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Os Acromiale

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

Updated Aug 2026
A hand-drawn illustration of an anatomical drawing of an os acromiale, the acromion with a separate unfused bony fragment.
Os acromiale: the front portion of the acromion has not fused with the rest of the acromion during skeletal maturation. Kieran Hirpara 4.0

What you're feeling

You may feel a deep ache in the top of your shoulder. This pain often sits right above the joint, where the shoulder blade meets the arm bone. For many people, this condition is linked to wear-and-tear of the rotator cuff tendons. These are the muscles that help you lift and rotate your arm. Because of this connection, your pain might feel like a standard shoulder strain, but it stays focused on that upper ridge.

The pain often flares up when you raise your arm overhead. Simple tasks like reaching for a cup on a high shelf or placing a bag on the top rack of your car can trigger a sharp twinge. This happens because the extra bone fragment moves abnormally. It rubs against the tendons below, causing irritation and inflammation. You might notice the discomfort gets worse after you have been active all day.

Resting your arm by your side usually brings some relief. However, you might still feel stiffness or tenderness when you first wake up in the morning. Lying on that shoulder at night can be difficult, especially if you press directly on the sore spot. Some people report a lingering soreness that does not go away quickly after exercise.

In rare cases, a fall or direct blow to the shoulder can injure the joint between the bone fragments. This sudden trauma can cause immediate, intense pain and swelling. If you have had previous shoulder surgery, such as a reverse total shoulder replacement, you might notice local tenderness at this site. For most patients, this postoperative soreness fades away on its own over time. The presence of this extra bone fragment does not typically stop your shoulder from healing well after major surgery.

If your symptoms persist despite rest and basic care, your surgeon will look for signs of impingement. This is where the moving parts of your shoulder rub together uncomfortably. Understanding exactly where the pain comes from helps us choose the right path forward. Whether that means gentle management or a minor procedure, we aim to reduce that daily friction so you can move freely again.

What's actually happening

Your shoulder blade has a bony flap called the acromion. Normally, this bone fuses into one solid piece during childhood. In some people, it remains as two separate pieces joined by a flexible band of tissue. This is what we call os acromiale. It is not uncommon. In patients with shoulder issues needing an MRI, about 2 in 100 have this extra bone fragment.

Think of this joint like a loose hinge on a door. Instead of moving smoothly as one unit, the two pieces shift slightly against each other. This abnormal motion can rub against the tendons above it. These tendons form your rotator cuff, which acts like a strong rope to lift your arm. The constant rubbing can irritate these tissues. This irritation often leads to wear and tear, or even tears in the rotator cuff. The pain you feel is often the result of this friction and inflammation.

Sometimes, this condition stays quiet for years. You might not notice it until a minor injury strains the area. The flexible joint between the bone pieces can get injured, though this is rare. For most people, the fragment stays stable. However, if the movement becomes too erratic, it can cause ongoing discomfort. We see this often in young athletes who put heavy stress on their shoulders. Careful examination and imaging help us confirm if this loose bone is the source of your pain.

If you are having shoulder replacement surgery, this extra bone fragment does not usually cause problems. Studies show that having os acromiale does not negatively impact the success of the procedure. You might feel some local tenderness after surgery. This happens in about one out of four patients. The good news is that this soreness usually goes away on its own as you heal. Your surgeon will check for this during your assessment to ensure the best plan for your recovery.

What we can do about it

At Mater Private Hospital Rockhampton, Dr Kieran Hirpara approaches this condition by matching the treatment to your specific symptoms and activity level. Most people start with non-surgical care. We aim to reduce pain and improve shoulder movement through guided exercise. A physiotherapist will teach you exercises to strengthen the muscles around your shoulder blade. This helps stabilise the area and takes pressure off the painful bone fragment. We usually recommend giving this approach at least six to twelve weeks to work. During this time, you may need to modify activities that cause sharp pain or grinding sensations.

If exercise alone does not provide enough relief, we may discuss medical management options. Over-the-counter pain relievers or anti-inflammatory medications can help manage daily discomfort. For more persistent pain, we might suggest an injection into the shoulder joint. Cortisone injections reduce inflammation and can provide relief for several weeks to a few months. Other injection types, such as hyaluronic acid or platelet-rich plasma (PRP), are sometimes used to support tissue healing, though their long-term effects vary. These injections are not a cure, but they can create a window of reduced pain that allows you to participate more effectively in physiotherapy.

Surgery is considered only when conservative measures have failed to give you enough improvement. If your symptoms remain severe and limit your daily life, we may discuss operative options. The goal of surgery is to either remove the unstable bone fragment or secure it in place so it can heal properly. This decision is made together, weighing the potential benefits against the risks of recovery. For most patients, surgery is a last resort after a thorough trial of non-operative care has been completed.

What to expect

Os acromiale is a small, extra bone fragment in your shoulder blade. It affects about 1 in 50 people. Many people have no symptoms at all. When it does cause pain, the discomfort often comes and goes. It may flare up with overhead activities or heavy lifting.

If you manage your symptoms with rest, physical therapy, and anti-inflammatory medication, many people find relief. Your surgeon will guide you through these non-surgical options first. For most patients who respond well to this care, the pain settles down and does not return frequently. You can often continue your daily activities with minor adjustments.

However, if your pain persists despite conservative care, surgery may be discussed. Operative treatment for symptomatic os acromiale that has not improved with other methods typically leads to decreased symptoms and better shoulder function. You can expect a gradual improvement in how your shoulder feels over the following weeks and months.

Some patients experience local tenderness at the site of the bone fragment after surgery. This occurs in about 1 out of 4 patients. In the majority of cases, this tenderness resolves on its own over time. You do not need specific treatment for it; it simply fades as your body heals.

It is important to know that os acromiale is often linked with rotator cuff injuries. The abnormal motion at the bone fragment can irritate the surrounding tendons. If you have a rotator cuff tear alongside os acromiale, your surgeon will address both issues. The presence of an os acromiale does not negatively impact the outcomes of reverse total shoulder arthroplasty. This procedure remains a safe and effective option if you require joint replacement.

For professional tennis players, surgical treatment is usually not recommended. The demands of the sport can complicate recovery, so non-surgical management is typically preferred. Your outlook depends on the severity of your symptoms and whether other shoulder structures are involved. With appropriate care, most patients achieve a comfortable and functional shoulder.

When to see someone

See your GP if you have persistent shoulder pain that does not improve with rest. Ask for a specialist review if you notice weakness, instability, or a feeling of locking. Symptoms that interfere with sleep or work also warrant attention. Sudden worsening of pain is another reason to seek care. Awareness of this condition in young athletes is crucial for proper diagnosis. Your surgeon will use clinical examination and imaging to confirm the issue. This helps determine if the pain stems from the extra bone or an associated rotator cuff injury. Early assessment ensures you get the right support for your shoulder health.

Reviewed by AI synthesis (v2) — pending human review · 18 May 2026.

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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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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.

Creative Commons may be contacted at creativecommons.org.