Abstract: The invention provides a sample collection device (1) for collection of a nasal sample from an individual. The sample collection device comprises: a frame (2) having at least one frame member (4) configured to be received and retained or accommodated within a nostril of the individual; and a collector element (8) provided on and/or carried by the at least one frame member (4) for receiving and collecting the nasal sample, which sample is usually in a liquid or semi-solid form. The collector element (8) is provided on and/or carried by the frame member (4) such that, when the frame member (4) is retained or accommodated within a nostril, the collector element (8) contacts and/or engages with an inner surface or tissue of the nasal cavity to receive and collect the sample. The invention also provides a sample collection kit (20) comprising the sample collection device (1) and a sample container (21) for receiving and storing the collector element (8).

Abstract: The present invention provides a disposable saliva collector for a wind instrument, comprising polygonal soft and flexible material bounded by straight or curved sides; wherein, the polygonal soft and flexible material is bound by straight or curved sides encompassing an absorbent material and leak guards on sides of the absorbent material; an anchoring hole on the opposite axis of the leak guard; and fastening straps on the same axis as the leak guards.

Abstract: The casing for capturing and analysing animal urine comprises a first urine receptacle (188) and a second urine receptacle (191) which is provided with a support (187) for a strip (195) which carries test specimens comprising reagents, the receptacles being separated by a partition wall (156) which is provided with a passage (157), and at least one support which forms a tilting axis between: a first configuration in which, when the passage is open, the urine flows as a result of gravity into the first receptacle and a second configuration in which, when the passage is open, the urine flows as a result of gravity into the second receptacle.

Abstract: A biopsy needle system includes a needle extending from a tissue piercing distal end to a proximal end. The needle defines a lumen extending from the distal end at least a portion of a length thereof and houses a target tissue. The system also includes an elongated member defining a channel therethrough open at a proximal end. The channel is sized and shaped to permit passage of the needle therethrough. Further, the system includes an end cap coupled to the distal end of the elongate member. The end cap includes a hole extending through a lateral wall thereof. The hole is sized and shaped to permit passage of the needle therethrough. The end cap further includes a ramp extending from the channel to the hole to guide the needle through the hole. The ramp is angled with respect to a longitudinal axis of the elongated member.

Abstract: In accordance with the inventive concepts, provided is a tissue sampling apparatus and method. In various embodiments, the tissue sampling apparatus and method is a cryobiopsy tissue sampling apparatus and method. A cryobiopsy apparatus can be a cardiac cryobiopsy apparatus that includes an intravenous probe having at least one tip capable of reaching temperatures sufficient to freeze tissue such that the tissue adheres to the tip. The tip preferably remains at the freezing temperature through retraction of the probe so that the adhered tissue can be collected for its intended post-extraction purpose.

Abstract: A medical specimen retrieval device with an actuator connected to an introducer tube, a funnel removably attached to an end of the introducer tube, a retracting element extending from an interior of the funnel wherein the biasing retracting element is retractable through the funnel and into an interior of the introducer tube by an actuator, and a medical specimen bag removably coupled to the retracting element.

Abstract: Provided are surgical instrument including a base body, a shaft unit extending in a direction from the base body and having an end at which an end effector is mounted, a gear unit including a first gear mounted on the base body and a second gear mounted on another end of the shaft unit and engaged with the first gear, and a bearing unit positioned between the base body and the first gear.

Abstract: A device for treating heart failure in a patient. The device comprising a body, at least one passage through the body, at least one one way valve in the passage and a mounting means adapted for mounting the body in an opening provided in the patient's atrial septum. In use, the device is oriented such that, when the patient's left atrial pressure exceeds the patient's right atrial pressure by a predetermined amount, the one way valve(s) opens to allow blood flow through the passage(s) from the left atrium to the right atrium to thereby reduce the left atrial pressure.

Abstract: The present application is generally directed to improved instruments and instrument features for distraction and tissue retraction. In particular, the present application is directed to distraction blades and wide blocking blades that can be used together, or individually, to assist in the distraction of bone and the retraction of tissue during a surgical procedure, such as a spinal fusion procedure.

