Case Report
The Journal of Hand Surgery (Asian-Pacific Volume) 2017;22(3):355-358 • DOI: 10.1142/S0218810417200222
Dorsal Wrist Ganglion Associated with Extensor Digitorum Brevis Manus: Case Report and Review of the Literature Adam M. Feintisch, Ramazi Datiashvili
J Hand Surg Asian-Pac Vol 2017.22:355-358. Downloaded from www.worldscientific.com by UNIVERSITY COLLEGE LONDON (UCL) on 09/23/17. For personal use only.
Division of Plastic and Reconstructive Surgery, Department of Surgery, Rutgers University - New Jersey Medical School, Newark, New Jersey, USA
Aberrant accessory muscles are rare entities in the hand. The extensor digitorum brevis manus (EDBM) muscle is amongst them and may be seen in association with dorsal ganglion cysts. Distinguishing an EDBM muscle is relevant in the diagnostic consideration of a dorsal ganglion in order to facilitate and guide its proper treatment. To date, there have been only few reports of an EDBM in association with a dorsal ganglion cyst. We report our experience with an incidental intraoperative finding of an intramuscular EDBM dorsal ganglion cyst and follow with a literature review and guide to management. Keywords: Cyst, Extensor digitorum brevis manus, Ganglion, Hand, Wrist
INTRODUCTION Ganglion cysts are the most common soft tissue tumors of the hand. They tend to occur in specific locations, however, have been observed in nearly every joint of the hand and wrist. While ganglions are frequently asymptomatic, they have been known to cause clinical symptoms secondary to pressure on nearby structures. Although less common, ganglions may be associated with other conditions of the hand, such as carpometacarpal boss, Heberden’s nodes of the distal interphalangeal joints, tenosynovitis, as well as compression neuropathies.1) They have also been documented to occur in conjunction with anomalous hand musculature, in particular, the extensor digitorum brevis manus (EDBM).2-5) However, to date there have been few clinical cases in the literature describing a ganglion in association with an EDBM.2-10) The incidence of both entities coexisting is Received: Aug. 25, 2015; Revised: Feb. 4, 2016; Accepted: Feb. 9, 2016 Correspondence to: Adam M. Feintisch Division of Plastic and Reconstructive Surgery, Department of Surgery, Rutgers University - New Jersey Medical School, 140 Bergen Street, Suite E1620, Newark, New Jersey 07103, USA Tel: +1-973-972-5377, Fax: +1-973-972-8268 E-mail: [email protected]
therefore unknown. Knowledge of the coexistence of these two entities is important in order to avoid confusion at the time of surgery. While most authors previously advocated complete surgical excision of the EDBM in totality with the ganglion, we believe our decision to preserve the anomalous muscle, albeit with a few clinical caveats, is more in line with current standards of care. In this respect, the potential for index finger extension in the absence of an extensor indicis proprius (EIP) would be preserved. We report our experience with an incidental intraoperative finding of an intramuscular EDBM dorsal ganglion cyst and follow with a literature review and guide to management.
CASE REPORT A 16-year-old, right-handed male presented with a mass on the dorsum of his hand overlying the carpometacarpal joint of the left middle finger. The patient stated that the mass had grown slowly over the course of 2.5 years. He had pain and functional limitations, particularly during wrist flexion and extremes of extension. The mass was approximately 2 × 3 cm and was noted to be mobile and cyst-like in nature without any overlying skin changes. It did not appear to move with finger extension and he did not display any range of motion defi-
356
J Hand Surg Asian-Pac Vol 2017.22:355-358. Downloaded from www.worldscientific.com by UNIVERSITY COLLEGE LONDON (UCL) on 09/23/17. For personal use only.
