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ECU Tendinopathy and Instability

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For patients: a plain-language version of this topic is available. See the patient guide.

Overview

Extensor carpi ulnaris (ECU) pathology covers two overlapping problems that share a compartment, an examination and a differential: tendinopathy / stenosing tenosynovitis of the tendon within the sixth dorsal compartment, and instability of the tendon, where it subluxates or dislocates out of the ulnar groove — the "snapping ECU". They frequently coexist, and both present as ulnar-sided dorsal wrist pain in a racquet, club or bat athlete.

Two findings should govern how confidently the diagnosis is made. ECU signal change on MRI has a positive predictive value of 6% [7], and 6.6% of entirely asymptomatic wrists snap, with 44% of those snappers showing subluxation or dislocation on ultrasound [8]. Neither an MRI abnormality nor a demonstrable snap establishes that the ECU is the source of the pain. This is a clinical diagnosis that imaging can support but not make.

The evidence base is thin. The only critical-analysis review of the topic grades every recommendation it makes as Grade C [1].

Anatomy & Pathophysiology

The ECU runs in the sixth dorsal compartment within a groove on the dorsoulnar distal ulna. It is restrained there not by the extensor retinaculum, which passes superficial to it, but by a distinct fibro-osseous subsheath.

It is the distal subsheath that matters — the single most surgically relevant finding in this area, and three independent studies converge on it. In a cadaveric sectioning study, dividing the distal subsheath increased tendon displacement by a mean of 2.1 mm (p < 0.001) while proximal sectioning produced only 0.3 mm (not significant); in supination with the wrist flexed, distal sectioning produced 6.0 mm more displacement than proximal sectioning (p < 0.01) [2]. A second study identified a discrete distal extension of the subsheath running from the ulnar styloid to the dorsal radioulnar ligament, and found that resecting it alone dislocated the tendon in 3 of 5 specimens while resecting the proximal part alone dislocated none [3]. Dynamic ultrasound confirmed the same: sectioning the subsheath over the groove produced no notable subluxation, whereas additionally releasing the distal extension did [4].

The practical consequences are that reconstruction should be targeted distally, at the ulnar margin of the distal groove [4], and that the position to avoid in rehabilitation is combined supination and wrist flexion [2] — which is also the provocative position clinically.

Groove morphology varies considerably, but depth does not reliably predict instability [6]. This matters because it undercuts the rationale for routinely deepening the groove.

The ECU is also a dynamic stabiliser of the distal radioulnar and ulnar carpal joints, not merely a wrist extensor — which is part of why an unstable or painful ECU produces symptoms out of proportion to its size, and why simply releasing or transposing it is not a free move.

Accessory tendon slips are common and under-recognised, found in 18 of 50 wrists (36%) in one anatomical series [3], and were present in 2 of the 3 non-operative failures in a classic injection series [1]. Stenosis is also not confined to the groove: it can occur more distally around the ulnar styloid and triquetrum, and should be suspected when pain is provoked by pronation [3].

Classification

For instability, the Inoue and Tamura classification is used by essentially every subsequent operative paper, and is assigned at surgery [11]:

  • Type A — the sheath ruptures ulnarly and the torn sheath lies superficial to the tendon. Direct suture is usually impossible; reconstruction with a retinacular strip.
  • Type B — the sheath ruptures radially and the torn sheath lies in the groove beneath the tendon. Amenable to direct suture over the tendon.
  • Type C — the periosteum is stripped from the ulna in continuity with the sheath, forming a false pouch. The authors liken it to a Bankart lesion; treatment is to obliterate the pouch with transosseous sutures.

Type distribution is heavily series-dependent — type C accounted for all 21 cases in one series and 82.6% in another [12][14] — which suggests referral pattern as much as biology. It cannot be determined preoperatively, which is the basis for the argument that all symptomatic dislocations warrant exploration with the repair chosen at operation [11].

