Biomechanics research tool
Waajacu's Medical
Explore regional posture and modeled muscle activation.
Right upper limb
Click a muscle to inspect · left-drag to rotate · right-drag to move · scroll to zoom
About this model
What the model shows
Model: MS-Human-700, using its primary full-body model and detailed manipulation hand variant. The complete skeleton is shown as quiet context while the selected region remains in focus: — relevant muscles, — articulated bodies, and — surface meshes.
Posture and paths: choose one body region at a time. Its own posture controls, muscle inventory and presets replace the previous region cleanly; paths are recalculated through the model's attachment sites and wrapping surfaces at every posture.
Muscle rendering: switch between procedural anatomical bodies and technical path lines. Anatomical bodies use smoothed, muscle-family-specific surface profiles while following the model path; path lines show the exact calculated centerline. Body shape and thickness are illustrative and do not vary with activation; color represents activation.
Activation: colors show a static, gravity-only model estimate. The calculation includes passive model forces and assumes the rest of the body is externally supported.
Detailed hand: finger posture and intrinsic-hand muscles come from the articulated right-hand variant. Hand presets are unloaded shapes without object contact; they do not estimate grip or pinch force. Mirror display does not change the calculated side.
Methods and limitations
Static only: there is no held object, contact force, measured support, speed, acceleration, fatigue or person-specific co-contraction. Dynamic movement can require different activation.
Quality checks: colors appear only when paths and values are valid and the posture passes the static balance and reserve-torque limits. A failed result remains gray.
Interpretation: activation and active tensile-force contribution are model outputs—not measured effort, personal force, tissue load, pain, damage or diagnostic evidence. Joint reaction forces are not calculated.
Assessment: the guided sequence remains a separate right upper-limb workflow. Explorer region choices do not change its protocol. It cannot identify a painful tissue, rule out urgent conditions or replace a qualified clinician.
Technical details: Loading the browser runtime… Checking model integrity… This distribution includes documented source-model modifications; see the source-change record below.
Credits, licenses and citation
Waajacu's Medical: original application code and interface © 2026 Waajacu's Medical contributors, licensed under the MIT License.
MS-Human-700: by the LNS Group, sourced through MuJoCo Menagerie. Modified and compiled browser assets remain under Apache-2.0; changes are listed in the source record.
MuJoCo 3.10.0: WebAssembly runtime by Google DeepMind, Apache-2.0. three.js r180: © 2010–2025 three.js authors, MIT.
Academic citation: Zuo, C., He, K., Shao, J. & Sui, Y. (2024), “Self Model for Embodied Intelligence,” IEEE ICRA, 13062–13069. DOI 10.1109/ICRA57147.2024.10610081.
Provenance: Waajacu has not independently verified every model parameter or mesh. Local modifications are not endorsed by the upstream authors. See the third-party notices for complete boundaries.
Safety references: NHS shoulder guidance and a systematic review of shoulder examination tests. These sources do not validate this application.