Adam M. Feintisch and Ramazi Datiashvili. Ganglion Associated with EDBM
cits on exam. The mass showed weak transillumination. There was no epitrochlear or axillary lymphadenopathy. He had no history of trauma to the hand. His right hand did not display any abnormalities. A presumptive diagnosis of a dorsal wrist ganglion cyst was made based on clinical and physical exam and the patient was scheduled for surgery. This was done without any further diagnostic workup or imaging as the patient’s exam was felt to be consistent with a ganglion cyst and we did not believe additional time or expense would alter our treatment plan. On operative exploration, a muscular mass was encountered immediately upon subcutaneous dissection (Fig. 1). On close inspection, there was noted to be a large, 1.7×2.2 cm cyst-like lesion within the substance of this muscle. A presumed diagnosis of an intramuscular ganglion within an aberrant EDBM was made and the cyst was excised with preservation of the anomalous musculature (Fig. 2). Pathologic exam was consistent with a ganglion cyst. On 8-month follow-up, although a visible EDBM was still present, the patient remained pain free with no ganglion recurrence or functional limitations.
DISCUSSION The EDBM is an aberrant finger extensor muscle occurring on the dorsum of the hand. First described in 1734 by Albinus, and later by Wood in 1864, the origins of this muscle continue to incite debate.11) It has been suggested to represent a failure of proximal migration of the ulnocarpal antebrachial muscle mass, a delamination of extensor musculature, or a variant of the extensor
Fig. 1. Intramuscular dorsal wrist ganglion associated with EDBM in situ.
indicis proprius tendon. 3,12) Some authors have suggested an incidence of up to 10%, however this may be due to erroneous reports including variations in other intrinsic hand musculature which may closely resemble the EDBM. Current literature reports the EDBM being present in approximately 2–3% of the population, with a potential hereditary component as well as an incidence of bilateralism in up to about 54% of cases.7,10-13) There does not appear to be a gender predilection.10) Several anatomical classifications of the EDBM have been made relying primarily on cadaver dissections and case reports.13,14) The muscle may originate from the distal end of the radius, dorsal radiocarpal ligament and wrist joint capsule, dorsal metacarpal surface or extensor tendons.12-14) It tends to lie volar to the extensor retinaculum within the fourth compartment in the dorsum of the hand extending distally via a single muscle belly between the extensor tendons and the metacarpals. There have also been reports of multiple, variable sized muscle bellies.11) Its insertion has been observed to occur into the extensor hoods of the index, middle, ring or little finger either individually or as a combined insertion.10,12,14) Insertion into the index finger is most common followed by the middle finger. When an index finger insertion is present, it may be alternatively referred to as the extensor indicis brevis.9,11) The EDBM has also been reported to insert on the ulnar aspect of the extensor digitorum communis tendons.9,12,13) Interestingly, absence of the extensor indicis proprius (EIP) has been observed in up to 16% of EDBM cases, with 50.5% of those absences occurring when the EDBM inserts into the index finger
Fig. 2. Dorsal wrist ganglion dissected free of surrounding EDBM in preparation for complete cyst excision in situ.
357
J Hand Surg Asian-Pac Vol 2017.22:355-358. Downloaded from www.worldscientific.com by UNIVERSITY COLLEGE LONDON (UCL) on 09/23/17. For personal use only.