Clinical Presentation

Pain is dorsoulnar, localised over the sixth compartment, and provoked by supination, ulnar deviation and wrist flexion. Ask about racquet sports, golf, and bat sports; a two-handed backhand and the non-dominant hand in the golf swing are classic.

Tendinopathy gives pain and tenderness along the tendon with a painful arc through forearm rotation, sometimes with crepitus or a fusiform swelling.

Instability gives a painful snap or clunk as the tendon leaves the groove, usually reproduced by taking the forearm into supination with the wrist flexed and ulnarly deviated, then bringing it back. The patient can often demonstrate it themselves.

Useful tests:

  • ECU synergy test — with the elbow flexed, forearm supinated and fingers extended, the patient radially abducts the thumb against resistance. This co-contracts the ECU, which becomes palpable and taut; reproduction of dorsoulnar pain suggests the pain is intrinsic to the ECU rather than intra-articular [10]. This is the single most useful bedside discriminator between ECU pathology and ulnocarpal pathology.
  • String test — a more recently described test for ECU tendonitis [24]; not yet independently validated, and the subject of published correspondence.

The interpretive trap. Partial subluxation of the ECU is normal. In asymptomatic wrists the tendon has been shown to translate up to 40% beyond the volar lip of the groove in 45% of wrists, and the tendon does not leave the groove entirely in normal wrists [1]. Partial displacement is a normal finding; complete dislocation out of the groove is not. Combined with the 6.6% asymptomatic snapping rate [8], the sign has to be interpreted alongside symptoms, not instead of them.

Investigations

Ultrasound is the investigation of choice because it is dynamic — the tendon can be watched through pronation and supination while the patient reproduces the snap. It also distinguishes subluxation (tendon leaves the groove 50–99%) from frank dislocation (100%) [8].

MRI should be interpreted with real caution. In 4,301 consecutive hand and wrist MRIs, ECU signal change was present in 13% overall and 10% of scans performed for indications unrelated to ulnar wrist pain. Against a clinical diagnosis as reference standard, MRI had sensitivity 57%, specificity 88%, and a positive predictive value of 6% — with a negative predictive value of 99% [7]. Nearly half of patients with a clinical diagnosis had no signal change at all. The authors' own conclusion is that "MRI is not helpful in the management of ECU tendinopathy" [7]. Its value here is in excluding other pathology, not in confirming this one.

Reported ECU abnormality rates in asymptomatic volunteers range from 4% to 85% across the literature. Treat an incidental ECU finding on a scan ordered for something else as noise until the examination says otherwise [7][20].

Differential diagnosis of dorsoulnar wrist pain that must be worked through: TFCC tear, DRUJ instability or arthritis, lunotriquetral pathology, pisotriquetral arthritis, and ulnar impaction. ECU pathology and TFCC injury frequently coexist, so finding one does not exclude the other [21].

Treatment

Non-Operative

Tendinopathy. Activity modification, a period of immobilisation, and NSAIDs are first line. Reported success rates for non-operative management vary enormously — 93% in one series of 43, 53% in a series of 15, and 12.5% in a series of 72 [1] — a spread the authors attribute to inconsistent diagnostic criteria across studies.

Corticosteroid injection is reasonable and, in the only primary injection study in the corpus, effective: 13 patients with ultrasound- or MRI-confirmed stenosing tenosynovitis all had some relief and 10 of 13 (77%) had complete resolution, with 4 requiring re-injection and none proceeding to surgery; at a mean follow-up of 4 years 8 months, 6 of 10 contacted were pain-free [18]. A useful prognostic signal from that series: 6 of 7 patients with complete relief after the first injection were pain-free at final follow-up, whereas all 3 with only partial early relief had residual pain [18].

Technique varies. One protocol used 10 mg triamcinolone with 0.25 mL lidocaine injected superficial to the ulnocarpal joint under ultrasound guidance where available [18]; another used 40 mg triamcinolone with 3 mL lidocaine into the sheath, entering proximal to the DRUJ to avoid inadvertently injecting the joint [10].

