The scapulothoracic articulation is a sliding junction between the deep aspect of the scapula and thoracic rib cage at the levels of ribs 2 through 7. Motion at this articulation is dynamically stabilized by a variety of muscular attachments, allowing for controlled positioning of the glenoid to assist in glenohumeral joint function. A thorough understanding of the complex anatomic relationships, including the various muscles, and bursa, is critical to the evaluation of patients presenting with scapulothoracic disorders. The snapping scapula syndrome is caused by either osseous lesions or scapulothoracic bursitis and can be difficult to recognize and treat. The purpose of this review is to discuss the anatomy of the scapulothoracic articulation with an emphasis on the pathology associated with snapping scapula syndrome. 1. Introduction The scapulothoracic articulation is a complex anatomical structure that plays a substantial role in overall shoulder function. The osseous, ligamentous, and muscular periscapular relationships are intricate. While scapulothoracic pathology is uncommon, a thorough appreciation of the anatomy, including the various muscular relationships and bursal planes, is critical to the evaluation of patients presenting with scapulothoracic disorders [1]. Snapping scapula syndrome is caused by either osseous lesions or scapulothoracic bursitis, and appropriate recognition and treatment of these disorders is dependent on a solid foundation in periscapular anatomy [2, 3]. The purpose of this review is to discuss the anatomy of the scapulothoracic articulation with an emphasis on the pathology associated with snapping scapula syndrome. 2. Anatomical Description of the Scapula The scapula is a flat bone (Figures 1 and 2) that rests on the posterolateral aspect of the thoracic cavity overlying ribs 2 through 7 [1, 3]. The scapula serves as a site for multiple muscular origins and insertions [1] and is thin and triangular shaped with three distinct borders (superior, axillary, and vertebral) and three angles (superomedial, inferomedial, and lateral (glenoid)) [4] (Figures 1 and 2). The superomedial angle, formed by the superior border and the vertebral border of the scapula, normally measures 124 to 162 degrees [5]. These anatomical variations in the superomedial angle may have clinical implications in the development of snapping scapula syndrome [5]. The anterior surface of the scapula is undulating. Scapular thickness ranges from 10.5 to 26.7？mm [5]. Figure 1: Three-dimensional reconstruction of the scapula demonstrating the (a) superior
References
[1]
G. C. Terry and T. M. Chopp, “Functional anatomy of the shoulder,” Journal of Athletic Training, vol. 35, no. 3, pp. 248–255, 2000.
[2]
T. Gaskill and P. J. Millett, “Snapping scapula syndrome: diagnosis and management,” Journal of the American Academy of Orthopaedic Surgeons, vol. 21, no. 4, pp. 214–224, 2013.
[3]
M. A. Lazar, Y. W. Kwon, and A. S. Rokito, “Snapping scapula syndrome,” Journal of Bone and Joint Surgery A, vol. 91, no. 9, pp. 2251–2262, 2009.
[4]
W. J. Mallon, H. R. Brown, J. B. Vogler III, and S. Martinez, “Radiographic and geometric anatomy of the scapula,” Clinical Orthopaedics and Related Research, no. 277, pp. 142–154, 1992.
[5]
A. Aggarwal, P. Wahee, H. Harjeet, A. K. Aggarwal, and D. Sahni, “Variable osseous anatomy of costal surface of scapula and its implications in relation to snapping scapula syndrome,” Surgical and Radiologic Anatomy, vol. 33, no. 2, pp. 135–140, 2011.
[6]
A. M. Halder, E. Itoi, and K. An, “Anatomy and biomechanics of the shoulder,” Orthopedic Clinics of North America, vol. 31, no. 2, pp. 159–176, 2000.
[7]
M. Peat, “Functional anatomy of the shoulder complex,” Physical Therapy, vol. 66, no. 12, pp. 1855–1865, 1986.
[8]
L. U. Bigliani, J. B. Ticker, E. L. Flatow, L. J. Soslowsky, and V. C. Mow, “The relationship of acromial architecture to rotator cuff disease,” Clinics in Sports Medicine, vol. 10, no. 4, pp. 823–838, 1991.
[9]
L. U. Bigliani, J. B. Ticker, E. L. Flatow, L. J. Soslowsky, and V. C. Mow, “The relationship of the acromial architecture to diseases of the rotator cuff,” Orthopade, vol. 20, no. 5, pp. 302–309, 1991.
