Simple Clinical Test to Detect Deltoid Muscle Dysfunction Causing Weakness of Abduction—“Akimbo” Test

Abstract

Introduction Full range of motion and powerful shoulder abduction can be performed without any deltoid muscle function by the supplemental action of the supraspinatus and biceps brachii muscles. For evaluation of deltoid muscle function, we need to negate these actions, which can be done with the “akimbo test,” in which patients place their hands on the iliac crest with abduction in the coronal plane and internal rotation of the shoulder joint while simultaneously flexing the elbow joint and pronating the forearm.

Methods We examined the akimbo test in five patients with incomplete upper-type brachial plexus injury, five patients with suprascapular nerve palsy, and six patients with axillary nerve palsy. Presence of some abduction is a prerequisite to perform this test.

Results No patient with incomplete upper-type brachial plexus injury could demonstrate this sign when the deltoid did not show a certain level of the power to abduct the shoulder joint. All patients with suprascapular nerve could demonstrate this sign as the deltoid was normal. No patient with axillary nerve paralysis could demonstrate this sign.

Conclusion The akimbo test is a simple clinical test to determine deltoid muscle paralysis or dysfunction, especially when patients can demonstrate shoulder abduction due to supplementary action of other muscles.

Keywords

axillary nerve paralysis - akimbo test - diagnosis

• References

• 1 Colachis Jr SC, Strohm BR. Effect of suprascauular and axillary nerve blocks on muscle force in upper extremity. Arch Phys Med Rehabil 1971; 52: 22-29
• 2 Colachis Jr SC, Strohm BR, Brechner VL. Effects of axillary nerve block on muscle force in the upper extremity. Arch Phys Med Rehabil 1969; 50 (11) 647-654
• 3 Poppen NK, Walker PS. Forces at the glenohumeral joint in abduction. Clin Orthop Relat Res 1978; (135) 165-170
• 4 Sigholm G, Herberts P, Almström C, Kadefors R. Electromyographic analysis of shoulder muscle load. J Orthop Res 1984; 1: 379-386
• 5 Rockwood Jr CA, Matsen FA. The Shoulder. Philadelphia: Saunders; 2009: 252-258
• 6 Kuechle DK, Newman SR, Itoi E, Morrey BF, An KN. Shoulder muscle moment arms during horizontal flexion and elevation. J Shoulder Elbow Surg 1997; 6: 429-439
• 7 Peat M, Grahame RE. Electromyographic analysis of soft tissue lesions affecting shoulder function. Am J Phys Med 1977; 56: 223-240
• 8 Bechtol CO. Biomechanics of the shoulder. Clin Orthop Relat Res 1980; (146) 37-41
• 9 Markhede G, Monastyrski J, Stener B. Shoulder function after deltoid muscle removal. Acta Orthop Scand 1985; 56: 242-244
• 10 Wuelker N, Schmotzer H, Thren K, Korell M. Translation of the glenohumeral joint with simulated active elevation. Clin Orthop Relat Res 1994; (309) 193-200
• 11 Otis JC, Jiang CC, Wickiewicz TL, Peterson MG, Warren RF, Santner TJ. Changes in the moment arms of the rotator cuff and deltoid muscles with abduction and rotation. J Bone Joint Surg Am 1994; 76: 667-676
• 12 Kapandji IA. The shoulder. In: The Physiology of the Joints. Vol. 1, Upper Limb. 6th ed. Philadelphia: Churchill Livingstone; 2007: 2-74
• 13 Nishijma N, Yamamuro T, Fujio K, Ohba M. The swallow-tail sign: a test of deltoid function. J Bone Joint Surg Br 1995; 77: 152-153