referring now to the drawings , preferred illustrative embodiments are shown in detail . although the drawings represent some embodiments , the drawings are not necessarily to scale and certain features may be exaggerated , removed , or partially sectioned to better illustrate and explain the present disclosure . further , the embodiments set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description . referring to fig1 , a perspective view of an exemplary biopsy device 10 in accordance with the present disclosure is illustrated . a separate and optional introducer assembly 12 is also illustrated . as shown , biopsy device 10 is a handheld device and includes a housing 14 to which a stylet 16 is attached . biopsy device 10 includes several release members 18 , 20 , and 22 , to be explained in further detail below . referring to fig2 , an exploded view of biopsy device 10 is illustrated . as shown , in the exemplary embodiment housing 14 is a two piece member , including a first housing member 14 a and a second housing member 14 b . in one embodiment , first and second housing members 14 a and 14 b are configured snap together to house actuation components of biopsy device 10 . for example , first housing member 14 a includes one or more slot members 24 positioned on top and bottom portions of first housing member 14 a . slot members 24 cooperate with and receive latch members 26 that are positioned on top and bottom portions of second housing member 14 b . an interior of housing 14 is generally hollow to receive the actuation components . while housing 14 has been described as snapping together , it is also understood that first and second housing members 14 may alternatively be secured together using fastening elements . a top portion of each housing member 14 a and 14 b includes a holder 28 for securing a portion of a resilient bridge member 30 . each holder 28 extends upwardly from the top portion 32 and includes a groove 34 ( best seen in fig1 ) that receives mounting knobs 36 of a mounting member 38 positioned on a first end 35 of resilient bridge member 30 . an actuating lever 40 is pivotally attached to housing 14 by pivot arm 42 at a proximal end 44 of biopsy device 10 . a forward end 46 of actuating lever 40 may rise upwardly from a top surface of housing 14 due to pivot arm 42 . a lever release assembly 48 that carries a release mechanism 18 is attached to actuating lever 40 . lever release assembly 48 includes a downwardly extending latch arm 46 that selectively engages with a portion of a retaining member 50 disposed on a cam member 52 carried by a pickup carriage 54 ( shown in fig3 - 5 ). a spring mechanism 53 serves to bias release mechanism 18 to an actuation position . pickup carriage 54 includes a pair of holders 56 that extend upwardly from a top surface thereof . housing 14 includes an open channel 58 formed in the top surface thereof when pickup carriage 54 is positioned within housing 14 , holders 56 extend through channel 58 ( seen in fig1 ). each holder 56 includes a groove 60 that receives a mounting knob 36 from a mounting member 38 positioned on a second end 62 of resilient bridge member 30 . referring to fig1 , resilient bridge member 30 includes a plurality of sections that are separated by hinge members 64 a and 64 b . hinge members 64 a and 64 b are created by v - shaped notches that form thinned sections . first end 35 of resilient bridge member 30 is secured to holders 28 and second end 62 is secured to holders 56 such that resilient bridge member 30 is positioned directly below actuation lever 40 when biopsy device 10 is assembled . due to the configuration of resilient bridge member 30 , when actuation lever 40 is depressed , actuation lever 40 pushes down on resilient bridge member 30 . the pushing action flattens out resilient bridge member 30 , thereby sliding pickup carriage member 54 away from a distal end of biopsy device 10 . secured to a top portion of housing 14 is an actuation button carrier 66 that carries release mechanisms 20 and 22 . release mechanism 20 includes a downwardly extending latch arm 68 that extends downwardly into first housing member 14 a though an opening 70 formed therein . as will be explained in further detail below , release mechanism 20 is actuated to release stylet 16 . more specifically , an end of latch arm 68 is configured to grip a retaining arm 72 of stylet 16 . when release mechanism 20 is depressed , the end of latch arm 68 is biased upwardly , thereby releasing its grip on retaining arm 72 of stylet 16 and permitting stylet to advance forward . release mechanism 22 also includes a downwardly extending latch arm ( not shown ). as will be explained in further detail below , the latch arm of release mechanism 22 releases an outer cutting cannula 