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The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression
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MODEL
Journal of Plastic, Reconstructive & Aesthetic Surgery (2013) xx, e1ee3
CASE REPORT
The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression* A. Cherchel*, C. Zirak, A. De Mey Brugmann University Hospital, Free University of Brussels, Brussels, Belgium Received 12 July 2012; accepted 10 April 2013
KEYWORDS Radial nerve; Compression; Entrapment; Brachioradialis
Summary Radial nerve compression is seldom encountered in the upper arm, and most commonly described compression syndromes have their anatomical cause in the forearm. The teres major, the triceps muscle, the intermuscular septum region and the space between the brachialis and brachioradialis muscles have all been identified as radial nerve compression sites above the elbow. We describe the case of a 38-year-old male patient who presented with dorso-lateral forearm pain and paraesthesias without neurological deficit. Surgical exploration revealed radial nerve compression at the humeral origin of the brachioradialis muscle. Liberation of the nerve at this site was successful at relieving the symptoms. To our knowledge, this compression site has not been described in the literature. ª 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Commonly known radial nerve compression syndromes are located in the forearm.1 Compression at the arcade of Frohse is the most frequent compression site, and many structures surrounding the area of the supinator origin are liable to have mechanical effects on the nerve.2 Radial nerve entrapment above the elbow is infrequent. It may occur due to compression of the radial nerve for an
* This paper was presented at the Spring Meeting of the Royal Belgian Society for Plastic Surgery in Genk, Belgium, on 28 April 2012. * Corresponding author. CHU Brugmann, Plastic Surgery Department, Pl. A. van Gehuchten, 4, 1020 Laeken, Belgium. Tel.: þ32 2 477 39 97; fax: þ32 2 477 21 61. E-mail address: [email protected] (A. Cherchel).
extended amount of time in the context of drug or alcohol abuse, or in the presence of an exostosis.1 Proximally located anatomical compression sites that have been described include the teres major,3 the triceps,4e6 the intermuscular septum region7,8 and the space between the brachialis and brachioradialis muscles.9 In some instances, the occurrence of symptoms is linked to muscular effort.3,5 We describe the case of a patient who presented with a proximal radial nerve entrapment located at the origin of the brachioradialis muscle.
Case We report the case of a 38-year-old right-handed construction worker, who complained of right upper limb pain
1748-6815/$ - see front matter ª 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.bjps.2013.04.023
Please cite this article in press as: Cherchel A, et al., The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression, Journal of Plastic, Reconstructive & Aesthetic Surgery (2013), http://dx.doi.org/10.1016/j.bjps.2013.04.023
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e2 since 1 year. The patient’s medical history revealed an appendicectomy, a stomach ulcer and reflux oesophagitis. His daily medication included omeprazole. He was an active smoker and drank two beers daily. The patient complained of pain and paraesthesias irradiating from his right elbow to the radial metacarpal heads. Clinical examination was unremarkable. Palpation of the lateral epicondyle was painless. There was no Tinel sign and no sensory or motor deficit in the affected limb. Electromyography (EMG) revealed polyphasic potentials of the extensor carpi radialis longus (ECRL), extensor carpi radialis brevis and extensor indicis proprius muscles, which are a sign of chronic damage. As the ECRL was not spared, the results were against a posterior interosseous syndrome. The neurophysiologist suggested that the compression site was located at the lateral head of the triceps. On the basis of the above clinical information, a radiologist performed an ultrasound centred on the elbow: epicondylitis, a synovial cyst and intra-articular effusion were excluded. Magnetic resonance imaging of the right upper limb was normal. Six months of anti-inflammatory treatment had already been attempted in the patient’s native country without success. We therefore proceeded with a surgical exploration. Under general anaesthesia, a dorso-lateral arm incision was performed. The radial nerve was exposed between the triceps and the brachialis muscles. The humeral origin of the brachioradialis muscle compressed the nerve tightly at its entrance in the space between the brachioradialis and brachialis muscles (Figure 1). The aponeurotic expansion was sectioned to free the nerve. An epineurectomy was performed on 4 cm of the radial nerve at the compression site. Complete liberation was checked by inserting a finger distally between the brachialis and brachioradialis muscles. The immediate and long-term postoperative evolution was favourable with a complete disappearance of the complaints within 2 weeks.
