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Pronator Syndrome and Anterior Interosseous Nerve Syndrome

High median nerve compression: pronator syndrome (sensory, thenar/palm sparing distinguishes from CTS) and AIN palsy (pure motor, OK-sign), with observation-first management and decompression for refractory cases.

Overview

Pronator syndrome and anterior interosseous nerve (AIN) syndrome represent distinct median nerve pathologies requiring specific surgical timing. Surgical decompression for pronator syndrome is indicated when symptoms persist for more than 6 months [1], whereas AIN syndrome requires a minimum of 12 months with no signs of motor improvement [1]. The diagnosis of pronator syndrome lacks objective pathophysiology and is supported only by subjective operative findings and relief after surgery [4]. A prolonged nonsurgical approach is warranted in most cases of median nerve or anterior interosseous nerve compression [6], and surgical decompression of the median nerve or AIN in the forearm is rarely indicated [6].

Anatomical variations significantly influence management. The ulnar head of the pronator teres is fibrotic or fibromuscular in 71.5% of cases, and its morphology and location relative to the median nerve are critical for surgical treatment [3]. Resection of a segment of the persistent median artery is the recommended treatment for pronator syndrome associated with this anomaly [5]. While an endoscopically assisted, minimally invasive approach adequately and safely decompressed all anatomical points of compression and improved DASH scores [7], there is a paucity of controlled trials demonstrating that operative treatment for pronator syndrome is more effective than other treatments or sham surgery [4].

AIN syndrome is characterized as a non-compressive neuropathy defined by median nerve fascicular constrictions in the arm [2]. An isolated anterior interosseous nerve injury may not by itself be an indication for urgent surgery [11]. For nerve transfer scenarios, standardized outcome measures, early intervention, and comprehensive rehabilitation are important for optimizing supercharged end-to-side anterior interosseous nerve to ulnar nerve transfer outcomes [12].

Anatomy & Pathophysiology

Anterior interosseous nerve syndrome is characterized by median nerve fascicular constrictions in the arm [2]. The ulnar head of the pronator teres is fibrotic or fibromuscular in 71.5% of cases [3], and its morphology and location relative to the median nerve are critical determinants for surgical treatment of pronator syndrome [3]. A palmaris longus variant featuring a central muscle belly with both distal and proximal tendinous insertions can cause dynamic median nerve compression at the mid-forearm level [28].

Neuropathies in this distribution arise from diverse etiologies including osseous trauma, iatrogenic injury, and compartment pressure. Details regarding the origin and course of the anterior interosseous nerve explain the high incidence of palsy in pediatric supracondylar elbow fractures [25]. Type 4 median nerve entrapment represents a severe form of this rare complication following elbow dislocation [18]. Iatrogenic causes include traction or mass effect from packing during open capsular release for elbow stiffness [17], delayed-onset stretch injury one week after open elbow contracture release [13], and fluid extravasation from shoulder arthroscopy which is hypothesized as the singular cause of neuropathies presenting as anterior interosseous nerve palsy [20]. Anterior interosseous nerve neuropraxia can also occur secondary to shoulder arthroscopy and open subpectoral long head biceps tenodesis [29]. While median nerve palsy is a rare but potentially devastating complication of arthroscopic elbow contracture release [19], dissection along the ulnar side of the median nerve may decrease the risk of injury to the anterior interosseous nerve during decompression [26].

Classification

Surgical Indications: Decompression for pronator syndrome is indicated when symptoms persist for greater than 6 months [1]. For anterior interosseous nerve (AIN) syndrome, surgical intervention requires a minimum of 12 months with no signs of motor improvement [1]. Conservative treatment for at least 6 months is recommended before considering surgery for AIN syndrome [10]. An isolated AIN injury may not by itself be an indication for urgent surgery [11]. Surgical decompression of the median nerve or AIN in the forearm is rarely indicated, and a prolonged nonsurgical approach is warranted in most cases [6].

