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Although the rotator cuff interval and the adjacent ligaments are gaining interest because of their importance for glenohumeral instability and adhesive capsulitis, there seems to be some confusion about their anatomy. This study reinvestigates the superior capsular structures in 110 cadaveric shoulders by a combination of arthroscopy, dissection, histology, and functional analysis. The structure of the superior capsule was found to be more complex than suspected until now. The coracohumeral, coracoglenoid, and superior glenohumeral ligaments joined with a circular transverse band to form the anterior limb of a suspension sling. This was 9 to 26 mm wide at its midportion. In 90% of the specimens, there also was a posterior limb composed of a broad fibrous sheet, 6 to 26 mm wide at its midportion. This hitherto unrecognized posterosuperior glenohumeral ligament joined posterolaterally with the circular transverse band. Four types of configuration for the superior complex could be identified. The suspension sling formed by the superior complex functions in the same way as the hammock formed by the inferior glenohumeral ligament complex. The posterior limb seems to restrict internal rotation, like the anterior limb restricts external rotation. The expanded knowledge of the superior capsular complex increases the understanding of the pathology involved in anterosuperior and posterosuperior impingement, as well as articular-sided rotator cuff tears. It also has clinical implications for rotator cuff interval and biceps pulley lesions, because these areas are bordered by the anterior limb of the superior complex, as well as for adhesive capsulitis, where we can now understand why internal rotation is limited and why the release needs to be extended posterosuperiorly.

The shoulder is the most unstable joint in the human body and is therefore susceptible not only to acute dislocations but also to minimal states of subluxation related to overuse. The latter condition is known as microinstability and is translated clinically into internal impingement syndromes. Both in dislocations due to acute traumatism and in microinstability, a series of injuries to the glenoid lip, glenohumeral capsule, the articular cartilage, the head of the humerus, the tendons of the rotator cuff, the long tendon of the biceps, the glenohumeral ligaments, and coracohumeral ligament can occur. Glenoid lip lesions are the most common and may present as isolated lesions or in combination with lesions of any of the other structures. These lesions most often affect the anteroinferior margin of the glenoids (the classic Bankard lesion), with different characteristics and variations on its location, (Bankard variants). Another predominant location of glenoid lip lesions is the superior margin (SLAP lesions). Magnetic resonance imaging (MRI), especially after intra-articular injection of contrast material, has shown great diagnostic accuracy in this type of lesions, although the interpretation of these images requires knowledge not only of the different lesions and combinations of lesions, but also of the normal variants that can easily be confused with these lesions.

This study reviews available information on the anatomy of the long head of the biceps tendon and its function in the shoulder. The tendon appears during the sixth to seventh week of gestation, and developmental anomalies in the form of absence or ectopic position have been described. The tendon has dual origin from the supraglenoid tubercle and glenoid labrum and courses toward the bicipital groove, protected by suspension sling in the rotator interval. The morphology of the bicipital groove has significant variability, affects the biomechanics of the tendon, and certain morphologic characteristics have been implicated in the development of bicipital tendinitis. Stability in the bicipital groove is inferred by the subscapularis tendon as well as the supraspinatus and coracohumeral ligament. The tendon has no avascular areas and contains sensory and sympathetic nerve fibers. Significant controversy exists regarding the exact function of the long head of the biceps tendon. The tendon depresses the humeral head in the glenoid and augments the stability of the glenohumeral joint. This role appears to be more prominent in the setting of a coexisting rotator cuff tear or shoulder instability.

To evaluate the elasticity of the coracohumeral ligament (CHL) in healthy individuals and patients with clinical findings suggestive of unilaterally involved adhesive capsulitis of the shoulder (ACS).The institutional review board approved this single-institution prospective study, which was performed between November 15, 2012, and July 8, 2014. Informed consent was obtained from all subjects. Measurement of CHL thickness was performed in the axial oblique plane under shoulder maximal external rotation. Shear-wave elastography (SWE) was used to evaluate elasticity of the CHL in healthy individuals (11 men, 19 women aged 22-62 years) and those with clinical findings suggestive of ACS (nine men, 11 women aged 41-70 years). SWE was performed in the shoulder-neutral position and under maximal external rotation. The Wilcoxon signed-rank test was performed to compare the thickness and elastic modulus of the CHL between bilateral shoulders.In all subjects, the CHL elastic modulus was larger under maximal external rotation than in the neutral position (P.001 for all). For healthy subjects, there was no significant difference in the CHL elastic modulus between the dominant and nondominant shoulders. For patients presumed to have ACS, the CHL thickness was significantly greater in the symptomatic shoulder than in the unaffected shoulder (P.001). The CHL elastic modulus of the symptomatic shoulder (median, 234.8 kPa; interquartile range [IQR], 174.4-256.7 kPa) was significantly greater than that of the unaffected shoulder (median, 203.3 kPa; IQR, 144.1-242.7 kPa) in the shoulder-neutral position (P = .004) but not under maximal external rotation (P = .123). When bilateral shoulders were maintained at the same angle of external rotation, the CHL elastic modulus was greater in the symptomatic shoulder than in the unaffected shoulder (P = .005).In patients with clinical findings suggestive of ACS, SWE showed that the CHL is stiffer in the symptomatic shoulder than in the unaffected shoulder.

Background The coracohumeral ligament (CHL) is a thick capsular structure and markedly thickened when affected by adhesive capsulitis. Therapeutic stretching is the most commonly applied treatment for adhesive capsulitis, but optimal stretching postures for maximal therapeutic effects on the CHL have not been fully investigated. Objective To investigate the most effective stretching direction for the CHL by measuring the stretching intensity in 5 different directions and to determine whether the stretching intervention resulted in loosening of the ligament by comparing the changes of CHL tightness before and after stretching. Design Biomechanical cadaver study. Setting Academic institution cadaver laboratory. Participants Nine fresh frozen cadaveric shoulders. Methods A high-pressure balloon catheter inserted under the CHL and intraballoon pressure was measured, to evaluate CHL tightness without ligament damage as well as to augment and monitor stretching intensity. To find the optimal stretching direction, the glenohumeral joint was stretched from the neutral position into 5 directions sequentially under pressure-monitoring: flexion, extension [EX], external rotation [ER], EX+ER, and EX+ER+adduction [AD] directions. Main Outcome Measurements CHL tightness was determined by a surrogate parameter, the additional pressure created by the overlying CHL. The pressure increase (Δ P str ) by a specific directional stretch was considered as the stretching intensity. Results Δ P str by the 5 directions were mean (standard deviation) values of 0.03 ± 0.07 atm, 0.87 ± 1.31 atm, 1.13 ± 1.36 atm, 1.49 ± 1.32 atm, and 2.10 ± 1.70 atm, respectively, revealing the highest Δ P str by the EX+ER+AD stretch ( P P = .012) before and after the stretching manipulation. Conclusions EX+ER+AD of the glenohumeral joint resulted in the greatest increase in balloon pressure, implying that it could be the most effective stretching direction. A series of stretching manipulations assisted with an underlying pressure balloon were capable of decreasing CHL tightness. With further development and modification, high-pressure balloon-assisted stretching can be a potential therapeutic option to release tight CHL, including the advantage of augmenting and monitoring stretching intensity. Level of Evidence II

