Pain can occur either at the side, back or front of the shoulder of an injured deltoid muscle. A deltoid rupture can be identified when the front of the shoulder experiences a sudden muscular pain. Lifting the arm from the side towards the front and keeping it straight to avoid resistance will result in pain. Lifting the arm sideways upwards against some resistance will be painful as well. Where 
there is a muscle tear there will be swelling and tenderness also.
The big muscle on the shoulder is called the deltoid muscle. The three parts are the back or posterior, the middle and the front. The arm is lifted up sideways by the muscle. The forwards motion of the arm is supported by the front part, which is also named the shoulder flexion. The back part supports the backwards life, also known as the shoulder extension.
Deltoid injury may occur during sports activity, weight lifting or an auto accident among other traumatic events.
Grade 1 Deltoid Strain
The symptoms of a grade 1 deltoid strain are muscle tightness. When this type of injur occurs, the arms can still function normally and press ups can be performed too. Swelling is mild with this strain, and lifting the arm sideways or to the front or back is not painful.
The treatment for grade 1 deltoid strain involves the application of ice for the first 24 hours in 15 minute intervals and then heat application. Light exercise will help build weight and strength back gradually. A sports massage applied by a sports therapist or a doctor combined with electrical stimulation or ultrasound will speed up the recovery considerably.
Grade 2 Deltoid Strain
The symptoms of a grade 2 strain include not being able to do press ups or use the arm properly. During activity, sudden pain twinges occasionally occur. Swelling will be noticeable with this type of injury, and pressure will cause pain. Lifting the arm frontwards, sideways, or backwards against resistance will cause considerable pain.
The treatment for a grade 2 strain will involve the application of ice for a period of three to five days. Rehabilitation advice can be obtained from a sports injury specialist. For relief of pain, the application of heat in the form of hot water bottles, baths and ultrasound, are all recommended by specialists.
Four sets of exercise with 10 repetitions each will help. This is done three times per week. Cycling about two to three times a week and stretching five times a day where you hold the stretches for at least 30 seconds is recommended. Slowly getting back to sports activities on the fourteenth day is advised. A sports therapist or doctor can help speed recovery up by setting up a rehabilitation program.
Grade 3 Deltoid Strain
The symptoms of a grade 3 deltoid strain are inability to move the arm and severe pain. There will be the presence of semi-severe swelling. A bulge or a gap in the muscle may appear, and contracting the muscle will be painful. For a period of 3 to 12 weeks, it may not be possible to participate in competitions or strenuous activities.
The treatment for a grade 3 strain of the deltoid involves the immediate application of ice within the first week. The second week should have static contractions without pain using hot water bottle, bath or ultrasound. The third week keep all the above and increase static contractions intensity. The fourth week will have further pain free exercises. Start stretching five times a day. In the fifth week, build up exercises and progress to sports specific exercises are recommended. Additionally, grade 2 or 3 injury requires the attention of a sports injury specialist.
