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纽扣畸形

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Extensor central-slip injury at the middle finger joint; early splinting prevents the zigzag deformity, established cases need surgery.

Updated Jun 2026
指端钮扣畸形示意图——中间关节弯曲，指尖向后倾斜。
纽扣畸形：中指关节保持弯曲，指尖向后倾斜。 Kieran Hirpara 4.0

本页面由机器翻译，尚未经临床医生审核。英文版本为权威版本。

您的感受

您可能会注意到中指近端指间关节向内侧弯曲，而远端指间关节向外侧伸展。这种特定的形态称为纽扣花样畸形（boutonniere deformity）。当手指背侧的肌腱发生错位时，就会出现这种情况。这种形态变化可能是逐渐发展的，也可能在受伤后突然出现。

疼痛通常集中在手指的中节指间关节。不适感可能表现为深部酸痛，或在活动手指时出现刺痛。您可能会发现，完全弯曲手指比保持伸直状态引起更剧烈的疼痛。需要抓握或捏取的活动会变得困难。简单的日常任务，如扣衬衫纽扣、转动门把手或打字，可能会感到别扭或疼痛。

您的手指可能会感到僵硬，尤其是在早晨。您可能会注意到中节指间关节周围出现肿胀。这种僵硬会使握拳变得困难。如果您患有类风湿关节炎，畸形的进展方式可能与创伤引起的不同。在没有关节炎或外伤的情况下，约 13% 的人会出现这种情况。

您的手指末端也可能感到不稳定。在某些情况下，远端指间关节会比平时更向下弯曲。这会使您将手指平放在桌面上变得困难。您可能会发现难以用这只手推开沉重的门或提起轻物。侧卧睡觉时，身体可能会压迫变形的指头，引起不适。

区分这种真正的畸形与外观相似的另一种损伤——假性纽扣花样畸形（pseudoboutonniere）非常重要。这两种情况需要不同的治疗。您的外科医生会仔细观察您手指的活动情况以进行鉴别。准确了解您的症状有助于为您制定最佳的治疗方案。

实际发生了什么

您的手指关节是一个由骨骼、肌腱和保护性套筒（称为关节囊）组成的复杂铰链结构。在健康的手指中，中央肌腱沿手指正中垂直下行，协助手指伸直。这根肌腱就像拉动手指张开的主绳索。

在纽扣畸形（Boutonnière deformity）中，这根中央肌腱受损或减弱。它可能因创伤而撕裂，或因类风湿关节炎等疾病而被拉长。当这一中央支撑失效时，手指内的力量平衡发生改变。通常协助弯曲手指的侧方肌腱开始过度牵拉。

这就像一条脱轨的拉链。部件仍然存在，但不再平滑地滑动。由于中央肌腱无法将结构固定到位，侧方肌腱向两侧滑移。这导致手指的中节指间关节向内弯曲，而远端指间关节可能向外突出。

这种张力的改变导致手指看起来弯曲且感觉僵硬。通常保持关节稳定的关节囊变得紧张且失衡。随着时间的推移，组织会适应这种新的错误位置。这就是为什么即使尝试夹板固定或治疗等保守治疗，畸形仍可能持续存在。

该问题中最重要的因素是肌腱及相关结构的变化。这些变化发生得很早，因此准确诊断至关重要。您的外科医生需要区分真正的纽扣畸形和一种类似的问题，称为假性纽扣畸形（pseudoboutonniere injury）。治疗路径完全取决于能否正确做出这一区分。

如果损伤在早期被发现，您的外科医生可能会专注于恢复中央肌腱的位置。在某些情况下，他们可能会使用取自另一根肌腱的一小块组织来重建中央腱束。这种新移植物模拟原始肌腱的功能，同时保持其他手指活动的完整性。目标是保持关节居中且稳定，以便您能够再次活动它。

然而，如果畸形已存在很长时间，组织可能发生永久性改变。在这些慢性病例中，简单修复可能无效。该疾病的自然病程通常导致持续性问题，尤其是当涉及类风湿关节炎时。在这些情况下，软组织重建的长期结果可能不可靠。有时，需要进行更确定的挽救性手术来矫正手指的形状和功能。

我们能采取的措施

我们从非手术治疗开始，以恢复关节活动度。您将尝试系列石膏固定以获得充分的伸展。随后需佩戴相对运动屈曲支具三个月。您的外科医生也可能建议进行物理治疗。通过非手术治疗可实现一到两个等级的活动度改善。然而，即使经过系统的保守治疗，畸形仍可能持续存在。我们使用相对运动屈曲支具来增加远端指间关节的主动屈曲。这有助于改善您中指关节的伸展。在考虑手术之前，必须给予这种方法足够的时间来发挥作用。