On steroid and tendon rupture. No numbered rate of steroid-attributed ECU rupture exists. Against the reassuring long-term series above, one group reported two patients referred with ECU rupture after injection and consequently abandoned the practice for instability [12], and there is in-vitro evidence that both corticosteroids and NSAIDs inhibit collagen repair [1]. The only quantified limit in the literature is a ceiling of up to three injections, itself Grade C [1]. Counsel accordingly, and be more conservative in the throwing or racquet athlete.

Instability. The mechanically coherent immobilisation position — and the one prescribed by most sources — is pronation, with the wrist in slight extension and radial deviation, for 4–6 weeks, which is the exact opposite of the provocative supination-flexion position [9][17]. Be aware that the literature is genuinely inconsistent here: recommendations range from 5 days to 3 months, and at least one source recommends ulnar deviation for tendinopathy, which puts the tendon in the position every biomechanical study calls provocative. There is no comparative study of either position or duration [1].

Non-operative treatment may be mechanically futile in a true acute subsheath rupture. Intraoperative findings have shown the torn subsheath edges separated by at least 7 mm regardless of wrist position, implying apposition and healing cannot occur through immobilisation alone [1]. This is the main argument for early exploration in a clear acute traumatic subluxation.

When to operate. Commonly cited triggers are persistent instability after a trial of casting, and inability to return to previous activities at around two months [9]. One widely used practical threshold treats an injury presenting at less than 3 weeks non-operatively, and favours surgery beyond that [1].

Operative

Tendinopathy. Options are subsheath release with tenosynovectomy, debridement with longitudinal division of degenerate fibres, and excision of any accessory slips [1]. Reassuringly, a review of 22 patients undergoing subsheath release reported no cases of subsequent tendon instability at a mean 43 months [1]. Where the floor of the compartment is eroded to bone, a strip of retinaculum can be used to reconstruct it [1]. Tendoscopy has described safe portals but no clinical outcome data [23].

Instability. The reconstruction techniques all produce good published results and none has been compared against another:

Series n Technique Groove Outcome
MacLennan 2008 [12] 21 Groove deepened 2–3 mm + suture anchors, sheath imbricated Deepened 20/21 (95%) returned to index activity; 1 asymptomatic anchor loosening
Mastroianni 2023 [14] 33 Radially based retinacular sling passed volar to the tendon Coplaned flush All returned to pre-injury level; elite athletes at ~14 weeks
Fram 2018 [16] 12 Transposition out of the groove onto the fifth compartment Left empty All returned by 3 months; 1 needed two further procedures for scar
Kaiser 2019 [15] 12 Pedicled radially based retinacular flap Not deepened Grip 92% of contralateral; 1 CRPS
Inoue 2001 [11] 12 Type-directed per classification Not deepened No recurrent dislocation; no scores reported

Two caveats belong in any consent discussion.

First, clinical success and anatomical success are not the same thing here. Every series reports 0% clinical recurrence, but the only series that imaged its patients postoperatively found the displacement pattern unchanged in 5 of 11 assessable wrists (4 frank dislocations, 1 subluxation) — four of whom nonetheless had excellent outcome scores and satisfaction of 8–10 out of 10 [15]. The operation appears to relieve symptoms whether or not it anatomically relocates the tendon.

Second, the functional gains are small. The most-cited series originally reported a DASH improvement of 97 to 58, which was corrected after published correspondence to 56.0 to 23.4 [13]; the authors concede that their 2 kg grip gain "is not clinically significant" and that the repair "corrected and relieved pain but did not provide clinically significant improvement in range of motion and grip strength" [13]. The ROM gains of 3–4° across all series fall within goniometer error [13].