Two novel cadaveric models of a thrower's shoulder were evaluated. Both models included the capsuloligamentous and osseous components of the glenohumeral joint. In model 1 the coracohumeral ligament was retained and the glenoid was positioned parallel to the ground whereas the humerus was positioned at 60 degrees of glenohumeral elevation in the scapular plane. In model 2 the coracohumeral ligament was resected and the glenoid was positioned vertically at 30 degrees of scapular elevation whereas the humerus was positioned at 60 degrees of glenohumeral elevation in the scapular plane. Each specimen was sequentially tested under 3 conditions: intact, after nondestructive anterior capsular stretch, and after simulated posterior capsular contracture. Measurements included rotational range of motion and relative glenohumeral position from neutral to maximum external rotation of the humerus. In model 2 the glenohumeral forces were also measured by use of a 6-degree-of-freedom load cell. The stretching of the anterior capsule in model 1 was performed while the humeral head was constrained in the glenoid and in model 2 while the humeral head was unconstrained. Both models showed increased humeral external rotation and decreased humeral internal rotation similar to that seen in throwing athletes. Both models also showed an increased humeral shift inferiorly after anterior capsular stretching. Model 1 demonstrated a subsequent humeral shift superiorly after posterior capsule plication. Unconstrained specimens of model 2 dislocated posteriorly and inferiorly after posterior capsule plication when the humerus was rotated to maximum external rotation. On the basis of these findings, for future studies, constrained capsular stretching models will be further investigated.

Massive, contracted, immobile rotator cuff tears involving the subscapularis, supraspinatus, and infraspinatus tendons present difficult surgical challenges to the arthroscopic surgeon. We describe the interval slide in continuity, a release and resection of a portion of the coracohumeral ligament and rotator interval. This technique improves the mobility of the subscapularis and supraspinatus tendons but also maintains an important lateral bridge of tissue spanning the interval between the subscapularis anteriorly and the supraspinatus tendon superiorly. After repair of the subscapularis tendon, this lateral rotator interval tissue can greatly facilitate repair of the posterosuperior rotator cuff.

Purpose: In some cases of larger and chronic rotator cuff tears, the supraspinatus tendon may be held in a retracted position by the contracted tissue of the rotator interval and the attached coracohumeral ligament. This study was performed to evaluate the utility and clinical effectiveness of an arthroscopic release of the rotator interval from the supraspinatus tendon combined with repair of the rotator cuff. Type of Study: Prospective clinical follow-up study. Methods: Forty-three arthroscopic rotator cuff repairs were performed and followed up for an average of 32 months. All of these patients had large, contracted tears that could not be adequately mobilized without a rotator interval release. In each case, an arthroscopic rotator interval release and superior capsular release were performed to improve cuff mobility. End-to-bone and side-to-side repair was performed depending on the configuration of the tear. Postoperatively, the patients were evaluated using a modified University of California Los Angeles (UCLA) rating system. Results: Forty-two repairs were available for at least 2-year follow-up. No cases of deltoid morbidity or progressive superior migration of the humeral head were seen. The average overall preoperative score was 17.4 (range, 9–26). The average postoperative score was 36.4 (range, 20–45). We saw 21 excellent, 6 good, 11 fair, and 4 poor results based on prior criteria established for smaller tears. All of the average postoperative scoring categories were improved from preoperative scores. Only 3 patients were not satisfied with their results. Conclusions: The use of the interval slide technique greatly improves supraspinatus mobility in the case of large retracted tears. Although average improvements were less than in our previous study of smaller tears, complete or partial repair of these tears yields good results and high patient satisfaction.

Objective To investigate the association between the magnetic resonance imaging (MRI) findings of adhesive capsulitis and shoulder muscle fat percentages using a multi-echo Dixon method. Materials and methods Twenty-four patients with clinical diagnoses of adhesive capsulitis and either intact rotator cuffs or Ellman grade 1 partial tears as indicated by MRI scans were included. Two radiologists independently evaluated MRI scans of adhesive capsulitis as follows: presence or absence of axillary recess capsular and extracapsular hyperintensities; thickness of the coracohumeral ligament; thickness of abnormal rotator interval soft tissue; and thickness of glenoidal/humeral axillary recess capsules. Fat quantifications of the supraspinatus, infraspinatus, teres minor, subscapularis, teres major and posterior deltoid muscles were performed using multi-echo Dixon imaging at three locations. Inter-rater agreement was assessed. Differences in fat percentages were assessed and correlations between fat percentages and quantitative measurements were evaluated. Results The fat percentage of the supraspinatus was significantly higher in patients with extracapsular hyperintensity (present, 3.00 ± 1.74%; absent, 1.81 ± 0.80%; p = 0.022). There were positive correlations between the fat percentage of the teres minor and the thicknesses of the abnormal rotator interval soft tissue (r = 0.494, p = 0.014) and the glenoidal axillary recess capsule (r = 0.475, p = 0.019). After controlling for the effects of age, sex and clinical stage, the relationship between the teres minor fat percentage and the thickness of the abnormal rotator interval soft tissue was statistically significant (r = 0.384, p = 0.048). Inter-rater agreement was almost perfect for fat quantification (intraclass correlation coefficients [ICC] > 0.9) and qualitative analyses (k = 0.824), but were variable for quantitative measurements (ICC, 0.170-0.606). Conclusion Several MRI findings of adhesive capsulitis were significantly related to higher fat percentages of shoulder muscles.

The aim of rehabilitation after humerus fractures is the restoration of muscle power and the functionality of the joint. The shoulder joint is the most flexible joint in the human body. The articulation surface is incongruent and is composed of the glenohumeral joint and the subacromial space. Because of these circumstances, the shoulder joint is not as stable as other joints. In everyday life, it is mostly affected by tensile loading. Stabilization of the joint is primarily facilitated by musculature and the capsule-ligament apparatus. The most important ligaments are the glenohumeral ligament and the coracohumeral ligament, the so-called cruciate ligaments of the shoulder joint.

The rotator cuff interval can be found in the anterior superior aspect of the glenohumeral joint between the supraspinatus and subscapularis muscles. It consists of the coracohumeral ligament , superior and middle glenohumeral ligaments, long head of the biceps, and corresponding shoulder capsule. It is not only an important landmark for arthroscopy and surgical entry into the shoulder but also a critical anatomic structure in adhesive capsulitis and instability pathology. The coracohumeral ligament, the focus of this chapter, is the most superficial of the rotator interval components and blends its fibers with the other components of the rotator interval to create a multidirectional support sling that keeps the humeral head elevated and resists external rotation. For this reason, when the coracohumeral ligament and rotator interval becomes contracted, as in adhesive capsulitis, the humeral head elevates and loses external rotation; when they are patulous and incompetent, the biceps tendon and glenohumeral joint develop instability.