74 . more specifically , when release mechanism 22 is depressed , the end of the latch arm of release mechanism 22 is biased upwardly , thereby releasing outer cutting cannula 74 and permitting outer cannula 74 to advance forward . other components of biopsy device 10 includes a stylet assembly 76 , an outer cannula assembly 78 , a cam member assembly 80 , a support rib 82 , and a piston member 84 . each element will be discussed in turn below . stylet assembly 76 is shown in fig7 . stylet assembly 76 includes stylet 16 , a first arm sub - assembly 86 , and a second arm sub - assembly 88 . stylet 16 extends between a distal end 90 and an open proximal end 92 . adjacent distal end 90 is a tissue opening 94 . distal end 90 may further include a trocar piercing tip 95 . stylet 76 further defines an inner lumen 96 that extends between tissue opening 94 and proximal end 92 . positioned adjacent proximal end 92 are first and second seal members 98 , 100 , respectively . first seal member 98 is attached a first cap member 102 that is attached to second arm sub - assembly 88 . second seal member 100 positioned adjacent to a chamber wall member 103 , which is positioned adjacent second end cap 104 . second end cap 104 is fixedly secured to stylet 16 . second seal member 100 ( see fig2 ) is disposed between first end cap 102 and chamber wall member 103 . thus , first end cap 102 , chamber wall member 103 , and first and second seal members 98 , 100 cooperate with a cylinder 106 to define a vacuum chamber 108 , to be explained in further detail below . a notch 110 is cut into stylet 16 , between first end cap 102 and chamber wall member 103 . notch 110 is in communication with inner lumen 96 , which , in turn , is in communication with tissue opening 94 . a one - way valve member 109 ( to be discussed in further detail below ) is attached to open proximal end 92 ( see , e . g ., fig2 ). first arm sub - assembly 86 includes is generally l - shaped and includes a leg member 112 and a carrier member 114 . carrier member 114 is fixedly secured to stylet 16 . carrier member 114 includes a fitting member 116 that cooperative engages a side of complimentary member 118 that is disposed on a carrier member 120 that is part of second arm sub - assembly 88 . second arm sub - assembly 88 includes a long leg member 122 and a short leg member 124 that are connected together by carrier member 120 . when assembled ( and as best seen in fig7 ), short leg member 124 is disposed beneath leg member 112 of first arm sub - assembly 86 , with carrier member 114 being positioned above carrier member 120 . first cap member 102 is attached to carrier member 120 . first cap member 120 is fixedly secured to cylinder 106 . thus , as vacuum chamber 108 moves , so does second arm sub - assembly 88 . referring to fig9 , outer cannula assembly 74 includes an outer cutting cannula 126 that is fixedly attached to an outer cannula hub 128 at its proximal end . outer cannula hub 128 includes a positioning member 130 on one side and a retaining member 132 on another . retaining member 132 includes a retaining finger 134 . a distal end 136 of outer cannula 126 is sharpened to sever tissue . referring to fig2 , outer cannula assembly 74 is assembled to stylet assembly 76 as follows . first , a bumper member 138 is positioned over stylet 16 and into contact with a mounting face 140 . support rib 82 is next slid onto stylet 16 . support rib 82 ( best seen in fig2 ) includes first and second mounting grooves 142 , 144 . first mounting groove 142 is configured to receive short leg member 124 of second arm sub - assembly 86 and leg member 112 of first arm sub - assembly 86 . second mounting groove 144 is configured to receive long leg member 122 of second arm sub - assembly 86 . an outwardly extending spring mount 146 is formed on support rib 82 . a biasing member 148 , such as a spring is positioned on spring mount 146 . outer cannula hub 128 includes a spring mount 150 that receives and end of biasing member 148 . referring now to fig3 - 6 , pickup carriage 54 and cam member 52 will be described . pickup carriage 54 includes a first elongated groove 152 and a second shortened groove 154 . a mounting hole 156 is positioned opposite second groove 154 . an access opening 158 . cam member 52 includes a mounting member 160 that is received within mounting hole 156 . a first pivot member 162 from cam member 52 is positioned within first groove 152 of pickup carriage 54 . a second pivot member 164 from cam member 52 ( seen in fig2 ) is positioned within second groove 154 . retaining member 50 is positioned on an end of cam member 52 and is received within access opening 158 . a biasing member 166 received on a mounting portion 168 of pickup carriage 54 . a distal end 170 of biasing