Internal Rotation Lag Sign

Internal Rotation Lag Sign is used to check for the integrity of the subscapularis tendon of the rotator cuff of the shoulder.

How do you perform Internal Rotation Lag Sign?

• The patient is sitting or standing with his or her back to the examiner.
• The affected arm is held by the examiner in almost maximal internal rotation.
• The elbow is flexed to 90 degrees, and the shoulder is held at 20 degrees of elevation and 20 degrees of extension.
• The dorsum of the hand is passively lifted away from the lumbar region until almost full internal rotation is reached.
• The patient is asked to maintain this position actively as the examiner releases the wrist while maintaining support at the elbow.

See Also: Neer Test

What does a positive Internal Rotation Lag Sign mean?

If there is a tear of the subscapularis tendon, the patient is unable to actively hold the submaximally internally rotated position. The arm recoils against the back.

Sensitivity & Specificity

A study by Hertel et al.¹ reported high sensitivity and specificity with this test:

• Sensitivity: 97 %
• Specificity: 96 %

Another study by Caroline A Miller ² found that the specificities of the drop sign and internal rotation lag sign were 77% and 84%, respectively, and a sensitivity of 73% and 100%, respectively.

Diagnostic Utility of Internal rotation lag sign for Identifying Subscapularis Tears:

Population	Reference Standard	Sens	Spec	+LR	-LR
37 patients with shoulder pain	Subscapularis tear diagnosed via ultrasound	1.0	.84	6.2 (1.9, 12.0)	.00 (.00, 2.50)
55 patients suffering from subacromial and/or glenohumeral impingement syndrome scheduled for an arthroscopic procedure	Subscapularis tear diagnosed via arthroscopic visualization	.71	.60	1.8	.48
312 patients scheduled to undergo arthroscopic shoulder surgery	Subscapularis tear diagnosed via arthroscopic visualization	.20	.97	6.7	.83

Related Anatomy

Subscapularis Muscle

• Subscapularis Muscle originates from Ventral scapula.
• It inserts on Humerus (lesser tuberosity).
• Its action include Internally rotates the arm and provided anterior stability to the shoulder joint.
• It innervates from upper and lower subscapular nerves.

Reference

1. Hertel R, Ballmer FT, Lombert SM, et al: Lag signs in the diagnosis of rotator cuff rupture. J Elbow Shoulder Surg Am 5:307–313, 1996. PMID: 8872929.
2. Caroline A Miller, Gail A Forrester, Jeremy S Lewis: The validity of the lag signs in diagnosing full-thickness tears of the rotator cuff: a preliminary investigation. Arch Phys Med Rehabil. 2008 Jun. PMID: 18503815.
3. Miller CA, Forrester GA, Lewis JS. The validity of the lag signs in diagnosing full-thickness tears of the rotator cuff: a preliminary investigation. Arch Phys Med Rehabil. 2008 Jun;89(6):1162-8. doi: 10.1016/j.apmr.2007.10.046. PMID: 18503815.
4. Bartsch M, Greiner S, Haas NP, Scheibel M. Diagnostic values of clinical tests for subscapularis lesions. Knee Surg Sports Traumatol Arthrosc. 2010 Dec;18(12):1712-7. doi: 10.1007/s00167-010-1109-1. Epub 2010 Apr 8. PMID: 20376624.
5. Yoon JP, Chung SW, Kim SH, Oh JH. Diagnostic value of four clinical tests for the evaluation of subscapularis integrity. J Shoulder Elbow Surg. 2013 Sep;22(9):1186-92. doi: 10.1016/j.jse.2012.12.002. Epub 2013 Feb 20. PMID: 23434234.
6. Clinical Tests for the Musculoskeletal System 3rd Edition.
7. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
8. Netter’s Orthopaedic Clinical Examination An Evidence-Based Approach 3rd Edition Book.