Elbow assembly of a humanoid robot

A humanoid robot comprising:

• an upper region including a torso and at least one arm assembly operably connected to the torso, and wherein when said arm assembly is in an extended state, the arm assembly includes:
• an upper arm twist actuator assembly with a rotational upper arm twist axis;
• a lower humerus with:
• (i) a lower humerus extender operably coupled to the upper arm twist actuator assembly and having a lower humerus center, and (ii) an elbow actuator mating assembly integrally formed with an extent of the lower humerus extender, and wherein an extent of the elbow actuator mating assembly has a curvilinear external surface;
• an upper forearm with:
• (i) an upper forearm coupling assembly that includes an external surface having a curvilinear extent that resides within a first plane, and (ii) an upper forearm extender integrally formed with an extent of the upper forearm coupling assembly and that includes an upper forearm center and an external surface having a curvilinear extent that resides within a second plane that is oriented perpendicular to the first plane;
• and
• an electric elbow actuator having:
• (i) an elbow axis that is offset from a plane that extends between the lower humerus center and the upper forearm center, (ii) a first extent positioned within a portion of the elbow actuator mating assembly, and (iii) a second extent positioned within a portion of the upper forearm coupling assembly, and wherein said elbow actuator mating assembly and said upper forearm coupling assembly collectively surround a majority of said electric elbow actuator.