member 166 contacts first pivot member 162 and biases first pivot member 162 toward a first end 172 of first groove 152 . pickup carriage 54 may further include a tang member 174 that partially retains a portion of biasing member 166 . a proximal end 176 of pickup carriage 54 includes a mounting post 178 . a biasing member 180 is received on mounting post 178 . an end of biasing member 180 engages an internal wall 182 formed by first and second housing members 14 a and 14 b when pickup carriage 54 is installed therewithin . when pickup carriage 54 is installed , holders 56 are oriented to extend upwardly through channel 58 formed through housing 14 . cam member 52 is installed on a bottom surface 184 of pickup carriage 54 as shown in fig3 . referring to fig1 - 20 , operation of biopsy device 10 will now be described . assuming biopsy device 10 is packaged in the fired position ( see fig1 ), biopsy device 10 must first be moved into the cocked position . to move biopsy device 10 into the cocked position , first release latch 18 is actuated to release actuation lever 40 from housing 14 ( see fig1 ). actuation lever 40 is then depressed , pushing down on bridge member 30 , which is attached to holders 56 of pickup carriage 54 . accordingly , when bridge member 30 is depressed , pickup carriage 54 is moved toward proximal end 44 of biopsy device 10 . as pickup carriage 54 moves toward proximal end 44 of biopsy device 10 , a first pickup member 186 contacts a first tang member 188 that is carried on carrier member 120 that is part of second arm sub - assembly 88 , and retracts vacuum chamber 108 proximally , as shown in fig1 . a first piston spring member 190 that is at least partially positioned over vacuum chamber 108 , is compressed between a proximal face 192 of carrier member 120 and a first lower internal face 194 positioned within housing 14 . a second spring member 196 is compressed between second end cap 104 and a second lower internal face 198 positioned within housing 14 . this action also collapses the vacuum chamber 108 , moving first end cap 102 towards chamber wall member 103 . air within vacuum chamber 108 is directed out through seal member 109 that is secured to proximal end 92 of stylet 16 . in one embodiment , seal member 109 is a configured as a duck - bill style valve member 109 ( fig2 ). valve member 109 includes a body member 103 having an open distal end 105 that is connected to a tapered , duck bill , normally closed proximal end 107 . proximal end 107 includes a slit which is forced open when positive pressure is generated within stylet 16 . open distal end 105 is secured to proximal end 92 of stylet 16 . an alternative embodiment of seal member 109 ′ is shown in fig2 a - 21d . seal member 109 ′ includes a body member 111 having an open distal end 119 and a normally closed proximal end . adjacent to the proximal end of seal member 109 ′ is a slit 113 that cooperates with a land member 115 to form a flap member 117 . slit 113 extends along a substantial portion of body member 111 such that land member 115 acts as a hinge for flap member 117 . in operation , as positive pressure is generated within the system , flap member 117 will be forced open . spring member 180 biases pickup carriage 54 back toward a distal end of biopsy device 10 . actuation lever 40 is depressed again . the second depression of actuation lever 40 causes pickup carriage 54 to move in the proximal direction again . as pickup carriage 54 moves , a second pickup member 200 positioned on cam member 54 contacts a second tang member 202 that is carried on outer cannula hub 128 . such action retracts outer cannula assembly 74 , moving distal end 136 thereof away from distal end 90 of stylet 16 . retaining member 132 is compressed inwardly until retaining finger 134 grips an internal ledge ( not shown ) formed in first housing member 14 a . retraction of outer cannula assembly 74 causes biasing member 148 to compress between a proximal face 204 of outer cannula hub 128 and a distal face 206 of support rib 82 . spring member 180 biases pickup carriage 54 once again and actuation lever 40 is depressed a third time . the third depression of actuation lever 40 causes pickup carriage 54 to move proximally once again . as pick up carriage 54 moves proximally , first pickup member 186 engages with fitting member 116 that is carried on carrier member 114 of first arm sub - assembly 86 and pulls first arm sub - assembly 86 towards second arm sub - assembly 88 . once carrier 114 of first arm sub - assembly 86 reaches carrier 120 of second arm sub - assembly 88 , stylet 16 is pulled into outer cannula 126 and stylet 16 is locked into the cocked position . on the third depression , actuation lever 40 locks down and latch release assembly 48 retains