular cross-section and is offset laterally from the barrel to facilitate creation of a wider, outwardly facing, substantially flat display surface during manufacture. The substantially flat display surface desirably comprises at least one side that is proximal to the fluid chamber of the barrel and thereby provides an opportunity, if desired, for molding volumetric dosage markings or other indicia onto the otherwise flat display surface or embossing the indicia on or into the display surface.

[0009] Another embodiment of the subject syringe comprises a barrel and plunger as disclosed above in combination with a frontal attachment having a forwardly projecting, rearwardly biased needle. The frontal attachment and barrel are desirably cooperatively configured so that the frontal attachment slidably engages a front portion of the barrel along an axis that is transverse to the longitudinal axis through the needle. When the syringe is disposed in the use position, the needle is aligned with a first opening in the front of the barrel that is communicates with a substantially cylindrical fluid chamber inside the barrel to establish a coaxially aligned fluid flow path between the fluid chamber and the needle. A fluid seal is desirably seated around the first opening to resist fluid leakage between the frontal attachment and the barrel. The needle retraction cavity extends rearwardly from a second opening in the front of the barrel. in parallel and spaced-apart relation to the fluid chamber in the barrel, and desirably shares a common wall with at least a portion of fluid chamber. Following use of the syringe, relative transverse movement between the barrel and the frontal attachment repositions the rearwardly biased needle into alignment with the needle retraction cavity, thereby releasing the needle to be forced by the biasing means, typically a compressed spring, into a retracted position wherein the needle no longer projects forwardly from the syringe.

[0010] Another embodiment of the subject syringe embodies wider, substantially flat display surfaces disposed on a medical syringe having a unitary barrel and needle retraction cavity that cooperate with substantially flat edge portions of the surrounding flange to help prevent the syringe from rolling off a tray or other flat surface. The substantially flat surfaces also allow the flange around the barrel to be proportionally narrower as compared to the flanges of conventional syringes having tubular barrels and still provide larger surface areas that are more easily graspable by a user. The oppositely facing, substantially flat surfaces also improve stability and the degree of control that can be exercised over the syringe by a user during an injection or other procedure. Because the subject syringe has a barrel with a laterally offset needle retraction cavity that can be molded integrally with the fluid chamber, at least one, and preferably two (oppositely facing), substantially flat, outwardly facing surface areas are provided that are useful for the placement of an array comprising a volumetric scale or other indicia that are easily readable by the user and thereby reduce the likelihood of dosing errors during aspiration or injection.

[0011] Another embodiment of the invention comprises the subject syringe in combination with a selectively releasable needle cover that can also comprise a locking member configured to engage a portion of the barrel and resist sliding lateral movement of the barrel relative to the frontal attachment to prevent accidental retraction of the needle prior to using the syringe. Retraction of the needle following use of the syringe reduces the likelihood of reusing the syringe or of accidental needle sticks and the inadvertent transmission of blood- borne pathogens.

[0012] Another embodiment of the invention comprises the subject syringe in combination with a plunger cap that is releasably attached to the rear portion of the syringe, typically behind the finger flange, and is selectively removable prior to fluid aspiration or use. When both the needle cover and the plunger cap are in place, the needle and the internal, fluid-contacting portions of the syringe are enclosed and protected from contamination whether or not the syringe is also enclosed inside another package. Because of this, the syringes can be assembled and shipped in bulk prior to packaging and sterilization.

[0013] Although the subject syringe is especially useful in administering relatively small doses of a medicinal fluid such as insulin or a vaccine to a user by injection or infusion, the structure and operation of the apparatus is not limited to particular sizes, doses or procedures. For example, syringes configured as disclosed here can also be configured for use in aspirating fluid samples from patients during clinical procedures such as knee or spinal taps. Because the overall syringe length is reduced through use of the disclosed frontal attachment in combination with the novel barrel of the invention, longer needles can be used and still be retracted into the syringe following use. As used in this disclosure, “retracted” or“retraction” refer to the process by which a needle is moved from a forwardly projecting use position to a post-use position in which the needle point no longer projects forwardly from the frontal attachment, no matter whether the force acting upon the needle is pushing or pulling the needle tip rearwardly from the forwardly projecting position.

