Time of appearance and approximate time of fusion of secondary ossification centers, by sex and age

Secondary ossification center	Girls	Boys
Secondary ossification center	Age (range) of appearance
Capitellum	5 (1 to 11) months	7 (1 to 26 ) months
Radial head	4 (3 to 6) years	5 (3 to 6) years
Inner (medial epicondyle)	5 (5 to 8) years	7 (7 to 9) years
Trochlea	8 (7 to 11) years	9 (8 to 13) years
Olecranon	9 (8 to 10) years	10 (8 to 11) years
External (lateral epicondyle)	11 (8 to 11) years	12 (9 to 13) years
	Approximate age of fusion
Trochlea	10 years	12 years
External (lateral epicondyle)	11+ years	12+ years
Capitellum	12 years	14 years
Olecranon	13 years	15 years
Radial head	14 years	16 years
Inner (medial epicondyle)	15 years	17 years

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