Subscapularis

Structure

This course describes the anatomy and integrated function of the subscapularis, which is 1 of 4 rotator cuff muscles (a.k.a. SITS muscles). Sometimes referred to as the anterior rotator cuff, the subscapularis originates from a depression that covers the majority of the anterior surface of the scapula (shoulder blade), known as the subscapular fossa. The subscapularis courses distally into the subscapularis tendon which inserts into the the superior and medial aspect of the lesser tubercle of the humerus and capsule of the glenohumeral (shoulder) joint. The subscapularis occupies its own fascial compartment, covered by a fascial sheath that may be a continuation of the axillary fascia and serratus anterior fascia by coursing medially, investing in the medial border of the scapula, and then folding back over itself covering the subscapularis. Research suggests that the subscapularis is a relatively large upper body muscle, contributing to approximately 6.6% of the total upper body muscle mass (for comparison, the pectoralis major contributes approximately 10%), and the subscapularis is the largest rotator cuff muscle (the infraspinatus is the 2nd largest rotator cuff muscle). Additionally, research suggests that the subscapularis is composed of only about 20 - 40% type I muscle fiber (4, 5).

Function:

The subscapularis muscle crosses the shoulder (glenohumeral) joint and contributes to internal rotation, adduction, and shoulder stabilization. This course also describes the role of the subscapularis on shoulder (glenohumeral) arthrokinematics, fascial integration, subsystem integration, and postural dysfunction. For example, the subscapularis may act synergistically with the latissimus dorsi, pectoralis major, and teres major to contribute to internal rotation and inferior glide of the humeral head in the glenoid fossa. If these actions occur excessively due to muscle over-activity, they may be a component of the sign "Arms Fall " during an Overhead Squat Assessment , and postural dysfunction (e.g. movement impairment) of the upper body.

Practical Application:

Sports medicine professionals (personal trainers, fitness instructors, physical therapists, massage therapists, chiropractors, occupational therapists, athletic trainers, etc.) must be aware of the integrated function of the subscapularis for detailed assessment and analysis of human movement, and the development of sophisticated exercise programs and therapeutic (rehabilitation) interventions. For example, altered activity and length of the subscapularis may contribute to rotator cuff injury, rotator cuff tears, shoulder pain, shoulder conditions, shoulder impingement syndrome (SIS), biceps tendon impingement and the resulting weakness and pain during motion such as external rotation and internal rotation. Altered subscapularis activity may also result in a reduction in infraspinatus and teres minor activity, resulting in a significant reduction in upper body speed, agility, and strength, and a reduction in the effectiveness of resistance training intended to improve upper body strength and hypertrophy (bodybuilding). Deeper knowledge of subscapularis anatomy is essential for optimal assessment, intervention selection, and building a repertoire of subscapularis specific techniques.

Pre-approved credits for:

• Human Movement Specialist (HMS) Certification

Pre-approved for Continuing Education Credits for:

• Athletic Trainers
• Chiropractors
• Group Exercise Instructors
• Massage Therapists
• Occupational Therapists - Intermediate
• Personal Trainers
• Physical Therapists
• Physical Therapy Assistants
• Physiotherapists
• Yoga Instructors

This Course Includes:

• AI Tutor
• Webinar
• Study Guide
• Text and Illustrations
• Audio Voice-over
• Research Review
• Technique Videos
• Case Study and Sample Routine
• Practice Exam
• Pre-approved Final Exam

Sample Intervention: Loss of Shoulder Range of Motion

• Client/Patient History: History of shoulder pain
• Overhead Squat Assessment:
  • Arms Fall
• Goniometry:
  • Shoulder External Rotation in Supine: < 90°
  • Shoulder Flexion (with Scapular Motion) : <180°
• Manual Muscle Testing :
  • Shoulder External Rotator: Weak

Sample Self-administered Intervention

• Release
  • Subscapularis Static Release
  • Latissimus Dorsi Static Release
• Mobilization or Manipulation
  • Shoulder Mobilization
• Lengthening
  • Subscapularis (and Pectoralis Major and Minor) Static Stretch
• Activation
  • Shoulder External Rotation Isolated Activation
  • Serratus Anterior Isolated Activation
  • Standing Cobras (Trapezius Activation)
• Reactive Activation
  • Trapezius Reactive Activation
• Integration
  • Squat to Row (Posterior Oblique Subsystem)

Additional Courses and Techniques:

Brookbush Institute’s most recommended techniques for the Subscapularis (see videos below):

• Introduction to Functional Anatomy: Lesson 9: Rotator Cuff
• Self-administered Release: Subscapularis Static Release
• Manual Release: Subscapularis Static Manual Release
• Static Stretch: Subscapularis (and Pectoralis Major and Minor) Static Stretch
• Dynamic Stretch: Dynamic Pec (Pectoralis Major and Minor) Subscapularis Stretch
• Isolated Activation: Subscapularis Isolated Activation

