Muscle Breakdown: Infraspinatus
Table of Contents
What Is the Infraspinatus
The Infraspinatus muscle is one of four muscles that make up the rotator cuff. The Infraspinatus is a triangular-shaped muscle and is located on the Scapula in the back of the shoulder. Often, the Infraspinatus and the Supraspinatus are grouped together as one unit because of their proximity and complementary functions.
Infraspinatus Muscle & Cadaver
Infraspinatus Function
The Infraspinatus has a few important functions. Some of the key functions of the Infraspinatus include,
Main external rotator of the Shoulder
Extension of the Shoulder
Abducts the Scapula
Stabilizes the shoulder along with the other muscles of the Rotator Cuff.
Infraspinatus Origin And Insertion
Infraspinatus Origin
The Infraspinatus originates from the Infraspinatus Fossa on the Scapula.
Infraspinatus Insertion
The Infraspinatus inserts into the Posterior Aspect of the Greater Tuberosity of the Humerus.
Infraspinatus Innervation
The Infraspinatus is innervated by the Suprascapular Nerve.
Infraspinatus Action
The Infraspinatus is associated with many activities that we perform every day and is involved in the movements of different sports. Some examples of the action of the Infraspinatus include,
Swimming
Tennis
Painters
Carpenters
Golfing
Sweeping
Infraspinatus Pain
Pain in the Infraspinatus can arise from different sources such as muscle tears, strains or tendinosis. Whenever you feel pain in any muscle, it is important to stop the activity and rest before you make a potential injury worse! Listening to the body, especially if you are an athlete can potentially reduce recovery time from an injury. The body needs time to rest and recover, so remember to take time off or include a rest day during your exercise routine.
Infraspinatus Tendon
Towards the insertion point of Infraspinatus, you will find the Infraspinatus Tendon. The tendons of all of the muscles in the Rotator Cuff come together to form Rotator Sleeve that helps to keep the Humeral Head in the Glenoid Fossa. Often, the tendons of muscles are subject to injuries such as strains, tears or tendinosis.
To avoid injury to the Infraspinatus Tendon, a proper warm-up should always be performed before activity, followed by a cool down after. If you are repeatedly using the Infraspinatus for sport or work, a proper shoulder mobility routine would be encouraged to maintain optimal shoulder health.
Infraspinatus Tendinosis
Infraspinatus Tendinosis can occur over time from repetitive use of the muscle. This is very common in tennis players, swimmers and carpenters who perform the same movements every day. Over time, the Infraspinatus will develop small microtears in the Infraspinatus Tendon that can cause pain if you do not allow time for the muscle to heal and recover properly between games or projects. These small tears will cause, pain, swelling, stiffness and a limited range of motion of the Infraspinatus.
Infraspinatus Tendinosis will most likely heal by itself over time with the proper rest and recovery plan. At home, ice, heat and anti-inflammatory medication can help to reduce symptoms. It is also suggested to consult a Physiotherapist, who will provide you will stretches and exercises that will help to relieve pain and strengthen the Infraspinatus.
Infraspinatus Tear
Two types of tears can occur to the Infraspinatus. A partial-thickness tear is when only a portion of the Infraspinatus Tendon is torn. This can occur from overuse or ageing. A full-thickness tear occurs then the entire Infraspinatus tendon is ruptured. This can occur from acute injuries such as falling or other severe trauma.
Symptoms of an Infraspinatus tear include,
Pain at night or at rest
Weakness of the arm
Pain with movement of the arm
Your doctor will be able to confirm an Infraspinatus tear by performing various physical tests and diagnostic imaging. From there, a proper treatment plan for your Infraspinatus tear will be formed and you will be advised to rest and ice the muscle.
Infraspinatus Test
An Infraspinatus test can be conducted to determine if your muscle pain is originating from the Infraspinatus, or if it is from another muscle in the shoulder or upper back. This manual test involves bending both arms to 90-degrees at the elbow. Keep both elbows tight to the torso. The examiner will push forwards on the arm as the patient attempts to externally rotate. A positive finding for this test is pain, which means you have an injury to the Infraspinatus.
Infraspinatus Exercise
External Rotation
Anchor a resistance band around a support at about elbow height. Hold the band in your right hand and step away from the support until you can feel some resistance in the band. The band should be coming across the body, so your left side will be closest to the support. Form a 90-degree angle at the right elbow and keep the elbow tight to the body. Slowly begin to externally rotate the forearm away from the body. Repeat this movement for 3 sets of 12 reps.
Side Lying External Rotation
Lie down on your side with one arm supporting the head, and the arm closest to the ceiling bent at 90-degrees holding a dumbbell. Keep the elbow tight to the body and slowly begin to externally rotate the forearm up and down. Repeat this movement for 3 sets of 12 reps.
Cuban Press
Begin with a dumbbell in each hand at your sides. Lift the dumbbells up to shoulder height in the same manner you would if you were performing an upright row. Once you are at the top of the row, rotate your wrists to press the dumbbells towards the sky as if you were performing a shoulder press. Repeat this movement for 3 sets of 12 reps.
Infraspinatus Stretch
Passive External Rotation
Hold a dowel or stick in front of you with your hands about shoulder-width apart. Keep the elbow of the side you are stretching close to the torso and push the dowel across the body towards this side. Hold the stretch for 30 seconds and perform 3 sets.
Sleeper Stretch
Lie on your side on the affected shoulder. The elbow should be in line with the shoulder and the forearm and wrist elevated in the air on top of the elbow. Use your free arm to push the wrist down towards the toes. When you begin to feel tension in the Infraspinatus, hold the stretch for 30 seconds and then repeat on the other side.