Pathophysiology and Diagnosis: AIN syndrome is characterized by median nerve fascicular constrictions in the arm but is classified as a non-compressive neuropathy [2]. It is a multifocal mononeuropathy selectively involving the motor fascicles within the main trunk of the median nerve that continue distally to form the AIN [9]. Compression of the AIN by normal surrounding tissues may not exist or is very rare [10]. Most cases of AIN syndrome likely represent neuritis rather than a surgically treatable entrapment neuropathy [9, 10]. The diagnosis of pronator syndrome lacks objective pathophysiology and is supported only by subjective operative findings and relief after surgery [4]. There is a paucity of controlled trials demonstrating that operative treatment for pronator syndrome is more effective than other treatments or sham surgery [4].

Anatomical Variants and Etiology: The ulnar head of the pronator teres is fibrotic or fibromuscular in 71.5% of cases, and its morphology and location relative to the median nerve are important for surgical treatment [3]. Resection of a segment of the persistent median artery is the recommended treatment for pronator syndrome associated with this anomaly [5]. Type 4 median nerve entrapment represents a severe form of a rare complication of elbow dislocation [18].

Surgical Approach and Assessment: Patients presenting with median nerve symptoms must be assessed both at the wrist and proximally to exclude compression elsewhere [8]. An endoscopically assisted, minimally invasive approach to treat pronator syndrome adequately and safely decompressed all anatomical points of compression and improved DASH scores [7].

Clinical Presentation

Clinical suspicion for anterior interosseous nerve (AIN) syndrome arises in the presence of isolated paralysis of the AIN-supplied muscles [22]. This condition is a multifocal mononeuropathy selectively involving the motor fascicles within the main trunk of the median nerve that continue distally to form the AIN [9]. In the majority of cases, AIN syndrome is not a surgically treatable entrapment neuropathy [9]. Most cases likely represent neuritis rather than compression by normal surrounding tissues, which may not exist or is very rare [10]. Consequently, an isolated AIN injury may not by itself be an indication for urgent surgery [11].

Surgical Indications: * Pronator Syndrome: Decompression is indicated for persistent symptoms greater than 6 months [1]. * Anterior Interosseous Nerve Syndrome: Decompression is indicated only after a minimum of 12 months with no signs of motor improvement [1].

For most cases of median nerve or AIN compression, a prolonged nonsurgical approach is warranted [6]. Conservative treatment for at least 6 months is recommended before considering surgery for AIN syndrome [10]. Surgical decompression of the median nerve or AIN in the forearm is rarely indicated [6]. The diagnosis of pronator syndrome lacks objective pathophysiology and is supported only by subjective operative findings and relief after surgery [4]. There is a paucity of controlled trials demonstrating that operative treatment for pronator syndrome is more effective than other treatments or sham surgery [4].

Anatomic Variations and Etiology: * Pronator Teres: The ulnar head is fibrotic or fibromuscular in 71.5% of cases [3]. The morphology and location of the ulnar head relative to the median nerve are important for surgical treatment [3]. * Persistent Median Artery: Resection of a segment of the persistent median artery is the recommended treatment for pronator syndrome associated with this anomaly [5]. * Proximal Variations: Anatomic findings of an ipsilateral supracondylar process and abnormal muscle mass are unique variations causing proximal compression of the median nerve [15]. Surgeons should be aware of musculotendinous variations causing proximal compression [15]. * Bifid Nerve: Bifid median nerve entrapment by forearm musculature is an anomaly that surgeons should bear in mind when assessing patients with symptoms of median nerve compression [16]. * Secondary Causes: Median nerve symptoms can occur secondary to lacertus fibrosus syndrome following distal biceps tendon repair [14]. Delayed-onset AIN palsy can develop one week after open elbow contracture release, likely due to a stretch injury [13].

Diagnostic Assessment: Patients presenting with median nerve symptoms must be assessed both at the wrist and proximally to exclude compression elsewhere [8]. An endoscopically assisted, minimally invasive approach to treat pronator syndrome adequately and safely decompressed all anatomical points of compression [7]. This approach also improved DASH scores [7].