Shoulder stiffness is a common problem with an unknown etiology that dramatically impacts shoulder range of motion and limits functional abilities. Risk factors for frozen shoulder commonly include diabetes, female gender, age 40–60 years, and prolonged immobilization. Conservative management is the appropriate first-line treatment, but it is not always successful. This chapter presents evidence to support options for surgical intervention including hydrodilatation, manipulation under anesthesia, coracohumeral ligament release, and arthroscopic 360° capsular release. Caution must be used when performing manipulation under anesthesia as it carries risk of iatrogenic fracture or soft tissue injury as a consequence of the forces used to break up capsular adhesions. Coracohumeral ligament release is a less frequently performed procedure because of the open approach, but it improves pain, function, and range of motion when a concomitant open procedure is indicated. Arthroscopic 360° capsular release is the treatment of choice for recalcitrant cases of frozen shoulder as it improves humeral head translation and shoulder range of motion with the least risk to the patient.

Evaluation of the shoulder can be a difficult and confusing task for many reasons. This book is meant to serve as a guide to physical examination of the shoulder through illustration and demonstration of the most important pathoanatomy, procedural elements, and clinical data involved with the examination process. It is our goal to provide the reader with the means to accurately and efficiently perform the shoulder examination with confidence and accuracy.

This chapter reviews the anatomy , function and variation of the glenohumeral joint capsulo-ligamentous complex. The variability in anatomy of these structures is significant, with normal and pathologic variations that are important to understand and differentiate. We describe these variations with respect to the superior, middle and inferior glenohumeral ligaments as well as outlining the pathoanatomy of the other, less well-studied ligaments, namely, the coracohumeral ligament, the capsular semicircular band (rotator cable) and the coracoglenoid ligament.

The anatomy of the glenohumeral ligaments has been shown to be complex and variable and their function is highly dependent on the position of the humerus with respect to the glenoid. The superior glenohumeral ligament with the coracohumeral ligament was shown to be an important stabilizer in the inferior direction, even though the coracohumeral ligament is much more robust than the superior glenohumeral ligament. The middle glenohumeral ligament provides anterior stability at 45 degrees and 60 degrees abduction whereas the inferior glenohumeral ligament complex is the most important stabilizer against anteroinferior shoulder dislocation. Therefore, this component of the capsule is the most frequently injured structure. An appropriate surgical procedure to repair the inferior glenohumeral ligament complex after shoulder dislocation must be considered. In addition, a detached labrum can lead to recurrent anterior instability and a compromised inferior glenohumeral ligament complex. However, additional capsular injury usually is necessary to allow anterior dislocation.

Purpose: The purpose of this cadaveric study was to examine the anatomy of the normal glenohumeral joint relevant to an arthroscopic rotator interval release and define both the endpoints of a complete release of the coracohumeral ligament and the relationship to surrounding tendons and nerves. Type of Study: An anatomic cadaveric study. Methods: Fifteen fresh-frozen cadaveric specimens were studied with 5 specimens in group I and 10 specimens in group II. Group I specimens were used to examine the relevant anatomy, including the structures at risk, the dimensions of the rotator interval, and potential endpoints for release of the coracohumeral ligament. Measurements included (1) the supraspinatus to the subscapularis distance, (2) the distance from the rotator interval to the deep surface of the coracoid process, and (3) the distance from the rotator interval to the coracoacromial ligament at the level of the glenoid. Group II specimens underwent arthroscopic release of the rotator interval using the appearance of the coracoacromial ligament as the superficial endpoint. Dissection was then performed to examine for complete release of the coracohumeral ligament and to assess the structures at risk of injury. Results: The distance from the anterior edge of supraspinatus to the superior edge of subscapularis at the glenoid rim was 21.6 mm, which increased to 27.8 mm with joint distention. The minimum distance from the rotator interval to the deep surface of the coracoid process was 11.4 mm. Before distention, the coracoacromial ligament was an average of 6.2 mm from the rotator interval capsule. Arthroscopic release from the supraspinatus to the subscapularis resulted in complete resection of the coracohumeral ligament in all 15 specimens. There were no specimens with evidence of injury to the biceps tendon, supraspinatus, subscapularis, or the conjoint tendon. Conclusions: This study confirms that intra-articularly directed arthroscopic release of the rotator interval can safely lead to complete release of the coracohumeral ligament if dissection is taken superficially to the level of the coracoacromial ligament. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 2 (February), 2002: pp 145–150

The function of the long head of the biceps tendon (LHB) in shoulder glenohumeral biomechanics is unclear. However, there is agreement that the biceps can develop tendinopathy resulting in pain over the anterior aspect of the shoulder, specifically in the bicipital groove1,2. With recent advancements in arthroscopy and more detailed imaging, selection of appropriate management for proximal biceps disorders is important. Compared with this proximal component, the anatomy, epidemiology, and underlying pathophysiology of the distal component of the biceps tendon are less well understood. Although distal biceps rupture has a low annual incidence, approximately 1.2 per 100,000 persons3, it can lead to substantial morbidity. The emerging understanding of the clinical importance of distal biceps ruptures and the effectiveness of distal biceps repair are the focal points for the increased attention to this topic. Patients are unique individuals who may be best suited for a specific treatment depending on their age, activity level, and goals. The ideal repair would be one that is anatomic, permits early motion, and has low surgical morbidity and minimal complications. Our review provides an overview of the anatomic, biomechanical, and clinical literature that fully encompasses the biceps brachii from origin to insertion with an emphasis on treatment indications, surgical approaches, fixation techniques, and clinical outcomes. ### Anatomy The LHB arises from the superior glenoid labrum and supraglenoid tubercle. This proximal, intra-articular portion of the biceps tendon has an asymmetric network of sensory sympathetic nerve fibers, predominantly near its origin, and is a primary pain generator in the anterior aspect of the shoulder4. The reflection pulley—composed of fibers from the superior glenohumeral ligament, coracohumeral ligament, and superior aspect of the subscapularis tendon—functions to stabilize the biceps tendon as it advances through the bicipital groove5 (Fig. 1). As the LHB enters …

The rotator interval contains several important anatomical structures that contribute to the stability and normal function of the shoulder joint including the biceps tendon, coracohumeral ligament, superior glenohumeral ligament, rotator interval capsule, anterior fibers of the supraspinatus tendon, and superior fibers of the subscapularis tendon. Rotator interval pathology is associated with biceps instability, glenohumeral instability, and adhesive capsulitis, all of which can be challenging to clinically diagnose and treat. The complex anatomy and orientation of the rotator interval structures within a relatively small space can make it difficult to evaluate by imaging; however, improvements in MR technology have allowed better detection of disease in this region. Furthermore, the rotator interval is not routinely evaluated arthroscopically unless the clinical examination or imaging findings suggest pathology at this level. Imaging, therefore, can play a significant role in helping the clinician make the diagnosis and initiate appropriate treatment. This article discusses the normal anatomy and biomechanics of the rotator interval and its structures as well as the normal and pathologic appearances on imaging and the treatment options of abnormalities of structures in this region.