The Journal of Hand Surgery (Asian-Pacific Volume) • Vol. 22, No. 3, 2017 • www.jhs-ap.org
extensor hood.13) This would suggest a compensatory EIP function for the anomalous EDBM. Innervation of EDBM has been demonstrated, both clinically and via EMG, as the posterior interosseus nerve.8,11) Distinguishing an EDBM from a dorsal wrist ganglion or other dorsal wrist pathology may prove difficult prior to operative intervention. In most instances, as was our experience, it is discovered as incidental intraoperative finding. However, there are some clinical findings that may aid in an accurate preoperative diagnosis. Although an EDBM may exist as an asymptomatic, unaesthetic mass, it typically presents with pain and discomfort in response to manual activity and labor.3) In such cases, heavy repetitive use of the hand results in muscle hypertrophy and impingement under the extensor retinaculum. This may result in a so called “fourth compartment” syndrome, causing increased compartment pressure and either direct or indirect compression of the posterior interosseus nerve.11,15) Pain may also occur secondary to chronic denervation.7,9,12) Physical exam may delineate a firm, fusiform mass most prominent during wrist flexion and finger extension whereas a pure dorsal wrist ganglion would project solely with wrist flexion. Bilateral EDBM may show a larger mass in the dominant hand.3,12) Ganglion transillumination or aspiration may conceal an EDBM and depending on the thickness or attenuation of the EDBM encapsulating the ganglion cyst, transillumination may or may not be present. Transillumination by itself, however, may be unreliable as it can be influenced by the thickness of a patient’s skin and/ or subcutaneous tissue. In such cases electromyography may be a helpful diagnostic aid.3,9) Radiographic examination may also be useful as MRI and ultrasonography have been used with success. 13) However, due to the variability in physical exam findings as well as increase health-care costs associated with diagnostic imaging, we believe that in many cases, identification of an EDBM can safely be performed during operative exploration. With such a low incidence of association of dorsal wrist ganglions with EDBM, current treatment guidelines largely rely on expert opinions. Suggestions have ranged from observation and splinting to complete surgical excision of both the ganglion and EDBM.3,11) While symptoms may abate with rest, resumption of activity would likely result in recurrence secondary to muscle hypertrophy and nerve compression. Fascial release had been advocated by a few, however, many surgeons suggested complete surgical excision of ganglion in totality with the EDBM.2,3,5,7,9) This recommendation was prefaced on the notion that the EDBM had
no functional implications. However, thanks to detailed anatomical studies, we now know that the EDBM may function as an extensor to compensate for an absent or weak EIP.10,13,14) Therefore, in such cases where an EIP is absent, the EDBM may be the sole muscle responsible for independent index finger extension. Cyst excision only with preservation of the EDBM and its compensatory function would therefore be more prudent, and is what we chose to do in our reported case. There may be instances where EDBM excision may prove beneficial, specifically those where a particularly small ganglion is encountered incidentally upon operative exploration and preoperative pain and discomfort can be attributed to the anomalous muscle. Additionally, cases where there is associated muscle fibrosis, obvious nerve impingement or surrounding synovitis, excision of the EDBM would be advised. However, it is our opinion that in the majority of instances where an EDBM is found in conjunction with a presumed symptomatic ganglion cyst, that the anomalous muscle be preserved in the event that it proves to be of functional significance to the hand. In cases where cyst excision proves to be inadequate for symptomatic relief, a decision regarding repeat operative exploration and muscle excision could then be made. Alternatively, there has been interest in wide awake hand surgery as a method for treating a variety of hand lesions and deformities. This may prove to be a viable option wherein manipulation of an anomalous EDBM intraoperatively while simultaneously asking an awake patient to range their digits may give a clear picture as to whether an EDBM is functional. In situations where an EDBM provides no extension, excision could then be safely performed. However one chooses to approach such clinical scenarios, these are challenging cases with widely variable presentations and sound clinical judgment must be made on a case-by-case basis so as not to iatrogenically jeopardize hand function.
CONFLICTS OF INTEREST All named authors hereby declare that they have no conflicts of interest to disclose. This article does not contain any studies with human or animal subjects. Informed consent was obtained from all individual participants included in the study.
REFERENCES 1. Athanasian, EA. Bone and Soft Tissue Tumors. In Wolfe
358
J Hand Surg Asian-Pac Vol 2017.22:355-358. Downloaded from www.worldscientific.com by UNIVERSITY COLLEGE LONDON (UCL) on 09/23/17. For personal use only.