药物治疗侧重于缓解不适和控制炎症。如果您的畸形与类风湿关节炎有关，我们将针对潜在的疾病活动进行治疗。止痛药和非甾体抗炎药有助于缓解不适。可能会提供注射治疗以减少关节肿胀。这些治疗旨在您在接受理疗期间保持关节活动自如且无痛。目标是在不进行手术的情况下稳定病情并改善您的日常功能。

当保守治疗达到极限时，会考虑手术治疗。在做出决定之前，我们会区分真性纽扣花样畸形与假性纽扣花样损伤。这一区别对于确定临床管理方案至关重要。成功的手术结果取决于完善的术前检查、畸形的正确分期以及适当的治疗时机。如果需要软组织重建，我们了解长期结果可能不可靠。复发性或持续性畸形最好通过补救性手术进行治疗。在某些情况下，Y形肌腱移植物可提供良好或极佳的效果。您的外科医生将在手术干预前确定真正的病因。这确保所选择的手术方案符合您的特定解剖结构和需求。

预期情况

您的预后很大程度上取决于这是真正的畸形还是称为假性纽扣孔畸形的类似损伤。您的外科医生必须先确诊，因为治疗路径完全取决于这一区分。如果您患有类风湿关节炎，软组织修复的长期结果通常不可靠。在这种情况下，持续或复发的畸形可能需要在后期进行挽救性手术。

对于大多数没有类风湿关节炎的患者，该病症并不总能自行消退。非手术治疗可以将您的活动度提高一到两个等级。然而，即使完成专门的保守治疗，可见的畸形仍可能持续存在。如果保守治疗不足，手术是一个强有力的选择。据报道，在系列病例中，Y形肌腱移植在18例患者中有16例取得了良好或优秀的结果。成功还取决于您的外科医生进行全面的检查、正确地对畸形进行分期，并选择正确的干预时机。

恢复是一个渐进的过程。如果您从非手术治疗开始，您可能使用系列石膏固定来伸直手指，随后使用相对运动屈位矫形器三个月。这种方法对于慢性病例产生的结果与其他方法相似，并且通常在考虑手术之前尝试。您应该预期佩戴矫形器数月，以维持伸直并改善屈曲。

如果需要手术，目标是恢复功能和排列。您需要密切遵循外科医生的具体指示。这种畸形的自然病程可能有所不同，但早期和准确的管理能带来最佳结果。对愈合过程保持耐心。肌腱和关节适应新位置需要时间。您的外科医生将指导您度过每个阶段，以确保尽可能好地恢复您的日常活动。

何时就诊

如果您发现手指中间关节出现弯曲且无法伸直，请咨询您的全科医生。如果持续疼痛且休息后无改善，请要求专科医生评估。如果您感到手指无力或不稳，请及时就医。如果手指在使用时出现卡住或突然无力，请就诊。如果症状干扰您的睡眠或工作，请联系您的外科医生。畸形突然加重也需要及时关注。准确的诊断对于适当的治疗至关重要。区分真正的畸形与类似损伤有助于确定正确的治疗方案。早期评估可确保手部功能获得最佳预后。

Reviewed by Dr Kieran Hirpara · 10 June 2026.

Talk to your treating clinician for advice specific to you.

For an appointment with the CQ Hand + Upper Limb team, ask your GP about a referral or visit www.cqupperlimb.com.

Evidence & references

Overview

  • Differentiating a true boutonniere deformity from a pseudoboutonniere injury is critical in determining clinical management [2].
  • An understanding of the anatomy, clinical presentation, treatment options, and expected outcomes is crucial for optimal treatment of posttraumatic boutonniere and swan neck deformities [4].
  • The natural history of the boutonnière deformity in rheumatoid arthritis is outlined, and a simple method of repair is described [3].
  • The prevalence of boutonnière deformity without rheumatoid arthritis or trauma is approximately 13% [5].
  • One to two grades of ROM improvement can be achieved with nonoperative treatment, although deformity can persist even after dedicated conservative management [8].
  • Similar results occurred for chronic boutonniere deformity using serial casting for adequate extension followed by 3 months of RMF orthotic use, which should be attempted prior to surgical intervention [1].
  • Long-term results following soft tissue reconstruction for boutonniere deformity in rheumatoid arthritis are unreliable, and recurrent or persistent deformity is best treated with a salvage procedure [9].
  • A successful operative result for swan-neck and boutonniere deformities in the rheumatoid hand depends on complete preoperative examination, correct staging of the deformity, and proper timing of treatment [10].
  • The Y-shaped tendon graft can be a useful procedure for the correction of chronic boutonniere deformity, providing good or excellent results in 16 of 18 patients in one series [6].
  • Detachment of up to two-thirds of the phalangeal length was effective in reducing extensor lag of the DIP joint and did not cause any boutonniere deformity in a cadaveric model of fractional Fowler tenotomy for chronic mallet finger [7].

