Adolescents mature at individual rates. Two procedures enable parents to determine the biological ages of their sons. Skeletal age predicts biological age much better than chronological age. Growth plate development estimates skeletal ages. When parents understand biological maturation, they better determine the appropriate amount and intensity of adolescent pitching that their sons should experience.
Chapter Four: Assessing the Biological Age of Adolescent MalesA few months after William K. Roentgen discovered X-rays, German professor Sydney Rowland and German researcher Joseph Ranke independently reported that the growth plate appearance and union sequences of children reliably assessed their skeletal ages. In 1905, Professor J. W. Pryor outlined the appearance and union sequences for the growth plates of the eight carpals, five metacarpals, fourteen phalanges, distal ulna and distal radius. In 1950, William Walter Greulich and S. Idell Pyle published their Radiographic Atlas of Skeletal Development of the Hand and Wrist. With this Atlas, parents can become expert skeletal age assessors.
1) Assessment StepsWith the development of scanning computers, someone should create a computer program for assessing skeletal ages from hand-wrist X-rays. With safer X-ray procedures, pediatricians should birthdate hand-wrist X-ray and evaluate patients. In this way, pediatricians could track the skeletal maturation patterns of their young patients.
3) The Skeletal Age Evaluation Sheet|------------------------------------------------------------------| | | | Skeletal Age Evaluation Sheet | | | | Subject___________________ Birthday___/___/___ Date___/___/___ | | | | Assessment Location 1st Read 2nd Read Average | | | | 1. Capitate __________ __________ __________ | | 2. Hamate __________ __________ __________ | | 3. Triquentral __________ __________ __________ | | 4. Lunate __________ __________ __________ | | 5. Schaphoid __________ __________ __________ | | 6. Trapezium __________ __________ __________ | | 7. Trapezoid __________ __________ __________ | | 8. Distal Radius __________ __________ __________ | | 9. Distal Ulna __________ __________ __________ | | 10. Metacarpal I __________ __________ __________ | | 11. Metacarpal II __________ __________ __________ | | 12. Metacarpal III __________ __________ __________ | | 13. Metacarpal IV __________ __________ __________ | | 14. Metacarpal V __________ __________ __________ | | 15. Proximal Phalange I __________ __________ __________ | | 16. Proximal Phalange II __________ __________ __________ | | 17. Proximal Phalange III __________ __________ __________ | | 18. Proximal Phalange IV __________ __________ __________ | | 19. Proximal Phalange V __________ __________ __________ | | 20. Middle Phalange II __________ __________ __________ | | 21. Middle Phalange III __________ __________ __________ | | 22. Middle Phalange IV __________ __________ __________ | | 23. Middle Phalange V __________ __________ __________ | | 24. Distal Phalange I __________ __________ __________ | | 25. Distal Phalange II __________ __________ __________ | | 26. Distal Phalange III __________ __________ __________ | | 27. Distal Phalange IV __________ __________ __________ | | 28. Distal Phalange V __________ __________ __________ | | | | Total __________ | | | | SKELETAL AGE = Total ____________ divided by 28 = ____________ | | | |------------------------------------------------------------------|b. Adolescent Male Sexual Maturity Indicators
In my 1979 doctoral dissertation, I developed another procedure for estimating the biological age of adolescent males. With my procedures, physicians and/or qualified educators assessed the primary and secondary sexual characteristic development of the 1571 adolescent males in my study.
1) Marshall Sexual Maturation Indicator Value (SMIV) Checklist|------------------------------------------------------------------| | | | SMIV Checklist | | | | Subject___________________ Birthday___/___/___ Date___/___/___ | | | | Facial Hair (Ask whether they shave) | | | | _____ No facial hair | | _____ Unpigmented, fine sideburn a/o mustache hair | | _____ Downy, lightly pigmented sideburn a/o mustache hair | | _____ Lightly pigmented, coarse sideburn a/o mustache hair | | _____ Darkly pigmented, coarse, defined sideburn a/o mustache | | | | Axillary Hair | | | | _____ No axillary hair | | _____ A few unpigmented axillary hairs | | _____ Downy, lightly pigmented hair in one or both axilla | | _____ Small patch of coarse, pigmented axillary hair | | _____ Well-developed long, coarse, pigmented axillary hair | | | | Pubic Hair | | | | _____ No pubic area hair | | _____ Fine, unpigmented pubic area hair | | _____ Sparse, pigmented, straight pubic area hair | | _____ Small patch of coarse, curly, pigmented pubic area hair | | _____ Curly, coarse, pigmented hair fills the pubic triangle | | | | Genitalia Development | | | | _____ Child sized and shaped genitalia | | _____ Slightly enlarged genitalia, one testes may show lower | | _____ Penis lengthened with glans proportionately small, | | one testes definitely descended lower | | _____ Penis proportionately sized with a darkened scrotal sac | | _____ Adult sized and shaped genitalia | | | |------------------------------------------------------------------|2) SMIV Regression Equation
My SMIV regression equation incorporates the primary and secondary sexual characteristics of facial hair (F), axillary hair (A), pubic hair (P) and genitalia development (G). SMIV scores range from 138.84 months (11.6 years) to 188.32 months (15.6 years).
SMIV = 126.47 + 1.74(F) + 1.20(A) + 2.75(P) + 6.68(G)If adolescent males have Facial Hair (F) evaluations of two, Axillary Hair (A) evaluations of three, Pubic Hair (P) evaluations of three and Genitalia (G) evaluations of two, then they have SMIV values of 155.16 months (12.9 years).
SMIV = 126.47 + 1.74(F) + 1.20(A) + 2.75(P) + 6.68(G)I needed my SMIV checklist and regression equation to estimate skeletal age. Therefore, I used the hand-wrist X-rays of thirty pre-selected adolescent males to determine their skeletal ages. With their chronological ages in months, their heights in inches, their weights in pounds and their Sexual Maturation Indicator Values, my Estimated Skeletal Age (ESA) regression equation estimates their Greulich-Pyle skeletal ages.
ESA = -15.15 + .277(CA) + .212(Ht) + .220(Wt) + .594(SMIV)My doctoral dissertation demonstrated that my ESA regression equation accounted for nearly eighty-three percent of the variability that explains the skeletal age differences between adolescent males.
5) A Sample ESA EvaluationIf adolescent males have chronological ages (CA) of one hundred and twenty-six months, heights (Ht) of fifty-eight inches, weights (Wt) of one hundred and forty-two pounds and Sexual Maturation Indicator Value (SMIV) evaluations of 155.16 months, then they have ESA values of 154.46 months (12.9 years).
ESA = -15.15 + .277(CA) + .212(Ht) + .220(Wt) + .594(SMIV)