Twelve cadaveric shoulders were used to determine the effects of release of the superior capsule and the coracohumeral ligament on the strain in the repaired rotator cuff tendon. A rotator cuff tear (2 cm wide and 1.5 cm long) was created and repaired under a 3-kg tensile force. The strain in the repaired tendon was measured with use of linear transducers with the arm in 50 different positions. Release of either the superior capsule or the coracohumeral ligament diminished the tension of the repaired rotator cuff by an average of 25% with the arm in adduction. Release of both of these structures further reduced the tension by an average of 44% in adduction and 43% to 60% with the arm in 15° of elevation. The maximum reduction of tension in the repaired rotator cuff occurred when both the superior capsule and coracohumeral ligament were divided and when the arm was positioned in adduction and in 60° of external rotation. Release of the coracohumeral ligament is equally as efficient as releasing the superior capsule in reducing the strain of the repaired rotator cuff. Releasing both structures seems to be desirable when releasing one structure or the other is not sufficient.

Purpose: The purpose of this study was to document the incidence of lesions of the rotator interval, illustrate the arthroscopic appearance of subtle differences in these lesions, and discuss how various lesions may affect biceps tendon stability in the bicipital groove. Type of Study: A Data Registry has been used in my office since 1995 (Microsoft Office Access). This study reports on the results of a retrospective database "query" of the prospectively entered data from 1995 to 1998. Thus, by default, the format of this study is a consecutive sample. Only patients with a disruption of rotator cuff tendons, labrum and/or gleno-coracohumeral ligaments are included by study design. Methods: This study has identified and reports on 46 arthroscopically identified subscapularis tears, 25 "hidden" rotator interval lesions (SGHL/MCHL complex) and 6 SGHL/CHL complex plastic deformation lesions in 165 patients undergoing shoulder arthroscopy for conditions ranging from anterior instability to rotator cuff tears. Arthroscopically identified lesions include partial or complete disruptions of the subscapularis tendon, disruptions of the superior glenohumeral/medial head coracohumeral ligament complex (SGHL/MCHL), disruptions of the lateral head coracohumeral ligament (LCHL), and various combinations of the above. Results: The incidence rate of subscapularis tendon involvement in 165 arthroscopically treated shoulder patients was 27%. The incidence rate of subscapularis tendon disruptions with rotator cuff pathology was 35%. The incidence rate of SGHL/MCHL lesions (tear or stretch) in 165 arthroscopically treated shoulder patients was 18%. The incidence rate of SGHL/MCHL tears in 165 arthroscopically treated shoulder patients was 15%. Forty-seven percent of all subscapularis tears involved the SGHL/CHL complex. Ten percent of all rotator cuff tears involving the supraspinatus tendon involved the LCHL. Conclusions: This study has recorded the incidence of lesions of the subscapularis, SGHL/MCHL complex and/or the LCHL, and combinations thereof in degenerative cuff and instability patients. Primary lesions of the rotator interval can occur and regardless of the associated pathology, and if these lesions are not repaired, biceps tendon subluxation may exist. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 2 (February), 2001: pp 173–180

A systematic evaluation of the glenohumeral joint should be routinely performed with all shoulder arthroscopy and include all anatomic areas. However, to date, less attention has been given to the insertion of the subscapularis tendon, superior glenohumeral ligament (SGHL), and medial head of the coracohumeral ligament (MCHL). This article outlines arthroscopic techniques that may aid in the evaluation of the anatomy of the rotator interval and bicipital sheath. In this apical region, the CHL contributes fibers to the SGHL (forming the internal reflection of the bicipital groove-SGHL/CHL complex), the subscapularis tendon, and the joint capsule. The CHL is more anterior to the SGHL. There is a distinct anatomic difference between the SGHL/CHL insertion complex and the subscapularis insertion. The normal insertion of the subscapularis tendon is into a small trough on the lesser tuberosity. Together, these structures make up the medial wall of the superior biceps pulley. With the arthroscope advanced to the anterior portion of the joint, the shoulder is elevated from 60 degrees to 90 degrees and a neuroprobe is advanced through the anterior cannula. By internally rotating the arm, the subscapularis tendon insertion and SGHL/CHL complex slacken. A neuroprobe can be placed under the insertion of the subscapularis tendon and SGHL/CHL complex. A 70 degrees arthroscope can aid in visualization with less shoulder elevation. These techniques allow for a thorough visualization of the structures of the rotator interval and medial bicipital sheath.

The purpose of this study was to determine change in glenohumeral joint translation after release of the coracoacromial ligament. Six fresh, frozen unpaired glenohumeral joints were tested in a neutral position and at 30 degrees internal and 30 degrees external rotation of the humerus at 0 degrees, 30 degrees, and 60 degrees of abduction on a custom glenohumeral joint translation testing apparatus. A joint compression load of 20 N was simulated; then a 15-N load was applied to the humerus in anterior, posterior, superior, and inferior directions, and translations on the glenoid were measured with an electromagnetic tracking device. The tests were then repeated after a 1.5-cm section of the coracoacromial ligament was released from the acromion. A multivariate analysis of variance was used for statistical analyses with a P value of.05 as the level of significance. At 0 degrees and 30 degrees of abduction, release of the coracoacromial ligament resulted in a significant increase in glenohumeral joint translations, in both the anterior and inferior directions. In addition, the differences in translation between before and after the release of the coracoacromial ligament decreased in all directions as glenohumeral abduction increased, and they were not significant at 60 degrees of abduction in any of the rotations. The results of this study suggest that the coracoacromial ligament has a role in static restraint of the glenohumeral joint. It provides a suspension function and may restrain anterior and inferior translations through an interaction with the coracohumeral ligament. Although this is a biomechanical study without simulation of the shoulder muscles, it indicates that the coracoacromial ligament contributes to glenohumeral stability. Caution should be exercised in the release of the coracoacromial ligament in those with rotator cuff pain associated with glenohumeral instability.

Objective. Identification and quantification of strain in shoulder capsular-ligamentous structures during clinical exams and validation of this testing on cadavers. Methods . Mercury strain gauges were sutured in seven locations on shoulders from cadavers. An electromagnetic tracker quantified humeral head translations during laxity exams. Strain and humeral position were acquired during performance of Sulcus, Feagin, Apprehension, Load and Shift, Drawer, and Hawkins tests. Results . Anterior humeral head translation in neutral position was primarily constrained by the coracohumeral ligament. With the arm abducted, anterior middle and inferior ligaments also became active. External rotation and abduction activated inferior and middle capsules. Posterior capsule constrained motion for posterior tests in neutral and abduction. Superior and inferior capsular ligaments were active during inferior tests in neutral position. With abduction, inferior ligaments provided primary translation constraint. Conclusion . Study of kinematics and strain evaluation on cadavers can yield useful information on mechanisms of glenohumeral instability. Relevance This study clarifies the contribution of specific structures of the shoulder to strain in the joint capsule. It also identifies which structures are challenged by provocative laxity exams commonly used by orthopaedic physicians.

