TRICEPS MOTOR NERVE BRANCHES AS A DONOROR RECEIVER IN NERVE TRANSFERS

OBJECTIVE: The pattern of triceps innervation is complex and, as yet, has not beenfully elucidated. The purposes of this study were 1) to clarify the anatomy of the tri-ceps motor branches, and 2) to evaluate their possible uses as a donor or receiver fornerve transfer.METHODS: The radial nerve and its motor and cutaneous branches were bilaterallydissected from the axilla and posterior arm regions of 10 embalmed cadavers.RESULTS: A single branch innervates the triceps long head, whereas double innervationwas identified for the lateral and medial heads. The upper branch to the lateral headoriginated from the radial nerve, whereas the lower branch to the lateral head stemmedfrom the lower medial head motor branch, which ultimately innervated the anconeusmuscle. Both the long head and the upper medial head motor branches originated inthe axillary region in the vicinity of the latissimus dorsi tendon.CONCLUSION: Each of the triceps’ motor branches might be used as a donor for trans-fer. The triceps long head motor branch should be used preferentially when the inten-tion is to establish triceps reinnervation.

KEY WORDS: Avulsion injuries, Axillary nerve, Brachial plexus, Nerve transfer triceps innervation, Tricepsmotor branches, Triceps muscle

Neurosurgery 61[ONS Suppl 2]:ONS333–ONS339, 2007 DOI: 10.1227/01.NEU.0000280127.60926.FE

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Jayme A. Bertelli, M.D., Ph.D.Department of Orthopedic Surgery,Governador Celso Ramos Hospital,Florianópolis, Brazil

Marcos A. Santos, M.D.Department of Orthopedic Surgery,Homero de Miranda Gomes Hospital,São José, Brazil

Paulo R. Kechele, M.D., M.Sc.Department of Operative Technique,Federal University of Santa Catarina,Florianópolis, Brazil

Marcos F. Ghizoni, M.D.Center of Biological and Health Sciences,University of Southern Santa Catarina,Tubarão, Brazil

Hamilton Duarte, Ph.D.Department of Anatomy,Federal University of Santa Catarina,Florianópolis, Brazil

Reprint requests:Jayme A. Bertelli, M.D., Ph.D.,Praça Getulio Vargas, 322,Florianópolis, SC, 88020030, Brazil.Email: bertelli@matrix.com.br

Received, September 27, 2006.

Accepted, January 8, 2007.

Nerve transfer, also called neurotizationor nerve crossing, consists of section-ing a normal nerve or branch and con-

necting its proximal stump to the distal stumpof an injured nerve. This involves the sacrificeof a healthy nerve, the function of whichshould be compensated by the remaininginnervated muscles. This functional compen-sation can be promoted by simple agonistmuscle hypertrophy or, when partial denerva-tion exists, by the development of largermotor units after terminal axonal sprouting atthe muscle level (4). Nerve transfers are usedwhen a proximal nerve stump is not availablefor repair. Occasionally, in longstandinginjuries when long grafts are needed forrepair, a nerve transfer close to the target mus-cle might be indicated to diminish the rein-nervation time. A variety of nerve transfershave been described for brachial plexus recon-struction (13).

Transfer of the triceps long head branch tosupply the axillary nerve first was used suc-cessfully by Colemann in 1946 as reported byCarayon and Bourrel (6). Lurje (12) reported a

single case in which two unnamed tricepsbranches were dissected using an extendeddeltopectoral approach and were connected tothe axillary nerve. Nath and Mackinnon (14)used a similar axillary approach and, afterintraneural dissection of the radial nerve,transferred triceps fascicles to the axillarynerve. Most recently, Leechavengvongs et al.(10) and Bertelli and Ghizoni (3) independentlyreported transferring the motor branch to thelong head of the triceps using a posterior armapproach after brachial plexus trauma. Bertelliand Ghizoni (3) also demonstrated similarresults with transfer of the branch to the lateralhead of the triceps. In C5–C6 injuries of thebrachial plexus, triceps motor branch transferis combined with accessory-to-suprascapularnerve transfer. These combined transfersresulted in 115 degrees of abduction among thefirst patients reported by Leechavengvongset al. (10). In this first report, the results forexternal rotation were not mentioned. Morerecently, Leechavengvongs et al. (11) reportedresults on eight additional patients who recov-ered an average of 115 degrees of abduction

PERIPHERAL NERVEAnatomic Report

and 97 degrees of external rotation. In the Bertelli and Ghizoni(3) series of 10 cases, the average result for abduction was 92degrees and the mean resultant range of external rotation was93 degrees. Importantly, in Bertelli and Ghizoni’s series (3), notonly patients with C5–C6 injuries, but also those with C5–C7injuries and less than normal triceps strength were included.

