Shoulder Flexion & Abduction

Electrode Placement
Application Instruction by Dr. Lucinda Baker

Electrode placements for shoulder flexion and abduction can be seen here with one electrode over the anterior deltoid and the other over the middle deltoid. The acromion is marked with the marker. In our first placement the negative electrode of the asymmetric waveform is placed over the anterior deltoid and you can see the resultant stimulation is one of dominantly flexion.

Shoulder Flexion & Abduction

Video Instruction
Audio Transcript:

Electrode placements for shoulder flexion and abduction can be seen here with one electrode over the anterior deltoid and the other over the middle deltoid. The acromion is marked with the marker. In our first placement the negative electrode of the asymmetric waveform is placed over the anterior deltoid and you can see the resultant stimulation is one of dominantly flexion.

The therapist is now putting the stimulator on pause and he is going to switch the polarity so that the middle deltoid electrode is now the negative electrode and the anterior deltoid will become the positive electrode. You can see the resultant stimulated contraction is one of dominant abduction. Placing the stimulator on pause, the electrode leads are being disconnected. A second stimulator that is programmed with a symmetric biphasic waveform is being connected. And now as the therapist increases the amplitude you will notice that both electrodes, anterior and middle deltoid, are equally excitable resulting in a motion that would be referred to as scaption, a combination of flexion and abduction.

Shoulder Flexion & Abduction

Muscle Anatomy

Muscles involved in shoulder flexion & abduction:

Deltoid
Origin: The anterior border and upper surface of the lateral third of the clavicle, acromion, spine of the scapula
Insertion: Deltoid tuberosity of humerus

Other muscles involved in shoulder flexion & abduction:

Biceps brachii, Serratus anterior, Supraspinatus, Trapezius

Shoulder Flexion & Abduction

Nerve Anatomy

Nerves involved in shoulder flexion:

Deltoid
Nerve innervation: Axillary nerve
Nerve root: C5, C6