In this section we will delve into the vital rotator cuff muscles and examine the implications of injury or limitations in these structures for shoulder-related issues. Additionally, we will discuss the necessary diagnostic procedures that must be conducted before commencing treatment.
Article Index:
Introduction
Examination & Diagnosis
Conclusion & References
Introduction
Rotator cuff injuries frequently occur among athletes and non-athletes, making early diagnosis crucial for determining causative factors, initiating appropriate treatment, and preventing additional injury.
The rotator cuff comprises four primary muscles and their corresponding tendons, which include:
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
The rotator cuff muscles are frequently called the SITS muscles (an acronym derived from the initial letter of each muscle). This group facilitates various upper limb movements such as flexion, abduction, internal, and external rotation.
Anatomy & Biomechanics
Let's start with the basic anatomy and biomechanics of
the rotator cuff (SITS) muscles.
Supraspinatus Muscle
Origin on Scapula: Supraspinous fossa.
Insertion: Superior facet of the greater tubercle.
Primary Function: Humerus abduction.
Innervation: Suprascapular nerve (C5).
Infraspinatus Muscle
Origin on Scapula: Infraspinous fossa.
Insertion: Middle facet of the greater tubercle.
Primary Function: Humerus external rotation.
Innervation: Suprascapular nerve (C5-C6).
Teres minor Muscle
Origin on Scapulae: Middle half of lateral border
Insertion: Inferior facet of the greater tubercle
Primary Function: Externally rotates the humerus
Innervation: Axillary nerve (C5)
Subscapularis muscle
Origin on Scapula: Subscapular fossa.
Insertion: Lesser tubercle.
Primary Function: Humerus internal rotation.
Innervation: Upper and Lower subscapular nerves (C5-C6).
Note: Apart from the supraspinatus, the remaining rotator cuff muscles help keep the humeral head in position (depressed). This downward force counteracts the deltoid muscle's upward pull during glenohumeral abduction.
Fascial Connections
To fully grasp the remarkable level of interconnectedness among the rotator cuff muscles, examining their fascial relationships is crucial. For instance:
Continuous fascial planes (both superficial and deep) link numerous structures.
These fasciae serve crucial roles in force transmission and neurological communication.
Consider these fascial connections as a 3D web, connecting multiple structures, often extending into areas that may not seem anatomically interrelated.
Image: Stecco, Carla;. Functional Atlas of the Human Fascial System Note: We highly recommend practitioners purchase the "Functional Atlas of the Human Fascial System."
For instance, some deep shoulder fascia originates from the connective tissue of two rotator cuff muscles (supraspinatus and infraspinatus).
This rotator cuff fascia directly connects to the neck (cervical spine) through two other muscles: the levator scapulae and omohyoid muscles.
Often, patients experience neck pain, but practitioners may not realize the pain is due to restrictions in the fascial connections within the rotator cuff muscles (or vice versa). The deep shoulder fascia also connects to the patient's chest (clavipectoral fascia) and even extends down their arm (short head of the biceps muscle and coracobrachialis muscle).
When patients experience arm pain, practitioners should consider that the cause may be due to restrictions in the shoulder structures. Furthermore, the deep shoulder fascia connects to the fascia covering the ribs (serratus anterior), which could affect respiratory function.
Rotator Cuff Injuries
Rotator cuff injuries frequently result from micro-trauma, degenerative changes, traumatic injuries (such as falls with outstretched hands, dislocations, etc.), and some secondary dysfunctions. (7,8,9)
Common types of rotator cuff injuries include tears, tendinitis, tendinopathy, and impingement syndrome. Increased instances of rotator cuff tears are found among smokers, individuals with Type 1 Diabetes, those with joint capsule inflammation, frozen shoulder, rheumatoid arthritis, thyroid conditions, and patients with poor vascularization.
Symptoms of a Rotator Cuff Injury
Patients experiencing a rotator cuff injury often present with the following symptoms (7,8):
Pain during overhead activities or when the arm is in a forward flexed position.
Severe pain at the time of injury and at night.