Anatomy & Pathophysiology

  • Boutonnière deformity can persist even after dedicated conservative management [8].
  • One to two grades of range of motion improvement can be achieved with nonoperative treatment of Boutonnière deformity [8].
  • Accurate diagnosis and treatment of finger metacarpophalangeal joint injuries begins with an understanding of all potential diagnoses [15].
  • Hand surgery and hand therapy practice interventions, including use of relative motion flexion orthoses for management of non-surgical and surgical extensor mechanism injuries, may benefit from an in-depth look at extensor mechanism zone III and IV anatomy and biomechanics [19].
  • The most important factor in the development of finger deformities is the changes occurring in the tendons and related structures, especially in early stages [21].
  • Reconstruction of the extensor central slip using a distally based flexor digitorum superficialis slip provides a robust repair that anatomically mimics the extensor central slip while maintaining the function of the donor FDS tendon [24].
  • The main goals of any treatment of a proximal interphalangeal joint complication are maintaining concentric reduction of the joint, restoring joint stability, and facilitating early range-of-motion exercises [33].

Classification

  • Differentiating a true boutonniere deformity from a pseudoboutonniere injury is critical in determining clinical management [2].
  • The natural history of the boutonnière deformity in rheumatoid arthritis is outlined [3].
  • The prevalence of boutonnière deformity without rheumatoid arthritis or trauma is approximately 13% [5].
  • A modified Terrono classification for Type 1 thumb deformity in rheumatoid arthritis could detect advanced deformity earlier and was more strongly correlated with hand function [17].

Clinical Presentation

  • Differentiating a true boutonniere deformity from a pseudoboutonniere injury is critical in determining clinical management [2].
  • An understanding of the clinical presentation is crucial for optimal treatment of posttraumatic boutonnière and swan neck deformities [4].
  • Accurate diagnosis of finger metacarpophalangeal joint injuries begins with an understanding of all potential diagnoses [15].
  • The natural history of the boutonnière deformity in rheumatoid arthritis is outlined in historical literature [3].
  • The prevalence of boutonnière deformity without rheumatoid arthritis or trauma is approximately 13% [5].
  • The swan neck deformity can progress significantly with time due to increasing distal interphalangeal joint flexion contracture [14].

Investigations

  • Differentiating a true boutonniere deformity from a pseudoboutonniere injury is critical in determining clinical management [2].
  • An understanding of the anatomy, clinical presentation, treatment options, and expected outcomes is crucial for optimal treatment of posttraumatic boutonnière and swan neck deformities [4].
  • Accurate diagnosis and treatment of finger metacarpophalangeal joint injuries begins with an understanding of all potential diagnoses [15].
  • It is necessary to determine the true etiology before surgical intervention [12].
  • A successful operative result depends on complete preoperative examination, correct staging of the deformity, and proper timing of treatment [10].
  • Cortical breaks were commonly visualized in MCP and PIP joints with HR-pQCT and microCT [37].

Treatment

  • Serial casting for adequate extension followed by 3 months of relative motion flexion (RMF) orthotic use should be attempted prior to surgical intervention for chronic boutonniere deformity [1].
  • Differentiating a true boutonniere deformity from a pseudoboutonniere injury is critical in determining clinical management [2].
  • A simple method of repair is described for the boutonnière deformity in rheumatoid arthritis [3].
  • Understanding the anatomy, clinical presentation, treatment options, and expected outcomes is crucial for optimal treatment of posttraumatic boutonnière and swan neck deformities [4].
  • The prevalence of boutonnière deformity without rheumatoid arthritis or trauma is approximately 13% [5].
  • The Y-shaped tendon graft is a useful procedure for the correction of chronic boutonniere deformity, providing good or excellent results in 16 of 18 patients in a reported series [6].
  • Detachment of up to two-thirds of the phalangeal length is effective in reducing extensor lag of the DIP joint and does not cause any boutonniere deformity in a cadaveric model [7].
  • One to two grades of ROM improvement can be achieved with nonoperative treatment, although deformity can persist even after dedicated conservative management [8].
  • Long-term results following soft tissue reconstruction for boutonniere deformity in rheumatoid arthritis are unreliable, and recurrent or persistent deformity is best treated with a salvage procedure [9].
  • A successful operative result for swan-neck and boutonniere deformities in the rheumatoid hand depends on complete preoperative examination, correct staging of the deformity, and proper timing of treatment [10].
  • Metacarpophalangeal joint arthroplasty improves function and deformity and achieves nearly uniform patient satisfaction in rheumatoid arthritis [11].
  • One technique does not treat all finger deformities uniformly, highlighting the need to determine the true etiology before surgical intervention [12].
  • The use of relative motion flexion orthoses (RMFO) is effective in increasing active distal interphalangeal joint flexion and improving PIP extension in patients with Burton stage 1 chronic boutonniere deformity [13].