Despite the sacrifice of either the long or the lateral headmotor branches, active elbow extension was preserved (3, 10,11). On the other hand, when completely paralyzed, restorationof triceps function by nerve transfers is considered to be a highsurgical priority (2). The purpose of this study was to investi-gate, in detail, the innervation of the heads of the triceps mus-cle to determine which motor branches are suitable for use asa donor or recipient during brachial plexus reconstructions.

MATERIALS AND METHODSBoth upper extremities of 10 embalmed cadavers were dissected.

The radial nerve was dissected together with the triceps motorbranches and the cutaneous branches. Dissections were performedfrom the axilla to the posterior region of the arm. After dissection wascomplete, digital photographs were obtained and measurements wereperformed using ImageJ 1.32j software (National Institutes of Health,Bethesda, MD). In the posterior arm, the distance between the originand the muscle entrance of the triceps motor branches was measured.For the triceps long and upper medial head branches, the distancemeasured was from the distal border of the teres major tendon to theentrance at the triceps muscle. Diameters of the nerve branches alsowere measured. The origin of the long and medial head motor branchwas investigated in the axillary region, and the latissimus dorsi tendonwas used as the anatomic landmark. A summary of the abbreviationsused in the figures and legends is provided in Table 1.

RESULTSMotor Branches of the Radial Nerve

In the posterior arm, the radial nerve and its branches were inclose proximity to the tendon of the teres major muscle, whichlay cephalad to the nerve (Fig. 1). In this region, in a counter-clockwise direction, the motor branch to the triceps long headwas the first branch to be identified followed by the upperbranch to the medial head, then the lower branch to the tricepsmedial head and anconeus muscle, and finally the upper lateralhead motor branch (Fig. 1). All the motor branches coursedmedially to the radial nerve, except for the upper lateral headmotor branch. From the distal border of the teres major tendonto the entrance of the spiral groove, the radial nerve gave off nomotor branches. Occasionally, cutaneous branches arose fromthe radial nerve at this level.

The triceps long head motor branch emerged from the radialnerve in the axilla (Figs. 2, 3, and 4). It had the shortest course inthe posterior arm. Its diameter and length are shown in Table 2. Inthe posterior arm, and in the vicinity of the teres major tendon, itwas the most cephalad branch, being located by dissectingbetween the radial nerve and the triceps long head. Before enter-ing the triceps long head, the nerve arborized into two or three ter-minal branches. This terminal arborization occurred among all

the triceps motor branches. The motor entry point of the tricepslong head could be visualized either by axillary or posterior armdissection. This was important for nerve branch identification.

The upper branch of the triceps medial head also had its ori-gin in the axilla just distal to the triceps long head motorbranch (Figs. 2, 3, and 4). Its diameter and length are shown inTable 2. Similar to the long head motor branch, it could be dis-sected through an anterior axillary or posterior arm approach.Its course was straight and parallel to the radial nerve in the

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TABLE 1. Abbreviations used in accompanying figures and legends

Abbreviation Definition

Muscles

TM Teres major

LDT Latissimus dorsi tendon

LoH Triceps long head

LaH Triceps lateral head

MH Triceps medial head

Motor nerves

RN Radial nerve

LoHM Long head motor branch

UMHM Upper medial head motor branch

LMHM Lower medial head motor branch

ULaHM Upper lateral head motor branch

LoLaHM Lower lateral head motor branch

AMB Anconeus motor branch

AN Axillary nerve

Cutaneous nerves

PCA Posterior cutaneous nerve of the arm

PCF Posterior cutaneous nerve of the forearm

SLCA Superior lateral cutaneous nerve of the arm

ILCA Inferior lateral cutaneous nerve of the arm

FIGURE 1. A dissection of the right posterior arm showing the commonpattern of radial nerve branching.

axillary and upper arm regions, whereas in the posterior arm,it was parallel to the ulnar nerve. This motor branch enteredthe medial head at its upper limit. Dissecting using the poste-rior approach, the upper medial head branch was located deepbetween the long head motor branch and the radial nerve. Onanterior dissection, it lay between the triceps long head motorbranch and the radial nerve over the triceps long head surface.

