Example embodiments relate to robotic arm assemblies. The robotic arm assembly may include upper arm segment and shoulder coupling joint assembly. Upper arm segment includes a motor. Shoulder coupling joint assembly connects upper arm segment to shoulder segment. Shoulder coupling joint assembly includes distal and proximal shoulder joint subassemblies. Distal shoulder joint subassembly is connected to the upper arm segment. Distal shoulder joint subassembly includes gear train system having gear stages including first distal elbow gear stage and second distal elbow gear stage. First distal elbow gear stage includes bevel gears. Second distal elbow gear stage includes a planetary gear assembly. Proximal shoulder joint subassembly connects the shoulder segment to the distal shoulder joint subassembly.