Complications

  • Differentiating a true boutonniere deformity from a pseudoboutonniere injury is critical in determining clinical management [2].
  • The prevalence of boutonniere deformity without rheumatoid arthritis or trauma is approximately 13% [5].
  • Detachment of up to two-thirds of the phalangeal length was effective in reducing extensor lag of the DIP joint and did not cause any boutonniere deformity in a cadaveric model [7].
  • Long-term results following soft tissue reconstruction for boutonniere finger deformity in rheumatoid arthritis are unreliable [9].
  • Recurrent or persistent deformity is best treated with a salvage procedure [9].
  • A successful operative result depends on complete preoperative examination, correct staging of the deformity, and proper timing of treatment [10].
  • One technique does not treat all deformities uniformly, highlighting the need to determine the true etiology before surgical intervention [12].
  • Swan neck deformity can progress significantly with time due to increasing DIPJ flexion contracture [14].

Recovery

  • Serial casting for adequate extension followed by 3 months of relative motion flexion (RMF) orthotic use yields similar results for chronic boutonniere deformity and should be attempted prior to surgical intervention [1].
  • One to two grades of range of motion (ROM) improvement can be achieved with nonoperative treatment, although deformity can persist even after dedicated conservative management [8].
  • The Y-shaped tendon graft is a useful procedure for the correction of chronic boutonniere deformity, providing good or excellent results in 16 of 18 patients in a reported series [6].
  • The use of relative motion flexion orthoses (RMFO) is effective in increasing active distal interphalangeal joint flexion and improving proximal interphalangeal (PIP) extension in patients with Burton stage 1 chronic boutonniere deformity [13].
  • Long-term results following soft tissue reconstruction for boutonniere deformity in rheumatoid arthritis are unreliable, and recurrent or persistent deformity is best treated with a salvage procedure [9].
  • A successful operative result for boutonniere deformity depends on complete preoperative examination, correct staging of the deformity, and proper timing of treatment [10].

Key Evidence

  • [L4] Similar results occurred for chronic boutonniere deformity using serial casting for adequate extension followed by 3 months of RMF orthotic use, which should be attempted prior to surgical intervention. [1] (10.1016/j.jht.2023.02.005)
  • [L5] Differentiating a true boutonniere deformity from a pseudoboutonniere injury is critical in determining clinical management. [2] (10.1016/j.jhsa.2022.10.019)
  • [L4] The natural history of the boutonnière deformity in rheumatoid arthritis is outlined, and a simple method of repair is described. [3] (10.2106/00004623-196951070-00009)
  • [L5] An understanding of the anatomy, clinical presentation, treatment options, and expected outcomes is crucial for optimal treatment of posttraumatic boutonnière and swan neck deformities. [4] (10.5435/jaaos-d-14-00272)
  • [L3] The prevalence of boutonnière deformity without rheumatoid arthritis or trauma is approximately 13%. [5] (10.1177/1753193417704610)
  • [L4] The Y-shaped tendon graft can be a useful procedure for the correction of chronic boutonniere deformity; in our patient series, this provided good or excellent results in 16 of 18 patients. [6] (10.1016/j.jhsa.2021.01.003)
  • [L5] Detachment of up to two-thirds of the phalangeal length was effective in reducing extensor lag of the DIP joint and did not cause any boutonniere deformity in this cadaveric model. [7] (10.1016/j.jhsa.2012.07.039)
  • [L3] One to two grades of ROM improvement can be achieved, although deformity can persist even after dedicated conservative management. [8] (10.1016/j.jht.2025.02.013)
  • [L5] Long-term results following soft tissue reconstruction are unreliable, and recurrent or persistent deformity is best treated with a salvage procedure. [9] (10.1016/j.jhsa.2011.05.029)
  • [L5] A successful operative result depends on complete preoperative examination, correct staging of the deformity, and proper timing of treatment. [10] (10.5435/00124635-199903000-00002)
  • [L5] Follow-up studies show that this surgery improves function and deformity and achieves nearly uniform patient satisfaction. [11] (10.5435/00124635-200305000-00005)
  • [L5] It emphasizes that one technique does not treat all deformities uniformly and highlights the need to determine the true etiology before surgical intervention. [12] (10.1016/j.jhsa.2022.07.008)
  • [L4] The use of RMFO is effective in increasing active distal interphalangeal joint flexion and improving PIP extension in patients with Burton stage 1 chronic boutonniere deformity. [13] (10.1016/j.jhsa.2022.08.007)
  • [L5] The swan neck deformity in this individual progressed significantly with time because of increasing DIPJ flexion contracture. [14] (10.1016/j.jht.2009.11.005)
  • [L5] Accurate diagnosis and treatment of finger metacarpophalangeal joint injuries in athletes begins with an understanding of all potential diagnoses, allowing for safe and early return to play. [15] (10.5435/jaaos-d-21-01031)
  • [L3] The modified classification could detect advanced deformity earlier and was more strongly correlated with hand function. [17] (10.1177/1753193419886719)
  • [L5] Hand surgery and hand therapy practice interventions, including use of RMF orthoses for management of non-surgical and surgical EM injuries may benefit from an in-depth look at the EM zone III and IV anatomy and biomechanics. [19] (10.1016/j.jht.2023.01.002)
  • [L4] The most important factor in the development of finger deformities is the changes occurring in the tendons and related structures, especially in early stages. [21] (10.2106/00004623-195739030-00006)
  • [L4] The modified technique provides a robust repair that anatomically mimics the extensor central slip yet maintains the function of the donor FDS tendon. [24] (10.1016/j.jhsa.2009.01.025)
  • [L5] The main goals of any treatment of a PIP joint complication are maintaining concentric reduction of the joint, restoring joint stability, and facilitating early range-of-motion exercises. [33] (10.1016/j.hcl.2017.12.014)
  • [L4] Cortical breaks were commonly visualized in MCP and PIP joints with HR-pQCT and microCT. [37] (10.1186/s12891-016-1148-y)

