Apparatus for the treatment, post-operative rehabilitation and / or prevention of hallux valgus disease

Abstract

The invention relates to an apparatus (2), system (1) and method for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease, the apparatus (2) comprising: • a fixed main part (4), sized to be located under and supporting Digitis Pedis II to V and at least the ball of a foot, particularly supporting Digitis Pedis II to V and the complete foot (3); • a movable element (5), to be located under and supporting Digitis Pedis I (7); • moving means (M1, M2) for applying a rotational movement to the movable element (5) relative to the fixed main part (4) in a first direction and a second direction, wherein the first direction and the second direction are orthogonal to each other; • a controller (12) for controlling the moving means (M1, M2) to generate a defined rotational movement of the movable element (5) relative to the fixed main part (4) in the first direction and the second direction; • wherein the moving means (M1, M2) comprise a first motor (M1) for generating the rotational movement of the movable element (5) relative to the fixed main part (4) in the first direction and a second motor (M2) for generating the rotational movement of the movable element (5) relative to the fixed main part (4) in the second direction.

Description

[0001] The invention relates to an apparatus for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease. The invention further relates to a method for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease.

[0002] Hallux valgus (bunion of the big toe) is the name given to a crooked position of the Digitis Pedis I (big toe), in which the Digitis Pedis I extends valgusly, i.e. from the center of the body in the direction of the Digitis Pedis II to V. This is called hallux valgus. The direction of pull of the tendons in the foot changes and increases the displacement of the Digitis Pedis I. At the same time, the first metatarsal bone deviates inward with its head, resulting in the typical bunion. In addition to cosmetic problems, hallux valgus can lead to painful pressure points, skin irritation, swelling or inflammation, for example, due to friction of the protruding bunion on the footwear. Consequential damage may include arthrosis or overloading of the neighboring joints of the Digitis Pedis II to V or the metatarsal bones. This malpositioning of the Digitis Pedis I often results from hereditary predisposition and is usually aggravated by wearing tight shoes or shoes with high heels.

[0003] Up to a certain stage, hallux valgus can be treated conservatively, as non-surgical, for example by foot gymnastics or wearing foot splints. Foot gymnastics for the treatment of hallux valgus includes exercises that promote the free movement of Digitis Pedis I in all directions. Preferably, foot exercises are performed by a physiotherapist.

[0004] In the course of such foot gymnastics, the physiotherapist makes various manipulations with the diseased toe DIGITIS PEDIS I aimed at restoring the circulation of joint fluid and blood circulation in the adjacent vessels. These manipulations may include all possible variants of bending the sore toe.

[0005] The most effective is simultaneous rotational flexion of the DIGITIS PEDIS I in two directions, i.e. in a vertical direction, as occurs with all toes when walking at the beginning of each step, and in a horizontal direction away from the other toes DIGITIS PEDIS II to V. The actual direction of rotational flexion is the resultant of these two directions.

[0006] However, alternate rotational flexion of the DIGITIS PEDIS I in the vertical direction and then in the horizontal direction is also very effective.

[0007] Before starting the exercises, the physiotherapist performs trial manipulations with each painful toe to see at what approximate angle of flexion the patient experiences unpleasant or even painful sensations. Having determined the limits of the bend, the physiotherapist starts the therapeutic exercises, which last approximately 15-20 minutes on both feet.

[0008] It is known that to achieve real effectiveness of treatment, the above described exercises should be performed daily. However, external circumstances usually do not allow the average patient to use the services of a physiotherapist on a daily basis, because health insurance companies, for example in Germany, only pay for 64 sessions of therapeutic gymnastics per year. The missing 300 sessions of gymnastics per year must either be paid for by the patient himself, or he must do it himself according to the physiotherapist's methods. Obviously, the vast majority of patients are not able to pay for such a large number of sessions. At the same time, unfortunately, as practice shows, the vast majority of patients also cannot make themselves do regular exercises on their own.