Caption: The subscapularis muscle as part of the rotator cuff

1. David B. Jenkins, Hollinshead's Functional Anatomy of the Limbs and Back: Eighth Edition © 2002 Saunders
2. Donald A. Neumann, “Kinesiology of the Musculoskeletal System: Foundations of Rehabilitation – 2nd Edition” © 2012 Mosby, Inc.
3. Florence Peterson Kendall, Elizabeth Kendall McCreary, Patricia Geise Provance, Mary McIntyre Rodgers, William Anthony Romani, Muscles: Testing and Function with Posture and Pain: Fifth Edition © 2005 Lippincott Williams & Wilkins
4. Holzbaur KR, Murray WM, Gold GE, Delp SL. Upper limb muscle volumes in adult subjects. J Biomech. 2007;40(4):742-9
5. Lovering, R. M., & Russ, D. W. (2008). Fiber type composition of cadaveric human rotator cuff muscles. journal of orthopaedic & sports physical therapy, 38(11), 674-680.
6. Cho, T. H., Hong, J. E., & Yang, H. M. (2023). Neuromuscular compartmentation of the subscapularis muscle and its clinical implication for botulinum neurotoxin injection. Scientific Reports, 13(1), 11167.
7. Cynthia C. Norkin, Pamela K. Levangie, Joint Structure and Function: A Comprehensive Analysis: Fifth Edition © 2011 F.A. Davis Company
8. Heuberer P, Kranzi A, Laky B, et al. (2015). Electromyographic analysis: shoulder muscle activity revisited. Arch Orthop Trauma Surg. 135: 549-563.
9. Wickham J, Pizzari T, Balster S, et al. (2014). The variable roles of the upper and lower subscapularis during shoulder motion. Clinical Biomechanics. 29: 885-891.
10. Reed D, Cathers I, Halaki M, Ginn KA. (2015). Does load influence shoulder muscle recruitment patterns during scapular plane abduction? Journal of Science and Medicine in Sport.
11. Inman VT, Saunders JB, Abbot JC, Observations on the function of the shoulder joint. J Bone Joint Surg 26:1 - 30, 1944
12. Lawrence, R.L., Braman, J.P., Staker, J.L., Laprade, R.F., Ludewig, P.M. (2014) Comparison of 3-dimensional shoulder complex kinematics in individuals with and without shoulder pain, Part 2: Glenohumeral joint. Journal of Orthopaedic & Sports Physical Therapy 44(9). 646-B3
13. Harryman DT II, Sidles JA, Clark JM, McQuade KJ, Gibb TD, Matsen FA 3rd: Translation of the humeral head on the glenoid with passive glenohumeral motion. J Bone Joint Surg Am 72:1334, 1990
    • Fascial Integration:
14. Benjamin, M. (2009). The fascia of the limbs and back–a review. Journal of anatomy, 214(1), 1-18.
15. Stecco, C., Porzionato, A., Lancerotto, L., Stecco, A., Macchi, V., Day, J. A., & De Caro, R. (2008). Histological study of the deep fasciae of the limbs. Journal of bodywork and movement therapies, 12(3), 225-230.
16. Stecco, C., Pavan, P. G., Porzionato, A., Macchi, V., Lancerotto, L., Carniel, E. L., … & De Caro, R. (2009). Mechanics of crural fascia: from anatomy to constitutive modelling. Surgical and Radiologic Anatomy, 31(7), 523-529.
17. Levangin, H.M. 2006. Connective tissue : a body-wide signaling network? Med. Hypoththeses 66, 1074-1077
18. Tom Myers, Anatomy Trains: Second Edition. © Elsevier Limited 2009
19. Tubbs, R. S., Shoja, M. M., Shokouhi, G., Loukas, M., & Oakes, W. J. (2008). Insertion of the pectoralis major into the shoulder joint capsule. Anatomical science international, 83(4), 291–293. https://doi.org/10.1111/j.1447-073X.2007.00214.x
    • EMG Activity:
    • Comparing Joint Actions
20. Dark, Alanna, Karen A. Ginn, and Mark Halaki. (2007). "Shoulder muscle recruitment patterns during commonly used rotator cuff exercises: an electromyographic study." Physical Therapy, 87 (8),1039-1046.
21. Gaudet, S., Tremblay, J., & Begon, M. (2018). Muscle recruitment patterns of the subscapularis, serratus anterior and other shoulder girdle muscles during isokinetic internal and external rotations. Journal of Sports Sciences, 36(9), 985–993. https://doi.org/10.1080/02640414.2017.1347697
22. Heuberer, P., Kranzl, A., Laky, B., Anderl, W., & Wurnig, C. (2015). Electromyographic analysis: shoulder muscle activity revisited. Archives of orthopaedic and trauma surgery, 135(4), 549–563. https://doi.org/10.1007/s00402-015-2180-3