References

[1] The relative motion concept in acute and chronic boutonniere deformity: Invited commentary. Journal of Hand Therapy. 2023. DOI: 10.1016/j.jht.2023.02.005 [2] Boutonniere Versus Pseudoboutonniere Deformities: Pathoanatomy, Diagnosis, and Treatment. The Journal of Hand Surgery. 2023. DOI: 10.1016/j.jhsa.2022.10.019 [3] Correction of the Rheumatoid Boutonnière Deformity. The Journal of Bone & Joint Surgery. 1969. DOI: 10.2106/00004623-196951070-00009 [4] Posttraumatic Boutonnière and Swan Neck Deformities. Journal of the American Academy of Orthopaedic Surgeons. 2015. DOI: 10.5435/jaaos-d-14-00272 [5] Thumb boutonnière deformity without rheumatoid arthritis or trauma. Journal of Hand Surgery (European Volume). 2017. DOI: 10.1177/1753193417704610 [6] Y-Shaped Tendon Graft—A Technique in the Reconstruction of Posttraumatic Chronic Boutonniere Deformity. The Journal of Hand Surgery. 2021. DOI: 10.1016/j.jhsa.2021.01.003 [7] Fractional Fowler Tenotomy for Chronic Mallet Finger: A Cadaveric Biomechanical Study. The Journal of Hand Surgery. 2012. DOI: 10.1016/j.jhsa.2012.07.039 [8] Nonoperative treatment of the Boutonniere deformity: Is there a difference in outcomes?. Journal of Hand Therapy. 2025. DOI: 10.1016/j.jht.2025.02.013 [9] Treatment of Boutonniere Finger Deformity in Rheumatoid Arthritis. The Journal of Hand Surgery. 2011. DOI: 10.1016/j.jhsa.2011.05.029 [10] Operative Correction of Swan-Neck and Boutonniere Deformities in the Rheumatoid Hand. Journal of the American Academy of Orthopaedic Surgeons. 1999. DOI: 10.5435/00124635-199903000-00002 [11] Metacarpophalangeal Joint Arthroplasty in Rheumatoid Arthritis. Journal of the American Academy of Orthopaedic Surgeons. 2003. DOI: 10.5435/00124635-200305000-00005 [12] Clarification of Extensor Tenotomy for Finger Deformities. The Journal of Hand Surgery. 2022. DOI: 10.1016/j.jhsa.2022.07.008 [13] The Use of Relative Motion Flexion Orthoses for Chronic Boutonniere Deformity. The Journal of Hand Surgery. 2024. DOI: 10.1016/j.jhsa.2022.08.007 [14] Swan Neck Deformity after Distal Interphalangeal Joint Flexion Contractures: A Biomechanical Analysis. Journal of Hand Therapy. 2010. DOI: 10.1016/j.jht.2009.11.005 [15] Finger Metacarpophalangeal Joint Injuries in Athletes: Evaluation, Diagnosis, Treatment, and Return to Play. Journal of the American Academy of Orthopaedic Surgeons. 2023. DOI: 10.5435/jaaos-d-21-01031 [17] A modified Terrono classification for Type 1 thumb deformity in rheumatoid arthritis: a cross-sectional analysis. Journal of Hand Surgery (European Volume). 2019. DOI: 10.1177/1753193419886719 [19] An in-depth look at zone III and IV anatomy of the finger extensor mechanism and some clinical implications for use of the relative motion flexion orthosis. Journal of Hand Therapy. 2023. DOI: 10.1016/j.jht.2023.01.002 [21] Finger Deformities Caused by Rheumatoid Arthritis. The Journal of Bone & Joint Surgery. 1957. DOI: 10.2106/00004623-195739030-00006 [24] Reconstruction of the Extensor Central Slip Using a Distally Based Flexor Digitorum Superficialis Slip. The Journal of Hand Surgery. 2009. DOI: 10.1016/j.jhsa.2009.01.025 [33] Complications of Proximal Interphalangeal Joint Injuries. Hand Clinics. 2018. DOI: 10.1016/j.hcl.2017.12.014 [37] Visual detection of cortical breaks in hand joints: reliability and validity of high-resolution peripheral quantitative CT compared to microCT. BMC Musculoskeletal Disorders. 2016. DOI: 10.1186/s12891-016-1148-y