The lower branch to the triceps medial head and anconeusmuscle was the longest branch (Fig. 5). Its diameter and lengthare shown in Table 2. Its origin was located distal to the teresmajor tendon border. It ran parallel and just medial to theradial nerve. It penetrated the medial head at the level of theentrance of the spiral groove for the radial nerve. At this site,one or two branches emerged from the lower medial head

motor branch to innervate the distal portion of the lateral head.We refer to this branch as the lower lateral head motor branch(Fig. 5). After penetrating the medial head of the triceps mus-cle, the lower branch of the medial head descended straight toinnervate the anconeus muscle. During this trajectory, severalshort branches arose at an obtuse angle from the main branchto innervate the distal portions of the medial head (Fig. 6).

The upper lateral head motor branch originated distal to theteres major margin (Fig. 1). It crossed the radial nerve and, to acertain extent, was a mirror image of the branch to the longhead. Its diameter and length are shown in Table 2. In two dis-sections, the upper lateral head motor branch arose not directlyfrom the radial nerve, but from a common trunk with the lowermedial head branch and the posterior cutaneous nerve of theforearm. In three dissections, the origin of the upper lateral motorbranch was more distally located and, in such cases, it originatedfrom the lower medial head branch (Fig. 7).

Triceps InnervationThe long head was innervated exclusively by the long head

motor branch. The lateral head received its first branch directlyfrom the radial nerve, and we called it the upper lateral headmotor branch. The lower lateral head motor branch stemmeddistally from the lower medial head motor branch. The medialhead was innervated by the upper medial head branch, butthe distal portion was innervated by the lower medial headmotor branch (Fig. 8).

Cutaneous Branches of the Radial NerveThe posterior cutaneous nerve of the arm arose in the axilla

proximal to the origin of the triceps long head motor branch(Fig. 4). It contoured the triceps long head medial margin andsplayed over the posterior and superior portion of the arm.

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FIGURE 2. Schematic representation showing the pattern of radial nervebranching in the axillary region for the long head motor branch (LoHM)and the upper medial head motor branch (UMHM). For clarity, all 20 dis-sections are represented as right-sided.

FIGURE 3. A dissection of the right axilla showing separate origins of thelong (LoHM) and upper medial (UMHM) head motor branches from theradial nerve (RN).

FIGURE 4. A dissection of the radial nerve (RN) in the right axilla reveal-ing the common origin of the long (LoHM) and upper medial (UMHM)head motor branches over the latissimus dorsi tendon (LTD). Note the pos-terior cutaneous nerve of the arm (PCA), which arises cephalad from theradial nerve.

The inferior lateral cutaneous nerve of the arm (Figs. 1 and 5)arose directly from the radial nerve (6 dissections) in the pos-terior arm region or, more commonly, from the lateral headmotor branch (11 dissections). In one dissection, there was acommon trunk for the inferior lateral cutaneous nerve of thearm and the posterior cutaneous nerve of the forearm. Thisnerve trunk arose directly from the radial nerve.

The posterior cutaneous nerve of the forearm (Figs. 1 and5–7) originated proximally in the posterior arm, arising directlyfrom the radial nerve (eight dissections), from the lower motorbranch to the triceps medial head (nine dissections), from acommon trunk with the upper branch to the lateral head andthe lower branch to the medial head (two dissections), or froma common trunk with the inferior lateral cutaneous nerve of theforearm (one dissection). The inferior lateral cutaneous nerve ofthe arm and the posterior cutaneous nerve of the forearm trav-eled alongside the radial nerve through the radial groove of the

humerus (Fig. 5). Occasionally, the inferior lateral cutaneousnerve of the arm perforated the triceps lateral head.