Abstract: A system includes a first tube, a sharp coil at a distal end of the first tube, a second tube displaceable within the first tube, and a sharp housing at a distal of the second tube for storing fasteners. The housing can be positioned at a first tissue, and the coil rotated to advance the coil into engagement with the first tissue. The first tube is retracted to retract the first tissue, and then a first fastener is deployed at the first tissue location. Then, without removing the system from the patient, the distal end of the system is moved adjacent a second tissue location, and the process is repeated for a second fastener at the second tissue location. A suture extends between the first and second fasteners, and tension is applied to the suture to draw the first and second tissues toward each other to reconfigure the tissue.

Abstract: A catheter device includes a tube that has a distal opening that is configured to be transluminally advanced into the subject; and an extracorporeal unit that is coupled to a proximal end of the tube. A series of cartridges is arranged along the extracorporeal unit, each of the cartridges having an initial position in which the cartridge holds a respective anchor. Each of the cartridges is, moveable from the initial position to a deployment position while remaining coupled to the extracorporeal unit. A driver is configured to, for each of the anchors, sequentially, while the respective cartridge is in the deployment position, move the anchor out of the respective cartridge and through the tube toward the distal opening. Other embodiments are also described.

Abstract: A suture device for use in combination with a delivery system including a lumen extending through the delivery system includes a needle usable to carry a suture, a distal shuttle configured to releasably secure the needle, a sleeve disposable over the distal shuttle, the distal shuttle movable relative to the sleeve between a locked position in which the needle is locked to the distal shuttle and an unlocked position in which the needle is releasable from the distal shuttle. The suture device includes a distal assembly including an elongate tool guide movable between a deployment configuration in which the elongate tool guide is substantially parallel with the distal assembly and a working configuration in which the elongate tool guide curves away from the distal assembly.

Abstract: A method for closing a wound in a tubular organ using a suture thread includes: a first step of connecting a first edge portion and a second edge portion with the suture thread; and a second step of connecting a third edge portion and a fourth edge portion with the suture thread. The first step includes passing the suture thread through a first position on a mucosal surface of at least one of the first edge portion and the second edge portion. The second step includes passing the suture thread through a third position on the mucosal surface of at least one of the third edge portion and the fourth edge portion. A shortest distance between the wound and the third position is larger than a shortest distance between the wound and the first position.

Abstract: Suture passers and methods of use. Described herein are suture passers preloaded with suture, including cartridges that couple to a suture passer to form a loaded suture passer; the suture passer may be operated to pass one or more lengths of suture without having to be manually reloaded. In particular, described herein are preloaded and automatically reloading apparatuses typically.

Abstract: A surgical stapling instrument comprising an elongate shaft assembly that includes a surgical end effector that is operably coupled thereto by an articulation joint. The surgical instrument may include a first distal articulation driver operably coupled to the surgical end effector and a second distal articulation driver that is coupled to the surgical end effector. At least one driver member may operably engage the first and second distal articulation drivers such that when the first distal articulation driver is moved in a distal direction, the least one driver moves the second distal articulation driver in a proximal direction and when the first distal articulation driver is moved in the proximal direction, the at least one driver member moves the second distal articulation driver in the distal direction.

Abstract: A surgical instrument comprising a firing drive including a leverage selection mechanism is disclosed.

Abstract: A surgical fastener applier having a housing containing a compartment therein, an elongated member extending distally from the housing and first and second jaws. A firing mechanism is positioned within the housing movable to a second position to effect firing of fasteners. A power pack is removably loadable into the compartment, the power pack having one or both of a) a first motor and a first engagement member removably engageable with the firing mechanism when the power pack is loaded into the compartment to effect movement of the firing mechanism; and b) a second motor and a second engagement member removably engageable with an articulating mechanism in the housing of the surgical fastener applier to effect movement of an articulation mechanism to effect articulation. One or both of a firing position and an articulation position are tracked during the surgical procedure. Sensors are provided to detect select parameters and instrument functions.

Abstract: A surgical instrument. In one form, the surgical instrument includes a housing that has an interchangeable shaft assembly removably attached thereto. The interchangeable shaft assembly includes an elongate shaft that has a surgical end effector operably coupled thereto for selective articulation relative to the elongate shaft. An articulation system is configured to selectively apply articulation motions to the surgical end effector when the articulation system is in an actuated orientation. A locking arrangement prevents detachment of the interchangeable shaft assembly from the housing when the articulation system is in the actuated orientation.