Adam M. Feintisch and Ramazi Datiashvili. Ganglion Associated with EDBM
SW, editor, Green’s Operative Hand Surgery, 6th Ed, Philadelphia, PA, Elsevier, 2011;2152-61. 2. Constantian MB, Zuelzer WA, Theogaraj SD. The dorsal ganglion with anomalous muscles. J Hand Surg Am. 1979;4:84-5. 3. Dostal GH, Lister GD, Hutchinson D, et al. Extensor digitorum brevis manus associated with a dorsal wrist ganglion: a review of five cases. J Hand Surg Am. 1995;20A:357. 4. Lucas GL. An intratendinous cyst in the extensor digitorum brevis manus tendon. J Hand Surg Am. 1979;4:176-7. 5. Murakami Y, Todani K. The extensor indices brevis muscle with an unusual ganglion. Clin Orthop Relat Res. 1982;162:207-9. 6. Antonio A. Extensor digitorum brevis manus associated with a dorsal wrist ganglion: case report. Clin Anat. 2008;21:794-5. 7. Gama C. Extensor digitorum brevis manus: A report on 38 cases and a review of the literature. J Hand Surg Am. 1983;8:578-82. 8. Han KJ, Lee YS, Hong KY. Unusual presentation of extensor digitorum brevis manus: two cases report. Clin Anat.
2011;24:974-7. 9. Reef TC, Brestin SG. The extensor digitorum brevis manus and its clinical significance. J Bone Joint Surg Am. 1975;57A:704-6. 10. Renade, AV, Rai R, Prabhu LV, et al. Incidence of Extensor Digitorum Brevis Manus Muscle. Hand. 2008;3:320-3. 11. Paraskevas G, Papaziogas B, Spanidou S, et al. Unusual variation of the extensor digitorum brevis manus: a case report. Orthop Traumatol. 2002;12:3. 12. Ogura T, Inoue H, Tanabe G. Anatomic and clinical studies of the extensor digitorum brevis manus. J Hand Surg Am. 1987;12:100-7. 13. Rodriguez-Niedenfuhr M, Vazquez T, Golano P, et al. Extensor digitorum brevis manus: anatomical, radiological and clinical relevance. Clin Anat. 2002;15:286-92. 14. El-Badawi MG, Butt MM, al-Zuhair AG, et al. Extensor tendons of the fingers: arrangement and variations. Clin Anat. 1995;8:391-8. 15. Hayashi H, Kojima T, Fukumoto K. The fourth-compartment syndrome: its anatomical basis and clinical cases. Handchir Mikrochir Plast Chir. 1999;31:61-5.
The Journal of Hand Surgery (Asian-Pacific Volume) 2017;22(3):355-358 • DOI: 10.1142/S0218810417200222
Dorsal Wrist Ganglion Associated with Extensor Digitorum Brevis Manus: Case Report and Review of the Literature Adam M. Feintisch, Ramazi Datiashvili
J Hand Surg Asian-Pac Vol 2017.22:355-358. Downloaded from www.worldscientific.com by UNIVERSITY COLLEGE LONDON (UCL) on 09/23/17. For personal use only.
Division of Plastic and Reconstructive Surgery, Department of Surgery, Rutgers University - New Jersey Medical School, Newark, New Jersey, USA
Aberrant accessory muscles are rare entities in the hand. The extensor digitorum brevis manus (EDBM) muscle is amongst them and may be seen in association with dorsal ganglion cysts. Distinguishing an EDBM muscle is relevant in the diagnostic consideration of a dorsal ganglion in order to facilitate and guide its proper treatment. To date, there have been only few reports of an EDBM in association with a dorsal ganglion cyst. We report our experience with an incidental intraoperative finding of an intramuscular EDBM dorsal ganglion cyst and follow with a literature review and guide to management. Keywords: Cyst, Extensor digitorum brevis manus, Ganglion, Hand, Wrist
INTRODUCTION Ganglion cysts are the most common soft tissue tumors of the hand. They tend to occur in specific locations, however, have been observed in nearly every joint of the hand and wrist. While ganglions are frequently asymptomatic, they have been known to cause clinical symptoms secondary to pressure on nearby structures. Although less common, ganglions may be associated with other conditions of the hand, such as carpometacarpal boss, Heberden’s nodes of the distal interphalangeal joints, tenosynovitis, as well as compression neuropathies.1) They have also been documented to occur in conjunction with anomalous hand musculature, in particular, the extensor digitorum brevis manus (EDBM).2-5) However, to date there have been few clinical cases in the literature describing a ganglion in association with an EDBM.2-10) The incidence of both entities coexisting is Received: Aug. 25, 2015; Revised: Feb. 4, 2016; Accepted: Feb. 9, 2016 Correspondence to: Adam M. Feintisch Division of Plastic and Reconstructive Surgery, Department of Surgery, Rutgers University - New Jersey Medical School, 140 Bergen Street, Suite E1620, Newark, New Jersey 07103, USA Tel: +1-973-972-5377, Fax: +1-973-972-8268 E-mail: [email protected]
therefore unknown. Knowledge of the coexistence of these two entities is important in order to avoid confusion at the time of surgery. While most authors previously advocated complete surgical excision of the EDBM in totality with the ganglion, we believe our decision to preserve the anomalous muscle, albeit with a few clinical caveats, is more in line with current standards of care. In this respect, the potential for index finger extension in the absence of an extensor indicis proprius (EIP) would be preserved. We report our experience with an incidental intraoperative finding of an intramuscular EDBM dorsal ganglion cyst and follow with a literature review and guide to management.