VariationsMajor variations concerned the origins of the branches. A com-

mon trunk for the lateral and lower medial head was identifiedin two cases (Figs. 5 and 7). A common trunk for the upper lat-eral, lower medial head, and posterior cutaneous nerve of theforearm was found during two dissections (Fig. 6). In one case,a common trunk for the upper and lower medial head brancheswas identified during posterior arm dissection. However, in theaxilla, this was a common finding (11 dissections).

DISCUSSION

The pattern of radial nerve branching for triceps innervationwas predictable, and we consistently identified four branches,including a branch to the long head, another to the lateral head,and two branches to the medial head. We demonstrated thatthe triceps motor branches might arise independently from the

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TABLE 2. Length and diameter measurements for the triceps motor branches, which originate directly from the radial nerve

Long head Lateral head Upper medial head Lower medial head

Diameter (mm)

Average 2.1 1.9 1.6 2

Range 1.4–3.7 1.1–3.4 1.1–2 1.5–2.5

Length (mm)

Average 31.6 44 65.1 93.7

Range 21–38 27–60 40–100 50–111

FIGURE 5. A photograph showing the dissection of the left posterior arm.Of particular note is the lower lateral head motor branch (LolaHM),which originates from the lower medial head motor branch (LMHM). Thiswas a common finding. Note also the courses of the posterior cutaneousnerve of the forearm (PCF) and the inferior lateral cutaneous nerve of thearm (ILCA) parallel to the radial nerve (RN). There is a common trunk forthe upper lateral head (ULaHM) and the lower medial head motorbranches, which was identified in two of 20 dissections. The axillary nerve(Ax) and its cutaneous branch (SLCA) are shown. Note that any tricepsmotor branch can be rotated to easily neurotize the axillary nerve.

FIGURE 6. A diagram showing the dissection of the right posterior arm.Note the long branch to the anconeus muscle (AMB). In the inset, there isa closeup view showing the common origin of the upper lateral (ULaHM)and lower medial head (LMHM) motor branches and the posterior cuta-neous nerve of the forearm (PNF). The long head motor branch (LoHM)and the upper medial head motor branch (UMHM) also can be seen.

radial nerve or together from a common nerve trunk. Weobserved that the cutaneous branch might originate from thesemotor branches.

Prior studies (8, 9, 15–17) have already identified the proxi-mal origin of the branch to the triceps long head. We observedthat both the long head motor branch and the upper medialhead motor branch had origins that were proximal in the axilla.Gray (8) pointed out the regular existence of a common nerveto the medial and lateral heads. Herein, this was only con-firmed in 5 of 20 dissections. We consistently identified a sec-ond or third branch to the lateral head stemming from thelower branch to the medial head as Hovelacque (9) already hasnoted. In their graphic representation of anatomic dissection,Hovelacque (9) and Testut and Latarjet (19) indicate a secondbranch originating directly from the radial nerve to the tricepslateral head. We did not identify this in any of our dissections.

In the patients with complete triceps palsy, elbow extensionreconstruction is considered to be a surgical priority. Because ofthe nerve’s location and potential access through an anteriorincision, triceps long head motor branch reinnervation wouldbe our method of choice. According to our anatomic findings,each of the triceps motor branches might be considered a donorfor transfer to the axillary nerve.

Because of their proximal origin in the axilla, the triceps longhead and the upper branch to the medial head might be trans-ferred to the axillary nerve by means of an axillary approach.The branch to the long head has a larger diameter, but using itcompletely denervates the long head. On the other hand, usingthe upper branch to the medial head does not result in com-plete denervation because of the medial head’s double innerva-tion. Neither the long nor the upper medial branches everdemonstrated any relationship to cutaneous nerves, and bothalso might be used as donors for transfer through a posteriorarm approach. The long head motor branch contains approxi-

mately 1200 myelinated fibers (20), similar to the accessorynerve, a well-known donor nerve for transfer (1).