Investigations

Other Considerations: Surgical indications for nerve decompression in pronator syndrome include persistent symptoms for more than 6 months [1], whereas anterior interosseous nerve syndrome (AINS) requires a minimum of 12 months with no signs of motor improvement [1]. A prolonged nonsurgical approach is warranted in most cases of median nerve or anterior interosseous nerve compression [6], and conservative treatment for at least 6 months is recommended before considering surgery for AINS [10]. An isolated anterior interosseous nerve injury may not by itself be an indication for urgent surgery [11]. AINS is characterized by median nerve fascicular constrictions in the arm [2] and is a multifocal mononeuropathy selectively involving motor fascicles within the main trunk of the median nerve that continue distally to form the anterior interosseous nerve [9]. In the majority of cases, AINS is not a surgically treatable entrapment neuropathy [9], and compression by normal surrounding tissues may not exist or is very rare [10]. Most cases of AINS likely represent neuritis [10].

Other Considerations: The diagnosis of pronator syndrome lacks objective pathophysiology and is supported only by subjective operative findings and relief after surgery [4]. There is a paucity of controlled trials demonstrating that operative treatment for pronator syndrome is more effective than other treatments or sham surgery [4]. Surgical decompression of the median nerve or the anterior interosseous nerve in the forearm is rarely indicated [6]. Anatomic findings of an ipsilateral supracondylar process and abnormal muscle mass are unique variations causing proximal compression of the median nerve [15]. Surgeons should bear in mind musculotendinous variations, such as a bifid median nerve, when assessing patients with symptoms of median nerve compression [16]. The ulnar head of the pronator teres is fibrotic or fibromuscular in 71.5% of cases [3], and its morphology and location relative to the median nerve are important for surgical treatment of pronator syndrome [3]. Resection of a segment of the persistent median artery is the recommended treatment for pronator syndrome associated with this anomaly [5]. Fluid extravasation from shoulder arthroscopy causing increased pressure in the upper arm and forearm is hypothesized to be the singular cause of neuropathies presenting clinically as anterior interosseous nerve palsy [20]. Median nerve symptoms can occur secondary to lacertus fibrosus syndrome following distal biceps tendon repair [14]. Patients presenting with median nerve symptoms must be assessed both at the wrist and proximally to exclude compression elsewhere [8]. An endoscopically assisted, minimally invasive approach to treat pronator syndrome adequately and safely decompressed all anatomical points of compression [7] and improved DASH scores [7].

Treatment

Non-Operative

A prolonged nonsurgical approach is warranted in most cases of median nerve or anterior interosseous nerve compression [6]. Conservative treatment for at least 6 months is recommended before considering surgery for anterior interosseous nerve syndrome [10].

Operative

Indications: Surgical indications for nerve decompression include persistent symptoms for greater than 6 months in patients with pronator syndrome [1]. For anterior interosseous nerve syndrome, indications include a minimum of 12 months with no signs of motor improvement [1]. However, an isolated anterior interosseous nerve injury may not by itself be an indication for urgent surgery [11], and the majority of anterior interosseous nerve syndrome cases are not surgically treatable entrapment neuropathies [9].

Surgical Approach / Technique: The morphology and location of the ulnar head of the pronator teres relative to the median nerve are important for surgical treatment of pronator syndrome [3], as the ulnar head is fibrotic or fibromuscular in 71.5% of cases [3]. Resection of a segment of the persistent median artery is the recommended treatment for pronator syndrome associated with this anomaly [5]. An endoscopically assisted, minimally invasive approach to treat pronator syndrome adequately and safely decompressed all anatomical points of compression [7]. Surgical decompression of the median nerve or the anterior interosseous nerve in the forearm is rarely indicated [6].

