Korean J Phys Anthropol.  2013 Mar;26(1):55-59. 10.11637/kjpa.2013.26.1.55.

An Unusual Communication between the Radial and the Ulnar Nerves

• Hur MS
• Lee KS

• KMID: 1430200
• DOI: http://doi.org/10.11637/kjpa.2013.26.1.55

Abstract

This case report describes an unusual communicating branch from radial to ulnar nerves in the axilla region on the right side of the Korean cadaver of a 59-year-old male. The brachial plexus containing the communicating branch were extracted en bloc. The extracted specimens were immersed in Guanidine-HCl (0.2 M) for two weeks and then treated several times with an ultrasonic cleaner for an hour to soften the connective tissue around the nerve bundles. The spinal root origins of this communicating branch were found to be largely C7 and some C8. Unexpectedly, the branches of the ulnar nerve innervated the medial two-third of the medial head of the triceps brachii muscle on the right side in the same cadaver. Numbers of nerve fibers of the communicating branch and the main distributing branch of the ulnar nerve to the triceps brachii muscle were 523 and 525, respectively. This result implies that nerve fibers moving from the radial to the ulnar nerves may innervate the original distributing territories of the radial nerve. Another possibility is that a part of radial muscular branch to the triceps beachii muscle may be fused to the ulnar nerve in their distributing territories.

Keyword

Radial to ulnar nerves communication; Radial nerve; Ulnar supply to triceps brachii muscle; Ulnar nerve

MeSH Terms

Axilla
Brachial Plexus
Cadaver
Connective Tissue
Head
Muscles
Nerve Fibers
Radial Nerve
Spinal Nerve Roots
Ulnar Nerve
Ultrasonics

Figure

• 

  Fig. 1. Photograph showing the communicating branch between the radial and the ulnar nerves and its spinal nerve components in the posterior aspect(right side). The communicating branch(arrow) arises as short distance from the origin point of the radial nerve(A). After separating nerve fascicles, the components of the communicating branch are confirmed that it derives from mainly C7 and some C8 (B). Ax: axillary nerve, Ul: ulnar nerve, Rd: radial nerve, Td: thoracodorsal nerve, LS: lower subscapular nerve, Mc: Musculocutaneous nerve, Md: median nerve.

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  Fig. 2. The branches of the ulnar nerve innervating the triceps brachii muscle. The branches(arrows) of the ulnar nerve innervate the medial two-third of the medial head(med.h) of the triceps bra-chii muscle. Ul: ulnar nerve, BA: brachial artery, Mc: musculocu-taneous nerve, Bra.m.: brachialis muscle.

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  Fig. 3. Histologic comparison of the communicating branch between the radial to the ulnar nerves (A) and main distributing branches to the medial head of the triceps brachii muscle (B). Numbers of nerve fibers of communicating branch and main distributing branch of the ulnar nerve to the triceps brachii muscle are 523 and 525, respectively.

Reference

References

1. Venieratos D, Anagnostopoulou S. Classification of communications between the musculocutaneous and median nerves. Clin Anat. 1998; 11:327–31.

2. Saeed M, Rufai AA. Median and musculocutaneous nerves: variant formation and distribution. Clin Anat. 2003; 16:453–7.

3. Shu HS, Chantelot C, Oberlin C, Alnot JY, Shao H. Martin-Gruber communicating branch: anatomical and histological study. Surg Radiol Anat. 1999; 21:115–8.

4. Meenakshi-Sundaram S, Sundar B, Arunkumar MJ. Marinacci communication: an electrophysiological study. Clin Neurophysiol. 2003; 114:2334–7.

5. Lee KS, Oh CS, Chung IH, Sunwoo IN. An anatomic study of the Martin-Gruber anastomosis: electrodiagnostic implication. Muscle Nerve. 2005; 31:95–7.

6. Budak F, Gönenç Z. Innervation anomalies in upper and lower extremities. Electromyogr Clin Neurophysiol. 1999; 39:231–4.

7. Bergman RA, Thompson SA, Afifi AK, Saadeh FA. Compendium of human anatomic variation. Baltimore: Urban & Schwarzenberg;1988. p. 142.

8. Lee KS. Variation of the spinal nerve compositions of tho-racodorsal nerve. Clin Anat. 2007; 20:660–2.

9. Lindner HH. Clinical anatomy. International ed. London: Appleton & Lange;1989. p. 536.

10. MaCluskey LF. Anomalous superficial radial sensory innervation of the ulnar dorsum of the hand: a cause of paradoxical presentation of ulnar sensory function. Muscle Nerve. 1996; 19:923–5.

11. Kurivilla A, Laaksonen S, Falck B. Anomalous superficial radial nerve: a patient with probable autosomal dominant. Muscle Nerve. 2002; 26:716–9.