Skeletal Radiol (1990) 19:519-520 Skeletal Radiology

The unilateral wavy clavicle

Bertram Levin, M.D.

Department of Diagnostic Radiology, Michael Reese Hospital and Medical Center, Chicago, Illinois, USA

Abstract. 14 patients are recorded in whom one clavicle has a wavy shape not related to trauma or to a known congenital anomaly. Since the affected clavicle is more often the right, it is suggested that this alteration may be related to the effect of subclavian artery pulsations, such as cause congenital pseudarthrosis of the clavicle.

Key words" Clavicle - Unilateral deformity - Clavicle deformity

pulsation on the developing clavicle is the cause for real- development. Normally, the right subclavian artery lies slightly higher than the left as it passes over the first rib beneath the clavicle. The right subclavian artery also develops from a more cephalad position than does the left. Left congenital pseudarthrosis of the clavicle has

I have encountered 14 patients in whom one of the clavi- cles, as seen on chest roentgenograms, has a gentle wavy contour for its entire length and breadth (Fig. 1). In all but I of the 14, it was the right clavicle that was so shaped; in no instance was the appearance bilateral. Nine patients were men, aged 40-70 years, and five were women, aged 25 72 years. The appearance does not re- semble deformity secondary to fracture, nor is there a known history of fracture. The shape is unrelated to the rhomboid fossa. No patients were known to have symptoms relating to the clavicle or shoulder.

Since becoming aware of this unusual shape of the clavicle I have seen chest or shoulder films of about 20000 different adults and have been alert to detect the deformity. No such deformity was seen in the films of about 2000 infants, children and adolescents. Obviously, then, the wavy shape is infrequent.

Efforts to explain the shape and the preponderance of right-sidedness in this small series bring to mind the work of Lloyd-Roberts et al. [6] in the study of congeni- tal pseudarthrosis of the clavicle. These authors have tried to account for the overwhelming preponderance of right-sided congenital pseudarthrosis of the clavicle. For example, each of the 33 patients reported by Owen [7] was affected on the right side. Lloyd-Roberts et al. present convincing evidence that exaggerated arterial

Address reprint requests to: Bertram Levin, M.D., Department of Diagnostic Radiology, Michael Reese Hospital and Medical Center, Lake Shore Drive at 31st, Chicago, IL 60616, USA

Fig. 1A-E. Representative films of patients with a wavy clavicle. A 59-year-old man, B 55-year-old man, C 40-year-old man, D 55- year-old woman, and E 50-year-old woman, the only one with left-sided involvement

�9 1990 International Skeletal Society

520 B. Levin: Unilateral wavy clavicle

been seen in patients with dextrocardia, in which the left subclavian artery is higher than the right [2, 6]. Left- sided congenital pseudarthrosis of the clavicle has, how- ever, also been reported in patients without dextrocardia [1, 3, 6, 8]; these instances are not clearly accounted for by the high subclavian artery theory. Moreover, a small number of patients has the condition bilaterally [2-51.

None of the patients with a wavy clavicle had cervical ribs or high first ribs, which Lloyd-Roberts et al. found in a majority of their series. They noted that these defor- mities cause the subclavian artery to be brought into closer proximity with the clavicle, increasing the me- chanical effect of the pulsations on the clavicle. I find attractive the notion that those patients without cervical ribs or first rib deformity may merely develop a wavy clavicle as a result of subclavian artery pulsations and be spared the pseudarthrosis. Any other suggestions as to the cause of "wavy clavicles" would be welcomed.

References

1. Ahmadi B, Steel HH (1977) Congenital pseudarthrosis of the clavicle. Clin Orthop 126:130

2. Gibson DA, Carroll N (1970) Congenital pseudarthrosis of the clavicle. J Bone Joint Surg [Br] 52 : 629

3. Herman S (1973) Congenital bilateral pseudarthrosis of the clavi- cles. Clin Orthop 91 : 162

4. Kite JH (1968) Congenital pseudarthrosis of the clavicle. South Med J 61:703

5. Levin B (1988) Normal variations, congenital anomalies, and miscellaneous conditions of the shoulder: radiologic appear- ances. In: Post M (ed) The shoulder: surgical and nonsurgical management, 2nd edn. Lea and Febiger, Philadelphia

6. Lloyd-Roberts GC, Apley AG, Owen R (1975) Reflections upon the aetiology of congenital pseudarthrosis of the clavicle. J Bone Joint Surg [Br] 57:24

7. Owen R (1970) Congenital pseudarthrosis of the clavicle. J Bone Joint Surg [Br] 52 : 644

8. Wall JJ (1970) Congenital pseudarthrosis of the clavicle. J Bone Joint Surg [Am] 52:1003