Continuing Education Activity

Shoulder impingement syndrome is the most common cause of shoulder pain in the outpatient setting, accounting for approximately 44% to 65% of all shoulder-related complaints. The condition is characterized by pain resulting from functional or structural narrowing of the subacromial space, which compresses the rotator cuff tendons and surrounding tissues. Shoulder impingement is commonly seen in individuals who perform repetitive overhead activities, particularly athletes and manual laborers whose work or sport places sustained mechanical demands on the shoulder. Diagnosis is primarily clinical and relies on a detailed patient history and a focused physical examination rather than advanced imaging alone. Early recognition is critical for preventing progressive tendon degeneration and chronic dysfunction. Management emphasizes targeted physical therapy to strengthen the shoulder girdle and optimize biomechanics, supplemented by pharmacologic strategies to reduce inflammation and pain.

Through this course, the participant develops a comprehensive understanding of the etiology, evaluation, and evidence-based management of shoulder impingement syndrome, with an emphasis on sound clinical reasoning, effective examination techniques, and the design of individualized rehabilitation programs. The course highlights the value of interprofessional collaboration, demonstrating how integration of the complementary expertise of physical therapists, primary care and specialty clinicians, nurses, and other healthcare professionals enhances patient outcomes. Coordinated, team-based care facilitates accurate diagnosis, timely intervention, consistent patient education, and improved adherence to treatment plans. This collaborative approach supports efficient symptom resolution, reduces the risk of chronic impairment, and promotes high-quality, patient-centered care across diverse clinical settings.

Objectives:

• Compare clinical examination maneuvers and conservative treatment options to determine relative diagnostic and therapeutic value.
• Identify the typical clinical presentation of shoulder impingement syndrome and differentiate it from other causes of shoulder pain. 
• Assess the nonoperative as well as the operative management options available for shoulder impingement syndrome. 
• Select appropriate conservative or referral-based management strategies in collaboration with physical therapists and other interprofessional healthcare team members to optimize patient outcomes.

Access free multiple choice questions on this topic.

Introduction

Shoulder pain is a common reason for visits to primary care and orthopedic clinics worldwide. The estimated prevalence of shoulder complaints ranges from 7% to 34%, with shoulder impingement syndrome historically considered the most frequent underlying etiology.[1] Subacromial impingement has been reported to account for approximately 44% to 65% of all shoulder complaints.[2] In the United Kingdom, 20% to 50% of people presenting to general clinicians with shoulder pain ultimately seek treatment, and roughly one-quarter of these individuals are diagnosed with shoulder impingement syndrome.[3] In a cohort, 54% of patients with shoulder pain reported persistent symptoms at 3 years.[3] Contemporary literature has shifted away from viewing impingement as a single pathoanatomic diagnosis toward understanding it as a clinical syndrome or cluster of symptoms often overlapping with rotator cuff–related shoulder pain.[2][3] 

Etiology

Shoulder impingement can be categorized by location (external or internal) and by underlying mechanism (primary or secondary).[4][5][6] 

External (Subacromial) vs Internal Impingement

External impingement refers to mechanical aggravation of the rotator cuff and subacromial bursa between the humeral head and the coracoacromial arch. Clinically, this impingement is the entity most often referred to as shoulder impingement syndrome and is characterized by pain during forward elevation and abduction, and is frequently associated with subacromial bursitis and rotator cuff tendinopathy.[7][8] 

Internal impingement occurs when the articular-sided fibers of the supraspinatus and infraspinatus tendons contact the posterosuperior glenoid rim and labrum, typically in the abducted and externally rotated position. Internal impingement is most commonly seen in overhead throwers and manual laborers; it is associated with articular-sided rotator cuff pathology, glenohumeral internal rotation deficit, and superior labrum anterior-posterior lesions.[9][10][11]