The Ligg. coracohumerale and coracoglenoidale are constant anatomical structures, represented in all the 34preparations investigated. The Lig. coracoglenoidale is a strong band of dense connective tissue, running from the Processus coracoideus to the Tuberculum supraglenoidale. In 27 specimens out of 34 it was the continuation of the M. pectoralis minor tendon. The Lig. coracohumerale consists of two separate parts. The "inferior part" originates from the Processus coracoideus and the Lig. coracoglenoidale, which separates it from the base of the coracoid process. It is composed of the joint capsule anteriorly and a remnant of the M. pectoralis minor tendon posteriorly. The "superior part" arises from the medio-posterior surface of the Processus coracoideus, just below the Lig. coracoacromiale. Both parts of the Lig. coracohumerale run into the shoulder joint capsule under the M. supraspinatus tendon and insert into a capsular semicircular band. According to the shape and course of fibres between the greater and lesser tubercles of the Humerus, we propose to name it the "Lig. semicirculare humeri". None of the two parts of the Lig. coracohumerale begins from the base of the Processus coracoideus, and fibres of the Lig. coracohumerale do not reach the Tuberculum majus et minus directly.

The late-cocking phase of throwing is characterized by extreme external rotation of the abducted arm; repeated stress in this position is a potential source of glenohumeral joint laxity. To determine the ligamentous restraints for external rotation in this position, 20 cadaver shoulders (mean age, 65 +/- 16 years) were dissected, leaving the rotator cuff tendons, coracoacromial ligament, glenohumeral capsule and ligaments, and coracohumeral ligament intact. The combined superior and middle glenohumeral ligaments, anterior band of the inferior glenohumeral ligament, and the entire inferior glenohumeral ligament were marked with sutures during arthroscopy. Specimens were mounted in a testing apparatus to simulate the late-cocking position. Forces of 22 N were applied to each of the rotator cuff tendons. An external rotation torque (0.06 N x m/sec to a peak of 3.4 N x m) was applied to the humerus of each specimen with the capsule intact and again after a single randomly chosen ligament was cut (N = 5 in each group). Cutting the entire inferior glenohumeral ligament resulted in the greatest increase in external rotation (10.2 degrees +/- 4.9 degrees). This was not significantly different from sectioning the coracohumeral ligament (8.6 degrees +/- 7.3 degrees). The anterior band of the inferior glenohumeral ligament (2.7 degrees +/- 1.5 degrees) and the superior and middle glenohumeral ligaments (0.7 degrees +/- 0.3 degrees) were significantly less important in limiting external rotation.

In the last 10 years we have found impingement of the coracoid process on the rotator interval in 12 patients (14 shoulders). Seven of these patients were women and 5 were men; the average patient age was 48.5 years. One patient had a calcified coracohumeral ligament, another patient had an anterior tear of a repaired deltoid flap, and a third had an aberrant pectoralis minor tendon inserted into the rotator interval. Eleven patients had a weak rotator interval, and in 4 cases the rotator interval had a small tear. We closed the rotator interval in all 12 patients. We also performed a coracoidoplasty in 5 of the patients. The condition of all shoulders improved clinically after operation; the average follow-up was 4.2 years. Three patients (4 shoulders) still had moderate pain, and 7 patients (9 shoulders) lacked strength. Internal rotation was the only shoulder movement that remained limited. Although impingement seemed obvious during surgery, experimental studies have reported contradictory findings.

The rotator interval between supraspinatus and subscapularis is proving to be an important anatomic and functional region of the shoulder. Appreciation of the anatomic structures, functional importance, and mechanisms of injury are invaluable in appropriate assessment, both by physical examination and diagnostic MR imaging. The long biceps tendon; the superior labrum and labral-biceps anchor; the coracohumeral ligament merging with the rotator interval capsule and the superior glenohumeral ligament; the ligamentous reflection pulley for the long biceps tendon at the far lateral margin of the interval extending to the lesser tuberosity and proximal bicipital groove, bounded by the distal superior margin of the subscapularis and anterior margin of the supraspinatus tendons; and the transverse humeral ligament extending between the lesser and greater tuberosities along the proximal bicipital groove all are intimately associated in this region and may be injured together. Understanding of the anatomy and function of the rotator interval continues to evolve. Rotator interval injury may be better understood as a complex or spectrum rather than an isolated lesion. When any one of the spectrum of associated injuries is suspected or found, all of the other possible associated injuries should be considered and evaluated, both on clinical and MR imaging evaluations.

This study examines the stabilizing factors of the glenohumeral joint against inferior translation over a range of subluxations. Factors examined included the glenohumeral capsular ligaments, the coracohumeral ligament, the rotator cuff forces, and the long head of the biceps force. Simulated muscle forces were applied to eight shoulder specimens with the arm near 0° abduction. Stability was defined as the force required to inferiorly sublux the joint to a specified translation from the centered position and was evaluated under varying configurations of capsule cuts, humeral rotation, and muscle loads. The supraspinatus and biceps muscle forces were found to be important active stabilizers. Thus tension in the long head of the biceps did not tend to depress the humeral head. The inferior glenohumeral ligament was an important passive stabilizer in external rotation. Understanding the effects of these factors adds insight into the underlying biomechanics of clinical shoulder instability. (J Shoulder Elbow Surg 1997;6:371-9.)

Rotator cuff repair is one of the most common procedures performed in orthopedic surgery. The goal of repair is to restore normal rotator cuff kinematics in an effort to improve glenohumeral function and reduce pain. Recent data has revealed that healing and anatomic integrity of the rotator cuff repair site correlates with improved outcomes, particularly with regard to strength and functional recovery. Rotator cuff pathology exists on a wide spectrum that ranges from cuff tendon edema and inflammation to partial- and full-thickness tears of one or more of the cuff tendons. Recent advances in diagnostic imaging modalities have led to an increase in clinician recognition of partial-thickness rotator cuff tears. As elegantly described by Clark and Harryman (J Bone Joint Surg 74A:713–725, 1992), the anatomy of the rotator cuff insertion onto the humerus is complex as the tendons, articular capsule, coracohumeral ligament (CHL), and glenohumeral ligament complex essentially blend to form a confluent, layered sheet prior to insertion onto the tuberosities.

From the time Neer first described the anatomy of the rotator interval in 1970, our understanding of the biomechanical role of its contributing structures has continued to evolve. This is in part due to a better understanding of the disability recognized in rotator interval pathology. Multiple studies have demonstrated the contribution of the rotator interval to humeral head translation and overall stability of the shoulder. Contractures are typically treated nonsurgically, whereas laxity is often combined with anterior-interior instability and may warrant possible surgical intervention. Surgical options, mainly for those with long head of biceps tendon related parts, are described.