[10]
G. P. Nicholson, D. A. Goodman, E. L. Flatow, and L. U. Bigliani, “The acromion: morphologic condition and age-related changes. A study of 420 scapulas,” Journal of Shoulder and Elbow Surgery, vol. 5, no. 1, pp. 1–11, 1996.
[11]
M. P. Banas, R. J. Miller, and S. Totterman, “Relationship between the lateral acromion angle and rotator cuff disease,” Journal of Shoulder and Elbow Surgery, vol. 4, no. 6, pp. 454–461, 1995.
[12]
J. B. Ticker, M. Djurasovic, R. J. Strauch et al., “The incidence of ganglion cysts and other variations in anatomy along the course of the suprascapular nerve,” Journal of Shoulder and Elbow Surgery, vol. 7, no. 5, pp. 472–478, 1998.
[13]
J. P. Warner, R. J. Krushell, A. Masquelet, and C. Gerber, “Anatomy and relationships of the suprascapular nerve: anatomical constraints to mobilization of the supraspinatus and infraspinatus muscles in the management of massive rotator-cuff tears,” Journal of Bone and Joint Surgery A, vol. 74, no. 1, pp. 36–45, 1992.
[14]
R. S. Churchill, J. J. Brems, and H. Kotschi, “Glenoid size, inclination, and version: an anatomic study,” Journal of Shoulder and Elbow Surgery, vol. 10, no. 4, pp. 327–332, 2001.
[15]
C. D. Bryce, A. C. Davison, G. S. Lewis, L. Wang, D. J. Flemming, and A. D. Armstrong, “Two-dimensional glenoid version measurements vary with coronal and sagittal scapular rotation,” Journal of Bone and Joint Surgery A, vol. 92, no. 3, pp. 692–699, 2010.
[16]
J. A. Hill, L. Tkach, and R. W. Hendrix, “A study of glenohumeral orientation in patients with anterior recurrent shoulder dislocations using computerized axial tomography,” Orthopaedic Review, vol. 18, no. 1, pp. 84–91, 1989.
[17]
P. L. Williams and R. Warwick, Eds., Gray's Anatomy, Longman, London, UK, 35th edition, 1973.
[18]
V. T. Inman, J. B. Saunders, and L. C. Abbott, “Observations of the function of the shoulder joint. 1944,” Clinical Orthopaedics and Related Research, no. 330, pp. 3–12, 1996.
[19]
M. L. Ballesteros, F. Buchthal, and P. Rosenfalck, “The pattern of muscular activity during the arm swing of natural walking,” Acta Physiologica Scandinavica, vol. 63, pp. 296–310, 1965.
[20]
C. M. Jobe and J. P. Lannotti, “Limits imposed on glenohumeral motion by joint geometry,” Journal of Shoulder and Elbow Surgery, vol. 4, no. 4, pp. 281–285, 1995.
[21]
Z. Dvir and N. Berme, “The shoulder complex in elevation of the arm: a mechanism approach,” Journal of Biomechanics, vol. 11, no. 5, pp. 219–225, 1978.
[22]
G. R. Williams Jr., M. Shakil, J. Klimkiewicz, and J. P. Iannotti, “Anatomy of the scapulothoracic articulation,” Clinical Orthopaedics and Related Research, no. 359, pp. 237–246, 1999.
[23]
D. K. Frank, E. Wenk, J. C. Stern, R. D. Gottlieb, and A. L. Moscatello, “A cadaveric study of the motor nerves to the levator scapulae muscle,” Otolaryngology, vol. 117, no. 6, pp. 671–680, 1997.
[24]
B. K. Chan, A. J. Chakrabarti, and S. N. Bell, “An alternative portal for scapulothoracic arthroscopy,” Journal of Shoulder and Elbow Surgery, vol. 11, no. 3, pp. 235–238, 2002.
[25]
L. J. Ruland III, C. M. Ruland, and L. S. Matthews, “Scapulothoracic anatomy for the arthroscopist,” Arthroscopy, vol. 11, no. 1, pp. 52–56, 1995.
[26]
J. E. Kuhn, K. D. Plancher, and R. J. Hawkins, “Symptomatic scapulothoracic crepitus and bursitis,” The Journal of the American Academy of Orthopaedic Surgeons, vol. 6, no. 5, pp. 267–273, 1998.
[27]
M. Kuhne, N. Boniquit, N. Ghodadra, A. A. Romeo, and M. T. Provencher, “The snapping scapula: diagnosis and treatment,” Arthroscopy, vol. 25, no. 11, pp. 1298–1311, 2009.
