Table 5.

Architectural properties of forelimb muscles

Muscle and primary joint action	Secondary joint action	Abbreviation	Muscle Mass, g	Optimal MTU length, mm	Optimal Fascicle Length, mm	Pennation Angle, deg	PCSA, cm2	Fiber type: SO, FOG, FG, %	nVmax, $L_0^M/s$	Joint Radius R1, mm	Joint Radius R2, mm
Shoulder protractors		Sh Prot	49.8	59.8	15.9	15	25.87	41.2,32.2,26.5	11.0	7.94	—
Acromiodeltoideus	Shoulder abductor	AD	2.79±0.47	59.1±15.2	13±2.9	31±14	2.04±0.6	21.9,78.1,0g	11.0	2.0	—
Coracobrachialis	Shoulder adductor	CB	0.31±0.04	31.0±12.0	11±7.2	0±0	0.34±0.25	56,19,25a	10.2	5.0	—
Infraspinatus	Shoulder abductor	IF	13.2±1.7	78.9±4.9	18.4±3.1	15±10	6.62±1.07	37,24,39a	11.6	3.0	—
Supraspinatus	-	SPS	17.2±1.8	86.1±4.2	27.2±5.6	6±3	5.94±1.33	49,23,28a	10.6	21.9	—
Subscapularis	Shoulder adductor	SSC	15.4±1.8	78.3±5.1	13.7±1.5	26±6	10.25±1.2	32,26,42a	12.0	6.2	—
Teres Minor	-	TN	0.93±0.22	32.2±4.9	12.5±3.8	12±8	0.7±0.16	51,23,25a	10.6	1.6	—
Shoulder retractors		Sh Ret	12.01	71.4	39.5	4	2.7	21.9,78.1,0	11	1.84	—
Spinodeltoideus	Shoulder abductor	SD	3.54±1.01	72.1±4.1	32.9±3.5	1±1	1.01±0.4	21.9,78.1,0g	11	1.8	—
Teres Major	-	TJ	8.5±1.4	84.7±2.6	46.1±5.7	7±5	1.69±0.38	21.9,78.1,0b	11	3.5	—
Shoulder Protr-Elbow Flex		Sh Prot-El Fl	5.9	70.5	25.1	10	2.27	20,21,59	11.9	10.0	5.30
Biceps Brachii	-	BB	5.9±1.0	81.0±8.7	25.1±7.6	10±10	2.27±0.81	20,21,59c	11.9	10.0	5.3
Shoulder Retr-Elbow Ext		Sh Ret-El Ex	22.9	98.8	23.9	13	9.2	26,17,57	11.4	4.40	11.90
Triceps Brachii Longus	-	TLONG	22.9±3.9	93.1±8.1	23.9±7.1	13±11	9.2±2.75	26,17,57c	11.4	4.4	11.9
Elbow extensors		El Ext	18.5	69.7	29.1	10	5.58	55.3,13.3,31.5	8.7	2.10	—
Anconeus	Forearm pronator	ANC	2.04±0.13	56.6±8.8	20.1±2.5	19±5	0.94±0.13	100,0,0c	4.7	2.4	—
Epitrochlearis	-	EPT	1.95±0.51	66.5±8.5	30.1±3.6	0±0	0.59±0.16	26,17,57g	11.4	2.1	—
Triceps Brachii Lateralis	-	TLAT	9.0±2.2	78.2±5.6	36.8±5.1	8±3	2.3±0.84	15,22,63c	12.3	5.8	—
Triceps Brachii Medialis	-	TMED	5.6±0.4	83.8±7.9	29.2±3.8	11±4	1.75±0.21	80,14,6c	6.4	8.4	—
Elbow flexors	-	El Fls	5.9	69.7	44.5	10	2.5	16.5,40.2,43.2	12.2	3.20	—
Brachioradialis	Forearm supinator	BCD	0.80±0.21	136.7±12.5	89.6±9.1	0±0	0.08±0.03	13,19,67a	13.1	5.8	—
Brachialis	-	BR	3.47±0.35	88.6±6.0	32.4±4.4	10±4	0.99±0.22	25,24,51c	11.4	6	—
Pronator Teres	Forearm pronator	PT	1.62±0.28	51.4±12.3	11.5±3.5	22±4	1.43±0.73	11.5,77.5,11.5b	12	4.2	—
Elbow flexor-Wrist dorsiflexors		El Fl-Wr dFl	11.8	76.5	27.4	7	4.35	4,30.8,65.2	13.3	5.40	3.50
Extensor Carpi Radialis	-	ECR	3.88±0.66	98.3±19.4	47.3±35.3	15±0	0.97±0.59	4,41.9,53.9d	13.1	5.5	3.5
Extensor Digitorum Communis	-	EDC	1.98±0.17	85.8±3.7	22.5±6.7	5±4	0.85±0.21	4,28,68e	13.3	5.3	6.1
Wrist plantarflexors		Wr pFl	65.4	79.8	13.2	8	36.97	20.1,30.4,49.4	11.7	2.70	—
Flexor Carpi Radialis	-	FCR	1.26±0.17	83.4±15.7	14.3±2.3	6±1	0.85±0.14	38.1,29.4,32.3f	10.1	2.7	—
Flexor Carpi Ulnaris	-	FCU	4.01±0.32	104.0±2.6	11.1±1.1	11±2	3.3±0.31	42.4,24.2,33.4f	9.7	5.6	—
Flexor Digitorum Profundus	-	FDP	9.27±2.00	103.9±6.1	21.5±2.7	7±12	3.97±1.07	8.1,34.6,57.2f	12.8	5.5	—
Flexor Digitorum Superficialis	-	FDS	0.18±0.05	29.1±4.3	5.85±2.2	3±3	0.29±0.07	26.8,29.2,43.9g	11.1	2.7	—
Palmaris Longus	-	PL	2.61±0.55	101.8±22.2	10.9±1.4	14±6	2.36±0.61	18.7,28.7,52.6f	11.9	6.3	—
Wrist dorsiflexors		Wr dFl	1.11	78.4	21	1	0.25	2,55,43	13.2	2.40	—
Extensor Pollicis Longus	-	EPL	0.55±0.07	86.1±8.1	21±6	1±1	0.25±0.08	2,55,43	13.2	2.4	—

