The Deltoid: Trigger Points and Referred Pain.

Where Are the Three Portions of the Deltoid Located?

Anatomography (en:Anatomography (setting page of this image)) [CC BY-SA 2.1 jp], via Wikimedia Commons

About the Three Portions of the Deltoid

The deltoid is a large, triangular muscle that covers the shoulder joint. Although it is one muscle, it has three distinct portions: the anterior deltoid, middle deltoid, and posterior deltoid. Each portion helps move the arm in a different direction and may produce a slightly different referred-pain pattern when trigger points develop. Pain caused by trigger points in the deltoid muscle does not radiate pain over long distances. Generally, the pain will be close to the trigger points and located in the upper arm.

Anatomically, the anterior portion primarily assists flexion and internal rotation, the middle portion primarily abducts the arm, and the posterior portion assists extension and external rotation.

Portion	Location	Primary Movements
Anterior Deltoid	Front of the shoulder	Raises the arm forward and assists with internal rotation
Middle Deltoid	Side of the shoulder	Raises the arm out to the side
Posterior Deltoid	Back of the shoulder	Moves the arm backward and assists with external rotation

Symptoms associated with deltoid trigger points may be mistaken for those of the following conditions:

Pinched cervical nerve.
Bursitis.
Biceps tendinitis
Rotator cuff injury

Important: Shoulder or arm pain can have causes other than muscular trigger points. Seek medical evaluation for severe or unexplained pain, significant weakness, numbness, tingling, pain following an injury, or symptoms that persist or worsen.

What may contribute to tension in the deltoid muscle?

Trauma (impact) during sports activities
Typing on a keyboard that is at an inappropriate height, either too high or too low.
Lifting or holding objects for too long at shoulder height.
Carrying objects heavy.

How to Help Prevent deltoid Trigger Points from Returning :

Use an ergonomic workstation
Avoid repetitive shoulder movements.
Do shoulder warm-up exercises before undertaking strenuous activities.

About the Anterior Deltoid

The anterior deltoid forms the front portion of the shoulder. It helps lift the arm forward and assists with inward rotation. Trigger points in this portion generally produce pain concentrated over the front of the shoulder.

The image above shows possible locations of Anterior Deltoid trigger points.

About the Middle Deltoid

The middle deltoid forms the rounded outer portion of the shoulder and is primarily responsible for lifting the arm out to the side. Because it is the largest of the three heads and works strongly during many arm movements, it may be particularly susceptible to overuse. Its referred pain is generally concentrated over the outer shoulder.

The image above shows possible locations of middle deltoid trigger points.

About the Posterior Deltoid

The posterior deltoid forms the back portion of the shoulder. It helps move the arm backward and assists with outward rotation. Trigger points in this portion generally produce pain over the back of the shoulder.

The image above shows possible locations of middle deltoid trigger points.

How to deactivate the Deltoid trigger points

Step 1: Locating the Deltoid muscle — Anterior Deltoid

Trigger points Deactivation with a supported thumb to avoid hurting the thumb

Step 2: Deltoid trigger points desactivation — Middle Deltoid

Middle Deltoid massage with a tennis ball, that will Deactivate the trigger points

Step 3: desactivation of the s trigger points with a tennis ball — Posterior Deltoid

Posterior Deltoid massage with a tennis ball, that will Deactivate the trigger points

Trigger points Deactivation

When using a tennis ball to massage the middle and posterior deltoid, you can either hold steady pressure on a tender area or make small, slow movements from side to side and up and down. Keep the pressure comfortable and avoid rolling directly over the shoulder joint or bone.

Tenderness may indicate a sensitive area, but it does not necessarily confirm the presence of a trigger point. Several short sessions may be more comfortable than one prolonged session.

Sources and References

Clair Davis & Amber Davis. The Trigger Point Therapy Workbook: Your Self-Treatment Guide for Pain Relief..New Harbinger Self-Help Workbook,2013.
The Deltoid: Anatomy and Function — TeachMeAnatomy.Com
Anatomy, Shoulder and Upper Limb, Deltoid Muscle — NIH

I hope you find this information helpful.

Thank you for reading,

Michel Bourgeois
Licensed Massage Therapist

This article is provided for educational purposes only and does not constitute medical advice, a diagnosis, or a treatment.