The classic literature describes the transverse humeral ligament (THL) as a distinct anatomic structure with a role in biceps tendon stability; however, recent literature suggests that it is not a distinct anatomic structure. The purpose of this study was to evaluate the gross and microscopic anatomy of the THL, including a specific investigation of the histology of this ligament. Thirty frozen, embalmed cadaveric specimens were dissected to determine the gross anatomy of the THL. Seven specimens were evaluated histologically for the presence of mechanoreceptors and free nerve endings. Two tissue layers were identified in the area described as the THL. In the deep layer, fibers of the subscapularis tendon were found to span the bicipital groove with contributions from the coracohumeral ligament and the supraspinatus tendon. Superficial to this layer was a fibrous fascial covering consisting of distinct bands of tissue. Neurohistology staining revealed the presence of free nerve endings but no mechanoreceptors. This study’s findings demonstrate that the THL is a distinct structure continuous with the rotator cuff tendons and the coracohumeral ligament. The finding of free nerve endings in the THL suggests a potential role as a shoulder pain generator.

Background: Only a few reports describe the extension of the coracohumeral ligament to the subscapularis muscle. The purposes of this study were to histo-anatomically examine the structure between the ligament and subscapularis and to discuss the function of the ligament. Methods: Nineteen intact embalmed shoulders were used. In 9 shoulders, the expansion of the ligament was anatomically observed, and in 6 of these 9, the muscular tissue of the supraspinatus and subscapularis was removed to carefully examine the attachments to the tendons of these muscles. Five shoulders were frozen and sagittally sectioned into 3-mm-thick slices. After observation, histologic analysis was performed on 3 of these shoulders. In the remaining 5 shoulders, the coracoid process was harvested to investigate the ligament origin. Results: The coracohumeral ligament originated from the horizontal limb and base of the coracoid process and enveloped the cranial part of the subscapularis muscle. The superficial layer of the ligament covered a broad area of the anterior surface of the muscle. Laterally, it protruded between the long head of the biceps tendon and subscapularis and attached to the tendinous floor, which extended from the subscapularis insertion. Histologically, the ligament consisted of irregular and sparse fibers abundant in type III collagen. Conclusion: The coracohumeral ligament envelops the whole subscapularis muscle and insertion and seems to function as a kind of holder for the subscapularis and supraspinatus muscles. The ligament is composed of irregular and sparse fibers and contains relatively rich type III collagen, which would suggest flexibility.

Recent evidence has shown that the superior glenohumeral ligament (SGHL) and coracohumeral ligament (CHL) are important static stabilizers. To clarify the function of these two ligaments, we studied their tensile properties with bone-ligament-bone complexes from fresh-frozen shoulders, 10 SGHLs and 10 CHLs. Each ligament's cross-sectional area was measured, and uniaxial tensile testing of each complex was performed. The stiffness, ultimate load, percent elongation, and energy absorbed to failure of each bone-ligament-bone complex were derived from its load-elongation curve. The cross-sectional area of the coracohumeral ligament was significantly greater than that of the superior glenohumeral ligament of their midportions (CHL, 53.7 +/- 3.2 mm2 vs. SGHL, 11.3 +/- 1.6 mm2, p0.05). Results also reveal significant differences between the tensile properties for the two ligaments, with the coracohumeral ligament possessing greater stiffness (CHL, 36.7 +/- 5.9 N/mm vs. SGHL, 17.4 +/- 1.5 N/mm, p0.05) and ultimate load (CHL, 359.8 +/- 40.3 N vs. SGHL, 101.9 +/- 11.5 N, p0.05) than the superior glenohumeral ligament. Our findings confirm that the coracohumeral ligament is an important capsuloligamentous structure of the glenohumeral joint.

The rotator interval is important in shoulder stability and movement. The rotator interval is enclosed in the triangular area bordered by the subscapularis anteroinferiorly, supraspinatus posterosuperiorly, and the coracoid process medially. The rotator interval contains the long head of the biceps tendon, coracohumeral ligament, superior glenohumeral ligament (SGHL), and the middle glenohumeral ligament (MGHL). The rotator interval contains multiple static stabilizers of the shoulder, and its integrity is important for anterior and inferior stability of the shoulder, especially when the shoulder is adducted. Furthermore, external rotation of the shoulder is altered with rotator interval pathology. For surgical intervention to have success, an intimate understanding of the rotator interval structures is necessary. Rotator Interval Anatomy The rotator interval of the shoulder is the area defined by the subscapularis anteroinferiorly, the supraspinatus posterosuperiorly, and the coracoid process medially. The long head of the biceps tendon traversing in the bicipital groove exits the joint just lateral to the insertion of the subscapularis tendon on the lesser tuberosity (Fig. 1a). The coracohumeral ligament originates from the proximal third of the dorsolateral aspect of the base of the coracoid process and runs on the bursal side of the SGHL, inserting mostly on the greater tuberosity and to a lesser extent on the lesser tuberosity (Ferrari 1990; Burkhart et al. 1993; Jost et al. 2000; Fig. 1a). The superior glenohumeral ligament (SGHL) originates from the glenoid labrum, frequently with the long head of the biceps tendon (Jost et al. 2000; Fig. 1b). The SGHL fibers insert mainly into the lesser tuberosity and also form a band around the biceps tendon and insert into the greater tuberosity contributing to the roof of biceps sling (Ferrari 1990; Burkhart et al. 1993; Jost et al. 2000; Werner et al. 2000; Kask et al. 2010; Fig. 2). During its course, the SGHL borders the biceps anteriorly (Figs. 1b, 2, 3a–d). The MGHL commonly originates in the anterosuperior aspect of the labrum or the supraglenoid tubercle (SGT). The MGHL then inserts onto the inferior aspect of the lesser tuberosity (Ferrari 1990; Jost et al. 2000; Pouliart and Gagey 2005; Kask et al. 2010; Felli et al. 2012). As it enters the shoulder joint in the bicipital groove, the long head of the biceps tendon has a sling formed around it consisting of the supraspinatus, subscapularis, SGHL, and coracohumeral ligament (Fig. 3). The medial aspect of the sling consists of from deep to superficial the SGHL, coracohumeral ligament, and subscapularis tendon, respectively. The lateral aspect of the sling from deep to superficial consists of the SGHL, deep coracohumeral ligament, supraspinatus tendon, and superficial *Email: johnpeggers@gmail.com Sports Injuries DOI 10.1007/978-3-642-36801-1_10-1 # Springer-Verlag Berlin Heidelberg 2013

Of 935 consecutive patients referred with shoulder pain, 50 fitted the criteria for primary frozen shoulder. Twelve patients who failed to improve after conservative treatment and manipulation had excision of the coracohumeral ligament and the rotator interval of the capsule. The specimens were examined histologically, using special stains for collagen. Immunocytochemistry was performed with monoclonal antibodies against leucocyte common antigen (LCA, CD45) and a macrophage/synovial antigen (PGMI, CD68) to assess the inflammatory component, and vimentin and smooth-muscle actin to evaluate fibroblasts and myofibroblasts. Our histological and immunocytochemical findings show that the pathological process is active fibroblastic proliferation, accompanied by some transformation to a smooth muscle phenotype (myofibroblasts). The fibroblasts lay down collagen which appears as a thick nodular band or fleshy mass. These appearances are very similar to those in Dupuytren's disease of the hand, with no inflammation and no synovial involvement. The contracture acts as a check-rein against external rotation, causing loss of both active and passive movement.