lever 40 against housing 14 ( see fig1 ), thereby providing a tactile indicator that biopsy device is in the cocked position . biopsy device may also include a visual indicator to indicate that biopsy device 10 is in the cocked position . in one embodiment , at least leg member 112 of first arm sub - assembly 86 may be constructed of a particular color that is different than the color of housing 14 and that will be visible through a window 208 only when biopsy device 10 is in the cocked position . for example , leg member 112 may be formed from a green material such that a portion of the green material is visible through window 208 when biopsy device 10 is in the cocked position so as to be in the “ biopsy ready position .” in contrast , when stylet 16 is in a non biopsy ready position , leg member 112 will be positioned away from indicator window 208 . once in the cocked position , or biopsy ready position , a biopsy may be performed . the operation will now be explained . typically , before a biopsy is performed , a targeted area must be identified . any suitable method may be used to identify a targeted area for biopsy . such methods include , but are not limited to , the methods and use of the devices described in co - pending application ser . no . 10 / 649 , 068 , the contents of which are incorporated herein by reference in its entirety . next , the entry site is prepared , as required ( such as applying anesthesia , cleaning the biopsy area , etc .). during this step , an introducer assembly 12 ( see fig1 ) may be positioned over outer cannula 112 to provide a pathway to the target area . introducer assembly 12 will be explained in further detail below . next , a tip of stylet 16 is placed at the targeted area . in one embodiment , stylet 16 may be fired prior to inserting biopsy device 10 into the patient . in another embodiment , stylet 16 is not fired until after biopsy device 10 is inserted into the patient . in one embodiment , the position and orientation of biopsy device 10 is maintained during the firing process . a stylet release or firing member 20 is depressed , thereby releasing stylet assembly 76 from its cocked position into the fired position ( fig1 ). such action exposes tissue opening 94 into which tissue may prolapse . tissue receiving opening 94 is connected to inner lumen 96 . inner lumen 96 is connected to vacuum chamber 108 . to differentiate between stylet release member 20 and an outer cannula release member 22 , stylet release member 20 may be a different color than housing 14 or outer cannula release member 22 ( to be described below ) to allow a user to visually differentiate between the two release members . in one embodiment , one of stylet and outer cannula release members 20 , 22 may alternatively include a tactile indicator , such as a raised bump 210 on the release member , to allow a user to feel the differences between the two release members ( see , e . g ., fig1 and 11 ). after stylet release member 20 is actuated , outer cannula release member 22 is then actuated . this action will release outer cannula assembly 78 . outer cannula assembly 78 is forced over stylet 16 by biasing members / springs 148 , 190 , and 196 , such that outer cannula assembly 78 rapidly fires forward . as outer cannula assembly 78 is fired forward , vacuum chamber 108 is expanded so as to create a vacuum by drawing air through tissue opening 94 and lumen 96 , and entering into vacuum chamber 108 through notch 110 . a further explanation of the vacuum chamber may be found in commonly owned and co - pending u . s . application ser . no . 11 / 389 , 274 , the contents of which are incorporated herein by reference in its entirety . in one embodiment ( not shown ), a vacuum valve having a slit that creates a flap may be provided that selectively covers the notch . when stylet 16 is fired forward , positive pressure generated inside vacuum chamber 108 closes the valve flap to prevent pressure from reaching the inside of lumen 96 . when outer cannula 74 fires forward , the negative pressure inside vacuum chamber 108 opens the valve , allowing vacuum to be delivered to tissue opening 94 in stylet 16 , through lumen 96 . as outer cannula assembly 78 is fired and vacuum is generated by the expansion of vacuum chamber 108 , the vacuum biases tissue toward tissue opening 94 and holds tissue in place while outer cannula 74 slides over tissue opening 94 . as outer cannula 74 slides , sharpened distal end 136 slices through the tissue , thereby severing the tissue so as to leave a biopsy core 212 within tissue opening 94 . once biopsy core 212 is acquired , to retrieve biopsy core 212 from biopsy device 10 , biopsy device 10 is removed from the patient . if an introducer assembly 12 is used , it is kept in position within