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NC NonCommercial — not for commercial use

Attribution-NonCommercial 4.0 International

Creative Commons Corporation ("Creative Commons") is not a law firm and does not provide legal services or legal advice. Distribution of Creative Commons public licenses does not create a lawyer-client or other relationship. Creative Commons makes its licenses and related information available on an "as-is" basis. Creative Commons gives no warranties regarding its licenses, any material licensed under their terms and conditions, or any related information. Creative Commons disclaims all liability for damages resulting from their use to the fullest extent possible.

Using Creative Commons Public Licenses

Creative Commons public licenses provide a standard set of terms and conditions that creators and other rights holders may use to share original works of authorship and other material subject to copyright and certain other rights specified in the public license below. The following considerations are for informational purposes only, are not exhaustive, and do not form part of our licenses.

Considerations for licensors: Our public licenses are intended for use by those authorized to give the public permission to use material in ways otherwise restricted by copyright and certain other rights. Our licenses are irrevocable. Licensors should read and understand the terms and conditions of the license they choose before applying it. Licensors should also secure all rights necessary before applying our licenses so that the public can reuse the material as expected. Licensors should clearly mark any material not subject to the license. This includes other CC- licensed material, or material used under an exception or limitation to copyright. More considerations for licensors: wiki.creativecommons.org/Considerations_for_licensors

Considerations for the public: By using one of our public licenses, a licensor grants the public permission to use the licensed material under specified terms and conditions. If the licensor's permission is not necessary for any reason--for example, because of any applicable exception or limitation to copyright--then that use is not regulated by the license. Our licenses grant only permissions under copyright and certain other rights that a licensor has authority to grant. Use of the licensed material may still be restricted for other reasons, including because others have copyright or other rights in the material. A licensor may make special requests, such as asking that all changes be marked or described. Although not required by our licenses, you are encouraged to respect those requests where reasonable. More considerations for the public: wiki.creativecommons.org/Considerations_for_licensees

Creative Commons Attribution-NonCommercial 4.0 International Public License

By exercising the Licensed Rights (defined below), You accept and agree to be bound by the terms and conditions of this Creative Commons Attribution-NonCommercial 4.0 International Public License ("Public License"). To the extent this Public License may be interpreted as a contract, You are granted the Licensed Rights in consideration of Your acceptance of these terms and conditions, and the Licensor grants You such rights in consideration of benefits the Licensor receives from making the Licensed Material available under these terms and conditions.

Section 1 -- Definitions.

a. Adapted Material means material subject to Copyright and Similar Rights that is derived from or based upon the Licensed Material and in which the Licensed Material is translated, altered, arranged, transformed, or otherwise modified in a manner requiring permission under the Copyright and Similar Rights held by the Licensor. For purposes of this Public License, where the Licensed Material is a musical work, performance, or sound recording, Adapted Material is always produced where the Licensed Material is synched in timed relation with a moving image.

b. Adapter's License means the license You apply to Your Copyright and Similar Rights in Your contributions to Adapted Material in accordance with the terms and conditions of this Public License.

c. Copyright and Similar Rights means copyright and/or similar rights closely related to copyright including, without limitation, performance, broadcast, sound recording, and Sui Generis Database Rights, without regard to how the rights are labeled or categorized. For purposes of this Public License, the rights specified in Section 2(b)(1)-(2) are not Copyright and Similar Rights.

d. Effective Technological Measures means those measures that, in the absence of proper authority, may not be circumvented under laws fulfilling obligations under Article 11 of the WIPO Copyright Treaty adopted on December 20, 1996, and/or similar international agreements.

e. Exceptions and Limitations means fair use, fair dealing, and/or any other exception or limitation to Copyright and Similar Rights that applies to Your use of the Licensed Material.

f. Licensed Material means the artistic or literary work, database, or other material to which the Licensor applied this Public License.

g. Licensed Rights means the rights granted to You subject to the terms and conditions of this Public License, which are limited to all Copyright and Similar Rights that apply to Your use of the Licensed Material and that the Licensor has authority to license.

h. Licensor means the individual(s) or entity(ies) granting rights under this Public License.

i. NonCommercial means not primarily intended for or directed towards commercial advantage or monetary compensation. For purposes of this Public License, the exchange of the Licensed Material for other material subject to Copyright and Similar Rights by digital file-sharing or similar means is NonCommercial provided there is no payment of monetary compensation in connection with the exchange.

j. Share means to provide material to the public by any means or process that requires permission under the Licensed Rights, such as reproduction, public display, public performance, distribution, dissemination, communication, or importation, and to make material available to the public including in ways that members of the public may access the material from a place and at a time individually chosen by them.

k. Sui Generis Database Rights means rights other than copyright resulting from Directive 96/9/EC of the European Parliament and of the Council of 11 March 1996 on the legal protection of databases, as amended and/or succeeded, as well as other essentially equivalent rights anywhere in the world.

l. You means the individual or entity exercising the Licensed Rights under this Public License. Your has a corresponding meaning.