[28]
F. Colas, J. Nevoux, and O. Gagey, “The subscapular and subcoracoid bursae: descriptive and functional anatomy,” Journal of Shoulder and Elbow Surgery, vol. 13, no. 4, pp. 454–458, 2004.
[29]
P. J. Millett, T. R. Gaskill, M. P. Horan, and O. A. van der Meijden, “Technique and outcomes of arthroscopic scapulothoracic bursectomy and partial scapulectomy,” Arthroscopy, vol. 28, no. 12, pp. 1776–1783, 2012.
[30]
A. H. Conduah, C. L. Baker III, and C. L. Baker Jr., “Clinical management of scapulothoracic bursitis and the snapping scapula,” Sports Health, vol. 2, no. 2, pp. 147–155, 2010.
[31]
H. L. Carlson, A. J. Haig, and D. C. Stewart, “Snapping scapula syndrome: three case reports and an analysis of the literature,” Archives of Physical Medicine and Rehabilitation, vol. 78, no. 5, pp. 506–511, 1997.
[32]
S. S. Burkhart, C. D. Morgan, and W. Ben Kibler, “The disabled throwing shoulder: spectrum of pathology Part I: pathoanatomy and biomechanics,” Arthroscopy, vol. 19, no. 4, pp. 404–420, 2003.
[33]
H. Milch, “Partial scapulectomy for snapping of the scapula,” The Journal of Bone and Joint Surgery, vol. 32, no. 3, pp. 561–566, 1950.
[34]
C. C. Huang, S. Ko, S. Ng et al., “Scapulothoracic bursitis of the chest wall: sonographic features with pathologic correlation,” Journal of Ultrasound in Medicine, vol. 24, no. 10, pp. 1437–1440, 2005.
[35]
E. O. Pearse, J. Bruguera, S. N. Massoud, G. Sforza, S. A. Copeland, and O. Levy, “Arthroscopic management of the painful snapping scapula,” Arthroscopy, vol. 22, no. 7, pp. 755–761, 2006.
[36]
A. Pavlik, K. Ang, J. Coghlan, and S. Bell, “Arthroscopic treatment of painful snapping of the scapula by using a new superior portal,” Arthroscopy, vol. 19, no. 6, pp. 608–612, 2003.
[37]
R. R. Richards and M. D. McKee, “Treatment of painful scapulothoracic crepitus by resection of the superomedial angle of the scapula. A report of three cases,” Clinical Orthopaedics and Related Research, no. 247, pp. 111–116, 1989.
[38]
H. Milch and M. S. Burman, “Snapping scapula and humerus varus. Report of six cases,” Archives of Surgery, vol. 26, no. 4, pp. 570–588, 1933.
[39]
J. G. Edelson, “Variations in the anatomy of the scapula with reference to the snapping scapula,” Clinical Orthopaedics and Related Research, no. 322, pp. 111–115, 1996.
[40]
M. N. Ermis, U. S. Aykut, M. O. Durakbasa, M. S. Ozel, F. S. Bozkus, and E. S. Karakas, “Snapping scapula syndrome caused by subscapular osteochondroma,” Eklem Hastaliklari ve Cerrahisi, vol. 23, no. 1, pp. 40–43, 2012.
[41]
M. F. Blacksin and J. Benevenia, “Neoplasms of the scapula,” American Journal of Roentgenology, vol. 174, no. 6, pp. 1729–1735, 2000.
[42]
J. F. Galate, J. M. Blue, and R. W. Gaines, “Osteochondroma of the scapula,” Missouri Medicine, vol. 92, no. 2, pp. 95–97, 1995.
[43]
N. Kumar, V. Ramakrishnan, G. V. Johnson, and S. Southern, “Endoscopically-assisted excision of scapular osteochondroma,” Acta Orthopaedica Scandinavica, vol. 70, no. 4, pp. 394–396, 1999.
[44]
O. S. Kwon and J. I. Kelly, “Delayed presentation of osteochondroma on the ventral surface of the scapula,” International Journal of Shoulder Surgery, vol. 6, no. 2, pp. 61–63, 2012.
[45]
L. T. Ford and R. H. Ramsey, “Chondrosarcoma of the pelvis and shoulder girdle,” Southern Medical Journal, vol. 55, pp. 901–906, 1962.
[46]
A. M. Strizak and M. H. Cowen, “The snapping scapula syndrome. A case report,” Journal of Bone and Joint Surgery A, vol. 64, no. 6, pp. 941–942, 1982.