Groove deepening is genuinely contested, and the page should say so. The only direct biomechanical comparison found that deepening added nothing: reconstruction alone abolished all 45 dislocation events, and adding a 2 mm deepening changed neither displacement (0.5 mm vs −0.3 mm) nor dislocation count (0 vs 0). Deepening a sectioned subsheath was no better than leaving it alone (8.4 vs 8.3 mm). The authors "recommend against routine deepening" [5]. Groove depth does not predict instability in four of the five studies that have looked [6], and several modern techniques deliberately coplane rather than deepen the dorsal-radial lip so that there is no rim to snap over [17].

Against that, the most-cited clinical series deepened by 2–3 mm and had no recurrences [12], and both major textbooks endorse deepening selectively for a demonstrably flat or very shallow groove. One recent cadaveric ultrasound study found no subluxation in any position when groove depth was ≥1.3 mm and marked subluxation below it [4], which supports a selective rather than routine indication.

Two practical points if deepening is done. The normative mean groove depth is about 1.4 mm, so a 2–3 mm deepening is a two-fold change, and it risks weakening the ulnar head with subsequent fracture or anchor failure. And an osteoperiosteal trapdoor — hinging a thin cortical flap, curetting no more than 2–3 mm of cancellous bone, then tamping the flap back — avoids leaving raw cancellous bone against the tendon, which is the main biomechanical objection to burring.

Technical points common to the described techniques: identify and protect the dorsal branch of the ulnar nerve, as painful neuroma is a named risk [17]; do not suture the supratendinous retinaculum to the ulna, which limits forearm rotation; and avoid overtightening, which restricts tendon excursion — a pediatric feeding tube placed alongside the tendon while the sheath is repaired is the described trick to prevent it.

Complications

Across every clinical series in the literature: recurrent clinical instability 0%; dorsal ulnar sensory nerve neuritis or irritation in 2 patients; CRPS in 1; scar-related stiffness requiring two further procedures in 1; asymptomatic anchor loosening in 1; and no reported infections [12][14][15][16]. One catastrophic early failure of a radially based flap at 8 weeks requiring free-tendon-graft salvage has been illustrated [19].

Named risks without denominators: painful neuroma of the dorsal ulnar sensory branch, overtightening with restricted excursion, ulnar fracture and anchor failure after deepening, loss of pronosupination, and stenosing tenosynovitis after anatomic repair or groove reforming [17][22].

Recovery

Post-operative regimens are broadly consistent: immobilisation in pronation with slight wrist extension for 4–6 weeks, progressing to a short-arm orthosis once approximately 45° of active rotation returns, strengthening from around 8–10 weeks, and sport-specific work at 3–4 months [14][17].

Return to sport after reconstruction is reported at a mean of 2.6 months in one series and approximately 14 weeks for elite athletes in another [14][16]. Non-operatively, graded return in baseball is described at 2–3 weeks for mild, 4–6 weeks for moderate and 6–8 weeks for severe injuries [19], while elite tennis players with acute complete subluxation treated in a cast took 5–6 months from diagnosis [1].

Asymptomatic subluxers do not need fixing. They can typically return to elite play with taping and symptom monitoring alone [19].