Abstract: Stapling assemblies for use with a surgical stapler are provided. In one exemplary embodiment, a stapling assembly can include a cartridge and a knitted adjunct that is configured to be releasably retained on the cartridge. The adjunct can have a tissue-contacting layer formed of at least first fibers, a cartridge-contacting layer formed of at least second fibers, spacer fibers intertwined with and extending between the tissue-contacting layer and the cartridge-contacting layer to thereby connect the tissue-contacting and cartridge-contacting layers together, and at least one fiber interconnecting at least a portion of a terminal edge of each of the tissue-contacting and cartridge-contacting layers to form a finished edge that substantially prevents fraying thereof.

Abstract: A method for assessing performance of a surgical instrument including one or more drivetrains is disclosed. The method includes sensing via one or more vibration sensors vibrations generated during operation of the one or more drivetrains of the surgical instrument, generating an output signal based on the sensed vibrations, filtering the output signal to generate a filtered signal of the sensed vibrations from the one or more drivetrains, processing the filtered signal to generate a processed signal of the sensed vibrations from the one or more drivetrains, and comparing predetermined threshold values for each of an acceptable status, a marginal status, and a critical status of the surgical instrument to corresponding values of the processed signal.

Abstract: A method implemented by a surgical instrument is disclosed. The surgical instrument includes first and second jaws and a flexible circuit including multiple sensors to optimize performance of a radio frequency (RF) device. The flexible circuit includes at least one therapeutic electrode couplable to a source of RF energy, at least two sensing electrodes, and at least one insulative layer. The insulative layer is positioned between the at least one therapeutic electrode and the at least two sensing electrodes. The method includes contacting tissue positioned between the first and second jaws of the surgical instrument with the at least one therapeutic electrode and at the least two sensing electrodes; sensing signals from the at least two sensing electrodes; and controlling RF energy delivered to the at least one therapeutic electrode based on the sensed signals.

Abstract: A driving device, a surgical instrument, and an operation method of the surgical instrument. The driving device is driven by a power assembly. The driving device includes a first driving assembly and a first motion conversion assembly. The first motion conversion assembly includes a first effective stroke structure and a first idle stroke structure. The driving device has a first state and a second state. In the first state, the power assembly drives the first effective stroke structure by the first driving assembly; and in the second state, the power assembly is coupled with the first idle stroke structure by the first driving assembly.

Abstract: A staple cartridge comprising a power management circuit is disclosed.

Abstract: A surgical stapler includes a jaw assembly at a distal end connected to a handle assembly that is configured to control the stapler and actuate the deployment of staples. The surgical stapler successfully eliminates intermediate caming portions commonly known as pushers that are located between the staples and a translating slider. The staples are located in pockets at an angle such that the base of the staple is parallel to an angled caming surface of the slider. The translating slider comes into direct contact with staples during deployment as the slider moves through each staple pocket where staples are partially supported by recesses along the slider pathway. The staples are deployed at an angle against the anvil surface. Because there are no pushers, a great deal of space is saved resulting in a much smaller diameter surgical stapler that is particularly suitable for laparoscopic stapling applications.

Abstract: A staple cartridge assembly comprising a tissue thickness compensator is disclosed. The tissue thickness compensator comprises a first fibrous, woven material and a second fibrous, woven material. The first fibrous, woven material comprises a density which is different than the density of the second fibrous, woven material. The tissue thickness compensator is configured to expand upon contact with a fluid in order to apply a compressive force to tissue captured within staples.

Abstract: A surgical instrument according to one or more embodiments may include: a base to be attached to a robot arm; a shaft including one end connected to the base; and a pair of jaw members provided to the other end of the shaft and provided to be rotatable about a first rotation axis so as to be opened and closed to each other, wherein opposing surfaces of the pair of jaw members include groove-shaped recesses, respectively, to hold a clip, and the recess of each of the jaw members includes a first section provided on a side of a distal end of the jaw member and having a first depth and a second section provided on a side of a first rotation axis of the jaw member with respect to the first section and having a second depth greater than the first depth.

Abstract: A surgical instrument including a power assist device, and its method of use for deploying surgical fasteners, is disclosed. The surgical instrument may include a handle, an elongated shaft extending from the handle, and a surgical fastener deployment system including a driveshaft. The driveshaft is actuatable between at least a first proximal position and a second distal position. A striker is movable relative to the driveshaft and an impact surface is associated with the driveshaft. The impact surface is constructed and arranged to be struck by the striker member to displace the driveshaft to the second distal position and deploy the surgical fastener.

