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Os Acromiale

Patient-facing topic on os acromiale — failed fusion of an acromial ossification centre that may cause shoulder pain and contribute to subacromial impingement.

Updated May 2026
Một minh họa vẽ tay của một bản vẽ giải phẫu về os acromiale, mỏm cùng với một mảnh xương riêng biệt chưa hợp nhất.
Os acromiale: phần trước của mỏm cùng vai chưa hợp nhất với phần còn lại của mỏm cùng trong quá trình trưởng thành xương. Kieran Hirpara 4.0

Trang này được dịch bằng máy và chưa được bác sĩ kiểm tra. Bản tiếng Anh là bản chính thức.

Những gì bạn đang cảm nhận

Bạn có thể cảm thấy đau ở phần trên của vai. Tình trạng này ảnh hưởng đến khoảng 2,13% bệnh nhân mắc các vấn đề về vai cần chụp cộng hưởng từ (MRI). Cơn đau thường bắt nguồn từ một vết rách ở nhóm cơ và gân xoay cuff (rotator cuff), đây là nhóm cơ và gân giúp cử động cánh tay của bạn. Vết rách này xảy ra do mảnh xương dư thừa di chuyển bất thường và cọ xát vào các mô khác của bạn.

Cơn đau của bạn có thể bùng phát sau khi thực hiện một số hoạt động nhất định. Nó cũng có thể khiến bạn thức dậy vào ban đêm hoặc gây đau khi bạn cố gắng nằm nghiêng về phía bên đó để ngủ. Các nhiệm vụ đơn giản trong sinh hoạt hàng ngày có thể trở nên khó khăn. Bạn có thể gặp khó khăn khi với tay ra sau lưng để cài áo ngực hoặc nhét áo vào quần. Những chuyển động này tạo áp lực lên khu vực nơi các mảnh xương không khớp nối hoàn toàn.

Nếu bạn đã từng phẫu thuật thay khớp vai, bạn có thể nhận thấy vùng nhạy cảm ngay trên mảnh xương này. Tình trạng này xảy ra ở 1 trong 4 bệnh nhân sau thủ thuật. Tin tốt là tình trạng đau nhức này thường tự khỏi theo thời gian ở hầu hết mọi người. Bác sĩ phẫu thuật của bạn sẽ kiểm tra các triệu chứng của bạn để quyết định xem mảnh xương dư thừa này có phải là nguyên nhân chính gây đau hay không.

Những gì thực sự đang xảy ra

Vai của bạn có một mảnh xương nhỏ gọi là os acromiale chưa hợp nhất với xương chính. Tình trạng này xảy ra ở khoảng 2,13% bệnh nhân mắc các vấn đề về vai cần chụp MRI. Hãy tưởng tượng vị trí chưa hợp nhất này như một miếng đệm lỏng lẻo giữa hai phần của xương vai. Thay vì di chuyển như một khối rắn duy nhất, mảnh xương lỏng lẻo này có thể cọ xát và dịch chuyển khi bạn cử động cánh tay.

Chuyển động bất thường này thường gây kích ứng các mô mềm lân cận. Múi xoay (rotator cuff) là một nhóm gân hoạt động như những sợi dây thừng để nâng và xoay cánh tay của bạn. Do mảnh xương lỏng lẻo di chuyển một cách bất thường, nó có thể chèn ép các gân này. Sự chèn ép này thường dẫn đến rách múi xoay. Ở các vận động viên trẻ, mô hình chấn thương cụ thể này khá phổ biến và cần được kiểm tra cẩn thận để xác nhận chẩn đoán.

Đôi khi mảnh xương lỏng lẻo này có thể bị tổn thương sau một cú ngã hoặc chấn thương, mặc dù điều này hiếm khi xảy ra. Nếu bạn phẫu thuật vì lý do khác, chẳng hạn như thay khớp vai toàn phần ngược, bạn có thể cảm thấy đau tại vị trí này ở 1 trong 4 bệnh nhân. Tình trạng đau nhức này thường tự khỏi theo thời gian. Việc có thêm mảnh xương này dường như không ảnh hưởng tiêu cực đến kết quả tổng thể từ phẫu thuật thay khớp vai lớn.