[0009] CN 112472388 A discloses a rehabilitation therapy device for treating hallux valgus. The disclosed device is motor driven for applying a rotation movement to Digitis Pedis I to V, which corresponds to the rotation of Digitis Pedis I to V during a normal walking movement, i.e. in a vertical direction. Furthermore, a translational movement can be applied to Digitis Pedis I. However, the disclosed device cannot apply a further rotational movement to Digitis Pedis I in a different direction than the first rotational movement, e.g. in a horizontal direction. The simultaneous rotational movement of Digitis Pedis I to V corresponds to a normal walking movement of the patient and hence the therapeutic effect if this movement corresponds to performing a walk. The translational movement of Digitis Pedis I is not supported by the joint of Digitis Pedis I and hence should be performed at all. Hence, the therapeutic effect of the disclosed device is very limited.

[0010] CN 101427971 A discloses a further device for treating hallux valgus. According to this device Digitis Pedis II to V are fixed, while Digitis Pedis I is rotated in a horizontal direction only.

[0011] Based on this prior art it is an object of the present invention to provide an apparatus and method for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease, which enables a patient to perform a foot exercise usually exercises by a physical therapist at any time and as often as desired.

[0012] The object is solved by the apparatus and system for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to claim 1 and 12. The object is further solved by the method for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to claim 16. Preferred embodiments of the invention are defined in the dependent claims.

[0013] According to the present invention, the apparatus for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease comprises: a fixed main part, sized to be located under and supporting Digitis Pedis II to V and at least the ball of a foot, particularly supporting Digitis Pedis II to V and the complete foot; a movable element, to be located under and supporting Digitis Pedis I; moving means for applying a rotational movement to the movable element relative to the fixed main part in a first direction and a second direction, wherein the first direction and the second direction are orthogonal to each other; a controller for controlling the moving means to generate a defined rotational movement of the movable element relative to the fixed main part in the first direction and the second direction; wherein the moving means (M1, M2) comprise a first motor (M1) for generating the rotational movement of the movable element (5) relative to the fixed main part (4) in the first direction and a second motor (M2) for generating the rotational movement of the movable element (5) relative to the fixed main part (4) in the second direction.

[0014] The fixed main part, which is located during the use of the apparatus under Digitis Pedis II to V and at least the ball of the foot, supports at least a part of the foot including Digitis Pedis II to V and thereby prevents a movement of Digitis Pedis II to V. The movable part is locate dunder Digitis Pedis I during the use of the apparatus and supports Digitis Pedis I. The apparatus further comprises moving means for applying a rotational movement to the movable element relative to the fixed main part in a first direction and a second direction, wherein the first direction and the second direction are orthogonal to each other. The first rotational movement and the second rotational movement are thereby applied to Digitis Pedis I, which rotates in the first direction and in the second direction relative to Digitis Pedis II to V, which are supported by the fixed main part. Hence, Digitis Pedis I is rotated about two axis relative to Digitis Pedis II to V. In the normal position of the foot, like when it rests on the floor, the first direction is horizontal, and the second direction is vertical.

[0015] The moving means comprise a first motor for generating the rotational movement of the movable element relative to the fixed main part in the first direction and a second motor for generating the rotational movement of the movable element relative to the fixed main part in the second direction. The first motor and the second motor are independent of each and can be active / deactivated separately or simultaneously. Thus, the movable element can be rotated relative to the main part either in the first direction or in the second direction separately or in the first direction and in the second direction simultaneously.

[0016] A motor according to the present invention is a device that applies a moving force to a movable part. The motor can be operated electrically, pneumatically, hydraulically or by other driving means.

[0017] The apparatus further comprises a controller for controlling the moving means to generate a defined rotational movement of the movable element relative to the fixed main part in the first direction and the second direction. The controller is used to apply defined rotational movements to Digitis Pedis I relative to Digitis Pedis II to V which are not uncomfortable or even painful to the patient. The defined movements mimic the movements usually applied by a physiotherapist to Digitis Pedis I and hence can be performed on a daily basis by the patient using the apparatus according to the present invention.