Positive Painful Arc Sign - The Painful Arc Test is used to identify possible subacromial impingement (Note that this test is not definitive, as many orthopedic tests are not, but they lead you in a direction).
Weakness in the specific torn muscle.
Pain related to a specific location, such as supraspinatus pain.
Patients may also complain of clicking, catching, stiffness, and crepitus.
Note: It's important to characterize the pain experienced by the patient in terms of:
Location (as specific as possible)
Radiation
Quality
Severity and quantity (including any functional limitations)
Precipitating factors
Relieving factors
Physical Examination
A thorough examination of the shoulder must include comprehensive orthopedic and neurological assessments. Diagnostic imaging is essential in traumatic cases, in cases unresponsive to manual therapy within 3 to 6 weeks, and for the aging population.
During the diagnosis of a shoulder injury:
A comprehensive history is critical for accurately diagnosing any shoulder injury.
Ensure you are dealing with a musculoskeletal injury and not a visceral disorder, or a serious or potentially life-threatening condition.
Orthopedic Evaluation
Orthopedic tests are essential in diagnosing a shoulder injury and can help exclude other differential diagnoses.
This video demonstrates how to identify common causes of shoulder pain using orthopedic examination procedures. T
Upper Limb Neuro Exam
The upper limb neurological examination is part of the over all neurological examination process, and is used to assess the motor and sensory neurons which supply the upper limbs. This assessment helps to detect any impairment of the nervous system.
Peripheral Vascular Examination - Key Points
A peripheral vascular examination is a valuable tool used for ruling out signs of vascular-related pathology. The detection and subsequent treatment of PVD can potentially mitigate cardiovascular and cerebrovascular complications. In this video we go over some of the common procedures we perform in daily clinical practice.
Imaging
When patient history and physical examination suggest the need for further investigation, advanced diagnostic imaging is essential. These techniques are crucial for detecting fractures, infections, degenerative joint conditions, osteoporosis, and underlying pathologies in chronic conditions unresponsive to conservative treatment.
MRI is the gold standard for shoulder imaging, providing detailed views of soft tissues and enabling accurate assessment of structures like the rotator cuff, muscles, labrum, and capsule. It can detect tears, tendinopathies, and inflammation.
Other imaging modalities may be used in certain cases:
X-rays: Useful for evaluating bone alignment, detecting fractures, and assessing arthritis.
CT scans: Provide detailed images of bones, useful for complex fractures and joint integrity.
Ultrasound: A non-invasive, real-time technique for assessing tendons, muscles, and other soft tissues during movement.
Integrating clinical findings with imaging results is crucial for accurate diagnosis and effective treatment planning.
Differential Diagnosis
Shoulder injuries must be differentiated from other conditions, some of the differentials are (7,8,9):
Acromioclavicular injury: Damage to the acromioclavicular (AC) joint, often due to direct impact or falls on the shoulder. Common symptoms include pain, swelling, and limited range of motion.
Adhesive Capsulitis: Also known as frozen shoulder, it is characterized by stiffness, pain, and limited range of motion in the shoulder. It occurs when the capsule surrounding the shoulder joint thickens and tightens.
Biceps Tendonitis/tendinopathy: Inflammation or degeneration of the biceps tendon, causing pain and weakness in the shoulder and upper arm.
Bursitis: Inflammation of the bursa, a fluid-filled sac that reduces friction between tissues, causing pain, swelling, and limited movement.
Calcific Tendonitis of the Shoulder: Calcium deposits form in the rotator cuff tendons, causing inflammation, pain, and limited range of motion.
Cervical nerve root injury, Cervical Radiculopathy, Cervical Spondylosis: Conditions related to the cervical spine, often causing pain, numbness, or weakness that radiates from the neck down the arm.
Glenohumeral ligament tears: Damage to the ligaments that stabilize the shoulder joint, causing pain, instability, and potential dislocation.
Glenoid labrum tear: Damage to the fibrocartilaginous rim around the shoulder socket, with SLAP and Bankart lesions being specific types of labral tears. Symptoms include pain, instability, and clicking or catching sensations.
Myocardial Infarction: A heart attack, which can cause referred pain to the shoulder and arm, along with chest pain, shortness of breath, and other symptoms.
