although typically thought to occur in older individuals , a hooked acromion causing shoulder impingement symptoms in younger populations is less recognized . this report illustrates a case of type iii acromial impingement in a younger athlete and the importance of early imaging in refining diagnosis . a 31-year - old right - hand dominant cross - fit personal trainer presented to an outpatient clinic complaining of left shoulder pain worsening over a 2-year period . the pain had become intermittently worse over the last 6 weeks , and was particularly flared the day following handstand push - ups and kipping . pain was reportedly worsened by shoulder abduction beyond 90 , bicep hammer curls and eccentric bench press . the patient perceived the left shoulder to be more elevated than the right at rest , and he had begun to note joint crepitus on circumduction . the pain was focal to the anterior aspect of the deltoid and upper biceps region with an occasional pulling sensation in the distolateral biceps . the patient was perplexed as to why the left shoulder was painful when he was right - handed . he described a 38/10 baseline daily pain , increasing to 10/10 with bicep curls and eccentric bench press . he pain with activities of daily living such as removing his shirt , lifting his 2-year - old child , and he was unable to sleep on his left side . despite the pain he took no medications , had no reported drug allergies or prior reactions to anesthesia . he was a non - smoker , and had been engaged in professional power lifting since 2008 . cervical spine ranges of motion were pain free and the spurling 's test with extension was negative . a painful arc was present upon left shoulder abduction with hitching a reported pain at 90. there was , however , no palpable or audible crepitus on left shoulder circumduction . however , there was a focal area of tenderness upon palpation 3 cm proximal to the left lateral epicondyle . mill 's & cozen 's tests were negative , and resisted muscle testing of the common extensor origin and extensor carpi radialis brevis was unremarkable . the left proximal biceps tendon and medial aspect of the left acromial - clavicular joint ( acj ) was focally tender on palpation . the initial diagnostic impression was of chronic left shoulder impingement ( query subacromial bursal effusion , early rotator cuff ( rc ) tear , down - sloped acromion ) , and mild acj osteoarthritis . although the physical examination was generally unremarkable , the history was indicative of some mild left extensor origin biceps tendonopathy . the patient was referred for a non - contrast magnetic resonance imaging ( mri ) of the left shoulder . the study reported high signal intensity within the belly of the supraspinatus muscle belly and tendon associated with a type iii downward - sloping acromion , which was interpreted to be causing  a degree of impingement . there was also a small amount of fluid in the subacromial space raising the possibility of associated subacromial bursitis ( fig . the report of imaging findings and prognostic discussion convinced the patient of the importance to alter the intensity of his upper body training activities . by simply avoiding repetitive overhead activities and modifying the intensity of his upper body exercise program , impingement symptoms abated considerably over a period of several weeks . as the patient was responding to conservative management and there was no evidence of rc tear on imaging , surgical referral was postponed . there are several functional and potentially reversible causes of shoulder impingement syndrome . however , identifying the presence of bony impingement of the subacromial space may aid in a better understanding of predispositions to rc pathology . the original bigliani acromial morphology classification of type 1-flat , type ii - curved and type iii - hooked has more recently in updated by vanarthos and monu , to include a type iv - convex morphology ( fig . some studies have identified a significant association between type iii acromial morphology and full thickness rc tears . although type iii acromion ( t3a ) may be rare in asymptomatic young athletes , the incidence of in a general population of both young and older individuals is still not completely understood . typically , older patients are noted to have a high incidence of t2a and t3a ( 93% of those over 70 ) and both of full and partial - thickness rc tears were more commonly with these morphologies than type i . neer concluded that 95% of rc tears are caused by mechanical impingement , associating rc tears with extremely hooked ( > 43 ) anterior acromial slope . other studies have looked at the lateral extension and angulation of the acromial slope also being important in diagnosing and managing impingement pathologies . although thought to be associated with older populations , t2 down - sloped and t3 hooked acromial impingement may occur in younger populations such as overhead athletes . impingement may be manifested by pain with overhead activities , shoulder weakness and decreased range of motion . early shoulder x - rays including the outlet  y view to define acromial morphology , or mri imaging may help to refine diagnosis , prevent inappropriate therapies , understand prognosis and expedite more effective management strategies . appropriate surgical referrals are patients with subacromial impingement syndrome refractory to 36 months of appropriate conservative treatment .