Những gì chúng tôi có thể làm về vấn đề này

Hầu hết mọi người bắt đầu bằng việc tự chăm sóc và vật lý trị liệu để kiểm soát cơn đau. Chuyên viên vật lý trị liệu của bạn sẽ hướng dẫn các bài tập nhằm tăng cường cơ vai và cải thiện phạm vi vận động. Phương pháp này nhằm mục đích giảm ma sát tại vị trí mảnh xương dư thừa. Bạn nên thử nghiệm kế hoạch không phẫu thuật này một cách nghiêm túc trước khi cân nhắc các bước tiếp theo.

Nếu cơn đau vẫn tiếp diễn, bác sĩ phẫu thuật của bạn có thể thảo luận về việc dùng thuốc hoặc tiêm. Các thuốc chống viêm có thể giúp giảm sưng và đau nhức xung quanh khớp. Trong một số trường hợp, tiêm cortisone được sử dụng để làm giảm viêm nhanh chóng. Mặc dù bằng chứng không nêu rõ thời gian chính xác cho các phương pháp điều trị này, nhiều bệnh nhân tìm thấy sự giảm đau trong khi thuốc phát huy tác dụng. Nếu bạn là vận động viên thi đấu, bác sĩ phẫu thuật sẽ cân nhắc cẩn thận các rủi ro, vì phẫu thuật thường không được khuyến nghị cho các tay vợt chuyên nghiệp.

Phẫu thuật thường chỉ được xem xét nếu các biện pháp bảo tồn này không kiểm soát được các triệu chứng của bạn. Mục tiêu của cuộc phẫu thuật là loại bỏ mảnh xương không ổn định hoặc cố định nó tại chỗ để ngăn chặn chuyển động gây đau. Quyết định này được đưa ra cùng với bác sĩ phẫu thuật của bạn sau khi xem xét trường hợp cụ thể và kết quả chẩn đoán hình ảnh của bạn.

Khi nào cần gặp bác sĩ

Hãy gặp bác sĩ đa khoa nếu bạn có đau vai dai dẳng không cải thiện khi nghỉ ngơi. Hãy yêu cầu đánh giá bởi bác sĩ chuyên khoa nếu bạn nhận thấy yếu cơ, mất vững khớp, hoặc khớp vai bị khóa hoặc đột ngột yếu đi. Các triệu chứng ảnh hưởng đến giấc ngủ hoặc công việc cũng cần được chú ý. Hãy tìm kiếm sự giúp đỡ nếu bạn trải qua tình trạng đau tăng lên đột ngột. Tình trạng này có liên quan đến các chấn thương nhóm cơ xoay vai, có thể gây ra chèn ép do chuyển động bất thường. Mặc dù hiếm gặp, khớp có thể bị tổn thương sau sang chấn. Nếu bạn là vận động viên quần vợt chuyên nghiệp, điều trị phẫu thuật thường không được chỉ định, nhưng một bác sĩ chuyên khoa có thể xác nhận chẩn đoán thông qua khám lâm sàng và chụp chiếu.