Key Evidence

  • [L5] The only critical-analysis review of ECU pathology grades every recommendation it makes as Grade C. [1] (10.2106/jbjs.rvw.n.00070)
  • [L2] In 4,301 consecutive MRIs, ECU signal change had a positive predictive value of just 6% (sensitivity 57%, specificity 88%, NPV 99%); the authors conclude MRI is not helpful in managing ECU tendinopathy. [7] (10.1007/s11552-015-9764-9)
  • [L2] 6.6% of 755 asymptomatic wrists snapped, and 44% of those snappers had ultrasound-confirmed subluxation or dislocation. [8] (10.1186/s12891-021-04271-z)
  • [L5] The distal subsheath, not the proximal, is the restraint: distal sectioning produced 6.0 mm more displacement than proximal in supination-flexion. Reconstruction should target it, and supination with wrist flexion should be avoided in rehabilitation. [2] (10.1016/j.jhsa.2015.10.024)
  • [L5] A discrete distal extension of the subsheath is the primary stabiliser — resecting it alone dislocated 3 of 5 specimens; resecting the proximal part alone dislocated none. [3] (10.1016/j.jhsa.2021.02.008)
  • [L4] Clinical and anatomical success diverge: the only series with post-operative imaging found unchanged displacement in 5 of 11 wrists despite good-to-excellent scores and high satisfaction. [15] (10.1007/s00402-019-03227-2)
  • [L4] Corrected DASH after subsheath reconstruction is 56.0 to 23.4, and the authors concede the grip and ROM gains are not clinically significant. [13] (10.1016/j.jhsa.2008.06.002)
  • [L4] Steroid injection for confirmed ECU stenosing tenosynovitis gave complete resolution in 10 of 13, with none proceeding to surgery and 6 of 10 pain-free at a mean 4 years 8 months. [18] (10.1177/1753193418821561)
  • [L4] The ECU synergy test reproduces dorsoulnar pain when the pain is intrinsic to the tendon, helping separate it from ulnocarpal pathology. [10] (10.1016/j.jhsa.2008.08.018)
  • [L4] The Inoue and Tamura A/B/C subsheath classification cannot be determined preoperatively, which is the argument for exploring all symptomatic dislocations and choosing the repair at operation. [11] (10.1054/jhsb.2001.0615)
  • [L5] Groove deepening added nothing over soft-tissue reconstruction biomechanically, and groove depth does not predict instability. [5][6] (10.1016/j.jhsa.2017.06.007)
  • [L4] Subsheath release for tenosynovitis did not destabilise the tendon in 22 patients at a mean 43 months. [1] (10.2106/jbjs.rvw.n.00070)

See Also

References

[1] Kollitz KM, Iorio ML, Huang JI. Assessment and treatment of extensor carpi ulnaris tendon pathology. JBJS Rev. 2015;3(6):e4. DOI: 10.2106/JBJS.RVW.N.00070

[2] Ghatan AC, Puri SG, Morse KW, Hearns KA, Carlson MG. Relative contribution of the subsheath to extensor carpi ulnaris tendon stability: implications for surgical reconstruction and rehabilitation. J Hand Surg Am. 2016;41(2):225-32. DOI: 10.1016/j.jhsa.2015.10.024

[3] Omokawa S, Gumpangseth T, Komutrattananont P, Inchai C, Mahakkanukrauh P, Tanaka Y. Anatomical study of stabilizing structures of the extensor carpi ulnaris tendon around the wrist. J Hand Surg Am. 2021;46(10):930.e1-930.e9. DOI: 10.1016/j.jhsa.2021.02.008

[4] Inoue T, Iida A, Omokawa S, Kawamura K, Tanaka Y. Ultrasonographic evaluation of extensor carpi ulnaris tendon subluxation at the ulnar groove. J Hand Surg Am. 2025;50(12):1476-82. DOI: 10.1016/j.jhsa.2025.09.006

[5] Puri SK, Morse KW, Hearns KA, Carlson MG. A biomechanical comparison of extensor carpi ulnaris subsheath reconstruction techniques. J Hand Surg Am. 2017;42(10):837.e1-837.e7. DOI: 10.1016/j.jhsa.2017.06.007

[6] Shoap SC, Dennis ER, Lombardi JM, Wilkerson J, Rosenwasser MP, Strauch RJ. An analysis of extensor carpi ulnaris groove morphology and tendon instability. HAND. 2022;19(3):400-6. DOI: 10.1177/15589447221105539

[7] Kuntz MT, Janssen SJ, Ring D. Incidental signal changes in the extensor carpi ulnaris on MRI. HAND. 2015;10(4):750-5. DOI: 10.1007/s11552-015-9764-9

[8] Erpala F, Ozturk T. "Snapping" of the extensor carpi ulnaris tendon in asymptomatic population. BMC Musculoskelet Disord. 2021;22(1):387. DOI: 10.1186/s12891-021-04271-z