23. Wickham, J., Pizzari, T., Balster, S., Ganderton, C., & Watson, L. (2014). The variable roles of the upper and lower subscapularis during shoulder motion. Clinical Biomechanics (Bristol, Avon), 29(8), 885–891. https://doi.org/10.1016/j.clinbiomech.2014.07.003
24. Day, A., Taylor, N. F., & Green, R. A. (2012). The stabilizing role of the rotator cuff at the shoulder--responses to external perturbations. Clinical Biomechanics (Bristol, Avon), 27(6), 551–556. https://doi.org/10.1016/j.clinbiomech.2012.02.003
    • Strength Training
25. Hintermeister, R. A., Lange, G. W., Schultheis, J. M., Bey, M. J., & Hawkins, R. J. (1998). Electromyographic activity and applied load during shoulder rehabilitation exercises using elastic resistance. The American Journal of Sports Medicine, 26(2), 210–220. https://doi.org/10.1177/03635465980260021001
26. Decker, M. J., Tokish, J. M., Ellis, H. B., Torry, M. R., & Hawkins, R. J. (2003). Subscapularis muscle activity during selected rehabilitation exercises. The American Journal of Sports Medicine, 31(1), 126–134. https://doi.org/10.1177/03635465030310010601
27. Swanik, K. A., Huxel Bliven, K., & Swanik, C. B. (2011). Rotator-cuff muscle-recruitment strategies during shoulder rehabilitation exercises. Journal of Sport Rehabilitation, 20(4), 471–486. https://doi.org/10.1123/jsr.20.4.471
    • Passive and Active Range of Motion (ROM) Exercise
28. Jung, M. C., Kim, S. J., Rhee, J. J., & Lee, D. H. (2016). Electromyographic activities of the subscapularis, supraspinatus, and infraspinatus muscles during passive shoulder and active elbow exercises. Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA, 24(7), 2238–2243. https://doi.org/10.1007/s00167-015-3586-8
29. Cross, J., Devries, J., Mocarski, M., Ketchum, N. Compty, N., Kimmer, E., Fritz, J., Vetter, C. (2020)."Electromyography of the shoulder musculature during passive rehabilitation exercises." Journal of Shoulder and Elbow Arthroplasty, 170(4),
30. Gurney, A. B., Mermier, C., LaPlante, M., Majumdar, A., O'Neill, K., Shewman, T., & Gurney, J. G. (2016). Shoulder Electromyography Measurements During Activities of Daily Living and Routine Rehabilitation Exercises. The Journal of Orthopaedic and Sports Physical Therapy, 46(5), 375–383. https://doi.org/10.2519/jospt.2016.6090
    • Clinical Tests Performed by Healthy Individuals
31. Tokish, J. M., Decker, M. J., Ellis, H. B., Torry, M. R., & Hawkins, R. J. (2003). The belly-press test for the physical examination of the subscapularis muscle: electromyographic validation and comparison to the lift-off test. Journal of Shoulder and Elbow Surgery, 12(5), 427–430. https://doi.org/10.1016/s1058-2746(03)00047-8
32. Chao, S., Thomas, S., Yucha, D., Kelly, J. D., 4th, Driban, J., & Swanik, K. (2008). An electromyographic assessment of the "bear hug": an examination for the evaluation of the subscapularis muscle. Arthroscopy: The Journal of Arthroscopic & Related Surgery: official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 24(11), 1265–1270. https://doi.org/10.1016/j.arthro.2008.01.022
33. Pennock, A. T., Pennington, W. W., Torry, M. R., Decker, M. J., Vaishnav, S. B., Provencher, M. T., Millett, P. J., & Hackett, T. R. (2011). The influence of arm and shoulder position on the bear-hug, belly-press, and lift-off tests: an electromyographic study. The American Journal of Sports Medicine, 39(11), 2338–2346. https://doi.org/10.1177/0363546510392710
34. Ginn, K. A., Reed, D., Jones, C., Downes, A., Cathers, I., & Halaki, M. (2017). Is subscapularis recruited in a similar manner during shoulder internal rotation exercises and belly press and lift-off tests? Journal of Science and Medicine in Sport, 20(6), 566–571. https://doi.org/10.1016/j.jsams.2016.10.018
    • Throwing
35. Gowan, I. D., Jobe, F. W., Tibone, J. E., Perry, J., & Moynes, D. R. (1987). A comparative electromyographic analysis of the shoulder during pitching. Professional versus amateur pitchers. The American Journal of Sports Medicine, 15(6), 586–590. https://doi.org/10.1177/036354658701500611