The upper lateral head motor branch, if selected as the donorfor transfer, should be dissected through a posterior armapproach. Its entrance into the lateral head should be identifiedand the nerve traced from distal to proximal so as to eliminateany cutaneous branches, specifically the upper lateral cuta-neous nerve of the arm, which might arise from this motorbranch. If the triceps lateral motor branch originates proximallyfrom the radial nerve, has a suitable diameter, and generatesstrong muscle contraction after transoperative electric stimula-tion, it might be used to reconstruct the axillary nerve. In suchcircumstances, its use is simpler than using the long head. Thepresence of the lower branch of the lateral head prevents totallateral head denervation. We previously have demonstratedthe usefulness of transferring the lateral head motor branch tothe axillary nerve (3). The lower branch to the triceps medialhead is the longest branch and has a diameter equal to that ofthe long head. Using this branch does not completely denervatethe medial head, which represents a major advantage. Itsgreater length allows for nerve coaptation to the deltoid motorbranch very close to the muscle. This is relevant in palsies thathave lasted longer than 8 months, in which any delay in rein-

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FIGURE 7. A dissection of the left posterior arm showing the emer-gence of the upper lateral head motor branch (ULaHM) not directlyfrom the radial nerve, but from the upper medial head motor branch. Thiswas identified during two of 20 dissections. Note the lower lateral headmotor branch (LoLaHM), which arises from the lower medial head motorbranch (LMHM). Also note the upper medial head motor branch(UMHM) entering the medial head through its upper limit. The tricepslong head motor branch (LoHM) is the shorter branch when dissectedthrough the posterior arm.

FIGURE 8. A schematic representation showing tri-ceps head innervation. A single branch innervates thelong head, whereas double innervation is identified forthe lateral and medial heads. The lower branch to thelateral head (LoLaHM) is a branch to the lower medialhead motor branch, which ultimately innervates theanconeus muscle.

nervation might further compromise the final outcome.Because the posterior cutaneous nerve of the forearm mightoriginate from the lower branch of the triceps medial head,after identification of its muscle entry point, the nerve shouldbe dissected from distal to proximal.

In C5 and C6 root injuries, the strength of the triceps mus-cle is preserved, and any motor branch is suitable for transfer.However, in more extended palsies, the triceps heads might beaffected differently because there are large variations in theorigins of their motor neurons. The triceps long head motorfibers predominantly stem from C8, but origins from C7 havebeen observed. This also is true of the branches to the medialhead, but an origin from the C6 root has been described. Thelateral head motor branch carries fibers originating from C6through C8 with a predominance of fibers from C7 (9). Withbrachial plexus lesions, not only anatomic variations, but alsothe degree of nerve injury interferes with residual function ofthe triceps muscle. If only one triceps portion remains inner-vated, its motor branch should not be used because tricepsfunction should not be sacrificed entirely. However, if twoheads are functional, we believe that the stronger motorbranch to the triceps should be left intact. Most often, this willbe the long head motor branch. The lateral or the medial headmotor branches would be suitable for transfer and the poste-rior arm approach preferred.

Neither isolating sections of the lateral or long head motorbranches (3, 10, 11) nor sacrificing the long head as a muscleflap (18) decrease triceps strength. The uniarticular triceps lat-eral and medial heads contribute 70 to 90% to isometric elbowextension. The anconeus contributes significantly (up to 15%) atlesser degrees of elbow extension. The long head becomesactive only with forceful elbow extension (21). We observedthat the triceps long head’s function is dependent on shoulderposition and that it is particularly active when the shoulder isfully abducted (unpublished observations). The biarticular longhead is more active in isotonic tasks such as climbing (5).Because of its origin in the glenoid cavity, the triceps long headcontributes to stabilization of the shoulder (7). However, theimportance of this contribution remains undetermined. Basedon anatomic and biomechanical aspects, our preference is touse the triceps long head for transfer. However, some patientswith upper-type lesions of the brachial plexus and preservedtriceps function are capable of abducting the shoulder by con-tracting the triceps long head while the shoulder is internallyrotated. In these patients, the long head motor branch shouldnot be sacrificed.

CONCLUSION

In the upper-type injuries of the brachial plexus with pre-served triceps function, our preference is to neurotize the axil-lary nerve by means of an axillary approach using the tricepslong head or the upper medial head motor branch. If the tricepsis partially paralyzed, the triceps lateral head should be usedand the long head preserved. If triceps function is to be recon-structed, the triceps long head should be reinnervated.