A three-dimensional biomechanical model of the shoulder is developed for force predictions in 46 shoulder structures. The model is directed towards the analysis of static working situations where the load is low or moderate. Arbitrary static arm postures in the natural shoulder range may be considered, as well as different kinds of external loads including different force and moment directions. The model can predict internal forces for the shoulder muscles, for the glenohumeral, the acromioclavicular and the sternoclavicular joint as well as for the coracohumeral ligament. A solution to the statistically indeterminate force system is obtained by minimising an objective function. The default function chosen for this is the sum of the squared muscle stresses, but other objective functions may be used as well. The structure of the model is described and its ingredients discussed. The internal consistency of the model, its structural stability and the compatibility of the elements that go into it, is investigated.

Twelve fresh-frozen cadaver shoulders were dissected to study the anatomy and histology of the coracohumeral ligament. Based on the gross and microscopic anatomy, the ligament was found in three variations. In the most common pattern (nine of 12 specimens), the coracohumeral ligament represented a folded portion of glenohumeral joint capsule in the rotator interval between subscapularis and supraspinatus. Because of its inverted "v"-shaped origin from the coracoid base, tension on this structure creates the appearance of a prominent ligamentous structure. However, histologic cross-sections of this pattern of coracohumeral ligament reveal that it is lined by synovium on its undersurface and contains no discretely organized collagen bundles representative of a ligament. The second pattern (two of 12 specimens) was similar, except that the capsular reflection representing the ligament was fused together, giving the structure a more clearly definable anterior edge. In only one specimen was the ligament a truly ligamentous structure. In its normal state the coracohumeral ligament usually appears as a capsular reflection on the coracoid base, and though it courses toward the superior aspect of the intertubercular groove, it is not a true ligamentous structure. These findings support the position of those authors who state that the coracohumeral ligament is unlikely to play a significant role as a suspensory structure in its physiologic state.

The objective of our study was to evaluate the performance of MRI for the diagnosis of adhesive capsulitis using signal intensity changes of the inferior glenohumeral ligament on T2-weighted fat-saturated sequences.MR images of 34 shoulders with a final clinical diagnosis of adhesive capsulitis were compared with those of an age-matched control group (34 shoulders) with no clinical signs of adhesive capsulitis. MR images were acquired before and after IV injection of gadolinium and were evaluated by two readers. The T2 signal intensity at the inferior glenohumeral ligament, the thickness of the coracohumeral ligament, and whether there was obliteration of subcoracoid fat were evaluated on unenhanced images. Enhancement at the inferior glenohumeral ligament and enhancement at the rotator interval were evaluated on contrast-enhanced images. The sensitivity, specificity, and interobserver variability of these signs were calculated.T2 hyperintensity of the inferior glenohumeral ligament showed a high sensitivity (85.3-88.2%) and high specificity (88.2%) for the diagnosis of adhesive capsulitis with excellent interobserver variability (κ = 0.85). Signal analysis at the inferior glenohumeral ligament presented a higher sensitivity and a better interobserver agreement than the other signs of adhesive capsulitis evaluated. Gadolinium injection did not increase the performance of the inferior glenohumeral ligament signal analysis. An extracapsular hyperintense layer on T2-weighted images was identified as a new sign of adhesive capsulitis.T2 capsular signal intensity change offers a high performance for the diagnosis of adhesive capsulitis without the need for IV or intraarticular contrast injection.

The rotator cable is an extension of the coracohumeral ligament coursing along the undersurface of the supraspinatus and infraspinatus tendons. The rotator cable is thought to play a role in the biomechanical function of the intact and torn rotator cuff. It can be seen on all the imaging planes used for the conventional magnetic resonance imaging of the shoulder. Clinically, the integrity of the rotator cable can play a role in the treatment selection for patients with a rotator cuff tear.

Exploration of the rotator interval during repair of 116 apparently "isolated" supraspinatus tendon lesions have revealed "hidden lesions" of the coracohumeral ligament, the superior glenohumeral ligament, and the superior portion of the subscapularis tendon in 19 cases. Epidemiologic characteristics were comparable with other series with the exception of involvement of the dominant shoulder in 95%. Arthroscopic computed tomography documented the lesion in 85% of the cases. At surgery the superficial layer of the coracohumeral ligament was always intact. After splitting of the rotator interval the lesion was visible and consisted of a local disinsertion of the common insertion of the superior glenohumeral ligament and the coracohumeral ligament and the deep superior fibers of the subscapularis tendon. It measured 1 to 2 cm in the superior-inferior direction. The biceps tendon was ruptured in 2 cases, subluxated in 14, and in its normal position in 5. The treatment consisted of intraosseous reinsertion of the supraspinatus tendon, recentering of the biceps, and reinsertion of the torn structures to reconstruct a functional pulley system. The patients have been reviewed with a mean follow-up of 20 months (range 12 to 36 months). A secondary rupture of the long head of the biceps has been observed in 25% of the cases after recentering of the tendon.

BACKGROUND: Recent studies have demonstrated that the coracohumeral ligament (CHL) is shortened and thickened in a frozen shoulder. We analyzed the rate in CHL visualization between patients with frozen shoulder and normal volunteers using Magnetic Resonance Imaging (MRI) to determine the CHL thickness in the patients with a frozen shoulder. METHODS AND FINDINGS: There were 72 shoulder joints in 72 patients (50 femles and 22 males with a mean age of 53.5 years) with clinical evidence and MR imaging evidence of frozen shoulder. These were prospectively analyzed to identify and measure the maximum thickness of the CHL. The control group, which included 120 shoulder joints in 60 normal volunteer individuals (30 females and 30 males with a mean age of 50.5 years) was also referred for MR imaging. A chi-square test was used to analyze the data of the rate of CHL visualization between the patients with frozen shoulder and the control group. A two-way ANOVA was used to analyze the mean maximal thickness of CHL. The CHL was visualized in 110 out of 120 shoulders in the control group (91.7%), and in 57 out of 72 shoulders for the frozen shoulder group (79.2%), there was significant difference, using a chi-square test (P0.05). CONCLUSIONS: MR Imaging is a satisfactory method for CHL depiction, and a thickened CHL is highly suggestive of frozen shoulder.

The purpose of this study was to determine the contri butions of specific capsuloligamentous structures to restraining superior-inferior translation of the glenohu meral joint. Eleven cadaveric shoulders were tested using a four degrees-of-freedom test apparatus. The humerus was free to translate in three planes and free to flex and extend when a superior and inferior force of 50 N was applied. Testing was performed in three positions of abduction (0°, 45°, and 90°) and three positions of rotation (neutral, maximum internal, and external). Shoulders were tested intact, vented, and after division of specific capsuloligamentous structures. The primary restraint to inferior translation of the ad ducted shoulder was the superior glenohumeral liga ment. The coracohumeral ligament appeared to have no significant suspensory role. With progressive abduc tion, the anterior and posterior portions of the gleno humeral ligament become the main static stabilizers resisting inferior translation: the anterior portion was the primary capsular restraint at 45° of abduction, while the posterior portion was the primary restraint at 90° of abduction, neutral rotation. Our results indicate that clinical assessment of glenohumeral translation in the superior-inferior plane should be performed in multiple positions of abduction and rotation.

