Deltoid Tendonitis


Deltoid tendonitis is an injury to the deltoid muscle which covers the shoulder joint. The deltoid muscle is a large muscle which lifts the arm up sideways and can be divided into three parts: the front or the anterior part which helps in flexion or lifting the arm up forwards, the middle part and the back or posterior which helps in extension or lifting the arm up backwards.

The deltoid, which stems from the lateral part of the acromion and clavicle and goes into the lateral aspect of humerus, is a very powerful muscle and is necessary for athletic endeavours.


There can be many causes of deltoid muscle tendonitis like:

  • Injury during sports or activities that cause over-stressing of the deltoid muscle. This includes activities like skiing, weightlifting, swimming, carrying children, working with heavy tools and highly repetitive activity like typing and gardening.
  • Injury or trauma to the deltoid muscle caused by shoulder dislocation or accidents.
  • Damage to the axillary nerve which is located near the neck and is used to stimulate the activity of the deltoid muscle. Damage to these nerves occurs due to direct injury, long-term pressure on the nerve (from cast or splints), shoulder injury and impairs the functioning of the deltoid muscle.
  • Problems in trigger points can also result in pain that seems to be in the deltoid but is actually originating from elsewhere. The activation of the trigger points in the deltoid may also be a cause of tendonitis.


The affected shoulder may show the following signs and symptoms:

  • Presence of visible swelling, bruising to the area (from damaged to small blood vessels under the skin) or redness
  • Pain and soreness when at rest
  • Muscle stiffness
  • Severely limited or absent range of movement.

Types Of Deltoid Tendonitis

On the basis of severity of injury to muscle, deltoid tendonitis can be categorized into three grades:

  • Grade I Deltoid Strain: This is comparatively less severe and only causes mild pain in the shoulders. Although there is muscle tightness and limitation of the range of muscle movement, but the individuals with Grade-I strains can still use their shoulder for activities without much difficulty or pain.
  • Grade II Deltoid Strain: This is the next level of severity and occurs due to a partial tearing of the Deltoid Muscle. Increased shoulder pain, swelling and difficulty in movement of the shoulder are usually the characteristics of this condition.
  • Grade III Deltoid Strain: This is the most severe form of Deltoid Strain in which there is a complete rupture of the Deltoid Muscle. Severe pain and inability to use the affected shoulder for activity are seen in this stage.

Treatment of Deltoid Tendonitis

The following treatment strategies can be used for this condition:

  • Generally, deltoid injuries can be treated using the P.R.I.C.E principle which involves – Protection, Rest, Icing, Compression and Elevation.
  • For the symptomatic relief of the pain, anti-inflammatory medications (ibuprofen) can be used.
  • Additionally, brief periods of physical therapy may be helpful in decreasing pain and increasing motion in the arm. This is more commonly given in case of grade III injury.

Let’s examine these treatments in more detail.

For a Grade I deltoid strain, you should use a compression wrap to reduce swelling. Apply ice intermittently over the first 24 hours. After this time has passed, you can use a heating pad to relieve the pain and discomfort. It is important that you let the shoulder to rest.

For a Grade II deltoid strain, you need to apply ice for a longer period. Using ice for three to five days can help to reduce swelling. For these injuries, alternative between warming and cooling packs may help to reduce pain. You will need to give your shoulder time to heal. Be very careful with exercises. Ensure they are not overly intense or long.

For a Grade III deltoid strain, you can try at-home remedies but if they don’t work, you will need to go to a doctor or physiotherapist. Apply an ice pack to the injury elevate the arm if you can. Try not to use the arm and shoulder. You may need to take painkillers to reduce the discomfort. A professional will be able to offer additional ways to speed up recovery and managing pain.

Exercises to Protect the Deltoid

It is best to avoid injuring the deltoid muscle. You need to make sure you warm up, cool down and stretch properly before engaging in more strenuous activities. Exercises can improve flexibility and prevent injury. Gentle stretching can also help with recovery after injury. Here are some stretches you can try.

  1. Bend forward at a 45-degree angle and let the injured arm dangle. Swing the arm gently back and force to loosen the muscles and ease the pain. Do this for three to five minutes.
  2. Try a doorway chest stretch. Stand in front of a doorframe and place your forearms on either side. Lean into the doorway for 30-second periods.
  3. Stand upright or sit in a chair. Pull the injured arm across your chest and use the other arm to create mild tension. Hold this position for 30 seconds.
  4. Lie flat and raise the affected arm and let the fingertips point toward the ceiling. If you need to, you can use the other arm to help support the injured arm. Keep the arm straight and swing it backward towards the head and then forwards towards the knee. Try to do this for three to five minutes.
  5. Stand and bring the arms behind the back and clasp the hands together. Gently lift the hands toward the ceiling as far as you can comfortably go.

Preventing Deltoid Tendonitis

In addition to warming up properly, you can take a additional steps to avoid overworking your deltoid muscle. You can try:

  • Taking adequate time to allow the muscle to recover after strenuous exercise
  • Ensuring you use proper safety equipment and follow best practises if the injury is work-related.
  • Getting sports massages regularly to relieve tension in the muscles.
  • Seeking tailored suggestions from fitness trainers, therapists and medical professionals.

When to Seek Medical Help

If you have trouble moving your arm accompanied by swelling in the shoulder and pain when you try to use your arm, you should see a doctor. This indicates your deltoid injury is serious. If you can’t lift your arm at all, you may have a severe muscle tear and you should see a doctor immediately.