Discussion The radial nerve is a terminal branch of the posterior cord of the brachial plexus. It travels behind the axillary and brachial arteries and in front of the long head of the triceps muscle. It then takes a lateral and posterior course to reach the spiral groove, where it lies between the lateral and medial heads of the triceps. The radial nerve innervates the triceps muscle and then reaches the anterior compartment of the arm by passing through the intermuscular septum at a distance of about 10 cm proximal to the lateral epicondyle. Proximal to the elbow, muscular branches are sent to the brachialis, brachioradialis, anconeus and ECRL muscles. As it reaches the epicondyle the nerve divides into a sensory branch and a motor branch, becoming the posterior interosseous nerve.1 Radial nerve compression has been reported as high up as the teres major muscle.3 The EMG evaluation of our patient was in favour of tricipital compression. In this location, the radial nerve can be trapped either by the muscular fibres4 or by a fibrous arch.5,6 Lotem performed a series of dissections where a fibrous arch originating from the tendon of the lateral head of the triceps and bridging over the spiral groove was identified. Those arches were of
A. Cherchel et al.
Figure 1 Perioperative view of the radial nerve compression site. The triceps (1) has been reclined, allowing exposure of the compression of the radial nerve by the brachioradialis (2). The brachialis muscle (3) is visible medially.
variable tightness, making them able to create a local compression.5 More distally, the intermuscular septum may compress the radial nerve7 and a case of lateral arm pain radiating to the forearm has been cured by the section of a compressive fibrous canal located just proximal to the intermuscular septum.8 A radial nerve compression between the brachialis and brachioradialis muscles can also induce a sensori-motor radial deficit.9 Mehta et al. have found an accessory muscle belly, which they describe as belonging to the brachioradialis muscle and as a potential compression site. This muscle merged with the deltoid near its insertion and coalesced with the brachioradialis at the lateral epicondyle. The radial nerve was located between the accessory muscle and the brachioradialis.10 A bifid brachioradialis muscle belly has also been reported. The superficial branch of the radial nerve was located in the space between these muscle bellies and thus at risk for compression.11 In our case, the brachialis and brachioradialis muscles were located on either side of the nerve at the level of the entrapment, and the brachialis was not involved in the compressive mechanism. However, a tight angle of the brachioradialis muscle fibres compressed it against the humerus. The part of the brachioradialis visualised in our surgical field was not bifid, and no additional muscle belly was identified.
Please cite this article in press as: Cherchel A, et al., The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression, Journal of Plastic, Reconstructive & Aesthetic Surgery (2013), http://dx.doi.org/10.1016/j.bjps.2013.04.023
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Humeral origin of brachioradialis muscle Endoscopic peripheral nerve release is an elegant and minimally invasive alternative to an open surgical approach. For example, it would have been possible to approach the radial nerve from the lateral muscular septum proximally to the entrapment site and follow it distally. A larger incision could be reserved as a complement to the procedure, or to cases where the entrapment site is not clearly defined by the endoscopy. However, while endoscopic carpal tunnel release has been practised at our institution in the past, endoscopic nerve release procedures have since then been altogether abandoned. The amount of muscle mass and muscular exercise seem to influence radial nerve entrapment. Lotem’s patients all developed acute palsy after a muscular effort.5 Other authors describe radial nerve deficit in the context of intense muscular efforts such as body building,3 wrestling4 or professional manual activities, as in our patient. It seems reasonable to imagine that repeated muscular efforts sustained over time may have contributed to the evolution of his pathology.
Conclusion We described a case of lateral arm pain and paraesthesias due to a high radial nerve compression by the brachioradialis muscle at its origin on the humerus. The electromyographic results were in accordance with a compression proximal to the posterior interosseous nerve sparing the triceps muscle. We demonstrated that the origin of the brachioradialis muscle can be considered as an alternate compression site of the radial nerve in similar clinical situations.
Conflict of interest statement We have no conflicts of interest to declare. No funding was provided for this study.