Nerve entrapment: Compression of nerves near the shoulder, causing pain, numbness, or tingling that may radiate down the arm.
Osteoarthritis: Degeneration of the joint cartilage, leading to pain, stiffness, and reduced range of motion in the shoulder.
Shoulder dislocation: The humeral head slips out of the shoulder socket, usually due to trauma, causing severe pain, swelling, and an inability to move the joint.
Subacromial Impingement: Compression of the rotator cuff tendons and/or bursa between the humerus and acromion process, causing pain, inflammation, and limited range of motion.
TOS (Thoracic Outlet Syndrome): Compression of nerves and blood vessels between the collarbone and first rib, causing pain, numbness, and weakness in the shoulder, arm, and hand.
CONCLUSION - PART 3
In conclusion, understanding the vital role of the rotator cuff muscles is essential for diagnosing and treating shoulder-related issues. Injuries or limitations in these muscles can significantly impact shoulder function, necessitating a thorough examination and appropriate diagnostic procedures. By integrating clinical findings with advanced imaging techniques, healthcare professionals can develop accurate diagnoses and effective treatment plans, ensuring optimal outcomes for patients suffering from shoulder conditions.
In the concluding blog of this 4-part series, we will present a coherent framework for creating a comprehensive therapy and exercise program aimed at effectively addressing shoulder injuries.
References - Part 3
Leffert RD, and G Gumley. (1987). The relationship between dead arm syndrome and thoracic outlet syndrome. Clin Orthop, 223, pp. 20-31.
Gerber C, and Ganz R. (1984). Clinical assessment of instability of the shoulder. J Bone Joint Surg Br, 66, pp. 551-556
Davies GJ, Gould JA, and Larson RL. (1981). Functional examination of the shoulder girdle. Phys Sports Med, 26(2), pp. 325-337. 9, pp. 82- 104.
Abelson, B., Abelson, K., & Mylonas, E. (2018, February). A Practitioner's Guide to Motion Specific Release, Functional, Successful, Easy to Implement Techniques for Musculoskeletal Injuries (1st edition). Rowan Tree Books.
Boody SG, Freedman L, and Waterland JC. (1970). Shoulder movements during abduction in the scapular plane. Arcg Phy Med Rehabil, 12, pp. 1-30. 51(10), pp. 595-604.
Kuhn JE, Plancher KD, and Hawkins RJ. (1995). Scapular winging. J m Acad Orthop Surg, 3(6), pp 319-325
Neumann, D.A. (2017). Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd Edition. St. Louis, MO: Mosby Elsevier.
Magee, D.J. (2014). Orthopedic Physical Assessment. 6th Edition. St. Louis, MO: Saunders Elsevier.
Lewis, J.S. (2016). Rotator Cuff Tendinopathy: Navigating the Diagnosis-Management Conundrum. Journal of Orthopaedic & Sports Physical Therapy, 46(11), 923-937.
Cheatham, S.W., Kolber, M.J., & Cain, M. (2015). The Rotator Cuff: Anatomical and Pathological Considerations. Strength and Conditioning Journal, 37(2), 5-11.
Kibler, W.B., Sciascia, A., & Wilkes, T. (2012). Scapular Dyskinesis and its Relation to Shoulder Injury. Journal of the American Academy of Orthopaedic Surgeons, 20(6), 364-372.
Stecco, C. (2014). Functional Atlas of the Human Fascial System. Churchill Livingstone Elsevier.
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DR. BRIAN ABELSON, DC. - The Author
With over 30 years of clinical practice and experience in treating over 25,000 patients with a success rate of over 85%, Dr. Abelson created the powerful and effective Motion Specific Release (MSR) Treatment Systems.
As an internationally best-selling author, he aims to educate and share techniques to benefit the broader healthcare community.
A perpetual student himself, Dr. Abelson continually integrates leading-edge techniques into the MSR programs, with a strong emphasis on multidisciplinary care. His work constantly emphasizes patient-centred care and advancing treatment methods. His practice, Kinetic Health, is located in Calgary, Alberta, Canada.
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