[47]
J. T. Lehtinen, J. C. Macy, E. Cassinelli, and J. J. P. Warner, “The painful scapulothoracic articulation: surgical management,” Clinical Orthopaedics and Related Research, no. 423, pp. 99–105, 2004.
[48]
W. B. Kibler, A. Sciascia, and T. Wilkes, “Scapular dyskinesis and its relation to shoulder injury,” Journal of the American Academy of Orthopaedic Surgeons, vol. 20, no. 6, pp. 364–372, 2012.
[49]
J. P. Warner, L. J. Micheli, L. E. Arslanian, J. Kennedy, and R. Kennedy, “Scapulothoracic motion in normal shoulders and shoulders with glenohumeral instability and impingement syndrome: a study using Moire topographic analysis,” Clinical Orthopaedics and Related Research, no. 285, pp. 191–199, 1992.
[50]
G. A. Paletta Jr., J. J. P. Warner, R. F. Warren, A. Deutsch, and D. W. Altchek, “Shoulder kinematics with two-plane x-ray evaluation in patients with anterior instability or rotator cuff tearing,” Journal of Shoulder and Elbow Surgery, vol. 6, no. 6, pp. 516–527, 1997.
[51]
W. B. Kibler and J. McMullen, “Scapular dyskinesis and its relation to shoulder pain,” The Journal of the American Academy of Orthopaedic Surgeons, vol. 11, no. 2, pp. 142–151, 2003.
[52]
V. E. Wood and J. M. Verska, “The snapping scapula in association with the thoracic outlet syndrome,” Archives of Surgery, vol. 124, no. 11, pp. 1335–1337, 1989.
[53]
M. J. Boyle, P. Misur, S.-M. Youn, and C. M. Ball, “The superomedial bare area of the costal scapula surface: a possible cause of snapping scapula syndrome,” Surgical and Radiologic Anatomy, vol. 35, no. 2, pp. 95–98, 2013.
[54]
G. Mozes, J. Bickels, D. Ovadia, and S. Dekel, “The use of three-dimensional computed tomography in evaluating snapping scapula syndrome,” Orthopedics, vol. 22, no. 11, pp. 1029–1033, 1999.
[55]
T. Higuchi, A. Ogose, T. Hotta et al., “Clinical and imaging features of distended scapulothoracic bursitis: spontaneously regressed pseudotumoral lesion,” Journal of Computer Assisted Tomography, vol. 28, no. 2, pp. 223–228, 2004.
[56]
O. Ken, M. Hatori, and S. Kokubun, “The MRI features and treatment of scapulothoracic bursitis: report of four cases,” Upsala Journal of Medical Sciences, vol. 109, no. 1, pp. 57–64, 2004.
[57]
F. M. Solivetti, D. Bacaro, A. Di Luca Sidozzi, and P. Cecconi, “Elastofibroma dorsi: ultrasound pattern in three patients,” Journal of Experimental and Clinical Cancer Research, vol. 22, no. 4, pp. 565–569, 2003.
[58]
R. C. Manske, M. P. Reiman, and M. L. Stovak, “Nonoperative and operative management of snapping scapula,” American Journal of Sports Medicine, vol. 32, no. 6, pp. 1554–1565, 2004.
[59]
W. H. Chang, S. H. Im, J. A. Ryu, S. C. Lee, and J. S. Kim, “The effects of scapulothoracic bursa injections in patients with scapular pain: a pilot study,” Archives of Physical Medicine and Rehabilitation, vol. 90, no. 2, pp. 279–284, 2009.
[60]
J. Hodler, L. A. Gilula, K. T. Ditsios, and K. Yamaguchi, “Fluoroscopically guided scapulothoracic injections,” American Journal of Roentgenology, vol. 181, no. 5, pp. 1232–1234, 2003.
[61]
A. F. Tallia and D. A. Cardone, “Diagnostic and therapeutic injection of the shoulder region,” American Family Physician, vol. 67, no. 6, pp. 1271–1278, 2003.
[62]
G. P. Nicholson and M. A. Duckworth, “Scapulothoracic bursectomy for snapping scapula syndrome,” Journal of Shoulder and Elbow Surgery, vol. 11, no. 1, pp. 80–85, 2002.
[63]
G. D. Harper, S. Mcllroy, J. I. L. Bayley, and P. T. Calvert, “Arthroscopic partial resection of the scapula for snapping scapula: a new technique,” Journal of Shoulder and Elbow Surgery, vol. 8, no. 1, pp. 53–57, 1999.