[0018] Pursuant to a variant of the invention, the apparatus further comprises a platform having a cavity, in which at least the fixed main part and the movable element and the moving means are located, wherein the fixed main part and the movable element are a part of the upper surface of the platform and the moving means are located inside the platform. The platform can be located on the floor during use and user can place his foot on the platform in such a way that Digitis Pedis I is supported by the movable element and Digitis Pedis II to V are supported by the fixed main part. Therefore, the fixed main part and the movable element are part of the upper surface of the platform. The moving means are for example inside the platform, so that are out of sight and further protected against damages or contact with parts of the human body.

[0019] In a preferred variant of the invention, wherein the movable element comprises first means for fixing the Digitis Pedis I to the movable element and / or wherein the main part comprises second fixing means for fixing the Digitis Pedis II to V and at least a part of the foot relative to the main part. The first fixing means ensure that the rotational movements are correctly applied to Digitis Pedis I and the second fixing means ensures that Digitis Pedis II to V are fixed to the main part and do not move.

[0020] According to an advantageous variant of the invention, the apparatus comprises a joint between the fixed main part and the movable element, wherein the joint is located in the area of the joint between Digitis Pedis I and the foot. The joint is used for limiting the rotational movement of the movable part relative to the main part in the first direction and second direction. All other movements, like e.g. translational movement, are prevented by the joint. The joint is located in the area of the joint between Digitis Pedis I and the foot. Since the joint between Digitis Pedis I and the foot also only supports the rotational movements in the first direction and second direction and both joints are coincident, the joint of apparatus protects the joint between Digitis Pedis I and the foot against harmful movements.

[0021] Pursuant to an expedient variant of the invention, the rotation axis of the first rotational movement and the rotation axis of the second rotational movement orthogonally overlap at the joint between the fixed main part and the movable element. Thus, both rotational axes are coincident with the joint between Digitis Pedis I and the foot.

[0022] In a variant of the invention, the joint supports the rotational movement of the movable element relative to the fixed main part simultaneously in the first direction and in the second direction.

[0023] Pursuant to an expedient variant of the invention, the first motor and / or the second motor are electrical step motors. Step motors are easy to control, have a high accuracy, are durable and cheap.

[0024] In an advantageous variant of the invention, the controller further comprises communication means, particularly wireless communication means, for communicating with a mobile device or remote control, so that the apparatus can be controlled by the user using the mobile device or remote control. For example, the user can use the mobile device or remote control limit the range of rotational movements in the first direction and / or second direction, to avoid unpleasant or painful movements of the Digitis Pedis I relative to Digitis Pedis II to V. Furthermore, it is more convenient to control the apparatus using a mobile device or remote control, as the apparatus is located in the area of the feet during use, which is far away from the hands of the user.

[0025] According to a preferred variant of the invention, the controller can control the extend and speed of the rotational movement of the movable element relative to the fixed main part in the first direction and the second direction. Thereby, the controller can avoid unpleasant or painful movements of the Digitis Pedis I relative to Digitis Pedis II to V.

[0026] Pursuant to a further preferred variant of the invention, the controller comprises a storage for storing information regarding the user, the usage of the apparatus by each user, treatment programs and / or plans, or further information regarding the usage of the apparatus. Thus, the storage can be used for storing user specific information and or information regarding the treatment (rotational movements in first and / or second direction) to be executed. Further information regarding the past and / or future use of the device by the user can also be stored in the storage of the controller.

[0027] The invention further relates to a system for the simultaneous treatment, post-operative rehabilitation and / or prevention of Hallux Valgus of two feet, the system comprising two apparatuses according to the invention, wherein the first apparatus is designed for the left foot of the user and the second apparatus is designed for the right foot of the user and the controller can be a combined controller or separate controllers for the two apparatuses.

[0028] In a variant of the invention, the rotational movement of the movable elements of the two apparatuses can be different from each other, identical, synchronized and / or un-synchronized.