Abstract: A modular shaft assembly is disclosed. The modular shaft assembly includes one or more inputs configured to receive input motions from a surgical instrument system, such as a handle, for example. The shaft assembly further includes one or more on-board inputs configured to generate input motions. The input motions received and generated by the shaft assembly are transferrable to an end effector of the shaft assembly to perform various functions at the end effector. The end effector can include a staple cartridge and a firing member which is movable between a proximal position and a distal position to eject staples from the staple cartridge. The end effector can include a plurality of jaw members and the firing member can comprise camming members which are configured to position the jaw members relative to one another.

Abstract: A ligation clip loading device includes a cannula including a cannula body and an instrument lumen extending through a longitudinal axis of the cannula body, and a stack of ligation clips axially arranged about the instrument lumen. The ligation clips are accessible through a series of slots allowing for loading of an endoscopic clip applier with the ligation clips within a body cavity, such as an intra-abdominal cavity.

Abstract: An anastomosis set comprising: a first manipulator, with a first telescoping part at a distal end thereof, the first telescoping part is used for telescoping toward the first end to be anastomosed; a second manipulator, with a second telescoping part at a distal end thereof, the second telescoping part is used for telescoping toward the second end to be anastomosed; an anastomosis mechanism for anastomosing the first end with the second end; the first manipulator including a first exit part through which the first manipulator will be removed from the first end to be anastomosed after anastomosing; the second manipulator has a second exit part, through which the second manipulator will be removed from the second end to be anastomosed after anastomosing; an anastomotic auxiliary having with a first embedding end and a second embedding end; wherein the first embedding end is configured to embed into a first end of a blood vessel to be anastomosed, and the second embedding end is configured to embed into a second

Abstract: An apparatus includes an interface, and an elongate body coupled to the interface. An end effector is coupled to a distal end the elongate body and includes a first end effector element defining a first receptacle structured to hold a first coupler element of a coupler that receives an axial end of a first vessel, and a second end effector element defining a second receptacle structured to hold a second coupler element of the coupler that receives an axial end of a second vessel. The end effector is configured to move between a first configuration in which the first and second end effector elements are separate, and a second configuration in which first end effector element is proximate to the second end effector element such that the first coupler element is coupled to the second coupler element so as to couple the first vessel to the second vessel.

Abstract: A surgical device includes a handle assembly having a power source, a motor coupled to the power source, and a controller configured to control the motor. The device also includes an adapter assembly configured to selectively couple to the handle assembly, the adapter assembly including a stapling transmission assembly movable by the motor. The device also includes a reload configured to selectively couple to a distal portion of the adapter assembly, the reload including a plurality of staples ejectable from the reload by the stapling transmission assembly. The device also includes an anvil assembly selectively couplable to the distal portion of the adapter assembly, the anvil assembly being movable relative to the reload, where the controller may be further configured to control the motor to move the stapling transmission assembly to eject the staples while compensating for mechanical losses of the stapling transmission assembly.

Abstract: A device and assembly for ligating a target tissue to restrict blood flow to the tissue, where the device is a ligating device that is irreversibly tightened by a cinch component. The device further has a hook to hold the ligating element on a delivery tool. The ligating element can be a continuous loop or can be a clip and can be repositionable until the cinch is used to tighten it. The cinch holds the ligating device on the loop while being positioned, and then secures the ligating device once it is positioned around target tissue to which a user desires to restrict blood flow. A method of using the assembly includes an actuator assembly, drive wire, and pusher element to manipulate the ligating device and cinch component.

Abstract: An endovascular device providing several elements to help mechanically break up and/or lyse a clot inside vessels and/or remove a clot via aspiration, irrigation, maceration and/or rotation, without a filter. According to some embodiments, the devices are adapted to irrigate a blood vessel during thrombectomy; to macerate an obstruction during thrombectomy, to block blood flow in a blood vessel during aspiration of a thrombus.