Adjuncts: Early intervention is important for optimizing supercharged end-to-side anterior interosseous nerve to ulnar nerve transfer outcomes [12]. Comprehensive rehabilitation is important for optimizing supercharged end-to-side anterior interosseous nerve to ulnar nerve transfer outcomes [12]. Standardized outcome measures are important for optimizing supercharged end-to-side anterior interosseous nerve to ulnar nerve transfer outcomes [12].

Other Considerations: Patients presenting with median nerve symptoms must be assessed both at the wrist and proximally to exclude compression elsewhere [8]. Anterior interosseous nerve syndrome is characterized by median nerve fascicular constrictions in the arm [2] and is a multifocal mononeuropathy selectively involving the motor fascicles within the main trunk of the median nerve that continue distally to form the anterior interosseous nerve [9]. Compression of the anterior interosseous nerve by normal surrounding tissues may not exist or is very rare [10], with most cases likely representing neuritis [10]. The diagnosis of pronator syndrome lacks objective pathophysiology and is supported only by subjective operative findings and relief after surgery [4]. There is a paucity of controlled trials demonstrating that operative treatment for pronator syndrome is more effective than other treatments or sham surgery [4]. Anterior interosseous nerve palsy is a rare complication of open capsular release for elbow stiffness [17], likely caused by traction or mass effect from packing [17].

Complications

Nerve palsy: Surgical decompression for pronator syndrome is indicated only when symptoms persist for greater than 6 months [1], whereas anterior interosseous nerve (AIN) syndrome requires a minimum of 12 months with no motor improvement before surgery is considered [1]. Most cases of AIN syndrome likely represent neuritis rather than surgically treatable entrapment, as compression by normal surrounding tissues is rare or non-existent [10]. Consequently, AIN syndrome is characterized as a multifocal mononeuropathy selectively involving motor fascicles within the main trunk of the median nerve [9]. A prolonged nonsurgical approach is warranted in most cases of median nerve or AIN compression [6], with conservative treatment recommended for at least 6 months prior to considering surgery for AIN syndrome [10]. Surgical decompression of the median nerve or AIN in the forearm is rarely indicated [6]. Patients presenting with median nerve symptoms must be assessed both at the wrist and proximally to exclude compression elsewhere [8].

Other Considerations: The ulnar head of the pronator teres is fibrotic or fibromuscular in 71.5% of cases, and its morphology and location relative to the median nerve are critical for surgical treatment of pronator syndrome [3]. Resection of a segment of the persistent median artery is the recommended treatment for pronator syndrome associated with this anomaly [5]. The diagnosis of pronator syndrome lacks objective pathophysiology and is supported only by subjective operative findings and relief after surgery [4]. There is a paucity of controlled trials demonstrating that operative treatment for pronator syndrome is more effective than other treatments or sham surgery [4]. Median nerve palsy is a rare but possibly devastating complication of arthroscopic elbow contracture release [19].

Recovery

Surgical Indications: Surgical decompression for pronator syndrome is indicated only when symptoms persist for greater than 6 months [1]. In contrast, anterior interosseous nerve (AIN) syndrome requires a minimum of 12 months with no signs of motor improvement before surgical intervention is considered [1]. A prolonged nonsurgical approach is warranted in most cases of median nerve or AIN compression [6], and conservative treatment for at least 6 months is specifically recommended before considering surgery for AIN syndrome [10]. Surgical decompression of the median nerve or AIN in the forearm is rarely indicated [6].

Pathophysiology and Diagnostic Constraints: AIN syndrome is characterized by median nerve fascicular constrictions in the arm rather than being a compressive neuropathy [2]. In the majority of cases, AIN syndrome is not a surgically treatable entrapment neuropathy but a multifocal mononeuropathy selectively involving motor fascicles within the main trunk of the median nerve [9]. Compression of the AIN by normal surrounding tissues may not exist or is very rare [10], and most cases likely represent neuritis [10]. The diagnosis of pronator syndrome lacks objective pathophysiology and is supported only by subjective operative findings and relief after surgery [4]. There is a paucity of controlled trials demonstrating that operative treatment for pronator syndrome is more effective than other treatments or sham surgery [4].

