54 in detecting coracoid impingement on MRI is only 5.3% with speciﬁcity of 97.6% [17]. This suggests that subcor- acoid impingement appears to be largely a clinical diagnosis that may be supported or suggested, but not established, by MRI [17]. Patients with subcoracoid impingement also demonstrate increased soft tissue in the subcoracoid space because of redundancy or folding of the subscapularis tendon and capsular tissues when the shoul- der is in this provocative position of maximum internal rotation. A chevron-shaped (^) supraspinatus outlet also appears to be synonymous with a diagnosis of subcoracoid impingement. All the 12 cases of primary coracoid impingement syndrome treated surgically had chevron- shaped outlets similar to the shape used as US army rank insignia [18]. All the coracoid tips in these instances were inferior to the superior glenoid tubercle and the outlets were circumﬂex-shaped compared with normal (this com- pares to a 23% incidence of similar circumﬂex shaped outlets in a series of 150 cadaveric scapulae with a history of subacromial impingement) [19]. A ﬁnal way to make the diagnosis of coracoid impingement is direct arthroscopic observation of the contact [20]. In this case series of patients with a partial rupture of the subscapularis tendon, contact was noted with the subscapularis tendon impinging between the coracoid and lesser tuberosity with the arm in a position simulating that used to elicit the coracoid impingement sign. The fact that the subscapularis tendon was torn in this instance made the observation of the contact more likely. Management The ﬁrst line of treatment for coracoid impingement should be a program of activity modiﬁcation, with avoidance of the provocative positions of forward ﬂexion and medial rotation, and physical therapy to strengthen rotator cuff muscles and scapular stabilizer musculature [8, 10]. Fig- ure 4 shows an algorithm that can be used to approach this scenario. Surgical decompression of the subcoracoid space may be undertaken if the above conservative measures fail. The options include open or arthroscopic coracoplasty, a com- bination of coracoacromial ligament resection and acromioplasty, or anterior shoulder stabilization. Open book coracoplasty [13, 18] is performed with the patient under general anaesthetic and in the beach chair position. The shoulder is examined for laxity and a diag- nostic arthroscopy is performed to rule out other lesions. The coracoid is approached via a 6 cm anterior incision in the delto-pectoral groove. The musculocutaneous nerve is palpated for as well as the tip and base of the coracoid. The Curr Rev Musculoskelet Med (2009) 2:51–55 Fig. 5 Post-operative X-Ray showing the amount of coracoid resected after coracoplasty conjoined tendon is divided for 2 cm and the incision continues into the coracohumeral ligament for 2 cm. A subperiosteal dissection of the soft tissue from the lateral coracoid only is performed. After removal of the lateral portion of the coracoid process, the sharp edges of the bone are rounded and the conjoined tendon is repaired side to side to medially displace the soft tissue. A combination of resection of the coracoacromial liga- ment, acromioplasty, and coracoid resection is suggested by Gerber et al. 1985 [10] because of their belief that isolated coracoid impingement is rare. Some cases of coracoid impingement caused by anterior glenohumeral instability are best treated by anterior shoulder stabilisation [21]. Arthroscopic treatment of coracoid impingement is described in a case series of four patients [22]. An advantage of the arthroscopic approach is the avoidance of conjoined tendon detachment. In addition, this technique is less invasive and requires less surgical dissection. Figure 5 illustrates the post-operative ﬁlm obtained after coracoid resection. Conclusion Coracoid impingement should be included in the differ- ential diagnosis when evaluating a patient with activity-