This section describes Plug-in Gait upper body modeling, so you can determine if an upper body model will provide the data you require for your clinical analysis.

The following topics are covered:

For details about the labeling skeleton templates to be used with Plug-in Gait upper body models, see Plug-in Gait labeling skeleton templates (VSTs) in Vicon Nexus.

Outputs from Plug-in Gait upper body model

Use a Plug-in Gait upper body model if you require the kinematic and kinetic calculation outputs listed in the following table. The output variables are prefixed by the appropriate context (L for left or R for right).

OutputDescription
Kinematics: Angles
ElbowAnglesRelative. The angles between the upper arm and forearm.
HeadAnglesAbsolute. The angles between the head and the laboratory coordinate system.
NeckAnglesThe angles between head relative to thorax.
ShoulderAnglesRelative. The angles between the upper arm and thorax.
SpineAnglesThe angles between the thorax relative to the pelvis.
ThoraxAnglesAbsolute. The angles between the thorax and the laboratory coordinate system.
WristAnglesRelative. The angles between the forearm and hand.
Kinetics: Forces
ElbowForceThe force between the upper arm and forearm.
NeckForceThe force between the head relative to thorax.
ShoulderForceThe force between the upper arm and thorax.
WristForceThe force between the forearm and hand.
Kinetics: Moments
ElbowMomentThe moment between the upper arm and forearm.
NeckMomentThe moment between the head relative to thorax.
ShoulderMomentThe moment between the upper arm and thorax.
WristMomentThe moment between the forearm and hand.
Kinetics: Powers
ElbowPowerThe power between the upper arm and forearm.
NeckPowerThe power between the head relative to thorax.
ShoulderPowerThe power between the upper arm and thorax.
WristPowerThe power between the forearm and hand.

Marker sets for Plug-in Gait upper body modeling

The marker set for Plug-in Gait upper body modeling includes markers for the head, torso, and upper limbs.
There are two variations of the standard marker set for the upper body model:

The UPA and FRM markers are optional; however, using them improves marker tracking during dynamic trials.

Marker placement for Plug-in Gait upper body model

The following images show front, back, and side views to demonstrate where to attach the upper body markers to your patient. You do this before capturing a static trial as described in the Vicon Nexus User Guide. Some markers are shown from two views to help you better determine their position on your patient.

Important
As shown in the following images, some asymmetry is desirable as it helps the auto labeling routine distinguish right from left. For upper body modeling, you can place the UPA and FRM markers asymmetrically. Similarly, avoid symmetrical placement of marker clusters or groups of markers and also ensure markers are asymmetrical within each cluster/group.

The following image shows the front view. The left upper body markers are not labeled; attach markers on that side in a similar way to those on the right (with some asymmetry as described above).

The following image shows the back view. The right upper body markers are not labeled; attach markers in a similar way to those on the left (with some asymmetry as described above).

The following image shows the right side view. The left side view is not shown; attach markers on that side in a similar way to those on the right (with some asymmetry as described above).

The following tables list the markers defined in Plug-in Gait templates for upper body modeling and describe where to place them on the patient.

Head markers

The following table describes the markers positioned on the patient's head. To save time, many users buy a headband and permanently attach markers to it.

Marker labelDefinitionPosition on patient
LFHDLeft front headLeft temple
RFHDRight front headRight temple
LBHDLeft back headLeft back of head (defines the transverse plane of the head, together with the frontal markers)
RBHDRight back headRight back of head (defines the transverse plane of the head, together with the frontal markers)
Important
If the back markers cannot be placed level with the front markers, you must configure Plug-in Gait to compensate for this during the subject calibration process. To do this, in the Properties for the Process Static Plugin Gait Model pipeline operation, under Assume Horizontal, select Head.

Torso markers

The following table describes the markers positioned on the patient's torso. The torso markers (C7, T10, CLAV, STRN) define the thorax sagittal plane; therefore, their lateral positioning is most important.

Marker labelDefinitionPosition on patient
C77th cervical vertebraOn the spinous process of the 7th cervical vertebra
T1010th thoracic vertebraOn the spinous process of the 10th thoracic vertebra
CLAVClavicleOn the jugular notch where the clavicles meet the sternum
STRNSternumOn the xiphoid process of the sternum
RBAKRight backAnywhere over the right scapula
(This marker has no equivalent marker on the left side. This asymmetry helps the autolabeling routine determine right from left on the subject. Placement is not critical as it is not included in the Plug-in Gait model calculations.)

Upper limb markers

The following table describes the markers positioned on the patient's upper body.

Marker labels shown with an asterisk * are optional; however, using them improves marker tracking during dynamic trials.

Marker labelDefinitionPosition on patient
Left upper limb markers
LSHOLeft shoulderOn the acromio-clavicular joint
*LUPALeft upper armOn the upper lateral 1/3 surface of the left arm (Place asymmetrically with RUPA)
LELBLeft elbowOn the lateral epicondyle
*LFRMLeft forearmOn the lower lateral 1/3 surface of the left forearm (Place asymmetrically with RFRM)
LWRALeft wrist marker AAt the thumb side of a bar attached to a wristband on the posterior of the left wrist, as close to the wrist joint center as possible. Loose markers can be used but for better tracking of the axial rotations, a bar is recommended.
LWRBLeft wrist marker BAt the little finger side of a bar attached to a wristband on the posterior of the left wrist, as close to the wrist joint center as possible. Loose markers can be used but for better tracking of the axial rotations, a bar is recommended.
LFINLeft fingerJust proximal to the middle knuckle on the left hand
Right upper limb markers
RSHORight shoulderOn the acromio-clavicular joint
*RUPARight upper armOn the lower lateral 1/3 surface of the right arm (Place asymmetrically with LUPA)
RELBRight elbowOn the lateral epicondyle approximating the elbow joint axis
*RFRMRight forearmOn the lower lateral 1/3 surface of the right forearm (Place asymmetrically with LFRM)
RWRARight wrist marker AAt the thumb side of a bar attached symmetrically with a wristband on the posterior of the right wrist, as close to the wrist joint center as possible
RWRBRight wrist marker BAt the little finger side of a bar attached symmetrically with a wristband on the posterior of the right wrist, as close to the wrist joint center as possible
RFINRight fingerJust below the middle knuckle on the right hand