Abstract: Devices, systems, and methods for treating aneurysms are disclosed herein. According to some embodiments, the present technology includes a treatment system comprising a delivery shaft, a manipulation shaft slidably positioned within the lumen of the delivery shaft, and an occlusive device configured for implantation within the aneurysm. The occlusive device can comprise a plurality of filaments that are secured to one another at a proximal end of the occlusive device by a cured material. The occlusive device can comprise inner and outer layers of braided filaments, wherein the proximal end region of the inner layer has an exposed portion that extends proximally beyond the proximal end region of the outer layer, and wherein the cured material extends into and fills interstices between the braided filaments at the proximal end regions of the inner and outer layers.

Abstract: Devices, systems, and methods for treating aneurysms are disclosed herein. According to some embodiments, the present technology includes a treatment system comprising a delivery shaft, a manipulation shaft slidably positioned within the lumen of the delivery shaft, and an occlusive device configured for implantation within the aneurysm. The occlusive device can comprise a plurality of filaments that are secured to one another at a proximal end of the occlusive device by a cured material. The occlusive device can comprise inner and outer layers of braided filaments, wherein the proximal end region of the inner layer has an exposed portion that extends proximally beyond the proximal end region of the outer layer, and wherein the cured material extends into and fills interstices between the braided filaments at the proximal end regions of the inner and outer layers.

Abstract: A method for creating an engineered landing zone includes delivering a landing zone prosthesis in a radially compressed configuration to a site of an aneurysm within a vessel. The landing zone prosthesis includes a frame, an engineered landing zone, and graft material coupled at a first end to the frame and at a second end to the engineered landing zone. The method further includes radially expanding the frame at the site of the aneurysm while the engineered landing zone remains in the radially compressed configuration longitudinally spaced from the frame, securing to the vessel, longitudinally translating the engineered landing zone such that the engineered landing zone is at least partially disposed within the frame, and radially expanding the engineered landing zone.

Abstract: A device to occlude a body lumen such as the left atrial appendage of a heart of a subject is described. The device comprises an implantable occlusion apparatus comprising a proximal connecting hub and a radially expansible body configured for radial expansion upon deployment from a contracted configuration to a radially expanded configuration to fluidically occlude the left atrial appendage, an elongated deployment catheter having a central lumen, an elongated delivery catheter disposed in the central lumen of the elongated deployment catheter and having a distal connecting hub detachably attachable to the proximal connecting hub of the implantable occlusion apparatus for transluminal delivery of the implantable occlusion apparatus to the left atrial appendage, wherein the elongated deployment catheter is axially movable proximally relative to the elongated delivery catheter to deploy the implantable occlusion apparatus.

Abstract: Medical devices, systems and methods for occluding a left atrial appendage of a heart are provided. In one embodiment, the medical device includes an occluder portion and an anchor portion that are pivotably coupled to each other with hinge components. The hinge components each include a base with arms extending from the base such that the arms of each one of the hinge components extend through and capture a first eyelet of the occluder portion and a second eyelet of the anchor portion to facilitate pivotably coupling the anchor portion to the occluder portion.

Abstract: An embolic device for placement in a body lumen, includes: an elongated member having a linear configuration when in room temperature, the elongated member being configured to form a first three-dimensional structure in response to body temperature; wherein the elongated member comprises a first segment, a second segment, and a third segment, the second segment being located between the first segment and the third segment; wherein the first segment and the third segment are configured to change their respective shapes in response to the body temperature; and wherein the second segment that is located between the first segment and the third segment has a shape that is independent of the body temperature.

Abstract: A flat embolic braid having a first side comprising a first side surface, and a second side comprising a second side surface facing in an opposite direction than the first side surface, the braid having an elongated constrained configuration for being deployed through a delivery catheter, and a three-dimensional unconstrained configuration, wherein in the three-dimensional unconstrained configuration, the braid assumes a plurality of successive loops in which the braid is at least partially twisted between successive loops of the plurality, so that the first side surface faces externally of each loop, and the second side surface faces an interior of each loop, respectively, regardless of a change in direction and/or orientation of the braid.

Abstract: Provided herein is an occlusion device comprising: (a) continuous mesh structure comprising a medial pinch point; (b) a resilient mesh disc-shaped body extending distally and outward from the medial pinch point; and (c) a compressible mesh carriage extending distally from the medial pinch point on an opposing side of the resilient mesh body of (b), wherein the compressible mesh carriage comprises a pinch point on each end of the carriage, wherein one of the pinch points is the medial pinch point of (a); wherein the continuous mesh structure has a first delivery shape and a second expandable deployed shape, and wherein the length (x) of the resilient mesh body is greater than the length (y) of the compressible mesh carriage in free air and in the deployed shape.