[0029] According to a preferred variant of the invention, the system comprises a platform, on which the two apparatuses are mounted. The platform having two cavities, in which the respective apparatuses, i.e. the fixed main part and the movable element of each apparatus and the respective moving means are located. The fixed main part and the movable element of each apparatus are a part of the upper surface of the platform and the respective moving means are located inside the platform. The platform can be located on the floor during use and user can place his both feet apparatuses of the platform. Thus, the fixed main part and the movable element of each apparatus are part of the upper surface of the platform. The respective moving means are for example inside the platform, so that are out of sight and further protected against damages or contact with parts of the human body.

[0030] Pursuant to a variant of the invention, the platform contains the controller and the moving means of the two apparatuses.

[0031] The invention further relates to a method for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease, wherein the method uses an apparatus or system according to the invention for applying a controlled rotational movement to Digitis Pedis I relative to Digitis Pedis II to V in a first direction and a second direction.

[0032] In a variant of the invention, the method comprises an initiation step, in which the user can define the maximum rotational movement of Digitis Pedis I relative to Digitis Pedis II to V in the first direction and in the second direction. This initiation step is used to prevent any uncomfortable or painful movement of Digitis Pedis I relative to Digitis Pedis II to V.

[0033] According to a preferred variant of the invention, the method executes predefined rotational movement programs, which can be adapted to consider improvements in Hallux Valgus disease condition over time. The predefined rotational movement programs advantageously mimic the movement usually perform by a physiotherapist during treatment.

[0034] In the following the invention will be further explained with embodiments shown in the figures. It shows: Fig. 1a view of an apparatus for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to the present invention; Fig. 2a detailed view of the main part and the movable part of the apparatus shown in Fig. 1 in a first position; Fig. 3a detailed view of the main part and the movable part of the apparatus shown in Fig. 1 in a second position; Fig. 4different vertical positions of the movable element relative to the main part of the apparatus shown in Fig. 1; Fig. 5a view of a system for the simultaneous treatment, post-operative rehabilitation and / or prevention of Hallux Valgus of two feet.

[0035] Fig. 1 shows a view of an apparatus 2 for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to the present invention. The apparatus comprises a fixed main part 4 and a movable element 5. The fixed main part 4 is sized to be located under and supporting Digitis Pedis II to V and at least the ball of a foot, particularly supporting Digitis Pedis II to V and the complete foot 3. The movable element 5 is sized to be located under and supporting Digitis Pedis I 7.

[0036] The apparatus 2 further comprises moving means M1, M2 for applying a rotational movement to the movable element 5 relative to the fixed main part 4 in a first direction and a second direction, wherein the first direction and the second direction are orthogonal to each other.

[0037] A controller 12 (not visible in Fig. 1) of the apparatus 2 is used for controlling the moving means M1, M2 in order to generate a defined rotational movement of the movable element 5 relative to the fixed main part 4 in the first direction and the second direction. The controller 12 can control the extend and speed of the rotational movement of the movable element 5 relative to the fixed main part 4 in the first direction and the second direction.

[0038] Furthermore, the controller 12 can comprise communication means, particularly wireless communication means, for communicating with a mobile device 13 (not visible in Fig. 1) or remote control, so that the apparatus 2 can be controlled by the user using the mobile device 13 or remote control. In addition, the controller 12 may comprise a storage for storing information regarding the user, the usage of the apparatus 2 by each user, treatment programs and / or plans, or further information regarding the usage of the apparatus 2.

[0039] The movable element 5 comprises first means 8 for fixing the Digitis Pedis I 7 to the movable element 5. The main part 5 can comprises second fixing means (not shown in Fig. 1) for fixing the Digitis Pedis II to V and at least a part of the foot 3 relative to the main part 4.

[0040] Fig. 2 shows a detailed view of the main part 4 and the movable part 5 of the apparatus 2 shown in Fig. 1 in a first position and Fig. 3 shows a detailed view of the main part and the movable part of the apparatus shown in Fig. 1 in a second position. In the first position shown in Fig. 2 the movable element 5 is located directly adjacent to the fixed main part 4 and in the second position shown in Fig. 3 the movable element has been rotated by an angle β away from the fixed main part 4. This corresponds to a rotational movement in a second direction, particularly in a horizontal plane (when the apparatus 2 rests on the floor). The rotational movement in the first direction, i.e. in the vertical direction when the apparatus 2 rests on the floor, will be explained below with respect to Fig. 4.