Section 2 -- Scope.

a. License grant.

1. Subject to the terms and conditions of this Public License, the Licensor hereby grants You a worldwide, royalty-free, non-sublicensable, non-exclusive, irrevocable license to exercise the Licensed Rights in the Licensed Material to:

a. reproduce and Share the Licensed Material, in whole or in part, for NonCommercial purposes only; and

b. produce, reproduce, and Share Adapted Material for NonCommercial purposes only.

2. Exceptions and Limitations. For the avoidance of doubt, where Exceptions and Limitations apply to Your use, this Public License does not apply, and You do not need to comply with its terms and conditions.

3. Term. The term of this Public License is specified in Section 6(a).

4. Media and formats; technical modifications allowed. The Licensor authorizes You to exercise the Licensed Rights in all media and formats whether now known or hereafter created, and to make technical modifications necessary to do so. The Licensor waives and/or agrees not to assert any right or authority to forbid You from making technical modifications necessary to exercise the Licensed Rights, including technical modifications necessary to circumvent Effective Technological Measures. For purposes of this Public License, simply making modifications authorized by this Section 2(a) (4) never produces Adapted Material.

5. Downstream recipients.

a. Offer from the Licensor -- Licensed Material. Every recipient of the Licensed Material automatically receives an offer from the Licensor to exercise the Licensed Rights under the terms and conditions of this Public License.

b. No downstream restrictions. You may not offer or impose any additional or different terms or conditions on, or apply any Effective Technological Measures to, the Licensed Material if doing so restricts exercise of the Licensed Rights by any recipient of the Licensed Material.

6. No endorsement. Nothing in this Public License constitutes or may be construed as permission to assert or imply that You are, or that Your use of the Licensed Material is, connected with, or sponsored, endorsed, or granted official status by, the Licensor or others designated to receive attribution as provided in Section 3(a)(1)(A)(i).

b. Other rights.

1. Moral rights, such as the right of integrity, are not licensed under this Public License, nor are publicity, privacy, and/or other similar personality rights; however, to the extent possible, the Licensor waives and/or agrees not to assert any such rights held by the Licensor to the limited extent necessary to allow You to exercise the Licensed Rights, but not otherwise.

2. Patent and trademark rights are not licensed under this Public License.

3. To the extent possible, the Licensor waives any right to collect royalties from You for the exercise of the Licensed Rights, whether directly or through a collecting society under any voluntary or waivable statutory or compulsory licensing scheme. In all other cases the Licensor expressly reserves any right to collect such royalties, including when the Licensed Material is used other than for NonCommercial purposes.

Section 3 -- License Conditions.

Your exercise of the Licensed Rights is expressly made subject to the following conditions.

a. Attribution.

1. If You Share the Licensed Material (including in modified form), You must:

a. retain the following if it is supplied by the Licensor with the Licensed Material:

i. identification of the creator(s) of the Licensed Material and any others designated to receive attribution, in any reasonable manner requested by the Licensor (including by pseudonym if designated);

ii. a copyright notice;

iii. a notice that refers to this Public License;

iv. a notice that refers to the disclaimer of warranties;

v. a URI or hyperlink to the Licensed Material to the extent reasonably practicable;

b. indicate if You modified the Licensed Material and retain an indication of any previous modifications; and

c. indicate the Licensed Material is licensed under this Public License, and include the text of, or the URI or hyperlink to, this Public License.

2. You may satisfy the conditions in Section 3(a)(1) in any reasonable manner based on the medium, means, and context in which You Share the Licensed Material. For example, it may be reasonable to satisfy the conditions by providing a URI or hyperlink to a resource that includes the required information.

3. If requested by the Licensor, You must remove any of the information required by Section 3(a)(1)(A) to the extent reasonably practicable.

4. If You Share Adapted Material You produce, the Adapter's License You apply must not prevent recipients of the Adapted Material from complying with this Public License.

Section 4 -- Sui Generis Database Rights.

Where the Licensed Rights include Sui Generis Database Rights that apply to Your use of the Licensed Material:

a. for the avoidance of doubt, Section 2(a)(1) grants You the right to extract, reuse, reproduce, and Share all or a substantial portion of the contents of the database for NonCommercial purposes only;

b. if You include all or a substantial portion of the database contents in a database in which You have Sui Generis Database Rights, then the database in which You have Sui Generis Database Rights (but not its individual contents) is Adapted Material; and

c. You must comply with the conditions in Section 3(a) if You Share all or a substantial portion of the contents of the database.