Evidence & references

Overview

  • In Thai patients with shoulder problems requiring MRI evaluation, the prevalence of os acromiale was 2.13% [1].
  • Os acromiale is associated with rotator cuff injuries [5].
  • A multicenter study aimed to determine the prevalence of and factors associated with os acromiale in the Japanese population [6].
  • Operative management of a symptomatic os acromiale that has failed initial nonoperative treatment leads to decreased symptoms and improvement in clinical outcomes [2].
  • Surgical options for symptomatic os acromiale include arthroscopic sub-total excision [16].
  • Surgical options for symptomatic os acromiale include arthroscopic subacromial decompression of stable fragments [16].
  • Surgical options for symptomatic os acromiale include open reduction and internal fixation of unstable fragments [16].
  • Surgical treatment is usually not indicated for os acromiale in the professional tennis player [7].
  • Ipsilateral os acromiale may be a relative contraindication to the clavicle hook plate [12].
  • Postoperative local tenderness at the os acromiale can be expected in 1 out of 4 patients after reverse total shoulder arthroplasty [3].
  • Postoperative local tenderness at the os acromiale resolves spontaneously over time in the majority of patients after reverse total shoulder arthroplasty [3].
  • The presence of os acromiale does not appear to have a negative impact on clinical outcomes after reverse total shoulder arthroplasty [4].
  • The outcome of reverse total shoulder arthroplasty does not seem to be negatively affected by the presence of an os acromiale [9].

Anatomy & Pathophysiology

  • The prevalence of os acromiale in Thai patients with shoulder problems requiring MRI evaluation is 2.13% [1].
  • Os acromiale is associated with rotator cuff injuries [5].
  • A tear of the rotator cuff may often be associated with os acromiale, likely due to impingement from abnormal motion at the fibrous union site [8].
  • Fused os acromiale, which has not been described previously, might be mistaken for a free ossicle in the clinical setting [10].
  • Awareness of the os acromiale in the young athlete is crucial to confirm diagnosis through appropriate clinical examination and image studies [11].
  • The synchondrosis of an os acromiale can be injured following trauma, though rarely [13].
  • Postoperative local tenderness at the os acromiale can be expected in 1 out of 4 patients after reverse total shoulder arthroplasty [3].
  • Postoperative local tenderness at the os acromiale resolves spontaneously over time in the majority of patients [3].
  • The presence of os acromiale does not appear to have a negative impact on clinical outcomes after reverse total shoulder arthroplasty [4].
  • The outcome of reverse total shoulder arthroplasty does not seem to be negatively affected by the presence of an os acromiale [9].
  • Reverse shoulder arthroplasty improves range of motion, decreases pain, and increases patient satisfaction in patients with os acromiale and cuff tear arthropathy [24].
  • Surgical treatment is usually not indicated for os acromiale in the professional tennis player [7].

Classification

  • The prevalence of os acromiale in Thai patients with shoulder problems requiring MRI evaluation is 2.13% [1].
  • Os acromiale is associated with rotator cuff injuries [5].
  • A tear of the rotator cuff may often be associated with os acromiale, likely due to impingement from abnormal motion at the fibrous union site [8].
  • Fused os acromiale, which has not been described previously, might be mistaken for a free ossicle in the clinical setting [10].
  • Awareness of the os acromiale in the young athlete, appropriate clinical examination, and image studies are crucial to confirm diagnosis [11].
  • The synchondrosis of an os acromiale can be injured following trauma, though rarely [13].
  • Meta-os acromiale is the rarest subtype of os acromiale [15].

Clinical Presentation

  • The prevalence of os acromiale in Thai patients with shoulder problems requiring MRI evaluation was 2.13% [1].
  • Os acromiale is associated with rotator cuff injuries [5].
  • A tear of the rotator cuff may often be associated with os acromiale, likely due to impingement from abnormal motion at the fibrous union site [8].
  • The presence of os acromiale does not appear to have a negative impact on clinical outcomes after reverse total shoulder arthroplasty (rTSA) [4].
  • The outcome of reverse total shoulder arthroplasty (RTSA) does not seem to be negatively affected by the presence of an os acromiale [9].
  • Postoperative local tenderness at the os acromiale can be expected in 1 out of 4 patients following rTSA [3].
  • Postoperative local tenderness at the os acromiale resolves spontaneously over time in the majority of patients [3].
  • Surgical treatment is usually not indicated for os acromiale in professional tennis players [7].
  • Awareness of the os acromiale, appropriate clinical examination, and image studies are crucial to confirm diagnosis in young athletes [11].
  • Ipsilateral os acromiale may be a relative contraindication to the clavicle hook plate [12].
  • The synchondrosis of an os acromiale can be injured following trauma, though rarely [13].
  • Fused os acromiale, which has not been described previously, might be mistaken for a free ossicle in the clinical setting [10].
  • Meta-os acromiale is the rarest subtype of os acromiale [15].
  • Liberson reviewed 1800 shoulder girdles and identified an incidence of os acromiale of 1.4% [14].
  • The lesion of os acromiale is bilateral in 62% of patients according to Liberson's review [14].