Primary vs Secondary Impingement

Primary impingement refers to structural narrowing of the subacromial space that is present at rest and contributes to mechanical compression of the rotator cuff. Common causes include variations in acromial morphology, such as a Bigliani type II (curved) or type III (hooked) acromion, as well as the presence of subacromial osteophytes or acromioclavicular joint spurs. Posttraumatic deformity or malunion can further alter bony anatomy and reduce the available subacromial space. In addition, soft-tissue thickening resulting from chronic subacromial bursitis or calcific tendinopathy may contribute to persistent narrowing and impingement symptoms.[4][5][6] Secondary impingement occurs despite normal static anatomy and results from dynamic factors that allow superior migration of the humeral head during motion, such as rotator cuff weakness or fatigue resulting in loss of centralizing force, scapular dyskinesis from weakness or incoordination of the trapezius and serratus anterior, limiting upward rotation and posterior tilt of the scapula, and glenohumeral instability (micro- or macro-instability) leading to altered kinematics.[7]

Epidemiology

Shoulder impingement syndrome is particularly prevalent among individuals whose occupations or sports require repetitive overhead activities or sustained arm elevation. High-risk populations include overhead athletes (eg, swimmers, volleyball and handball players), manual laborers (eg, carpenters, painters, construction workers), and hairdressers. The incidence of shoulder impingement increases with age, peaking in the 6th decade of life, reflecting cumulative tendon degeneration and age-related changes in the acromion and acromioclavicular joint.[5] 

Extrinsic risk factors associated with subacromial impingement include repetitive or sustained overhead activities, heavy manual labor, and frequent lifting, all of which increase mechanical load on the shoulder. Lifestyle and systemic factors such as poor sleep quantity, insomnia, and smoking have also been associated with an increased risk of symptoms. In addition, certain medications, including fluoroquinolone antibiotics, have been linked to tendon pathology and may contribute to the development or exacerbation of subacromial impingement.[2][12] 

Pathophysiology

The subacromial space is bounded superiorly by the acromion and acromioclavicular joint, anteriorly by the acromion and coracoacromial ligament, and inferiorly by the humeral head. Within this space lie the supraspinatus tendon, portions of the infraspinatus and subscapularis tendons, the long head of the biceps tendon, and the subacromial–subdeltoid bursa. During normal shoulder elevation, coordinated scapulothoracic and glenohumeral motion maintains a stable relationship of the humeral head beneath the coracoacromial arch. The subacromial space, typically 1 to 1.5 cm in height, narrows physiologically with abduction and forward flexion. Superior migration of the humeral head or inadequate scapular upward rotation and posterior tilt further reduce this space.[2] Biomechanical studies underscore the importance of rotator cuff and scapular stabilizer strength in maintaining humeral head position and minimizing pathologic impingement.[7] 

Repetitive compression of the rotator cuff tendons and subacromial bursa between the humeral head and the acromion leads to a cascade of pathological changes. These include subacromial bursitis and rotator cuff tendinopathy, characterized by degenerative changes such as collagen disorganization and neovascularization. In susceptible individuals, continued mechanical stress may result in progression to partial- or full-thickness rotator cuff tears.

Histopathology

Neer described 3 stages of subacromial impingement: stage I, characterized by edema and hemorrhage and often reversible; stage II, marked by fibrosis and tendinosis; and stage III, involving full-thickness rotator cuff tears or bony changes.[13][14] While this staging system remains historically significant, current clinical practice more commonly uses the term “rotator cuff–related shoulder pain” to reflect the multifactorial contributors to symptoms, including both structural and functional factors.[5]

History and Physical

History 

A detailed patient history is essential for evaluating shoulder impingement syndrome and should include assessment of occupational and recreational overhead activity, training errors, and prior injuries.[15][16] Typical pain is dull and aching, localized to the anterolateral shoulder over the lateral acromion, and may radiate to the lateral mid-humerus. Symptoms are often exacerbated by overhead activities, reaching, lifting, or lying on the affected side, and night pain is common, particularly when rolling onto the involved shoulder. Onset is usually gradual or insidious over weeks to months, without a clear traumatic event. Functional limitations often include difficulty with grooming, dressing, or performing overhead tasks, and patients may report pain-limited weakness or stiffness, with loss of motion as a primary concern.[15][16] 