Abstract: Braided occluding devices having an access passage and methods including the same are described herein. The occluding device includes a braided frame which includes. The braided frame includes an annular distal disc portion, a waist member, and an annular proximal disc portion defining a passageway through the braided frame. The braided frame is formed with a closed end braid.

Abstract: A device for treating an intracranial aneurysm in accordance with an embodiment of the present technology includes an elongate conduit body defining an axial lumen through which the conduit body is configured to convey liquid embolic material toward the aneurysm. The conduit body includes a first flexibility zone defining a first average bending stiffness and a first outer diameter. The conduit body further includes a second flexibility zone distal to the first flexibility zone and defining a second average bending stiffness and a second outer diameter. The second average bending stiffness and the second outer diameter are less than the first average bending stiffness and the first outer diameter, respectively. The conduit body also includes a transition zone between the first and second flexibility zones. The transition zone defines a third outer diameter that transitions proximally-to-distally from the first outer diameter to the second outer diameter.

Abstract: The present invention relates to methods and devices for production of injectable foams, such as those used in the treatment of varicose veins and other venous disorders. The method requires the delivery or supply of foamable liquid sclerosing agent and a suitable gas or a gas mixture to a foam producing structure in which the liquid and gas are combined to produce foam, wherein the liquid is delivered independently of the delivery of gas. Devices for producing injectable foam comprise a foam producing structure in which liquid and gas are combined to produce foam, the structure comprising an inlet for liquid and gas and an outlet for foam; a liquid pathway in communication with the inlet; and a gas pathway in communication with the inlet, characterised in that the liquid pathway comprises a means for delivering liquid through the liquid pathway independently of gas delivery through the gas pathway. In preferred embodiments, the delivery of liquid and/or gas is controlled with volumetric pumps.

Abstract: A vascular bleeding control device that is used in managing bleeding at a puncture site, for example, after a surgical procedure when a large needle is required. The device has a resilient lever that extends away from a frame. The resilient lever extends away from the frame and resists pressure applied towards the frame. A pad on an outward face of the resilient lever contacts the puncture site and assists in managing bleeding until the blood vessel is sufficiently healed. The pad is manufactured of a hemostatic material that assists in decreasing healing time and can be easily removed from the puncture site without reopening the wound.

Abstract: A bone cutting guide may include a support that contains a shaft movable relative to the support. The shaft may carry a guide member having one or more cut guides through which a clinician inserts a cutting member to cut bone positioned under the guide cut guides. In operation, a clinician may fixate the support of the bone cutting guide to a bone and translate the guide member until the one or more cut guides are positioned at a desired cut location. The clinician may then perform a cut through the cut guide. In some examples, the bone cutting guide includes additional components, such as bridging member or secondary cut guide, to provide additional functionality.

Abstract: A surgical instrument for cutting a first tissue and detecting a second tissue includes a shaft, a cutting member, and a tissue monitor system. The shaft extends along a longitudinal axis and includes a shaft lumen and a shaft opening. The cutting member is disposed within the shaft lumen and configured to cyclically move from a first position to a second position relative to the shaft. The cutting member is further configured to cut a tissue portion of the first tissue for removal therefrom. The tissue monitor system is associated with at least one of the shaft or the cutting member configured to detect the second tissue distinct from the first tissue for selectively cutting and removing the first tissue relative to the second tissue.

Abstract: A system is disclosed to support installation of a prosthetic joint or a prosthetic component. The system includes at least one sensor to measure a parameter. The system uses one or more patient specific instruments in conjunction with a tensor to make one or more bone cuts. The patient specific instruments and tensor make the bone cuts such that an installed prosthetic joint is aligned, balanced, loaded correctly, and positioned optimally for performance and reliability. The use of the tensor simplifies the workflow required when using the patient specific instruments. In one embodiment, the patient specific instruments are bone cutting jigs configured for the patient anatomy.

Abstract: A patella drill guide includes a head having a convexly curved outer surface. Cylindrical channels extend through the head. The drill guide also includes collar having an inner surface that defines a concavity corresponding in shape to the convexly curved outer surface. The inner surface of the collar is fitted to the outer surface of the head to define an articular joint.