Anatomical Considerations and Surgical Technique: The ulnar head of the pronator teres is fibrotic or fibromuscular in 71.5% of cases [3], and the morphology and location of this head relative to the median nerve are important for surgical treatment of pronator syndrome [3]. Resection of a segment of the persistent median artery is the recommended treatment for pronator syndrome associated with this anomaly [5]. Endoscopically assisted, minimally invasive decompression for pronator syndrome adequately and safely decompressed all anatomical points of compression [7].

Functional Outcomes and Assessment: Endoscopically assisted decompression for pronator syndrome improved DASH scores [7]. Patients presenting with median nerve symptoms must be assessed both at the wrist and proximally to exclude compression elsewhere [8]. Delayed-onset anterior interosseous nerve palsy can develop one week after open elbow contracture release, likely due to a stretch injury [13].

Key Evidence

  • [Paper] Surgical indications for nerve decompression include persistent symptoms for >6 months in patients with pronator syndrome or for a minimum of 12 months with no signs of motor improvement in those with anterior interosseous nerve syndrome. (10.5435/jaaos-21-05-268)
  • [L4] Anterior interosseous nerve syndrome is a non-compressive neuropathy characterized by median nerve fascicular constrictions in the arm. (10.1002/mus.26768)
  • [L5] The ulnar head of the pronator teres is fibrotic or fibromuscular in 71.5% of cases, and its morphology and location relative to the median nerve are important for surgical treatment of pronator syndrome. (10.1016/j.otsr.2016.08.016)
  • [L5] The diagnosis of pronator syndrome lacks objective pathophysiology and is supported only by subjective operative findings and relief after surgery, with a paucity of controlled trials demonstrating that operative treatment is more effective than other treatments or sham surgery. (10.1016/j.jhsa.2011.02.014)
  • [Case_report] Resection of a segment of the persistent median artery is the recommended treatment for pronator syndrome associated with this anomaly. (10.2106/00004623-198769020-00026)
  • [L5] Surgical decompression of the median nerve or the AIN in the forearm is rarely indicated; a prolonged nonsurgical approach is warranted in most cases. (10.5435/jaaos-d-16-00010)
  • [L4] The endoscopically assisted, minimally invasive approach to treat pronator syndrome adequately and safely decompressed all anatomical points of compression and improved DASH scores. (10.1016/j.jhsa.2012.02.023)
  • [L4] The case demonstrates that patients presenting with median nerve symptoms must be assessed both at the wrist and proximally to exclude compression elsewhere. (10.1111/j.1758-5740.2010.00051.x)
  • [L4] Our data strongly support that AINS in the majority of cases is not a surgically treatable entrapment neuropathy but a multifocal mononeuropathy selectively involving, within the main trunk of the median nerve, the motor fascicles that continue distally to form the anterior interosseous nerve. (10.1212/wnl.0000000000000128)
  • [L5] Compression of the anterior interosseous nerve by normal surrounding tissues may not exist or is very rare, with most cases likely representing neuritis; conservative treatment for at least 6 months is recommended before considering surgery. (10.1177/17531934221074903)
  • [L4] An isolated anterior interosseous nerve injury may not by itself be an indication for urgent surgery. (10.2106/jbjs.n.00136)
  • [L3] The review highlights the importance of standardized outcome measures, early intervention, and comprehensive rehabilitation for optimizing supercharged end-to-side anterior interosseous nerve to ulnar nerve transfer outcomes. (10.1016/j.jhsg.2024.06.003)
  • [Case_report] The authors describe a case of delayed-onset anterior interosseous nerve palsy developing one week after open elbow contracture release, likely due to a stretch injury. (10.5397/cise.2022.00899)
  • [Case_report] This case presents a unique instance of median nerve symptoms secondary to lacertus fibrosus syndrome after distal biceps tendon repair. (10.1016/j.xrrt.2024.08.009)
  • [L4] The authors believe their anatomic findings are unique and should be added to the list of musculotendinous variations causing proximal compression of the median nerve that the surgeon must be aware of. (10.1016/j.jhsa.2007.10.006)
  • [L5] We encourage surgeons to bear such anomalies in mind when assessing patients with symptoms of median nerve compression. (10.1177/17531934251401431)
  • [L4] Anterior interosseous nerve palsy is a rare complication of open capsular release for elbow stiffness, likely caused by traction or mass effect from packing. (10.1016/j.jhsa.2008.10.019)
  • [L4] Type 4 median nerve entrapment is a severe form of a rare complication of elbow dislocation. (10.1007/s00402-003-0565-1)
  • [L4] We report a rare but possibly devastating complication of median nerve palsy after arthroscopic elbow contracture release. (10.1016/j.jse.2019.06.003)
  • [L4] The authors hypothesize that fluid extravasation from arthroscopy causing increased pressure in the upper arm and forearm is the singular cause of these neuropathies. (10.1016/j.jse.2016.04.037)
  • [L5] Clinical suspicion should arise in the presence of isolated paralysis of the AIN-supplied muscles. (10.1016/j.ijscr.2016.02.021)
  • [L4] Details about the origin and course of the AIN can explain the high percentage of AIN palsy in supracondylar elbow fractures in children. (10.1016/j.otsr.2013.04.002)
  • [L5] Dissection along the ulnar side of the median nerve can possibly decrease the chance of injury to the AIN during decompression. (10.1007/s11552-014-9639-5)
  • [L5] This case describes the first reported case of a palmaris longus variant with a central muscle belly and both distal and proximal tendinous insertions causing median nerve compression in a dynamic fashion at the mid forearm level. (10.1016/j.bjps.2012.03.023)
  • [L5] The authors critically analyze their operating room setup and patient positioning practices in light of existing biomechanical and cadaveric research to propose changes to standard practices that may help to reduce the incidence of this specific postoperative complication. (10.1155/2017/7252953)