Physical Examination

The physical examination should include inspection, palpation, assessment of active and passive range of motion (ROM), strength testing, and evaluation of scapular and cervical spine mobility.[4][5] Cervical spine ROM and neurologic assessment help rule out referred pain from radiculopathy or thoracic outlet syndrome. Inspection may reveal postural abnormalities, such as forward head posture and rounded shoulders, as well as scapular dyskinesis, including abnormal upward rotation, winging, or early shrugging during arm elevation. Palpation can identify tenderness over the greater tuberosity, anterolateral acromion, acromioclavicular joint, or bicipital groove if associated pathology is present. Passive ROM is often near full, whereas active ROM may be limited by pain, and a painful arc between approximately 70° and 120° of abduction is characteristic of subacromial pathology.[5] Strength testing frequently reveals weakness in abduction and external rotation (supraspinatus and infraspinatus) due to pain or underlying rotator cuff pathology; assessment should also include evaluation of subscapularis and biceps function.

Provocative Tests for Impingement 

Interpretation of individual tests should be cautious, as sensitivity and specificity vary. Clusters of tests improve diagnostic accuracy.[4][17] 

• Neer sign: With the scapula stabilized, the examiner passively forward flexes the arm in internal rotation. Anterior shoulder pain suggests subacromial impingement; posterior pain may indicate internal impingement. A negative Neer test indicates high specificity for excluding impingement.[18] 
• Hawkins-Kennedy test: With the shoulder in 90° of forward flexion and the elbow flexed to 90°, the examiner passively internally rotates the humerus. Pain over the lateral acromion suggests subacromial impingement.[4]
• Jobe (empty can) test: With the arms in 90° of abduction in the scapular plane and internally rotated (thumbs down), the patient resists downward pressure. Pain and/or weakness suggest supraspinatus pathology.[4]
• Painful arc test: Pain is reproduced between approximately 70° and 120° of active shoulder abduction, with relative relief beyond 120°, which is supportive of subacromial pathology.[5] While tests for instability, including the sulcus sign and anterior apprehension with relocation, are typically negative in cases of isolated impingement, they should be performed when shoulder instability is suspected to help differentiate underlying causes of pain.[19]

Evaluation

The diagnosis of shoulder impingement is primarily clinical, with physical examination demonstrating up to 90% sensitivity in some series.[5] Imaging is used to exclude alternative diagnoses, assess structural changes, and identify coexisting rotator cuff tears.

Plain Radiographs

Plain radiographs are a key component of the initial imaging evaluation for shoulder impingement syndrome and provide valuable information about bony anatomy and contributing structural factors. Standard shoulder radiographic assessment typically includes an anteroposterior, lateral (scapular Y), and often an outlet view.[5] The outlet view is beneficial for evaluating acromial morphology according to the Bigliani classification and for identifying subacromial spurs that may contribute to mechanical impingement.[5] The anteroposterior view allows measurement of the critical shoulder angle (CSA), which reflects the relationship between lateral acromial coverage and glenoid inclination. Larger CSAs, particularly those greater than 35°, have been associated with rotator cuff pathology and may increase the risk of impingement.[5]

Another essential measurement obtained from radiographs is the acromiohumeral distance, defined as the space between the inferior surface of the acromion and the proximal humeral head. Normal values are approximately 7 to 14 mm in men and 7 to 12 mm in women; decreased acromiohumeral distance suggests rotator cuff thinning or tearing, with subacromial space narrowing.[5] In addition to these measurements, plain radiographs assist in identifying associated conditions such as acromioclavicular joint arthritis, calcific tendinitis, osseous deformities, and glenohumeral osteoarthritis, all of which may influence clinical management.

