Table 6. Heterogeneity and publication bias metrics.

A p-value less than 0.05 was considered significant.

SS, suprascapular; SSN, suprascapular notch

Variant	I² (%)	Egger's regression	P-value (Egger's regression)
Absent SSN	94.02	2.944	0.003
U-shaped	96.03	1.460	0.144
V-shaped	97.58	2.209	0.027
SS foramen	72.23	2.655	0.008
SS foramen and notch	2.93	1.412	0.158
Incomplete ossification	90.09	1.895	0.058
Small V-shaped	96.91	2.337	0.019
J-shaped	N/A	N/A	N/A
Double foramen	N/A	N/A	N/A
“Polguj method” classification
Type IA	85.03	0.877	0.381
Type IB	82.53	3.270	0.001
Type IC	0	-0.153	0.879
Type II	0	0.110	0.913
Type IIIA	82.24	3.807	<0.001
Type IIIB	87.49	3.985	<0.001
Type IIIC	89.04	-0.320	0.749
Type IV	0	0.211	0.833
Type V	92.97	-0.203	0.839