See Also

References

[1] Pronator Syndrome and Anterior Interosseous Nerve Syndrome. Journal of the American Academy of Orthopaedic Surgeons. 2013. DOI: 10.5435/jaaos-21-05-268

[2] Fascicular constrictions above elbow typify anterior interosseous nerve syndrome. Muscle & Nerve. 2019. DOI: 10.1002/mus.26768

[3] Morphology and morphometry of the ulnar head of the pronator teres muscle in relation to median nerve compression at the proximal forearm. Orthopaedics & Traumatology: Surgery & Research. 2016. DOI: 10.1016/j.otsr.2016.08.016

[4] Pronator Syndrome. The Journal of Hand Surgery. 2011. DOI: 10.1016/j.jhsa.2011.02.014

[5] Pronator syndrome associated with a persistent median artery. A case report.. The Journal of Bone & Joint Surgery. 1987. DOI: 10.2106/00004623-198769020-00026

[6] Ulnar Tunnel Syndrome, Radial Tunnel Syndrome, Anterior Interosseous Nerve Syndrome, and Pronator Syndrome. Journal of the American Academy of Orthopaedic Surgeons. 2017. DOI: 10.5435/jaaos-d-16-00010

[7] Endoscopically Assisted Decompression for Pronator Syndrome. The Journal of Hand Surgery. 2012. DOI: 10.1016/j.jhsa.2012.02.023

[8] Median Nerve Compression Secondary to a High Insertion of Pronator Teres. Shoulder & Elbow. 2010. DOI: 10.1111/j.1758-5740.2010.00051.x

[9] Anterior interosseous nerve syndrome. Neurology. 2014. DOI: 10.1212/wnl.0000000000000128

[10] Compression to the anterior interosseous nerve is very rare: compression by the normal tissues surrounding it may not exist. Journal of Hand Surgery (European Volume). 2022. DOI: 10.1177/17531934221074903