Magnetic Resonance Imaging

Magnetic resonance imaging provides comprehensive visualization of bony and soft-tissue structures, and is often reserved for cases that do not improve after 6 weeks or more of appropriate therapy, or when a significant rotator cuff tear or other pathology is suspected.[5][20][21] Magnetic resonance imaging can confirm subacromial bursitis and rotator cuff tendinopathy or tearing, evaluate labral pathology and internal impingement in overhead athletes, and assess acromioclavicular and glenohumoral joint degeneration.

Ultrasound

Ultrasound is widely used in the evaluation of shoulder impingement syndrome and offers several important advantages, including cost-effectiveness and the absence of ionizing radiation; however, image quality and diagnostic accuracy are operator-dependent.[5][21] This imaging allows dynamic, real-time assessment of the rotator cuff tendons, subacromial bursa, and long head of the biceps tendon, which is particularly useful for identifying functional impingement during shoulder movement. Ultrasound is effective for detecting subacromial bursitis and bursal or tendon thickening, and it can reliably identify both partial- and full-thickness rotator cuff tears.[5][21] In addition to its diagnostic role, ultrasound is commonly used to guide subacromial injections, improving accuracy and therapeutic outcomes.[21]

Other Studies

Other diagnostic studies are used selectively in the evaluation of shoulder impingement syndrome. Computed tomography is rarely required and is reserved primarily for cases requiring detailed assessment of bony anatomy, such as complex fractures or significant osseous deformity. Electrodiagnostic studies may be indicated when symptoms or examination findings raise concern for cervical radiculopathy or peripheral nerve entrapment, helping to differentiate neurologic pathology from primary shoulder-related causes of pain.

Treatment / Management

The cornerstone of management for shoulder impingement syndrome is nonoperative care, centered around structured rehabilitation and activity modification. Evidence indicates that for most patients, surgery, including arthroscopic subacromial decompression (ASD), does not provide superior long-term outcomes compared to conservative therapy.[22][23] 

Nonoperative Management

Nonoperative management is recommended as the initial approach for patients with shoulder impingement syndrome who do not have a large or acute traumatic rotator cuff tear, with a typical trial period of 3 to 6 months.[2][5] This approach emphasizes symptom control, functional restoration, and prevention of further tissue irritation. Activity modification and patient education are key components of conservative care. Patients are advised to avoid aggravating activities, particularly repetitive overhead motions and heavy lifting, while ergonomic modifications are encouraged in both occupational and athletic settings to reduce mechanical stress on the shoulder. Pharmacologic therapy is commonly used as an adjunct to rehabilitation. Nonsteroidal anti-inflammatory drugs (NSAIDs), administered orally or topically, are frequently prescribed to reduce pain and inflammation, while acetaminophen may be added or substituted when appropriate. Opioids are not recommended for the management of chronic shoulder pain due to limited benefit and potential risk.

Physical therapy

Physical therapy is the cornerstone of treatment for shoulder impingement syndrome and should be tailored to each patient’s presentation, symptom severity, and functional goals. Structured exercise programs consistently outperform placebo or minimal interventions in patients with subacute and chronic subacromial pain. Evidence suggests that combining manual therapy with therapeutic exercise provides greater benefit than exercise alone, supporting a multimodal rehabilitation approach.[24] 

During the early phase of rehabilitation, treatment focuses on pain control and the restoration of a comfortable passive and active range of motion. Stretching of the posterior capsule and pectoralis minor is emphasized to address limitations in internal rotation and horizontal adduction that can contribute to altered shoulder mechanics. As symptoms allow, strengthening and neuromuscular control exercises are introduced, with particular emphasis on the rotator cuff, especially the supraspinatus and infraspinatus, to improve dynamic humeral head stabilization.