the patient . once removed from the patient , release member 18 is depressed once again to release latch member 26 . latch member 26 is depressed twice to pull back outer cannula 74 so as to expose tissue opening 94 ( see fig1 - 20 ) and biopsy core 212 . to obtain additional biopsy cores 212 , the latch member 26 is depressed a third time ( fig2 ) to retract stylet 16 into the biopsy ready position . referring to fig1 and 11 , introducer assembly 12 will now be explained . introducer assembly 12 includes an introducer cannula 214 that is fixedly connected to an introducer hub 216 . introducer cannula 214 is hollow and is sized to slide over outer cannula 74 so as to be spaced proximally from distal end of outer cannula 74 . introducer hub 216 may include a normally closed valve ( not shown ) and includes an opening that is in communication with introducer cannula 214 . disposed on introducer hub 216 is a selectively releasable latch member 218 that includes a connecting member 220 and a releasing member 222 . releasing member 222 is received within an opening 224 to secure introducer assembly 12 to biopsy device 10 . in operation , introducer assembly 12 is positioned over outer cannula 74 and slid along outer cannula 74 until connecting member 220 of latch member 218 is received within opening 224 , thereby connecting introducer assembly 12 to biopsy device 10 . introducer assembly 12 may be connected to biopsy device 10 either before or after biopsy device is placed in the biopsy ready position . once connected , biopsy device 10 is inserted into the patient with introducer cannula 214 . introducer cannula 214 operates to maintain a pathway to the biopsy site . once biopsy cores 212 are taken , biopsy device 10 may be detached from introducer assembly 12 by depressing releasing member 222 such that connecting member 220 is released from opening 224 . once freed , introducer cannula 214 remains within the patient &# 39 ; s body , to maintain the pathway to the biopsy site . use of introducer assembly 12 minimizes trauma to the patient and eliminates the need for multiple reinsertions of biopsy device 10 , as well as permits access to the biopsy site for treatment and other post biopsy activities . as such , after the biopsy cores 212 are removed from tissue opening 94 , biopsy device 10 may be reinserted into introducer cainula 214 to take addition biopsy cores 212 . alternatively , if desired , a biopsy marker ( not shown ) may be deployed into the biopsy cavity after biopsy cores 212 have been taken . in such a case , a site marker deployment device may be inserted within introducer assembly 12 after biopsy device 10 is removed therefrom . once such example of a site marker deployment device is disclosed in commonly owned and co - pending application ser . no . 11 / 238 , 295 , the contents of which are incorporated herein by reference in its entirety . while the embodiments of the present invention has been particularly shown and described with reference to the foregoing preferred embodiments , it should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims . it is intended that the following claims define the scope of the invention embodiments within the scope of these claims and their equivalents be covered thereby . this description of the invention should be understood to include all novel and non - obvious combinations of elements described herein , and claims may be presented in this or a later application to any novel and non - obvious combination of these elements . the foregoing embodiment is illustrative , and no single feature or element is essential to all possible combinations that may be claimed in this or a later application .
a biopsy device is disclosed that comprises a cutting element mounted to a handpiece and a vacuum chamber . the cutting element comprises a stylet assembly and an outer cannula assembly . the stylet assembly includes a stylet that includes an open proximal end and a tissue opening at a distal end thereof . the tissue receiving opening is in communication with a lumen extending through the stylet . the outer cannula assembly includes an outer cannula that is slidably mounted over the stylet and has an open distal end with a cutting edge formed thereon . the vacuum chamber is in communication with the lumen of the stylet . the stylet is selectively advanced distally outwardly with respect to outer cannula to expose the tissue opening to targeted tissue . the outer cannula is selectively advanced over the tissue opening to sever tissue , while vacuum is generated in the vacuum chamber and delivered to the tissue opening through the lumen . the vacuum causes tissue to be drawn into and maintained in the tissue opening while the outer cannula severs tissue to obtain a biopsy core .