[0014] These and other features of the present invention will be better understood from a consideration of the following detailed description of various embodiments and appended claims in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The syringe of the invention is further described and explained in relation to the following drawings wherein:

FIG. 1 is a top front perspective view of one embodiment of the invention in which the needle cover (including the locking member) and the plunger end cap are installed in the position in which the subject syringes can be packaged, shipped and stored, with the locking member of the needle cover restricting lateral sliding movement of the barrel relative to the frontal attachment prior to use;

FIG. 2 is a top front perspective view of the embodiment of FIG. 1 in which the needle cover is removed;

FIG. 3 is an exploded top front perspective view of the embodiment of

FIG. 1 ;

FIG. 4 is a right side elevation view of the embodiment of FIG. 2;

FIG. 5 is a cross-sectional view taken along line 5— 5 of FIG. 4;

FIG. 6 is an exploded detail perspective view, partially broken away, of the frontal attachment of the embodiment of FIG. 3 shown in juxtaposition to the front portion of the barrel of the embodiment of FIG. 3;

FIG. 7 is a top rear perspective view of the frontal attachment of FIG. 3;

FIG. 8 is a right side elevation view of the embodiment of FIG. 4 with the plunger cap removed and with the plunger withdrawn to an aspirated position;

FIG. 9 is a cross-sectional view taken along line 9— 9 of FIG. 8;

FIG. 10 is a right side elevation view of the embodiment of FIG. 8 with the needle retracted and with the plunger fully advanced inside the barrel;

FIG. 11 is a cross-sectional view taken along line 11— 11 of FIG. 10;

FIG. 12 is a front elevation view of the embodiment of FIG. 2; and

FIG. 13 is a front elevation view of the embodiment of FIG. 12 with the frontal attachment repositioned relative to the barrel and with the needle retracted to the position shown in FIGS. 10 and 11. DESCRIPTION OF PREFERRED EMBODIMENTS

[0016] Referring to FIG. 1 , syringe 20 comprises barrel 22 further comprising substantially flat display surface 23, frontal attachment 24, outside wall 25 of fluid chamber 75 (visible in FIG. 9), selectively removable needle cover 26, an array of volumetric measuring indicia 27, finger flange 28, removable plunger cap 30 and locking member 40. As shown in FIG. 1 , the principal volumetric measuring indicia 27 are applied to display surface 23, including for example at least the Arabic numerals identifying the number of fluid units and the associated principal measurement indicia. It should be appreciated, however, that the accompanying figures of the drawings are for illustrative purposes and are not drawn to scale and that placement of some features such as the secondary unit markings 27 relative to substantially flat display surface 23 can vary from the positions shown. At least a portion of each secondary (individual) unit indicia or markings desirably commences on display surface 23 or proximal to the edge of display surface 23, and optionally continues for a short distanced onto the curved outer wall of fluid chamber 25. Such placement is understood to be within the operational capabilities of conventional pad printing technology that is now readily available to those of ordinary skill in the art.

[0017] As depicted in FIG. 1 , syringe 20 has frontal attachment 24 shown in the“pre-use” configuration with needle cover 26 and locking member 40 in place to prevent frontal attachment 24 from shifting laterally relative to barrel 22 prior to use because of pressure inadvertently applied to textured touch pad 46 or to the opposite side of barrel 22. Removable plunger cap 30 is also installed behind finger flange 28 to prevent the plunger (not visible) from being accidentally withdrawn from barrel 22 and to prevent inadvertent contamination inside the rear opening of barrel 22 or around the rearwardly extending handle portion of the plunger, as seen in FIG. 9, which is discussed below.

[0018] Referring to FIGS. 2, 4-5 and 12, barrel 22 and frontal attachment 24 of syringe 20 are shown in the same position as in FIG. 1 except that needle cover 26 (with locking member 40) is removed. The front opening into needle retraction cavity 92 is more clearly visible, and needle 34 is also visible, projecting forwardly from needle support member 32 of frontal attachment 24. Circumferentially spaced, axially tapered ribs 33 are disposed around needle support member 32 and provide surfaces for frictional engagement with the inside surface of needle cover 26 prior to removal. In FIG. 2, needle 34 is desirably coaxially aligned with the longitudinal axis through fluid chamber 75 (FIG. 9).

[0019] Referring to FIG. 3, needle cap 26 of syringe 20 further comprises a forwardly facing, inwardly tapered, substantially cylindrical sidewall having front end 36, rearwardly facing annular collar 38, and locking member 40 projecting rearwardly past annular collar 38. Frontal attachment 24 further comprises forwardly projecting, substantially tubular needle support member 32 with front opening 42, upper guide member 44, lower guide member 45 (visible in FIG. 7), and laterally projecting textured touch pad 46.