CASE REPORT A 16-year-old, right-handed male presented with a mass on the dorsum of his hand overlying the carpometacarpal joint of the left middle finger. The patient stated that the mass had grown slowly over the course of 2.5 years. He had pain and functional limitations, particularly during wrist flexion and extremes of extension. The mass was approximately 2 × 3 cm and was noted to be mobile and cyst-like in nature without any overlying skin changes. It did not appear to move with finger extension and he did not display any range of motion defi-
356
J Hand Surg Asian-Pac Vol 2017.22:355-358. Downloaded from www.worldscientific.com by UNIVERSITY COLLEGE LONDON (UCL) on 09/23/17. For personal use only.
Adam M. Feintisch and Ramazi Datiashvili. Ganglion Associated with EDBM
cits on exam. The mass showed weak transillumination. There was no epitrochlear or axillary lymphadenopathy. He had no history of trauma to the hand. His right hand did not display any abnormalities. A presumptive diagnosis of a dorsal wrist ganglion cyst was made based on clinical and physical exam and the patient was scheduled for surgery. This was done without any further diagnostic workup or imaging as the patient’s exam was felt to be consistent with a ganglion cyst and we did not believe additional time or expense would alter our treatment plan. On operative exploration, a muscular mass was encountered immediately upon subcutaneous dissection (Fig. 1). On close inspection, there was noted to be a large, 1.7×2.2 cm cyst-like lesion within the substance of this muscle. A presumed diagnosis of an intramuscular ganglion within an aberrant EDBM was made and the cyst was excised with preservation of the anomalous musculature (Fig. 2). Pathologic exam was consistent with a ganglion cyst. On 8-month follow-up, although a visible EDBM was still present, the patient remained pain free with no ganglion recurrence or functional limitations.
DISCUSSION The EDBM is an aberrant finger extensor muscle occurring on the dorsum of the hand. First described in 1734 by Albinus, and later by Wood in 1864, the origins of this muscle continue to incite debate.11) It has been suggested to represent a failure of proximal migration of the ulnocarpal antebrachial muscle mass, a delamination of extensor musculature, or a variant of the extensor
Fig. 1. Intramuscular dorsal wrist ganglion associated with EDBM in situ.
indicis proprius tendon. 3,12) Some authors have suggested an incidence of up to 10%, however this may be due to erroneous reports including variations in other intrinsic hand musculature which may closely resemble the EDBM. Current literature reports the EDBM being present in approximately 2–3% of the population, with a potential hereditary component as well as an incidence of bilateralism in up to about 54% of cases.7,10-13) There does not appear to be a gender predilection.10) Several anatomical classifications of the EDBM have been made relying primarily on cadaver dissections and case reports.13,14) The muscle may originate from the distal end of the radius, dorsal radiocarpal ligament and wrist joint capsule, dorsal metacarpal surface or extensor tendons.12-14) It tends to lie volar to the extensor retinaculum within the fourth compartment in the dorsum of the hand extending distally via a single muscle belly between the extensor tendons and the metacarpals. There have also been reports of multiple, variable sized muscle bellies.11) Its insertion has been observed to occur into the extensor hoods of the index, middle, ring or little finger either individually or as a combined insertion.10,12,14) Insertion into the index finger is most common followed by the middle finger. When an index finger insertion is present, it may be alternatively referred to as the extensor indicis brevis.9,11) The EDBM has also been reported to insert on the ulnar aspect of the extensor digitorum communis tendons.9,12,13) Interestingly, absence of the extensor indicis proprius (EIP) has been observed in up to 16% of EDBM cases, with 50.5% of those absences occurring when the EDBM inserts into the index finger
Fig. 2. Dorsal wrist ganglion dissected free of surrounding EDBM in preparation for complete cyst excision in situ.