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References 1. Green D, Hotchkiss R, Pederson W, et al. Green’s operative hand surgery. 5th ed., vol. 1&2. Philadelphia PA: Elsevier Churchill Livingstone; 2005, p.1033e41. 2. Riffaud L, Morandi X, Goday B, et al. Anatomic bases for the compression and neurolysis of the deep branch of the radial nerve in the radial tunnel. Surg Radiol Anat 1999;21(4): 229e33. 3. Ng AB, Borhan J, Ashton HR, Misra AN, Redfern DR. Radial nerve palsy in an elite bodybuilder. Br J Sports Med 2003 Apr;37(2): 185e6. 4. Manske PR. Compression of the radial nerve by the triceps muscle: a case report. J Bone Jt Surg Am 1977 Sep;59(6): 835e6. 5. Lotem M, Fried A, Levy M, Solzi P, Najenson T, Nathan H. Radial palsy following muscular effort. A nerve compression syndrome possibly related to a fibrous arch of the lateral head of the triceps. J Bone Jt Surg Br 1971 Aug;53(3):500e6. 6. Nakamichi K, Tachibana S. Radial nerve entrapment by the lateral head of the triceps. J Hand Surg Am 1991 Jul;16(4): 748e50. 7. Wasmeier C, Pfadenhauer K, Kalbarzcyk H, Becker T, Ro ¨sler A. Subacute proximal entrapment neuropathy of the radial nerve at the hiatus radialis. Nervenarzt 2004 Aug;75(8): 780e4. 8. Adolfsson LE, Nettelblad H. Radial nerve entrapment in the upper arm as a cause of lateral arm pain: a report of four cases. Scand J Plast Reconstr Surg Hand Surg 2001 Jun;35(2): 217e20. 9. Lee YK, Kim YI, Choy WS. Radial nerve compression between the brachialis and brachioradialis muscles in a manual worker: a case report. J Hand Surg Am 2006 MayeJun;31(5): 744e6. 10. Mehta V, Suri R, Arora J, Rath G, Das S. Anomalous constitution of the brachioradialis muscle: a potential site of radial nerve entrapment. Clin Ter 2010;161(1):59e61. 11. R Dhuria, Mehta V, Roy S, Suri RK, Rath G. Clinico-anatomical report of a rare anomalous disposition of brachioradialis: a possible site for compressing superficial branch of radial nerve. Clin Ter 2011;162(3):235e7.
Please cite this article in press as: Cherchel A, et al., The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression, Journal of Plastic, Reconstructive & Aesthetic Surgery (2013), http://dx.doi.org/10.1016/j.bjps.2013.04.023
MODEL
Journal of Plastic, Reconstructive & Aesthetic Surgery (2013) xx, e1ee3
CASE REPORT
The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression* A. Cherchel*, C. Zirak, A. De Mey Brugmann University Hospital, Free University of Brussels, Brussels, Belgium Received 12 July 2012; accepted 10 April 2013
KEYWORDS Radial nerve; Compression; Entrapment; Brachioradialis
Summary Radial nerve compression is seldom encountered in the upper arm, and most commonly described compression syndromes have their anatomical cause in the forearm. The teres major, the triceps muscle, the intermuscular septum region and the space between the brachialis and brachioradialis muscles have all been identified as radial nerve compression sites above the elbow. We describe the case of a 38-year-old male patient who presented with dorso-lateral forearm pain and paraesthesias without neurological deficit. Surgical exploration revealed radial nerve compression at the humeral origin of the brachioradialis muscle. Liberation of the nerve at this site was successful at relieving the symptoms. To our knowledge, this compression site has not been described in the literature. ª 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Commonly known radial nerve compression syndromes are located in the forearm.1 Compression at the arcade of Frohse is the most frequent compression site, and many structures surrounding the area of the supinator origin are liable to have mechanical effects on the nerve.2 Radial nerve entrapment above the elbow is infrequent. It may occur due to compression of the radial nerve for an
* This paper was presented at the Spring Meeting of the Royal Belgian Society for Plastic Surgery in Genk, Belgium, on 28 April 2012. * Corresponding author. CHU Brugmann, Plastic Surgery Department, Pl. A. van Gehuchten, 4, 1020 Laeken, Belgium. Tel.: þ32 2 477 39 97; fax: þ32 2 477 21 61. E-mail address: [email protected] (A. Cherchel).
extended amount of time in the context of drug or alcohol abuse, or in the presence of an exostosis.1 Proximally located anatomical compression sites that have been described include the teres major,3 the triceps,4e6 the intermuscular septum region7,8 and the space between the brachialis and brachioradialis muscles.9 In some instances, the occurrence of symptoms is linked to muscular effort.3,5 We describe the case of a patient who presented with a proximal radial nerve entrapment located at the origin of the brachioradialis muscle.