Scapular stabilizer training targeting the lower and middle trapezius and serratus anterior is incorporated to correct scapular dyskinesis and enhance upward rotation and posterior tilt during arm elevation. Closed-chain and proprioceptive exercises further support motor control and functional stability. Manual therapy techniques, including joint mobilization and soft-tissue interventions, are commonly used as adjuncts to exercise. Modified posterior shoulder stretching programs have demonstrated improvements in mobility, pain, and function.[25][26] In contrast, the evidence supporting routine use of passive modalities such as hyperthermia, ultrasound, transcutaneous electrical nerve stimulation, and laser therapy is mixed and generally weaker than that for structured physical therapy interventions.[14]

Injection therapy

Injection therapy is considered for patients whose pain significantly limits participation in rehabilitation and should always be integrated into a broader treatment plan rather than used as a stand-alone intervention.

• Corticosteroid injections

  • Local corticosteroid combined with a local anesthetic is commonly injected into the subacromial space, typically via a posterior approach.[2][5] Landmark-based posterior injections are technically straightforward, though ultrasound guidance may improve accuracy.[27] Corticosteroid injections can provide short-term pain relief and facilitate engagement in physical therapy; however, repeated injections carry an increased risk of tendon rupture.[2][14] 
• NSAID injections

  • Subacromial NSAID injections may offer short-term pain relief comparable to corticosteroids, providing a potential steroid-sparing option for patients.[28]

Surgical Management

The role of surgery in subacromial impingement has evolved significantly. Multiple randomized controlled trials and meta-analyses indicate that ASD provides no clinically significant benefit over placebo (diagnostic arthroscopy) or structured exercise programs.[22][23]

Arthroscopic subacromial decompression

ASD typically involves bursectomy, anterior acromioplasty of the anterolateral acromion, and, in some techniques, resection of the coracoacromial ligament. Systematic reviews, including the FIMPACT study, demonstrate no long-term advantage of ASD over diagnostic arthroscopy or supervised exercise with respect to pain, function, or return to work or sport.[22]

Other Procedures

Isolated acromioplasty or bursectomy without decompression has not shown clear superiority over nonoperative care.[23] Reconstructive procedures, such as rotator cuff or labral repair, may be indicated when imaging confirms significant structural pathology, including reparable full-thickness rotator cuff tears, in conjunction with impingement symptoms.

Indications for Surgery

Surgical consultation may be appropriate for patients with persistent, function-limiting symptoms after 3 to 6 months of structured nonoperative management or for those with significant structural pathology, particularly younger or high-demand patients.

Postoperative Rehabilitation

Rehabilitation following surgery follows principles similar to nonoperative care, focusing on restoring range of motion, strengthening the rotator cuff and scapular musculature, and gradually resuming functional activities.[5]

Differential Diagnosis

The differential diagnosis for shoulder impingement syndrome is broad and includes:

• Rotator cuff pathology

  • Partial or full-thickness rotator cuff tear
  • Rotator cuff tendinopathy or calcific tendinitis
• Adhesive capsulitis (frozen shoulder) 
• Acromioclavicular joint pathology

  • Acromioclavicular joint arthritis
  • Acromioclavicular sprain or distal clavicle osteolysis
• Biceps tendon disorders

  • Bicipital tendinitis
  • Long head biceps tear or instability
• Glenohumeral joint pathology

  • Glenohumeral osteoarthritis
  • Labral tears, SLAP lesions
  • Glenohumeral instability
• Cervical and neurovascular conditions

  • Cervical radiculopathy
  • Thoracic outlet syndrome
• Other

  • Trapezius or periscapular muscle spasm
  • Referred pain from visceral or thoracic pathology (less common) [3][4][5] 

Prognosis

The prognosis for shoulder impingement syndrome is generally favorable with appropriate conservative treatment, though recovery can be protracted. Given the limited added benefit of decompression surgery over nonoperative care in most patients, long-term outcomes depend heavily on adherence to exercise therapy, addressing biomechanical factors, and activity modification rather than on surgical intervention.[1] Approximately 60% of patients report satisfactory outcomes with physical therapy, NSAIDs, injections, and activity modification within 2 years.[2][5] Many patients experience symptom improvement within several months of structured rehabilitation. Still, some individuals experience persistent or recurrent symptoms, particularly when occupational or sport-related demands remain high, and risk factors are not mitigated.[3] Factors associated with poorer outcomes include chronic symptoms, high physical work demands, older age, and coexisting rotator cuff tears or degenerative joint disease.[2][5] 