[0041] Figs. 2 and 3 further show a joint 6 of the apparatus 2 between the fixed main part 4 and the movable element 5. The joint 6 is located in the area of the joint between Digitis Pedis I 7 and the foot 3, particularly the ball of the foot 3. The rotation axis 9 of the first rotational movement and the rotation axis 10 of the second rotational movement orthogonally overlap in the area of joint 6 between the fixed main part 4 and the movable element 5.

[0042] The joint 6 supports the rotational movement of the movable element 5 relative to the fixed main part 4 simultaneously in the first direction and in the second direction.

[0043] Figs. 4a) to 4c) show different vertical positions of the movable element 5 relative to the fixed main part 4 of the apparatus shown in Fig. 1 caused by the rotational movement of the movable element 5 relative to the fixed main part 4 in the first direction. The movable element 5 is rotated by angle α around the first rotation axis 9.

[0044] As can be particularly seen from Figs. 2 to 4, the moving means M1, M2 comprise a first motor M1 for generating the rotational movement of the movable element 5 relative to the fixed main part 4 in the first direction and a second motor M2 for generating the rotational movement of the movable element 5 relative to the fixed main part 4 in the second direction. According to these Figs. 2 to 4, the first motor M1 causes a rotational movement in the first, vertical direction around the first rotation axis 9 and the second motor M2 causes a rotational movement in second, horizontal direction about second rotation axis 10. The first motor M1 and the second motor M2 can be operated simultaneously or separately. Preferably, the first motor M1 and the second motor M2 are electrical step motors. However, principally any motor, particularly electrical motor, can be used.

[0045] Fig. 5 shows a view of a system 1 for the simultaneous treatment, post-operative rehabilitation and / or prevention of Hallux Valgus of two feet 3 according to the invention. The system 1 comprises two apparatuses 2 according to the invention. The first apparatus 2 is designed for the left foot 3 of the user and the second apparatus 2 is designed for the right foot 3 of the user and the controller 12 can be a combined controller 12 or separate controllers 12 for the two apparatuses 2.

[0046] The rotational movement of the movable elements 5 of the two apparatuses 2 can be different from each other, identical, synchronized and / or un-synchronized.

[0047] As can be seen from Fig. 5, the system 1 comprises a platform 11, on which the two apparatuses 2 are mounted. The platform 11 having cavities for the two apparatuses 2. At least the fixed main part 4 and the movable element 5 and the moving means M1, M2 of each apparatus 2 are located in the respective cavity. The fixed main part 4 and the movable element 5 are a part of the upper surface of the platform 11 and the moving means M1, M2 are located inside the platform 11.

[0048] The platform 11 further contains the controller 12 for the two apparatuses 2. The controller 12 of Fig. 5 further comprises communication means, particularly wireless communication means, for communicating with a mobile device 13, so that the apparatuses 2 of the system 1 can be controlled by the user using the mobile device 13.List of references

[0049] 1system 2apparatus 3feet 4main part 5movable element 6joint 7Digitis Pedis I 8first fixing means 9first rotation axis 10second rotation axis 11platform 12controller 13mobile device

Claims

1. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease, the apparatus (2) comprising: a fixed main part (4), sized to be located under and supporting Digitis Pedis II to V and at least the ball of a foot, particularly supporting Digitis Pedis II to V and the complete foot (3); a movable element (5), to be located under and supporting Digitis Pedis I (7); moving means (M1, M2) for applying a rotational movement to the movable element (5) relative to the fixed main part (4) in a first direction and a second direction, wherein the first direction and the second direction are orthogonal to each other; a controller (12) for controlling the moving means (M1, M2) to generate a defined rotational movement of the movable element (5) relative to the fixed main part (4) in the first direction and the second direction; wherein the moving means (M1, M2) comprise a first motor (M1) for generating the rotational movement of the movable element (5) relative to the fixed main part (4) in the first direction and a second motor (M2) for generating the rotational movement of the movable element (5) relative to the fixed main part (4) in the second direction.

2. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to claim 1, further comprising a platform (11) having a cavity, in which at least the fixed main part (4) and the movable element (5) and the moving means (M1, M2) are located, wherein the fixed main part (4) and the movable element (5) are a part of the upper surface of the platform (11) and the moving means (M1, M2) are located inside the platform (11).

3. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to claim 1 or claim 2, wherein the movable element (5) comprises first means (8) for fixing the Digitis Pedis I (7) to the movable element (5) and / or wherein the main part (5) comprises second fixing means for fixing the Digitis Pedis II to V and at least a part of the foot (3) relative to the main part (4).

4. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to any of claims 1 to 3, further comprising a joint (6) between the fixed main part (4) and the movable element (5), wherein the joint (6) is located in the area of the joint between Digitis Pedis I (7) and the foot (3), wherein the rotation axis (9) of the first rotational movement and the rotation axis (10) of the second rotational movement preferably orthogonally overlap in the area of joint (6) between the fixed main part (4) and the movable element (5).

5. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to claim 4, wherein the joint (6) supports the rotational movement of the movable element (5) relative to the fixed main part (4) simultaneously in the first direction and in the second direction.

6. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to any of claims 1 to 5, wherein the first motor (M1) and / or the second motor (M2) are electrical step motors.

7. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to any of claims 1 to 6, wherein the controller (12) further comprises communication means, particularly wireless communication means, for communicating with a mobile device (13) or remote control, so that the apparatus (2) can be controlled by the user using the mobile device (13) or remote control.

8. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to any of claims 1 to 7, wherein the controller (12) can control the extend and speed of the rotational movement of the movable element (5) relative to the fixed main part (4) in the first direction and the second direction.

9. Apparatus (2) for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to any of claims 1 to 8, wherein the controller (12) comprises a storage for storing information regarding the user, the usage of the apparatus (2) by each user, treatment programs and / or plans, or further information regarding the usage of the apparatus (2).

10. System (1) for the simultaneous treatment, post-operative rehabilitation and / or prevention of Hallux Valgus of two feet (3), the system (1) comprising: two apparatuses (2) according to any of claims 1 to 9, wherein the first apparatus (2) is designed for the left foot (3) of the user and the second apparatus (2) is designed for the right foot (3) of the user and the controller (12) can be a combined controller (12) or separate controllers (12) for the two apparatuses (2), wherein the rotational movement of the movable elements (5) of the two apparatuses (2) preferably can be different from each other, identical, synchronized and / or un-synchronized.

11. System (1) for the simultaneous treatment, post-operative rehabilitation and / or prevention of Hallux Valgus of two feet according to claim 10, further comprises a platform (11), on which the two apparatuses (2) are mounted.

12. System (1) for the simultaneous treatment, post-operative rehabilitation and / or prevention of Hallux Valgus of two feet according to any of claims 10 or claim 11, wherein the platform (11) contains the controller (12) and the moving means (M1, M2) of the two apparatuses (2).

13. Method for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease, wherein the method uses an apparatus (2) according to any of claims 1 to 9 or system (1) according to any of claims 10 to 12 for applying a controlled rotational movement to Digitis Pedis I (7) relative to Digitis Pedis II to V in a first direction and a second direction.

14. Method for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to claim 13, wherein the method comprises an initiation step, in which the user can define the maximum rotational movement of Digitis Pedis I (7) relative to Digitis Pedis II to V in the first direction and in the second direction.

15. Method for the treatment, post-operative rehabilitation and / or prevention of Hallux Valgus disease according to claim 13 or 14, wherein the method executes predefined rotational movement programs, which can be adapted to consider improvements in Hallux Valgus disease condition over time.

Images