Case We report the case of a 38-year-old right-handed construction worker, who complained of right upper limb pain
1748-6815/$ - see front matter ª 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.bjps.2013.04.023
Please cite this article in press as: Cherchel A, et al., The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression, Journal of Plastic, Reconstructive & Aesthetic Surgery (2013), http://dx.doi.org/10.1016/j.bjps.2013.04.023
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MODEL
e2 since 1 year. The patient’s medical history revealed an appendicectomy, a stomach ulcer and reflux oesophagitis. His daily medication included omeprazole. He was an active smoker and drank two beers daily. The patient complained of pain and paraesthesias irradiating from his right elbow to the radial metacarpal heads. Clinical examination was unremarkable. Palpation of the lateral epicondyle was painless. There was no Tinel sign and no sensory or motor deficit in the affected limb. Electromyography (EMG) revealed polyphasic potentials of the extensor carpi radialis longus (ECRL), extensor carpi radialis brevis and extensor indicis proprius muscles, which are a sign of chronic damage. As the ECRL was not spared, the results were against a posterior interosseous syndrome. The neurophysiologist suggested that the compression site was located at the lateral head of the triceps. On the basis of the above clinical information, a radiologist performed an ultrasound centred on the elbow: epicondylitis, a synovial cyst and intra-articular effusion were excluded. Magnetic resonance imaging of the right upper limb was normal. Six months of anti-inflammatory treatment had already been attempted in the patient’s native country without success. We therefore proceeded with a surgical exploration. Under general anaesthesia, a dorso-lateral arm incision was performed. The radial nerve was exposed between the triceps and the brachialis muscles. The humeral origin of the brachioradialis muscle compressed the nerve tightly at its entrance in the space between the brachioradialis and brachialis muscles (Figure 1). The aponeurotic expansion was sectioned to free the nerve. An epineurectomy was performed on 4 cm of the radial nerve at the compression site. Complete liberation was checked by inserting a finger distally between the brachialis and brachioradialis muscles. The immediate and long-term postoperative evolution was favourable with a complete disappearance of the complaints within 2 weeks.
Discussion The radial nerve is a terminal branch of the posterior cord of the brachial plexus. It travels behind the axillary and brachial arteries and in front of the long head of the triceps muscle. It then takes a lateral and posterior course to reach the spiral groove, where it lies between the lateral and medial heads of the triceps. The radial nerve innervates the triceps muscle and then reaches the anterior compartment of the arm by passing through the intermuscular septum at a distance of about 10 cm proximal to the lateral epicondyle. Proximal to the elbow, muscular branches are sent to the brachialis, brachioradialis, anconeus and ECRL muscles. As it reaches the epicondyle the nerve divides into a sensory branch and a motor branch, becoming the posterior interosseous nerve.1 Radial nerve compression has been reported as high up as the teres major muscle.3 The EMG evaluation of our patient was in favour of tricipital compression. In this location, the radial nerve can be trapped either by the muscular fibres4 or by a fibrous arch.5,6 Lotem performed a series of dissections where a fibrous arch originating from the tendon of the lateral head of the triceps and bridging over the spiral groove was identified. Those arches were of
A. Cherchel et al.
Figure 1 Perioperative view of the radial nerve compression site. The triceps (1) has been reclined, allowing exposure of the compression of the radial nerve by the brachioradialis (2). The brachialis muscle (3) is visible medially.
variable tightness, making them able to create a local compression.5 More distally, the intermuscular septum may compress the radial nerve7 and a case of lateral arm pain radiating to the forearm has been cured by the section of a compressive fibrous canal located just proximal to the intermuscular septum.8 A radial nerve compression between the brachialis and brachioradialis muscles can also induce a sensori-motor radial deficit.9 Mehta et al. have found an accessory muscle belly, which they describe as belonging to the brachioradialis muscle and as a potential compression site. This muscle merged with the deltoid near its insertion and coalesced with the brachioradialis at the lateral epicondyle. The radial nerve was located between the accessory muscle and the brachioradialis.10 A bifid brachioradialis muscle belly has also been reported. The superficial branch of the radial nerve was located in the space between these muscle bellies and thus at risk for compression.11 In our case, the brachialis and brachioradialis muscles were located on either side of the nerve at the level of the entrapment, and the brachialis was not involved in the compressive mechanism. However, a tight angle of the brachioradialis muscle fibres compressed it against the humerus. The part of the brachioradialis visualised in our surgical field was not bifid, and no additional muscle belly was identified.