[0020] Syringe 20 desirably includes needle 34 with forwardly facing beveled needle tip 48, and a needle retraction mechanism further comprising coiled compression spring 50 and needle holder 52. Needle holder 52 further comprises an elongated shaft 54 with tubular bore 58 that is insertable into the rear of spring 50. The diameter of head 56 of needle holder 52 is sufficiently greater than the inside diameter of spring 50 that spring 50 can be held in compression by head 56 when frontal attachment 24 is slidably engaged with front portion 64 of barrel 22 as discussed in relation to FIGS. 6 and 7 below. The rear end of needle 34 is insertable into tubular bore 58 of needle holder 52 and attachable in fixed relation to the inside of elongated shaft 54 by any suitable, commercially available means such as an adhesive. Although a needle retraction mechanism as disclosed here is satisfactory for use in syringe 20, it will be appreciated that other similarly effective elements and mechanisms useful for rearwardly biasing needle 34 inside syringe 20 can also be used in making the invention. [0021] Still referring to FIG. 3, annular polymeric fluid seal 60 with tubular bore 62 is desirably insertable into recess 66 in front portion 64 of barrel 22 so that the forwardly facing end of seal 60 is disposed in abutting contact with rearwardly facing head 56 of needle holder 52 when the needle retraction mechanism is installed inside frontal attachment 24 and frontal attachment 24 is attached in slidable engagement with front portion 64 of barrel 22. When frontal attachment 24 of syringe 20 is assembled to front portion 64 of barrel 22 during manufacture, a continuous, substantially linear, fluid flow path is established through needle 34, needle holder 52 and annular fluid seal 60 into tubular, longitudinally extending fluid chamber 75 (visible in FIG. 9).

[0022] In addition to front portion 64, barrel 22 further comprises substantially flat display surface 23, curved outside wall surface 25, finger flange 28 and rearwardly projecting annular collar 70. During assembly of syringe 20, elastomeric plunger seal 76 is desirably installed on forwardly projecting boss 74 on the front end of plunger handle 72 opposite rearwardly facing plunger thumb pad 78, and plunger handle 72 is then inserted into a rearwardly facing opening defined by annular collar 70. Assembly of syringe 20 is then completed by installing substantially cylindrical plunger cap 30 on the rearwardly facing end of barrel 22. Plunger cap 30 further comprises open front end 80, cylindrical bore 82 and closed rear end 84. Plunger cap 30 is installed around around plunger thumb pad 78 and in frictional engagement with the outside wall of annular collar 70. Volumetric measuring indicia 27 applied as discussed in relation to FIG. 1 also appear on the outwardly facing portions of substantially flat display surface 23 and curved outside wall surface 25.

[0023] FIGS. 3, 6 and 11 further disclose the forwardly facing opening into needle retraction cavity 92 in relation to front portion 64 of barrel 22. Needle retraction cavity 92 has a closed rear end that is adjacent to finger flange 28, and is bounded by side walls 90, 95, bottom wall 94, and a top wall that also includes upwardly facing, substantially flat display surface 23 of barrel 22.

[0024] The assembly of frontal attachment 24 to front portion 64 of barrel 22 of syringe 20 is further described and explained in relation to FIGS. 6 and 7. Referring to FIG. 6, annular fluid seal 60 (visible in FIG. 3) is first inserted into recess 66 of front portion 64 of barrel 22. Front portion 64 further comprises laterally extending top rail 68 and bottom rail 69 that are disposed in transverse relation to the longitudinal axis through fluid chamber 75 (FIG. 9) of barrel 22. Rounded attachment guides 96, 98 are disposed forwardly of top and bottom rails 68, 69, respectively, and are configured to facilitate the assembly of frontal attachment 24 to front portion 64 of barrel 22 by passing above and below the arm connecting textured touch pad 46 to the back side of frontal attachment 24.