[11] Supracondylar Humeral Fractures with Isolated Anterior Interosseous Nerve Injuries: Is Urgent Treatment Necessary?. The Journal of Bone and Joint Surgery-American Volume. 2014. DOI: 10.2106/jbjs.n.00136

[12] Exploring Outcomes and Mediating Factors Following Supercharged End-to-Side Anterior Interosseous Nerve to Ulnar Nerve Transfer: A Scoping Review With Expert Insight. Journal of Hand Surgery Global Online. 2024. DOI: 10.1016/j.jhsg.2024.06.003

[13] Anterior interosseous nerve palsy in the early postoperative period after open capsular release for elbow stiffness: a case report. Clinics in Shoulder and Elbow. 2023. DOI: 10.5397/cise.2022.00899

[14] Acute median nerve compression secondary to lacertus fibrosis syndrome following distal biceps tendon reconstruction: a case report. JSES Reviews, Reports, and Techniques. 2025. DOI: 10.1016/j.xrrt.2024.08.009

[15] An Unusual Case of Pronator Syndrome With Ipsilateral Supracondylar Process and Abnormal Muscle Mass. The Journal of Hand Surgery. 2008. DOI: 10.1016/j.jhsa.2007.10.006

[16] Bifid median nerve entrapment by forearm musculature – a case report and systematic literature review. Journal of Hand Surgery (European Volume). 2025. DOI: 10.1177/17531934251401431

[17] Anterior Interosseous Nerve Palsy After Open Capsular Release for Elbow Stiffness: Report of 2 Cases. The Journal of Hand Surgery. 2009. DOI: 10.1016/j.jhsa.2008.10.019

[18] Type 4 median nerve entrapment in a child after elbow dislocation. Archives of Orthopaedic and Trauma Surgery. 2003. DOI: 10.1007/s00402-003-0565-1

[19] High median nerve injury after arthroscopic elbow contracture release with complete recovery at 6 months. Journal of Shoulder and Elbow Surgery. 2019. DOI: 10.1016/j.jse.2019.06.003

[20] Mixed neuropathy presenting clinically as an anterior interosseous nerve palsy following shoulder arthroscopy: a report of four cases. Journal of Shoulder and Elbow Surgery. 2016. DOI: 10.1016/j.jse.2016.04.037

[22] Anterior interosseous nerve syndrome diagnosis and intraoperative findings: A case report. International Journal of Surgery Case Reports. 2016. DOI: 10.1016/j.ijscr.2016.02.021

[25] The anatomical basis for anterior interosseous nerve palsy secondary to supracondylar humerus fractures in children. Orthopaedics & Traumatology: Surgery & Research. 2013. DOI: 10.1016/j.otsr.2013.04.002

[26] Median Nerve Compression at the Fibrous Arch of the Flexor Digitorum Superficialis: An Anatomic Study of the Pronator Syndrome. HAND. 2014. DOI: 10.1007/s11552-014-9639-5

[28] The dual tendon palmaris longus variant causing dynamic median nerve compression in the forearm. Journal of Plastic, Reconstructive & Aesthetic Surgery. 2012. DOI: 10.1016/j.bjps.2012.03.023

[29] Anterior Interosseous Nerve Neuropraxia Secondary to Shoulder Arthroscopy and Open Subpectoral Long Head Biceps Tenodesis. Case Reports in Orthopedics. 2017. DOI: 10.1155/2017/7252953

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

5. Downstream recipients.

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

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

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

b. Other rights.

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

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

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

Section 3 -- License Conditions.

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

a. Attribution.

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

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

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

ii. a copyright notice;

iii. a notice that refers to this Public License;

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

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

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

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

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

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

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

Section 4 -- Sui Generis Database Rights.

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

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

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

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

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

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

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

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

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

Section 6 -- Term and Termination.

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

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

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

2. upon express reinstatement by the Licensor.

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

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

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

Section 7 -- Other Terms and Conditions.

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

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

Section 8 -- Interpretation.

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

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

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

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

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

Creative Commons may be contacted at creativecommons.org.