Complications

Complications associated with shoulder impingement syndrome arise from both the underlying pathology and its treatment.[2][5][14] 

Disease-Related Complications

• Progression of rotator cuff tendinopathy to partial- or full-thickness tear
• Bicipital tendinopathy or rupture
• Chronic subacromial bursitis
• Secondary adhesive capsulitis due to prolonged disuse and pain-related guarding
• Persistent pain, weakness, and functional limitation

Treatment-Related Complications

• Injections

  • Local skin atrophy or depigmentation
  • Transient pain flare
  • Rare infection or tendon rupture with repeated corticosteroid injections

• Surgery (ASD or related procedures)

  • Infection, bleeding, or wound complications
  • Postoperative stiffness or adhesive capsulitis
  • Persistent pain or failure to improve (especially if underlying pathology is not addressed)
  • Deltoid detachment or weakness (rare with modern arthroscopic techniques) 

Deterrence and Patient Education

Education and prevention efforts for shoulder impingement syndrome focus on addressing modifiable risk factors and supporting adherence to rehabilitation strategies.[5][16] Lifestyle modifications, including smoking cessation, maintaining a healthy body weight, and optimizing sleep, contribute to overall musculoskeletal health and may enhance recovery.[2] Effective education empowers patients to actively participate in their rehabilitation, reduce the risk of recurrence, and safely return to functional activities.

Key Strategies

• Activity and load management: Temporarily avoid or reduce overhead activities and heavy lifting during symptomatic periods; gradually reintroduce overhead motion as pain improves under guidance from a clinician or therapist.
• Posture and ergonomics: Improve posture by reducing forward head positioning and rounded shoulders; use ergonomically designed workstations and tools, and adjust work height to minimize prolonged overhead tasks.
• Home exercise program: Continue the prescribed rotator cuff and scapular strengthening and stretching exercises even after symptom improvement to reduce the risk of recurrence.
• “Window of movement” strategy: Operate within a comfortable “window” in front of the body (approximately a 2–3 foot rectangle), minimizing overhead or behind-the-back movements until symptoms abate.[5][16] 

Enhancing Healthcare Team Outcomes

Effective management of shoulder impingement syndrome relies on an interprofessional team. Primary care and sports medicine clinicians handle initial evaluation, diagnosis, early conservative management, medication prescription, and referrals for imaging or physical therapy. Physical therapists and athletic trainers guide rehabilitation by designing individualized exercise programs, ensuring proper technique, monitoring progress, and providing feedback on readiness to resume work or sport. Patients who do not respond to conservative care or have structural pathology are evaluated by orthopedic surgeons, who interpret advanced imaging, perform surgical intervention when indicated, and coordinate postoperative rehabilitation with therapists. Nurses and allied health professionals reinforce education, monitor adherence, and communicate changes in symptoms or function to the team.

Ethical practice and professional responsibility are essential. Team members must respect the scope of practice, maintain confidentiality, obtain informed consent, and base care decisions on evidence while centering the patient. Clear interprofessional communication through structured handoffs, timely documentation, and collaborative discussion supports shared decision-making, reduces errors, and enhances patient safety. By coordinating care, maintaining consistent communication, and emphasizing exercise-based therapy with selective surgical intervention, the interprofessional team improves outcomes, reduces unnecessary interventions, and delivers high-quality, patient-centered care.

Review Questions

• Access free multiple choice questions on this topic.
• Click here for a simplified version.
• Comment on this article.

References

1.

Nazari G, MacDermid JC, Bryant D, Athwal GS. The effectiveness of surgical vs conservative interventions on pain and function in patients with shoulder impingement syndrome. A systematic review and meta-analysis. PLoS One. 2019;14(5):e0216961. [PMC free article: PMC6541263] [PubMed: 31141546]

2.