We investigated the structure of the myotendinous rotator cuff in thirty-two grossly intact cuffs from thirty fresh cadavera of subjects who had been seventeen to seventy-two years old at the time of death. We studied the gross anatomy of the capsule and ligaments of the cuff, as well as histological sections of the tendons of the subscapularis, supraspinatus, and infraspinatus muscles. The tendons were found to splay out and interdigitate to form a common, continuous insertion on the humerus. The biceps tendon was ensheathed by interwoven fibers derived from the subscapularis and supraspinatus tendons. The anterior margin and bursal surface of the supraspinatus tendon were enveloped by a thick sheet of fibrous tissue derived from the coracohumeral ligament. Fibers from the coracohumeral and glenohumeral ligaments were found concentrated in a plane between the capsule and the tendons of the cuff. Microscopically, in the region of the supraspinatus and infraspinatus tendons, the cuff was composed of five layers defined by the attachments and orientations of the fibrous elements in each of these layers.

A small, separate, bony density dorsal to the shoulder joint is radiographically visible in several species of large hawks and owls. Gross dissection and histological examination show the bone to lie on the deep surface of the major deltoid muscle in intimate association with the dorsal coracohumeral ligament of the shoulder joint. The tendon of the supracoracoideus muscle passes immediately cranial to the humeroscapular bone. Two ligaments distinct from the shoulder joint capsule attach the humeroscapular bone to the proximal humerus: one passes to the proximal edge of the pectoral crest of the humerus, and the other passes to the ventral tubercle of the humerus. The bone was described as the humeroscapular bone in reference to a similar fibrocartilaginous structure possessed by some birds. The humeroscapular bone is present in the great horned owl (Bubo virginianus), the screech owl (Otus asio), the barred owl (Strix varia), the red-tailed hawk (Buteo jamaicencis), the Cooper's hawk (Accipiter cooperii), and the sharp-shinned hawk (Accipiter striatus). The bone is absent in the barn owl (Tyto alba), the osprey (Pandion haliaetus), the golden eagle (Aquila chysaetos), and the turkey vulture (Cathartes aura), though some of these species possessed a similar fibrocartilaginous structure. Whether the humeroscapular structure develops as bone or cartilage in a given species may be related to other morphological features of the wing, and/or to characteristics of the predatory behavior of the species. Clinicians and anatomists dealing with birds of prey must be aware of the presence of the humeroscapular bone to avoid misinterpreting it as a fracture fragment.

The purpose of this study was to characterize the role of the capsule in the interval between the supraspinatus and subscapularis tendons with respect to glenohumeral motion, translation, and stability. We used a six-degrees-of-freedom position-sensor and a six-degrees-of-freedom force and torque-transducer to determine the glenohumoral rotations and translations that resulted from applied loads in eight cadaver shoulders. The range of motion of each specimen was measured with the capsule in the rotator interval in a normal state, after the capsule had been sectioned, and after it had been imbricated. Operative alteration of this capsular interval was found to affect flexion, extension, external rotation, and adduction of the humerus with respect to the scapula. Modification of this portion of the capsule also affected obligate anterior translation of the humeral head on the glenoid during flexion. Limitation of motion and obligate translation were increased by operative imbrication and diminished by sectioning of the rotator interval capsule. Passive stability of the glenohumeral joint was evaluated with the use of anterior, posterior, and inferior stress tests. Instability and occasional frank dislocation of the glenohumeral joint occurred inferiorly and posteriorly after section of the rotator interval capsule. Imbrication of this part of the capsule increased the resistance to inferior and posterior translation.

To evaluate the anomalous insertion of the pectoralis minor tendon with absence of the coracohumeral ligament on MR arthrography and to demonstrate the associated findings seen with this anatomical variation.We retrospectively reviewed the 335 MR arthrograms of the shoulder joint (mean age 37.8 years) performed from March 2000 to February 2008. Images were evaluated with attention to anomalous insertion of the pectoralis minor tendon and the coracohumeral ligament.Anomalous insertion of the pectoralis minor tendon was demonstrated in 5 out of 335 shoulders (1.5%). The pectoralis minor tendons crossed over the coracoid process and attached directly to a glenohumeral joint capsule, and the coracohumeral ligament was absent in these 5 patients. In these patients, injected contrast material was noted to extend over the coracoid process along the course of the pectoralis minor tendon. Among 5 patients, 3 patients (60%) were diagnosed with SLAP (superior labrum anterior to posterior) lesions.Anomalous insertion of the pectoralis minor tendon to the glenohumeral joint capsule and associated absence of the coracohumeral ligament is well demonstrated on MR arthrography. It is an unusual variant of the pectoralis minor muscle insertion, and may be a possible contributing factor in the development of a SLAP lesion.

Idiopathic frozen shoulder is a common medical diagnosis for patients seeking physical therapy. Radiographic and surgical evidence exists that describes the coracohumeral ligament (CHL) as a major contributor to lack of external rotation in patients diagnosed with frozen shoulder. No stretching techniques targeting the anatomical fiber orientation of the CHL have been reported in the literature. This single-patient case-report describes the use of a positional stretching technique of the CHL on a 51-year-old female diagnosed with phase I frozen shoulder. The patient completed 8 in-office visits and 17 home exercise program sessions of positional CHL stretching combined with a simple volitional rotator cuff exercise program in a 4-week period. The patient's Disabilities of the Arm Shoulder and hand (DASH) scores improved from 65 to 36 and Shoulder Pain and Disability Index (SPADI) scores improved from 72 to 8 and passive external rotation from 20 degrees to 71 degrees . While a cause-and-effect relationship cannot be inferred from a single case, this report may foster further investigation regarding the role of the CHL in patients with stage-I and stage-II frozen shoulder as well as therapeutic strategies to help reduce loss of mobility and function.

The magnetic resonance (MR) images from six patients with biceps tendon dislocation--two in whom it was surgically proved and four in whom it was suspected--were retrospectively evaluated. The dislocated tendon can be identified medial to the bicipital groove, best seen on the axial and oblique coronal and sagittal images. Associated abnormalities of the biceps tendon include thickening (n = 3), high signal intensity (n = 3), and surrounding fluid (n = 4). The factors thought to contribute to dislocation can also be well seen on MR images. These include abnormal shape of the bicipital groove (n = 2), disruption of the coracohumeral ligament (n = 6), disruption (n = 4) and thinning (n = 1) of the subscapularis tendon, and supraspinatus tendon tear (n = 4). Since MR imaging is becoming the modality of choice for the evaluation of shoulder derangements, familiarity with the appearance of biceps tendon dislocation on MR images is important.