357
J Hand Surg Asian-Pac Vol 2017.22:355-358. Downloaded from www.worldscientific.com by UNIVERSITY COLLEGE LONDON (UCL) on 09/23/17. For personal use only.
The Journal of Hand Surgery (Asian-Pacific Volume) • Vol. 22, No. 3, 2017 • www.jhs-ap.org
extensor hood.13) This would suggest a compensatory EIP function for the anomalous EDBM. Innervation of EDBM has been demonstrated, both clinically and via EMG, as the posterior interosseus nerve.8,11) Distinguishing an EDBM from a dorsal wrist ganglion or other dorsal wrist pathology may prove difficult prior to operative intervention. In most instances, as was our experience, it is discovered as incidental intraoperative finding. However, there are some clinical findings that may aid in an accurate preoperative diagnosis. Although an EDBM may exist as an asymptomatic, unaesthetic mass, it typically presents with pain and discomfort in response to manual activity and labor.3) In such cases, heavy repetitive use of the hand results in muscle hypertrophy and impingement under the extensor retinaculum. This may result in a so called “fourth compartment” syndrome, causing increased compartment pressure and either direct or indirect compression of the posterior interosseus nerve.11,15) Pain may also occur secondary to chronic denervation.7,9,12) Physical exam may delineate a firm, fusiform mass most prominent during wrist flexion and finger extension whereas a pure dorsal wrist ganglion would project solely with wrist flexion. Bilateral EDBM may show a larger mass in the dominant hand.3,12) Ganglion transillumination or aspiration may conceal an EDBM and depending on the thickness or attenuation of the EDBM encapsulating the ganglion cyst, transillumination may or may not be present. Transillumination by itself, however, may be unreliable as it can be influenced by the thickness of a patient’s skin and/ or subcutaneous tissue. In such cases electromyography may be a helpful diagnostic aid.3,9) Radiographic examination may also be useful as MRI and ultrasonography have been used with success. 13) However, due to the variability in physical exam findings as well as increase health-care costs associated with diagnostic imaging, we believe that in many cases, identification of an EDBM can safely be performed during operative exploration. With such a low incidence of association of dorsal wrist ganglions with EDBM, current treatment guidelines largely rely on expert opinions. Suggestions have ranged from observation and splinting to complete surgical excision of both the ganglion and EDBM.3,11) While symptoms may abate with rest, resumption of activity would likely result in recurrence secondary to muscle hypertrophy and nerve compression. Fascial release had been advocated by a few, however, many surgeons suggested complete surgical excision of ganglion in totality with the EDBM.2,3,5,7,9) This recommendation was prefaced on the notion that the EDBM had
no functional implications. However, thanks to detailed anatomical studies, we now know that the EDBM may function as an extensor to compensate for an absent or weak EIP.10,13,14) Therefore, in such cases where an EIP is absent, the EDBM may be the sole muscle responsible for independent index finger extension. Cyst excision only with preservation of the EDBM and its compensatory function would therefore be more prudent, and is what we chose to do in our reported case. There may be instances where EDBM excision may prove beneficial, specifically those where a particularly small ganglion is encountered incidentally upon operative exploration and preoperative pain and discomfort can be attributed to the anomalous muscle. Additionally, cases where there is associated muscle fibrosis, obvious nerve impingement or surrounding synovitis, excision of the EDBM would be advised. However, it is our opinion that in the majority of instances where an EDBM is found in conjunction with a presumed symptomatic ganglion cyst, that the anomalous muscle be preserved in the event that it proves to be of functional significance to the hand. In cases where cyst excision proves to be inadequate for symptomatic relief, a decision regarding repeat operative exploration and muscle excision could then be made. Alternatively, there has been interest in wide awake hand surgery as a method for treating a variety of hand lesions and deformities. This may prove to be a viable option wherein manipulation of an anomalous EDBM intraoperatively while simultaneously asking an awake patient to range their digits may give a clear picture as to whether an EDBM is functional. In situations where an EDBM provides no extension, excision could then be safely performed. However one chooses to approach such clinical scenarios, these are challenging cases with widely variable presentations and sound clinical judgment must be made on a case-by-case basis so as not to iatrogenically jeopardize hand function.