Consigliere P, Haddo O, Levy O, Sforza G. Subacromial impingement syndrome: management challenges. Orthop Res Rev. 2018;10:83-91. [PMC free article: PMC6376459] [PubMed: 30774463]

3.

Lewis JS. Rotator cuff tendinopathy/subacromial impingement syndrome: is it time for a new method of assessment? Br J Sports Med. 2009 Apr;43(4):259-64. [PubMed: 18838403]

4.

Cools AM, Cambier D, Witvrouw EE. Screening the athlete's shoulder for impingement symptoms: a clinical reasoning algorithm for early detection of shoulder pathology. Br J Sports Med. 2008 Aug;42(8):628-35. [PubMed: 18523035]

5.

Garving C, Jakob S, Bauer I, Nadjar R, Brunner UH. Impingement Syndrome of the Shoulder. Dtsch Arztebl Int. 2017 Nov 10;114(45):765-776. [PMC free article: PMC5729225] [PubMed: 29202926]

6.

Ellenbecker TS, Cools A. Rehabilitation of shoulder impingement syndrome and rotator cuff injuries: an evidence-based review. Br J Sports Med. 2010 Apr;44(5):319-27. [PubMed: 20371557]

7.

Ludewig PM, Braman JP. Shoulder impingement: biomechanical considerations in rehabilitation. Man Ther. 2011 Feb;16(1):33-9. [PMC free article: PMC3010321] [PubMed: 20888284]

8.

Varacallo MA, El Bitar Y, Mair SD. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 4, 2023. Rotator Cuff Tendonitis. [PubMed: 30335303]

9.

Davis DD, Nickerson M, Varacallo MA. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Nov 22, 2023. Swimmer's Shoulder. [PubMed: 29262079]

10.

Varacallo MA, Tapscott DC, Mair SD. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 4, 2023. Superior Labrum Anterior Posterior Lesions. [PubMed: 30855868]

11.

Varacallo MA, El Bitar Y, Sina RE, Mair SD. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Mar 5, 2024. Rotator Cuff Syndrome. [PubMed: 30285401]

12.

Lv Z, Cui J, Zhang J, He L. Lifestyle factors and subacromial impingement syndrome of the shoulder: potential associations in finnish participants. BMC Musculoskelet Disord. 2024 Mar 19;25(1):220. [PMC free article: PMC10949643] [PubMed: 38504237]

13.

Tsai YH, Huang TJ, Hsu WH, Huang KC, Li YY, Peng KT, Hsu RW. Detection of subacromial bursa thickening by sonography in shoulder impingement syndrome. Chang Gung Med J. 2007 Mar-Apr;30(2):135-41. [PubMed: 17596002]

14.

Dong W, Goost H, Lin XB, Burger C, Paul C, Wang ZL, Zhang TY, Jiang ZC, Welle K, Kabir K. Treatments for shoulder impingement syndrome: a PRISMA systematic review and network meta-analysis. Medicine (Baltimore). 2015 Mar;94(10):e510. [PMC free article: PMC4602475] [PubMed: 25761173]

15.

Dhillon KS. Subacromial Impingement Syndrome of the Shoulder: A Musculoskeletal Disorder or a Medical Myth? Malays Orthop J. 2019 Nov;13(3):1-7. [PMC free article: PMC6915323] [PubMed: 31890103]

16.

Koester MC, George MS, Kuhn JE. Shoulder impingement syndrome. Am J Med. 2005 May;118(5):452-5. [PubMed: 15866244]

17.

Varacallo MA, El Bitar Y, Mair SD. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 4, 2023. Comprehensive Shoulder Evaluation Strategies. [PubMed: 30855893]

18.

Ali Naqvi SMS, Sharif A, Javed L, Gul M, Bilal H, Arsh A. Clinical tests accuracy in diagnosing subacromial impingement syndrome: A systematic review. J Pak Med Assoc. 2023 Apr;73(4):843-847. [PubMed: 37051997]

19.