Investigations

  • The prevalence of os acromiale in Thai patients with shoulder problems requiring MRI evaluation is 2.13% [1].
  • Os acromiale is associated with rotator cuff injuries [5].
  • A tear of the rotator cuff may often be associated with os acromiale, likely due to impingement from abnormal motion at the fibrous union site [8].
  • Awareness of the os acromiale in the young athlete, appropriate clinical examination, and image studies are crucial to confirm diagnosis [11].
  • The synchondrosis of an os acromiale can be injured following trauma, though rarely [13].
  • Appropriate radiographic investigation for os acromiale injury includes axillary views [13].
  • Fused os acromiale, which has not been described previously, might be mistaken for a free ossicle in the clinical setting [10].
  • Liberson reviewed 1800 shoulder girdles and identified an incidence of os acromiale of 1.4% [14].
  • The lesion of os acromiale is bilateral in 62% of patients according to Liberson's review [14].

Treatment

  • Operative management of a symptomatic os acromiale that has failed initial nonoperative treatment leads to decreased symptoms and improvement in clinical outcomes [2].
  • Surgical options for symptomatic os acromiale include arthroscopic sub-total excision, arthroscopic subacromial decompression of stable fragments, and open reduction and internal fixation of unstable fragments [16].
  • Open reduction and internal fixation using cannulated screws or tension band wiring have superior outcomes in the literature in the treatment of symptomatic os acromiale [19].
  • A new arthroscopic technique of fixation of os acromiale with absorbable screws provides promising clinical, cosmetic, and radiologic results with high patient satisfaction [17].
  • A symptomatic os acromiale in a competitive female fastball pitcher was treated successfully with open reduction and internal fixation [21].
  • Special consideration must be given to the type of tension-band construct used to achieve adequate compression and fixation for meta-os acromiale, the rarest subtype of os acromiale [15].
  • Surgical treatment is usually not indicated for os acromiale in the professional tennis player [7].
  • Ipsilateral os acromiale may be a relative contraindication to the clavicle hook plate [12].
  • Postoperative local tenderness at the os acromiale can be expected in 1 out of 4 patients but resolves spontaneously over time in the majority of patients [3].
  • The presence of os acromiale does not appear to have a negative impact on the clinical outcomes after reverse total shoulder arthroplasty (rTSA) [4].
  • The outcome of reverse total shoulder arthroplasty (RTSA) does not seem to be negatively affected by the presence of an os acromiale [9].

Complications

  • The prevalence of os acromiale in Thai patients with shoulder problems requiring MRI evaluation was 2.13% [1].
  • Operative management of a symptomatic os acromiale that has failed initial nonoperative treatment leads to decreased symptoms and improvement in clinical outcomes [2].
  • Postoperative local tenderness at the os acromiale can be expected in 1 out of 4 patients following reverse total shoulder arthroplasty [3].
  • Postoperative local tenderness at the os acromiale resolves spontaneously over time in the majority of patients [3].
  • The presence of os acromiale does not appear to have a negative impact on clinical outcomes after reverse total shoulder arthroplasty [4].
  • Reverse total shoulder arthroplasty remains a safe and effective treatment option in the presence of os acromiale [4].
  • Os acromiale is associated with rotator cuff injuries [5].
  • A tear of the rotator cuff may often be associated with os acromiale, likely due to impingement from abnormal motion at the fibrous union site [8].
  • Surgical treatment is usually not indicated for os acromiale in professional tennis players [7].
  • Fused os acromiale, which has not been described previously, might be mistaken for a free ossicle in the clinical setting [10].
  • The incidence of os acromiale identified by Liberson was 1.4% [14].
  • The lesion of os acromiale was bilateral in 62% of patients in Liberson's review [14].