[0025] Referring to FIG. 7, annular opening 112 is provided in the back side of frontal attachment 24 to facilitate insertion of spring 50 and needle holder 52, discussed above in relation to FIG. 3, and spring 50 is desirably compressed between an annular shoulder inside front opening 42 (visible in FIG. 11 ) and is held in compression behind head 56 of needle holder 52 while frontal attachment 24 is moved into sliding engagement with front portion 64 of barrel 22. Frontal attachment 24 further comprises upper guide 44 having a downwardly facing, laterally extending recess 100 and lower guide 45 having an upwardly facing, laterally extending recess 102. Upper ramp and lower ramp 104, 106, respectively, of frontal attachment 24 are configured to slide over two laterally spaced-apart sets of opposed ramps with blocking shoulders 77, 79 (the lower set not being visible in FIG. 6). Laterally extending top rail 68 and bottom rail 69 of front portion 64 of barrel 22 are desirably cooperatively engaged with upper and lower recesses 100, 102, respectively, by sliding frontal attachment 24 onto front portion 64 of barrel 22 when frontal attachment 24 and front portion 64 are positioned as shown in FIG. 6. As pressure is applied to textured touch surface 46, frontal attachment 24 moves along rails 68, 69 until top and bottom blocking shoulders 108 of upper guide 44 pass over and then drops into facing relation to upper and lower blocking shoulders 77. At this time, needle support member 32 and needle holder 52 (not shown in FIGS. 6 and 7) are desirably coaxially aligned with the longitudinal axis of fluid chamber 75 (visible in FIG. 9). Any attempt to move frontal attachment 24 back to a disconnected position as shown in FIG. 6 will be resisted by facing and abutting contact between upper and lower blocking shoulders 77 of front portion 64 and top and bottom blocking shoulders 108, 110, respectively, of frontal attachment 24.

[0026] FIGS. 4 and 5 depict syringe 20 of FIG. 2 with the needle cover removed and with plunger cap 30 still in place and with textured touch surface 46 in the initial position relative to barrel 22 as described above. Needle 34 is installed inside bore 58 of needle holder 52, which is seated inside needle support member 32 of frontal attachment 24, with spring 50 compressed between head 56 (FIG. 3) of needle holder 52. Spring 50 applies a rearwardly directed biasing force to needle holder 52 and needle 34, and is pressed by spring 50 into facing and abutting contact with the front surface of annular fluid seal 60, thereby establishing a coaxially aligned fluid path through needle 34, needle holder 52 and fluid seal 60 into fluid chamber 75 (visible in FIG. 9) of barrel 22. As shown in FIGS. 4 and 5, plunger seal 76 is pushed fully forward into substantially cylindrical fluid chamber 75 of barrel 22.

[0027] Referring to FIGS. 8-9, syringe 20 is configured so that fluid can be aspirated into the syringe, with textured touch pad 46 again in the same initial position as previously described. Plunger cap 30 (as seen in FIGS. 2, 4-5) is removed and plunger handle 72 is withdrawn as it would be while aspirating fluid into fluid chamber 75. In FIG. 9 it is seen that needle retraction cavity 92 is substantially coextensive in length with fluid chamber 75, thereby facilitating the placement of volumetric measuring indicia 27 on substantially flat surface 23 (visible in FIG. 3) that facilitates full utilization of the volume of fluid chamber 75 and also facilitating the retraction of needles such as biopsy needles that are often substantially longer than needle 34 (visible inside needle retraction cavity 92 in FIG. 11 below). Once fluid is aspirated into fluid chamber 75, fluid can also be injected into a patient or expelled from fluid chamber 75 by pressing forwardly on plunger thumb pad 78 while applying finger pressure against the forwardly facing side of flange 28.

[0028] Referring to FIGS. 10-11 and 13, plunger handle 72 and plunger seal 76 have been pushed forwardly to empty fluid chamber 75. To initiate needle retraction, pressure is applied to textured touch pad 46, which moves frontal attachment to a position where needle support member 32 is aligned with needle retraction cavity 92. Because needle retraction chamber 92 has a front opening that is larger than head 56 of repositioned needle holder 52, the biasing force of compressed spring 52 pushes needle holder 52 rearwardly and causes needle holder 52 and needle 34 to be propelled into the distal end of needle retraction cavity 92.

[0029] Referring again to FIGS. 6 and 7, the further application of force to textured touch surface 46 of frontal attachment 24 relative to barrel 22 as described above in relation to FIGS. 10-11 produces sliding relative movement between frontal attachment 24 and front portion 64 of barrel 22. This movement causes upper ramp 104 and lower ramp 106 to slide over the second set of opposed ramps and blocking shoulders 79 so that top and bottom blocking shoulders 108, 110 are placed in facing and abutting contact with upper and lower blocking shoulders 79, thereby preventing frontal attachment 24 from being returned to the use position relative to barrel 22.

[0030] It will become apparent to those of ordinary skill in the art upon reading this specification in relation to the accompanying drawings that various other modifications and alterations can also be made to the embodiments disclosed here, and it is intended that the scope of the invention be limited only by the broadest interpretation of the appended claims to which the inventors are legally entitled.