For the avoidance of doubt, this Section 4 supplements and does not replace Your obligations under this Public License where the Licensed Rights include other Copyright and Similar Rights.

Section 5 -- Disclaimer of Warranties and Limitation of Liability.

a. UNLESS OTHERWISE SEPARATELY UNDERTAKEN BY THE LICENSOR, TO THE EXTENT POSSIBLE, THE LICENSOR OFFERS THE LICENSED MATERIAL AS-IS AND AS-AVAILABLE, AND MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND CONCERNING THE LICENSED MATERIAL, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHER. THIS INCLUDES, WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT, ABSENCE OF LATENT OR OTHER DEFECTS, ACCURACY, OR THE PRESENCE OR ABSENCE OF ERRORS, WHETHER OR NOT KNOWN OR DISCOVERABLE. WHERE DISCLAIMERS OF WARRANTIES ARE NOT ALLOWED IN FULL OR IN PART, THIS DISCLAIMER MAY NOT APPLY TO YOU.

b. TO THE EXTENT POSSIBLE, IN NO EVENT WILL THE LICENSOR BE LIABLE TO YOU ON ANY LEGAL THEORY (INCLUDING, WITHOUT LIMITATION, NEGLIGENCE) OR OTHERWISE FOR ANY DIRECT, SPECIAL, INDIRECT, INCIDENTAL, CONSEQUENTIAL, PUNITIVE, EXEMPLARY, OR OTHER LOSSES, COSTS, EXPENSES, OR DAMAGES ARISING OUT OF THIS PUBLIC LICENSE OR USE OF THE LICENSED MATERIAL, EVEN IF THE LICENSOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSSES, COSTS, EXPENSES, OR DAMAGES. WHERE A LIMITATION OF LIABILITY IS NOT ALLOWED IN FULL OR IN PART, THIS LIMITATION MAY NOT APPLY TO YOU.

c. The disclaimer of warranties and limitation of liability provided above shall be interpreted in a manner that, to the extent possible, most closely approximates an absolute disclaimer and waiver of all liability.

Section 6 -- Term and Termination.

a. This Public License applies for the term of the Copyright and Similar Rights licensed here. However, if You fail to comply with this Public License, then Your rights under this Public License terminate automatically.

b. Where Your right to use the Licensed Material has terminated under Section 6(a), it reinstates:

1. automatically as of the date the violation is cured, provided it is cured within 30 days of Your discovery of the violation; or

2. upon express reinstatement by the Licensor.

For the avoidance of doubt, this Section 6(b) does not affect any right the Licensor may have to seek remedies for Your violations of this Public License.

c. For the avoidance of doubt, the Licensor may also offer the Licensed Material under separate terms or conditions or stop distributing the Licensed Material at any time; however, doing so will not terminate this Public License.

d. Sections 1, 5, 6, 7, and 8 survive termination of this Public License.

Section 7 -- Other Terms and Conditions.

a. The Licensor shall not be bound by any additional or different terms or conditions communicated by You unless expressly agreed.

b. Any arrangements, understandings, or agreements regarding the Licensed Material not stated herein are separate from and independent of the terms and conditions of this Public License.

Section 8 -- Interpretation.

a. For the avoidance of doubt, this Public License does not, and shall not be interpreted to, reduce, limit, restrict, or impose conditions on any use of the Licensed Material that could lawfully be made without permission under this Public License.

b. To the extent possible, if any provision of this Public License is deemed unenforceable, it shall be automatically reformed to the minimum extent necessary to make it enforceable. If the provision cannot be reformed, it shall be severed from this Public License without affecting the enforceability of the remaining terms and conditions.

c. No term or condition of this Public License will be waived and no failure to comply consented to unless expressly agreed to by the Licensor.

d. Nothing in this Public License constitutes or may be interpreted as a limitation upon, or waiver of, any privileges and immunities that apply to the Licensor or You, including from the legal processes of any jurisdiction or authority.

Creative Commons is not a party to its public licenses. Notwithstanding, Creative Commons may elect to apply one of its public licenses to material it publishes and in those instances will be considered the “Licensor.” The text of the Creative Commons public licenses is dedicated to the public domain under the CC0 Public Domain Dedication. Except for the limited purpose of indicating that material is shared under a Creative Commons public license or as otherwise permitted by the Creative Commons policies published at creativecommons.org/policies, Creative Commons does not authorize the use of the trademark "Creative Commons" or any other trademark or logo of Creative Commons without its prior written consent including, without limitation, in connection with any unauthorized modifications to any of its public licenses or any other arrangements, understandings, or agreements concerning use of licensed material. For the avoidance of doubt, this paragraph does not form part of the public licenses.

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