Recovery

  • Operative management of a symptomatic os acromiale that has failed initial nonoperative treatment leads to decreased symptoms and improvement in clinical outcomes [2].
  • Postoperative local tenderness at the os acromiale can be expected in 1 out of 4 patients but resolves spontaneously over time in the majority of patients [3].
  • The presence of os acromiale does not appear to have a negative impact on the clinical outcomes after reverse total shoulder arthroplasty (rTSA) [4].
  • Reverse total shoulder arthroplasty (rTSA) remains a safe and effective treatment option in patients with os acromiale [4].
  • The outcome of reverse total shoulder arthroplasty (RTSA) does not seem to be negatively affected by the presence of an os acromiale [9].
  • Surgical treatment is usually not indicated for os acromiale in professional tennis players [7].

Key Evidence

  • [L3] In Thai patients with shoulder problems who required MRI evaluation, the prevalence of os acromiale was 2.13%. [1] (10.1177/23259671221078806)
  • [L4] Operative management of a symptomatic os acromiale that has failed initial nonoperative treatment leads to decreased symptoms and improvement in clinical outcomes. [2] (10.1016/j.jse.2019.05.047)
  • [L3] Postoperative local tenderness at the os acromiale can be expected in 1 out of 4 patients but resolves spontaneously over time in the majority of patients. [3] (10.1177/2325967120965131)
  • [L4] The presence of os acromiale does not appear to have a negative impact on the clinical outcomes after surgery and rTSA remains a safe and effective treatment option. [4] (10.1016/j.xrrt.2025.01.002)
  • [L3] The study supports previous findings that os acromiale is associated with rotator cuff injuries. [5] (10.1016/j.jseint.2025.05.015)
  • [L3] This multicenter study aimed to determine the prevalence of and factors associated with os acromiale in the Japanese population. [6] (10.1016/j.jse.2025.01.008)
  • [L4] Surgical treatment is usually not indicated for os acromiale in the professional tennis player. [7] (10.1177/2325967118773723)
  • [L4] A tear of the rotator cuff may often be associated with os acromiale, likely due to impingement from abnormal motion at the fibrous union site. [8] (10.2106/00004623-198466080-00029)
  • [L4] The outcome of RTSA does not seem to be negatively affected by the presence of an os acromiale. [9] (10.1016/j.jse.2017.02.012)
  • [L4] An anatomical study showed that fused os acromiale, which has not been described previously, might be mistaken for a free ossicle in the clinical setting. [10] (10.2106/00004623-200003000-00010)
  • [L4] Awareness of the os acromiale in the young athlete, appropriate clinical examination, and image studies are crucial to confirm diagnosis. [11] (10.1016/j.jseint.2020.02.008)
  • [L4] Ipsilateral os acromiale may be a relative contraindication to the clavicle hook plate. [12] (10.1186/s12891-021-04841-1)
  • [L4] This case highlights that the synchondrosis of an os acromiale can be injured following trauma, though rarely, and emphasizes the need for appropriate radiographic investigation including axillary views and a flexible surgical approach. [13] (10.1016/j.jse.2008.02.012)
  • [L4] Meta–os acromiale is the rarest subtype of os acromiale, and special consideration must be given to the type of tension-band construct used to achieve adequate compression and fixation. [15] (10.1177/03635465211028238)
  • [L5] Surgical options for symptomatic os acromiale include arthroscopic sub-total excision, arthroscopic subacromial decompression of stable fragments, and open reduction and internal fixation of unstable fragments. [16] (10.5435/jaaos-d-17-00011)
  • [L4] This new arthroscopic technique of fixation of os acromiale with absorbable screws provides promising clinical, cosmetic, and radiologic results with high patient satisfaction. [17] (10.1016/j.jse.2011.12.011)
  • [L4] Open reduction and internal fixation using cannulated screws, or tension band wiring have superior outcomes in the literature in the treatment of symptomatic os acromiale. [19] (10.1302/2058-5241.4.180100)
  • [L4] A symptomatic os acromiale in a competitive female fastball pitcher was treated successfully with open reduction and internal fixation. [21] (10.1177/0363546506288305)
  • [L4] Reverse shoulder arthroplasty improved ROM, decreased pain, and increased patient satisfaction in patients with os acromiale and cuff tear arthropathy. [24] (10.5397/cise.2019.00409)