Lizzio VA, Meta F, Fidai M, Makhni EC. Clinical Evaluation and Physical Exam Findings in Patients with Anterior Shoulder Instability. Curr Rev Musculoskelet Med. 2017 Dec;10(4):434-441. [PMC free article: PMC5685956] [PubMed: 29043566]

20.

Jaggi A, Lambert S. Rehabilitation for shoulder instability. Br J Sports Med. 2010 Apr;44(5):333-40. [PubMed: 20371558]

21.

Kadi R, Milants A, Shahabpour M. Shoulder Anatomy and Normal Variants. J Belg Soc Radiol. 2017 Dec 16;101(Suppl 2):3. [PMC free article: PMC6251069] [PubMed: 30498801]

22.

Paavola M, Kanto K, Ranstam J, Malmivaara A, Inkinen J, Kalske J, Savolainen V, Sinisaari I, Taimela S, Järvinen TL., Finnish Shoulder Impingement Arthroscopy Controlled Trial (FIMPACT) Investigators. Subacromial decompression versus diagnostic arthroscopy for shoulder impingement: a 5-year follow-up of a randomised, placebo surgery controlled clinical trial. Br J Sports Med. 2021 Jan;55(2):99-107. [PMC free article: PMC7788208] [PubMed: 33020137]

23.

Vandvik PO, Lähdeoja T, Ardern C, Buchbinder R, Moro J, Brox JI, Burgers J, Hao Q, Karjalainen T, van den Bekerom M, Noorduyn J, Lytvyn L, Siemieniuk RAC, Albin A, Shunjie SC, Fisch F, Proulx L, Guyatt G, Agoritsas T, Poolman RW. Subacromial decompression surgery for adults with shoulder pain: a clinical practice guideline. BMJ. 2019 Feb 06;364:l294. [PubMed: 30728120]

24.

Gebremariam L, Hay EM, van der Sande R, Rinkel WD, Koes BW, Huisstede BM. Subacromial impingement syndrome--effectiveness of physiotherapy and manual therapy. Br J Sports Med. 2014 Aug;48(16):1202-8. [PubMed: 24217037]

25.

Tahran Ö, Yeşilyaprak SS. Effects of Modified Posterior Shoulder Stretching Exercises on Shoulder Mobility, Pain, and Dysfunction in Patients With Subacromial Impingement Syndrome. Sports Health. 2020 Mar/Apr;12(2):139-148. [PMC free article: PMC7040949] [PubMed: 32017660]

26.

Tauqeer S, Arooj A, Shakeel H. Effects of manual therapy in addition to stretching and strengthening exercises to improve scapular range of motion, functional capacity and pain in patients with shoulder impingement syndrome: a randomized controlled trial. BMC Musculoskelet Disord. 2024 Mar 02;25(1):192. [PMC free article: PMC10908164] [PubMed: 38431547]

27.

Daniels EW, Cole D, Jacobs B, Phillips SF. Existing Evidence on Ultrasound-Guided Injections in Sports Medicine. Orthop J Sports Med. 2018 Feb;6(2):2325967118756576. [PMC free article: PMC5826008] [PubMed: 29511701]

28.

Rhim HC, Ruiz J, Taseh A, Afunugo W, Crockett Z, Schon J, Pan X, Shin J, Schowalter S, Jang KM, Robinson DM. Nonsteroidal Anti-Inflammatory Drug Injections versus Steroid Injections in the Management of Upper and Lower Extremity Orthopedic Conditions: A Systematic Review with Meta-Analysis. J Clin Med. 2024 Feb 17;13(4) [PMC free article: PMC10889729] [PubMed: 38398445]

Disclosure: Julie Creech declares no relevant financial relationships with ineligible companies.

Disclosure: Aundrea Busse declares no relevant financial relationships with ineligible companies.

Disclosure: Daniel Li declares no relevant financial relationships with ineligible companies.

Disclosure: Seth Pinkerman declares no relevant financial relationships with ineligible companies.

Disclosure: Sabrina Silver declares no relevant financial relationships with ineligible companies.