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Insights into Imaging
Fig. 2 | Insights into Imaging

Fig. 2

From: CT angiography and MRI of hand vascular lesions: technical considerations and spectrum of imaging findings

Fig. 2

The SPA classification by Coleman and Anson [12] with two groups: group I with complete arch and group II with incomplete arch. In group I, contributing vessels anastomose with each other or the UA extends to the thumb. Group I is further divided into five types: Type A, classical radio ulnar arch, formed by the superficial palmar branch of RA and the main stem of the UA; Type B, arch formed entirely by the UA; Type C, median-ulnar arch, composed of the UA and an enlarged median artery; Type D, radio-median-ulnar arch, three vessels enter into formation of the arch; and Type E, arch initiated by the UA and completed by a large-sized vessel derived from the deep arch. In group II, contributing vessels do not anastomose with each other or the UA fails to reach the thumb. Group II is further divided into four types: A, B, C, and D, similar to group I (except Type E, which has no representation in group II). Some other subtypes have also been described. Types A and B of group I represent 70% of the cases

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