CONFLICTS OF INTEREST All named authors hereby declare that they have no conflicts of interest to disclose. This article does not contain any studies with human or animal subjects. Informed consent was obtained from all individual participants included in the study.
REFERENCES 1. Athanasian, EA. Bone and Soft Tissue Tumors. In Wolfe
358
J Hand Surg Asian-Pac Vol 2017.22:355-358. Downloaded from www.worldscientific.com by UNIVERSITY COLLEGE LONDON (UCL) on 09/23/17. For personal use only.
Adam M. Feintisch and Ramazi Datiashvili. Ganglion Associated with EDBM
SW, editor, Green’s Operative Hand Surgery, 6th Ed, Philadelphia, PA, Elsevier, 2011;2152-61. 2. Constantian MB, Zuelzer WA, Theogaraj SD. The dorsal ganglion with anomalous muscles. J Hand Surg Am. 1979;4:84-5. 3. Dostal GH, Lister GD, Hutchinson D, et al. Extensor digitorum brevis manus associated with a dorsal wrist ganglion: a review of five cases. J Hand Surg Am. 1995;20A:357. 4. Lucas GL. An intratendinous cyst in the extensor digitorum brevis manus tendon. J Hand Surg Am. 1979;4:176-7. 5. Murakami Y, Todani K. The extensor indices brevis muscle with an unusual ganglion. Clin Orthop Relat Res. 1982;162:207-9. 6. Antonio A. Extensor digitorum brevis manus associated with a dorsal wrist ganglion: case report. Clin Anat. 2008;21:794-5. 7. Gama C. Extensor digitorum brevis manus: A report on 38 cases and a review of the literature. J Hand Surg Am. 1983;8:578-82. 8. Han KJ, Lee YS, Hong KY. Unusual presentation of extensor digitorum brevis manus: two cases report. Clin Anat.
2011;24:974-7. 9. Reef TC, Brestin SG. The extensor digitorum brevis manus and its clinical significance. J Bone Joint Surg Am. 1975;57A:704-6. 10. Renade, AV, Rai R, Prabhu LV, et al. Incidence of Extensor Digitorum Brevis Manus Muscle. Hand. 2008;3:320-3. 11. Paraskevas G, Papaziogas B, Spanidou S, et al. Unusual variation of the extensor digitorum brevis manus: a case report. Orthop Traumatol. 2002;12:3. 12. Ogura T, Inoue H, Tanabe G. Anatomic and clinical studies of the extensor digitorum brevis manus. J Hand Surg Am. 1987;12:100-7. 13. Rodriguez-Niedenfuhr M, Vazquez T, Golano P, et al. Extensor digitorum brevis manus: anatomical, radiological and clinical relevance. Clin Anat. 2002;15:286-92. 14. El-Badawi MG, Butt MM, al-Zuhair AG, et al. Extensor tendons of the fingers: arrangement and variations. Clin Anat. 1995;8:391-8. 15. Hayashi H, Kojima T, Fukumoto K. The fourth-compartment syndrome: its anatomical basis and clinical cases. Handchir Mikrochir Plast Chir. 1999;31:61-5.