REFERENCES1. Allieu Y, Cenac P: Neurotization via the spinal accessory nerve in complete

paralysis due to multiple avulsion injuries of the brachial plexus. Clin OrthopRelat Res 237:67–74, 1988.

2. Bertelli JA, Ghizoni MF: Contralateral motor rootlets and ipsilateral nervetransfers in brachial plexus reconstruction. J Neurosurg 101:770–778, 2004.

3. Bertelli JA, Ghizoni MF: Reconstruction of C5 and C6 brachial plexus avul-sion injury by multiple nerve transfers: Spinal accessory to suprascapular,ulnar fascicles to biceps branch, and triceps long or lateral head branch toaxillary nerve. J Hand Surg (Am) 29:131–139, 2004.

4. Bertelli JA, Taleb M, Mira JC, Ghizoni MF: Functional recovery improvementis related to aberrant reinnervation trimming. A comparative study using freshor predegenerated nerve grafts. Acta Neuropathol (Berl) 111:601–609, 2006.

5. Bonnel F: The biomechanical concept of the shoulder, in Duparc J (ed):Surgery of the Shoulder [in French]. Paris, Expansion Scientifique Française,1993, pp 1–16.

6. Carayon A, Bourrel P: Extended approaches and seldom used procedures inperipheral nerve surgery [in French]. Ann Chir 19:225–236, 1965.

7. Eiserloh H, Drez D, Guanche CA: The long head of the triceps: A detailedanalysis of its capsular origin. J Shoulder Elbow Surg 9:332–335, 2000.

8. Gray H: Gray’s Anatomy. London, Elsevier, 2005, ed 38, p 857.9. Hovelacque A: Anatomy of the cranial and rachidian nerves and the sympthetic sys-

tem in man [in French]. Paris, Gaston, Doin et Cie Editeurs, 1927, pp 491–500.10. Leechavengvongs S, Witoonchart K, Uerpairojkit C, Thuvasethakul P: Nerve

transfer to deltoid muscle using the nerve to the long head of the triceps, partII: A report of 7 cases. J Hand Surg (Am) 28:633–638, 2003.

11. Leechavengvongs S, Witoonchart K, Uerpairojkit C, Thuvasethakul P,Malungpaishrope K: Combined nerve transfers for C5 and C6 brachial plexusavulsion injury. J Hand Surg (Am) 31:183–189, 2006.

12. Lurje AC: Concerning surgical treatment of traumatic injury of the upperdivision of the brachial plexus (Erb’s type). Ann Surg 127:317–326, 1948.

13. Midha R: Nerve transfers for severe brachial plexus injuries: A review.Neurosurg Focus 16:E5, 2004.

14. Nath RK, Mackinnon SE: Nerve transfers in the upper extremity. Hand Clin16:131–139, 2000.

15. Rouvière H, Delmas A: Human Anatomy [in French]. Paris, Editions Masson,2000, pp 201–203.

16. Stanescu S, Post J, Ebraheim NA, Bailey AS, Yeasting R: Surgical anatomy ofthe radial nerve in the arm: Practical considerations of the branching patternsto the triceps brachii. Orthopedics 19:311–315, 1996.

17. Sunderland S: Nerve and nerve injuries [in Spanish]. Barcelona, Salvat Editores,1985, pp 815.

18. Sundine MJ, Malkani AL: The use of the long head of triceps interpositionmuscle flap for treatment of massive rotator cuff tears. Plast Reconstr Surg110:1266-1274, 2002.

19. Testut L, Latarjet A: Textbook of Human Anatomy [in Spanish]. Barcelona, SalvatEditores, 1983, pp 287–293.

20. Witoonchart K, Leechavengvongs S, Uerpairojkit C, Thuvasethakul P,Wongnopsuwan V: Nerve transfer to deltoid muscle using the nerve to thelong head of the triceps, part I: An anatomic feasibility study. J Hand Surg(Am) 28:628–632, 2003.

21. Zhang LQ, Nuber GW: Moment distribution among human elbow extensormuscles during isometric and submaximal extension. J Biomech 33:145–154,2000.

