TABLE 5

Marrow Cellularities and Fractional Tissue Distributions in Skeleton of ICRP Reference Male

Skeletal region	Bone groups*	ICRP 70 cellularity (age, 25 y)	ICRP 70 cellularity (age, 40 y)	f_TAM (age, 25 y)	f_TAM (age, 40 y)	f_TBS	f_TBV	Average cellularity (age, 25 y)	Average cellularity (age, 40 y)
Legs, upper	80% FH, 20% FN	0.30	0.25	0.033	0.030	0.167	0.163	0.010	0.008
Legs, middle	50% FH, 50% FN	0.00	0.00	0.000	0.000	0.169	0.165	0.000	0.000
Legs, lower	50% FH, 50% FN	0.00	0.00	0.000	0.000	0.040	0.040	0.000	0.000
Arms, upper	80% FH, 20% FN	0.30	0.25	0.023	0.021	0.031	0.030	0.007	0.005
Arms, middle	50% FH, 50% FN	0.00	0.00	0.000	0.000	0.026	0.025	0.000	0.000
Arms, lower	50% FH, 50% FN	0.00	0.00	0.000	0.000	0.026	0.026	0.000	0.000
Pelvis	60% IC, 40% LV	0.58	0.48	0.333	0.303	0.018	0.018	0.193	0.146
Spine, upper	100% CV	0.72	0.70	0.027	0.029	0.110	0.107	0.019	0.020
Spine, middle	50% CV, 50% LV	0.72	0.70	0.174	0.186	0.282	0.276	0.125	0.130
Spine, lower	100% LV	0.72	0.70	0.098	0.105	0.071	0.069	0.071	0.073
Skull, cranium	100% PB	0.42	0.38	0.056	0.056	0.012	0.026	0.024	0.021
Skull, facial	100% PB	0.42	0.38	0.028	0.028	0.006	0.013	0.012	0.011
Ribs	100% RB	0.72	0.70	0.192	0.206	0.031	0.030	0.138	0.144
Clavicles	60% IC, 40% LV	0.37	0.33	0.008	0.008	0.002	0.002	0.003	0.003
Scapulae	60% IC, 40% LV	0.42	0.38	0.028	0.028	0.009	0.009	0.012	0.011
			Totals:	1.000	1.000	1.000	0.999	61.3%	57.1%
					Total active marrow mass:					1,170 g	1,090 g

↵* FH = femur head; FN = femur neck; IC = illiac crest; LV = lumbar vertebrae; CV = cervical vertebrae; PB = parietal bone; RB = ribs.