Clinical diagnosis
Case 225
【Progress】
She returned to the original orthopedic clinic with a diagnostic MRI report made by our radiologist.
【Discussion】
There are five bursae in scapular joint: subscapularis, subcoracoid, subacromial (subdeltoid), supra-acromial and coracoclavicular (1). Of these, subdeltoid bursa is the largest. Fluid retention in the bursae indicate an injury of synovial membrane associated with adjacent ligament or rotator cuff. The mere injury of synovial membrane might be a rare situation. These bursae function as a cushion against stress burden to rotator cuff and ligaments. Bursae do not communicate with scapular joint lumen in a normal situation.
It is reported that subscapularis recess and subcoracoid bursa situate adjacent together and its differentiation is important because fluid retention of subcoracoid bursa implies injury of rotator cuff or ligament, while subscapularis recess directly communicates with scapular joint space, although scapular joint space is always closed in normal situation (2-5). Subscapularis recess is called Rotator Cuff Loose (Sparse) space in Japan. Rotator Cuff Loose space is thought to be cushion for stress burden. Apart from shoulder arthritis causing fluid retention in the subscapularis recess and rotator cuff tear causing fluid retention in the subcoracoid bursa, fluid retention alone in Rotator Cuff space (or subscapularis recess) without shoulder arthritis or rotator cuff tear is often encountered. It is called Rotator Cuff Loose inflammation or Rotator Cuff Loose injury in Japan (6).
Long head tendon of biceps brachii arises from supraglenoid tubercle and the adjacent supraglenoid labrum, lies between greater and lesser tuberosities, and runs anterior to humerus and attaches to bicipital tuberosity of proximal radius (7, 8). Long head tendon is covered with transverse ligament which is continuously linked by fascia of subscapularis muscle where it lies between greater and lesser tuberosities. Then, long head tendon dislocation is usually associated with subscapularis muscle tear. Then, it is important to check whether long head tendon is dislocated or not when subscapularis muscle tear is encountered (6-8). Long head tendon comes out from rotator cuff and is covered with tendon of pectoralis major (6). In our case, long head tendon tear plus pectoralis major tendon tear were found on fat suppression T2 WI MRI (Fig 1A to 1C).
Short head tendon of biceps brachii arises from coracoid process, travels distally, and attaches to bicipital tuberosity of proximal radius. In our case, short head tendon tear associated with long head tendon tear is shown on fat suppression T2WI MRI (Fig. 1A, 1B).
【Summary】
We present a seventy seven year-old female for a suspicious injury of right rotator cuff tear. Right shoulder MRI showed rotator cuff tear, tears of long head tendon and short head of biceps brachii muscle, and rotator cuff loose tear. It is borne in mind that five bursae exist in shoulder joint; supra-acromial, subacromial/subdeltoid, coracoacromial, subcoracoid, subscapularis. Bursae do not communicate with joint space in a normal situation. Fluid retention in bursae indicate synovial injury associated with tears of the adjacent rotator cuff and ligament. Rotator cuff loose space contain closed joint space, subcoracoid bursa and soft tissue. It is important to distinct whether fluid retention of loose rotator cuff space comes out from arthritis, rotator cuff tear or soft tissue damage. Long head tendon arises from supraglenoid labrum, lies between greater and lesser tuberosities, attaches to the proximal end of radius. It is covered with transverse ligament extending subscapularis muscle fascia. Then, long head tendon tear is often associated with subscapularis rotator cuff tear.
【References】
1.Bureau N, et al. Imaging of bursae around the shoulder joint. Skeletal Radiol.1996;25:513–517
2.Schraner AB, et al. MR imaging of the subcoracoid bursa. AJR Am J Roentgenol 1999;172(6): 1567–1571
3.Grainger AJ, et al. MR anatomy of the subcoracoid bursa and the association of subcoracoid effusion with tears of the anterior rotator cuff and the rotator interval. AJR Am J Roentgenol 2000;174(5):1377–1380
4.Yi-Hsuan Lee, et al. Subcoracoid Bursa: Imaging Diagnosis and Significance. J Radiol Sci 2013; 38: 111-118
5.Clark, JM, et al. Tendons, ligaments, and capsule of the rotator cuff: gross and microscopic anatom. J Bone Joint Surg [Am} 1992,;74: 713-725.
6.Saji R, et al. MRI on shoulder joint. Second edition by Medical View 2015, in Japanese.
7.Gumina S, et al. Rupture of the long head biceps tendon treated with tenodesis to the coracoid process. Results at more than 30 years. International orthopaedics 2011;35:713-6.
8.Elser F, et al. Anatomy, function, injuries, and treatment of the long head of the biceps brachii tendon. Arthroscopy: The Journal of Arthroscopic & Related Surgery 2011;27:581-92.
2021.3.24