AcknowledgmentInvestigations were performed in the Anatomy Laboratory of the Federal

University of Santa Catarina, Florianópolis, Brazil.

COMMENTS

Bertelli et al. have made a significant contribution to the rapidlygrowing literature on nerve-transfer procedures. This group has

been a leader in the use of triceps branches to reanimate the deltoid, agoal that previously has not been successfully accomplished byresearchers using other nerve transfers or muscle transfers.

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This report contains excellent descriptive anatomy, and the appropri-ate use of the various triceps branches is demonstrated on the basis ofpractical anatomy of the branches and relative strengths of the threemuscles of the triceps.

Combined with the two reports by Leechavengvongs et al. (1, 2),which are referred to in the text, this article provides a lucid and thor-ough explanation of the usefulness of the various triceps branches inreanimating the deltoid.

John E. McGillicuddyAnn Arbor, Michigan

1. Leechavengvongs S, Witoonchart K, Uerpairojkit C, Thuvasethakul P: Nervetransfer to deltoid muscle using the nerve to the long head of the triceps, partII: A report of 7 cases. J Hand Surg [Am] 28:633–638, 2003.

2. Leechavengvongs S, Witoonchart K, Uerpairojkit C, Thuvasethakul P,Malungpaishrope K: Combined nerve transfers for C5 and C6 brachial plexusavulsion injury. J Hand Surg [Am] 31:183–189, 2006.

Bertelli et al. performed an anatomic study on the triceps branchesof the radial nerve. They dissected 20 sides of 10 cadavers to pro-

vide an understanding of the consistency and variability of tricepsmotor branches anatomy. They demonstrated single innervation forthe triceps long head and double innervation for the lateral andmedial heads. They were able to consistently identify four majorbranches, including one for each of the long and lateral heads andtwo for the medial head. This study demonstrated the anatomic vari-ations of triceps motor branches relative to the teres major muscle viaa posterior arm approach and to the latissimus dorsi tendon from ananterior axillary incision, as well as providing data on their lengthsand diameters. Figure 8 and Table 2 nicely encapsulate the keyanatomical information.

This information is of enormous benefit in the setting of nerve-trans-fer procedures for the treatment of brachial plexus injuries. As theynote in the Discussion, the triceps branches of the radial nerve can beused either as nerve donors to the axillary nerve to reinnervate shoul-der abduction or as nerve recipients to reinstitute elbow extension. Thegreatest value of the present article is that it demonstrates the consis-

tency of the innervation for each of the heads of the triceps muscle.Bertelli et al. provide indirect evidence that taking a donor nerve fromeither the medial or lateral head does not completely denervate thatmuscle, and that muscle can return to its baseline power over time.Alternately, as shown by the senior author (JAB) and particularly byLeechavengvongs et al. (1), the triceps long-head branch is an excellentdonor for transfer to the axillary nerve, with little, if any, functionaldeficit incurred in resulting elbow extension.

As the authors point out in their well-written Discussion, the specificpattern of brachial plexus injury (C5 and C6 alone or combined with C7loss, and hence triceps muscle weakness) should be considered whendeciding which of the triceps branch nerves to sacrifice to reinnervatethe deltoid muscle via the axillary nerve. This study provides excellentanatomic information to aid with this decision-making process.

Ronald T. GrondinRajiv MidhaCalgary, Canada

1. Leechavengcongs S, Witoonchart K, Uerpairojkit C, Thuvasethakul P,Malungpaishrope K: Combined nerve transfers for C5 and C6 brachial plexusavulsion injury. J Hand Surg [Am] 31:183–189, 2006.

This is a thorough anatomic study from cadavers that is of specialvalue to surgeons performing nerve transfers to either the triceps

branches, or, more frequently, using triceps branches to this reinnervatethe axillary nerve. The former might be more readily done by an ante-rior approach, whereas the latter is usually best done using a posteriorapproach. Although the study and the conclusion drawn, as well as theexposition of the findings, are extremely thorough and worthwhile,their statement that these findings have not been fully elucidated is abit of a stretch; there have been good previous anatomic works regard-ing the triceps branches by anatomists and, more recently, by clini-cians. Nonetheless, it is nice to see such a thorough and focused studyin one article.

David G. Kline New Orleans, Louisiana

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