Notes. Five compartments of flexor digitorum profundus, four compartments of flexor digitorum superficialis, five compartments of palmaris longus, and two compartments of extensor pollicis longus (see Fig. 1B) are combined in the corresponding single muscles; SO, FOG and FG are percentage of slow oxidative, fast oxidative glycolytic and fast glycolytic fibers in the muscle; $n{V}_{\mathit{max}}^M$ is muscle maximum shortening velocity normalized to the optimal muscle fascicle length $\left(L_0^M\right)$. $n{V}_{\mathit{max}}^M$ was estimated from the percentage of SO, FOG and FG fibers in the muscles as $n{V}_{\mathit{max}}^M=(4.65\cdot SO+12.8\cdot FOG+14.0\cdot FG)/(SO+FOG+FG)$, where constants 4.65, 12.8 and 14.0 are maximum shortening velocities [in $\left[\mathrm{in}{L}_0^M/\text{s}\right]$ of SO, FOG and FG muscle fibers measured or estimated in (Spector et al., 1980; Scott et al., 1996; Singh et al., 2002). When no information on fiber composition in a cat forelimb muscle was available, we used this information from other mammalian species.

^aTaken from Macaca (Singh et al., 2002);

^btaken from Rabbit (Prado et al., 2005);

^ctaken from Cat (Collatos et al., 1977);

^dtaken from Rat (Watt et al., 1982);

^etaken from Mouse (Mathewson et al., 2012);

^ftaken from Cat (Gonyea et al., 1981);

^gtaken from the synergistic muscles due to lack of information in the literature.

Values of morphological variables in bold font indicate values computed by the optimization algorithm (see Methods, eqs. 6–11) or estimated from the literature for the 9 equivalent MTU groups.