[9] Iorio ML, Huang JI. Extensor carpi ulnaris subluxation. J Hand Surg Am. 2014;39(7):1400-2. DOI: 10.1016/j.jhsa.2014.03.037

[10] Ruland RT, Hogan CJ. The ECU synergy test: an aid to diagnose ECU tendonitis. J Hand Surg Am. 2008;33(10):1777-82. DOI: 10.1016/j.jhsa.2008.08.018

[11] Inoue G, Tamura Y. Surgical treatment for recurrent dislocation of the extensor carpi ulnaris tendon. J Hand Surg Br. 2001;26(6):556-9. DOI: 10.1054/jhsb.2001.0615

[12] MacLennan AJ, Nemechek NM, Waitayawinyu T, Trumble TE. Diagnosis and anatomic reconstruction of extensor carpi ulnaris subluxation. J Hand Surg Am. 2008;33(1):59-64. DOI: 10.1016/j.jhsa.2007.10.002

[13] Gohritz A, Knobloch K, Vogt PM, Spies M. Extensor carpi ulnaris subluxation: a problem of significance? J Hand Surg Am. 2008;33(9):1682-3. DOI: 10.1016/j.jhsa.2008.06.002

[14] Mastroianni MA, Leibman M, Belsky M, Vitale MA, Ruchelsman DE. Radially based extensor retinacular sling reconstruction for extensor carpi ulnaris subsheath injuries. J Hand Surg Glob Online. 2023;5(2):133-9. DOI: 10.1016/j.jhsg.2022.11.003

[15] Kaiser P, Haug L, Gabl M, et al. Mid-term outcome (11-90 months) of the extensor retinaculum flap procedure for extensor carpi ulnaris tendon instability. Arch Orthop Trauma Surg. 2019;139(9):1323-8. DOI: 10.1007/s00402-019-03227-2

[16] Fram B, Wall LB, Gelberman RH, et al. Surgical transposition for chronic instability of the extensor carpi ulnaris tendon. J Hand Surg Eur Vol. 2018;43(9):925-30. DOI: 10.1177/1753193418773036

[17] Ruchelsman DE, Vitale MA. Extensor carpi ulnaris subsheath reconstruction. J Hand Surg Am. 2016;41(11):e433-e439. DOI: 10.1016/j.jhsa.2016.08.009

[18] Tanabe K, Watanabe M. Steroid injection for stenosing tenosynovitis of the extensor carpi ulnaris. J Hand Surg Eur Vol. 2019;44(4):425-7. DOI: 10.1177/1753193418821561

[19] Graham TJ. Pathologies of the extensor carpi ulnaris (ECU) tendon and its investments in the athlete. Hand Clin. 2012;28(3):345-56. DOI: 10.1016/j.hcl.2012.05.049

[20] DaSilva MF, Goodman AD, Gil JA, Akelman E. Evaluation of ulnar-sided wrist pain. J Am Acad Orthop Surg. 2017;25(8):e150-e156. DOI: 10.5435/JAAOS-D-16-00407

[21] Dineen HA, Greenberg JA. Ulnar-sided wrist pain in the athlete. Clin Sports Med. 2020;39(2):373-400. DOI: 10.1016/j.csm.2019.12.008

[22] Mukohara S, Hartman Budnik JV, Viola RW. Reconstruction of the extensor carpi ulnaris subsheath using a fascia lata allograft. J Hand Surg Glob Online. 2026;8(3):100957. DOI: 10.1016/j.jhsg.2026.100957

[23] de Torres-de Torres E, Corella F, Kaempf de Oliveira R, et al. Description of specific portals for extensor carpi ulnaris tenoscopy: anatomical safety study. J Hand Surg Am. 2025;50(9):1132.e1-1132.e7. DOI: 10.1016/j.jhsa.2024.10.005

[24] Cooper TB, Raza MA, Yan H. The string test: a novel test for diagnosing extensor carpi ulnaris tendonitis. J Hand Surg Eur Vol. 2025;50(11):1551-3. DOI: 10.1177/17531934251329775

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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.