References

[1] Prevalence of Os Acromiale in Thai Patients With Shoulder Problems: A Magnetic Resonance Imaging Study. Orthopaedic Journal of Sports Medicine. 2022. DOI: 10.1177/23259671221078806 [2] Os acromiale: systematic review of surgical outcomes. Journal of Shoulder and Elbow Surgery. 2020. DOI: 10.1016/j.jse.2019.05.047 [3] Os Acromiale in Reverse Total Shoulder Arthroplasty: A Cohort Study. Orthopaedic Journal of Sports Medicine. 2020. DOI: 10.1177/2325967120965131 [4] Clinical implications of reverse total shoulder arthroplasty with an os acromiale: a systematic review. JSES Reviews, Reports, and Techniques. 2025. DOI: 10.1016/j.xrrt.2025.01.002 [5] Prevalence and factors associated with os acromiale: a multicenter study. JSES International. 2025. DOI: 10.1016/j.jseint.2025.05.015 [6] The prevalence and associated factors of os acromiale: a multicenter study. Journal of Shoulder and Elbow Surgery. 2025. DOI: 10.1016/j.jse.2025.01.008 [7] Os Acromiale in Professional Tennis Players. Orthopaedic Journal of Sports Medicine. 2018. DOI: 10.1177/2325967118773723 [8] Rotator cuff tears associated with os acromiale.. The Journal of Bone & Joint Surgery. 1984. DOI: 10.2106/00004623-198466080-00029 [9] Reverse shoulder arthroplasty in patients with os acromiale. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2017.02.012 [10] Os Acromiale: Frequency, Anatomy, and Clinical Implications. The Journal of Bone and Joint Surgery-American Volume. 2000. DOI: 10.2106/00004623-200003000-00010 [11] The unstable os acromiale: a cause of pain in the young athlete. JSES International. 2020. DOI: 10.1016/j.jseint.2020.02.008 [12] Os acromiale may be a contraindication of the clavicle hook plate: case reports and literature review. BMC Musculoskeletal Disorders. 2021. DOI: 10.1186/s12891-021-04841-1 [13] Fracture of an os acromiale with associated rupture of the coracoclavicular ligaments. Journal of Shoulder and Elbow Surgery. 2008. DOI: 10.1016/j.jse.2008.02.012 [14] Types of os acromiale according to Liberson. 2006. [15] Rare Symptomatic Meta–Os Acromiale in an Athlete. The American Journal of Sports Medicine. 2021. DOI: 10.1177/03635465211028238 [16] Symptomatic, Unstable Os Acromiale. Journal of the American Academy of Orthopaedic Surgeons. 2018. DOI: 10.5435/jaaos-d-17-00011 [17] Arthroscopically assisted internal fixation of the symptomatic unstable os acromiale with absorbable screws. Journal of Shoulder and Elbow Surgery. 2012. DOI: 10.1016/j.jse.2011.12.011 [19] Os acromiale: a review of its incidence, pathophysiology, and clinical management. EFORT Open Reviews. 2019. DOI: 10.1302/2058-5241.4.180100 [21] Surgical Stabilization of Os Acromiale in a Fast-Pitch Softball Pitcher. The American Journal of Sports Medicine. 2006. DOI: 10.1177/0363546506288305 [24] Reverse shoulder arthroplasty with os acromiale. Clinics in Shoulder and Elbow*. 2020. DOI: 10.5397/cise.2019.00409

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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.


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