36. Jobe, F. W., Tibone, J. E., Perry, J., & Moynes, D. (1983). An EMG analysis of the shoulder in throwing and pitching. A preliminary report. The American Journal of Sports Medicine, 11(1), 3–5. https://doi.org/10.1177/036354658301100102
37. Maffet, M. W., Jobe, F. W., Pink, M. M., Brault, J., & Mathiyakom, W. (1997). Shoulder muscle firing patterns during the windmill softball pitch. The American Journal of Sports Medicine, 25(3), 369–374. https://doi.org/10.1177/036354659702500317
38. Hess, S. A., Richardson, C., Darnell, R., Friis, P., Lisle, D., & Myers, P. (2005). Timing of Rotator Cuff Activation During Shoulder External Rotation in Throwers With and Without Symptoms of Pain. Journal of Orthopaedic & Sports Physical Therapy, 35(12), 812–820. doi:10.2519/jospt.2005.35.12.8
39. Glousman R, Jobe F, Tibone J, Moynes D, Antonelli D, Perry J. (1988). Dynamic Electromyographic analysis of the throwing shoulder with glenohumeral instability. J Bone Joint Surg 70A(2):220-226.
    • Swimming
40. Pink, M., Ruwe, P., Scovazzo, M. (1992). "The normal shoulder during the backstroke: an EMG and cinematographic analysis of 12 muscles." Clinical Journal of Sport Medicine 22 (6), 6-12.
41. Perry, J., Pink, M.M., Jobe, F.W., Kerrigan, J., Browne, A., & Scovazzo, M.L. (1992). The Painful Shoulder During the Backstroke: An Emg and Cinematographic Analysis of 12 Muscles. Clinical Journal of Sport Medicine, 2, 13-20.
    • Effects of Pain and Dysfunction
42. Scovazzo, M. L., Browne, A., Pink, M., Jobe, F. W., & Kerrigan, J. (1991). The painful shoulder during freestyle swimming: an electromyographic cinematographic analysis of twelve muscles. The American Journal of Sports Medicine, 19(6), 577-582.
43. Reddy, A. S., Mohr, K. J., Pink, M. M., & Jobe, F. W. (2000). Electromyographic analysis of the deltoid and rotator cuff muscles in persons with subacromial impingement. Journal of Shoulder and Elbow Surgery, 9(6), 519-523.
44. Myers, J. B., Hwang, J. H., Pasquale, M. R., Rodosky, M. W., Ju, Y. Y., & Lephart, S. M. (2003). Shoulder muscle coactivation alterations in patients with subacromial impingement. Medicine & Science in Sports & Exercise, 35(5), S346.
45. Kelly, B. T., Williams, R. J., Cordasco, F. A., Backus, S. I., Otis, J. C., Weiland, D. E., Altchek, D. W., Craig, E. V., Wickiewicz, T. L., & Warren, R. F. (2005). Differential patterns of muscle activation in patients with symptomatic and asymptomatic rotator cuff tears. Journal of Shoulder and Elbow Surgery, 14(2), 165–171. https://doi.org/10.1016/j.jse.2004.06.010
46. Myers, J. B., Ju, Y. Y., Hwang, J. H., McMahon, P. J., Rodosky, M. W., & Lephart, S. M. (2004). Reflexive muscle activation alterations in shoulders with anterior glenohumeral instability. The American Journal of Sports Medicine, 32(4), 1013-1021.
    • Movement Dysfunction
47. Wang HK, Cochorane T. (2001). Mobility impairment, muscle imbalance, muscle weakness, scapular asymmetry and shoulder injury in elite volleyball athletes. J Sport Med Phys Fitness 41(3): 403-10
48. Harryman, D. T., 2nd, Sidles, J. A., Clark, J. M., McQuade, K. J., Gibb, T. D., & Matsen, F. A., 3rd (1990). Translation of the humeral head on the glenoid with passive glenohumeral motion. The Journal of Bone and Joint Surgery. American Volume, 72(9), 1334–1343.
49. Ibarra, J. M., Ge, H. Y., Wang, C., Martínez Vizcaíno, V., Graven-Nielsen, T., & Arendt-Nielsen, L. (2011). Latent myofascial trigger points are associated with an increased antagonistic muscle activity during agonist muscle contraction. The Journal of Pain, 12(12), 1282–1288. https://doi.org/10.1016/j.jpain.2011.09.005
50. Sahrmann, S.A. Diagnoses and Treatment of Movement Impairment Syndromes, © 2002 Mosby Inc.
    • Trigger Point
51. David G. Simons, Janet Travell, Lois S. Simons, Travell & Simmons’ Myofascial Pain and Dysfunction, The Trigger Point Manual, Volume 1. Upper Half of Body: Second Edition,© 1999 Williams and Wilken