Study on the muscle architecture of the anterior muscles of upper arm

Objective The architectural feature of the anterior muscles of the upper arm was studied to evaluate their physiological function and supply morphologic materials for clinical application. Methods The muscles were got from 6 adult cadavers and studied by muscle architecture method. Results Muscle Weigh: the long head of biceps brachii was 81.72±23.26g, the short head was 67.20±20.43g and brachialis was 158.44±34.00g; Fiber Length: the long head of biceps brachii was 9.32 ±0.77cm, the short head was 10.24 ±0.70cm and brachialis was 8.09 ±0.35cm; Pinnation Angle: coracobrachialis was 20.8±3.06°. Cross Section Area / Muscle Weigh (CSA/MW): the long head of biceps brachii was 0.10± 0.009, the short head was 0.09±0.005 and brachialis was 0.12±0.009. Fiber Length/ Cross Section Area (FL/CSA): the long head of biceps brachii was 1.00±0.24, the short head was 1.74±0.78 and brachialis was 0.44±0.07. Conclusions Biceps brachii was designed for velocity production and brachialis was tend to be designed for power. Coracobrachialis was bipennate muscle which could maintain the gesture of upper limb and the stability of the shoulder joint.