Please cite this article in press as: Cherchel A, et al., The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression, Journal of Plastic, Reconstructive & Aesthetic Surgery (2013), http://dx.doi.org/10.1016/j.bjps.2013.04.023
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MODEL
Humeral origin of brachioradialis muscle Endoscopic peripheral nerve release is an elegant and minimally invasive alternative to an open surgical approach. For example, it would have been possible to approach the radial nerve from the lateral muscular septum proximally to the entrapment site and follow it distally. A larger incision could be reserved as a complement to the procedure, or to cases where the entrapment site is not clearly defined by the endoscopy. However, while endoscopic carpal tunnel release has been practised at our institution in the past, endoscopic nerve release procedures have since then been altogether abandoned. The amount of muscle mass and muscular exercise seem to influence radial nerve entrapment. Lotem’s patients all developed acute palsy after a muscular effort.5 Other authors describe radial nerve deficit in the context of intense muscular efforts such as body building,3 wrestling4 or professional manual activities, as in our patient. It seems reasonable to imagine that repeated muscular efforts sustained over time may have contributed to the evolution of his pathology.
Conclusion We described a case of lateral arm pain and paraesthesias due to a high radial nerve compression by the brachioradialis muscle at its origin on the humerus. The electromyographic results were in accordance with a compression proximal to the posterior interosseous nerve sparing the triceps muscle. We demonstrated that the origin of the brachioradialis muscle can be considered as an alternate compression site of the radial nerve in similar clinical situations.
Conflict of interest statement We have no conflicts of interest to declare. No funding was provided for this study.
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References 1. Green D, Hotchkiss R, Pederson W, et al. Green’s operative hand surgery. 5th ed., vol. 1&2. Philadelphia PA: Elsevier Churchill Livingstone; 2005, p.1033e41. 2. Riffaud L, Morandi X, Goday B, et al. Anatomic bases for the compression and neurolysis of the deep branch of the radial nerve in the radial tunnel. Surg Radiol Anat 1999;21(4): 229e33. 3. Ng AB, Borhan J, Ashton HR, Misra AN, Redfern DR. Radial nerve palsy in an elite bodybuilder. Br J Sports Med 2003 Apr;37(2): 185e6. 4. Manske PR. Compression of the radial nerve by the triceps muscle: a case report. J Bone Jt Surg Am 1977 Sep;59(6): 835e6. 5. Lotem M, Fried A, Levy M, Solzi P, Najenson T, Nathan H. Radial palsy following muscular effort. A nerve compression syndrome possibly related to a fibrous arch of the lateral head of the triceps. J Bone Jt Surg Br 1971 Aug;53(3):500e6. 6. Nakamichi K, Tachibana S. Radial nerve entrapment by the lateral head of the triceps. J Hand Surg Am 1991 Jul;16(4): 748e50. 7. Wasmeier C, Pfadenhauer K, Kalbarzcyk H, Becker T, Ro ¨sler A. Subacute proximal entrapment neuropathy of the radial nerve at the hiatus radialis. Nervenarzt 2004 Aug;75(8): 780e4. 8. Adolfsson LE, Nettelblad H. Radial nerve entrapment in the upper arm as a cause of lateral arm pain: a report of four cases. Scand J Plast Reconstr Surg Hand Surg 2001 Jun;35(2): 217e20. 9. Lee YK, Kim YI, Choy WS. Radial nerve compression between the brachialis and brachioradialis muscles in a manual worker: a case report. J Hand Surg Am 2006 MayeJun;31(5): 744e6. 10. Mehta V, Suri R, Arora J, Rath G, Das S. Anomalous constitution of the brachioradialis muscle: a potential site of radial nerve entrapment. Clin Ter 2010;161(1):59e61. 11. R Dhuria, Mehta V, Roy S, Suri RK, Rath G. Clinico-anatomical report of a rare anomalous disposition of brachioradialis: a possible site for compressing superficial branch of radial nerve. Clin Ter 2011;162(3):235e7.
Please cite this article in press as: Cherchel A, et al., The humeral origin of the brachioradialis muscle: An unusual site of high radial nerve compression, Journal of Plastic, Reconstructive & Aesthetic Surgery (2013), http://dx.doi.org/10.1016/j.bjps.2013.04.023