1) Factor of internal impingement
▷ Anterior capsular laxity
▷ Posterior capsular tightness
▷ Scapular dyskinesis
▷ Hyperangulation & hyperexternal rotation
=> but internal impingement is a normal physiological phenomenon
2) Factors of SAIS(subacromial impingement syndrom)
○ Intrinsic mechanics
overuse
tension overload
trauma of the tendons
○ Extrinsic mechanisc
dysfunctional rotator cuff musculature
weak or dysfunctional scapular musculature
posterior gleno-humeral capsule tightness
postural dysfunctions of the spinal column
○ SASI may lead th a full-thickness tear of the rotator cuff tendons & tendinopathy
3) Extrinsic acromial length
○ Acromial index (ratio), positive correlation in impingement and RCT
>Greater in East Asian than North American
4) Dysfunction of rotator cuff
○ Supraspinatus weakness
○ Fatigue of the infraspinatus and teres minor
less scapular posterior tilit (scapular retraction)
○ During the 30 to 90
Subcaupualris & infraspinatus was the only muscles with decreased activity
5) Role of subscapularis
○ Subscapularis is the “hidden culprit” of the rotator cuff
○ Fibrosis or scarring of the subcaupularis
○ Primary restrict passive external rotation at AB 90 and 0, limiting ER in the adducted position.
6) Weakness & dysfunction trapezius
○ Excessive upper trapezius activation
between 40 to 100
increased anterior tilt scapulo-thoracic joint
○ Lack of activity in the middle & lower trapezius & serratus anteror
7) abnormal posture
○ Forward postuer
Abduction and elevation of the scapula
Appear winging scaupular and medial rotationof humerus
Increase thoracic khyposis angle
Relatively more elevation, protraction, anterior tilt and a downwardly rotated posture
○ Cause
Tightness of pectoralis minor, biceps short head, levator scapular, upper trapezius
Weakness of middle, lower trapezius, serratus anterior
Leading th subacromial impingement syndrome
8) Role of latissimus dorsi
○ Teres major and latissimus dorsi can also provide humeral depression forces secondary to their anatomical alignment.
○ Tight latissimus dorsi
cause of chronic shoudler pain
▷ tendinous fascia connecting the latissimus dorsi th the thoracic and lumbar spine.
9) Functionally tightened muscles
○ Pectoralis minor & biceps short head
○ Levator scapulae & upper trapezius
○ Latissimus dorsi & subscapularis
○ Superficial cervical flexor muscles
10) Inhibited or weakened functionally
○ Rhombiodeus & mid and lower trapezius & serratus anterior
○ Teres minor & infraspinatus & posterior deltoid
○ Deep flexor cervical muscles
○ Especially, lower stabilizers of the scapula (serratus anterior, middle trapezius, and lower trapezius)
Reference
The lat length test ELEATE SPORTS ACADEMY
Musculoskeletal Evidence based Treatment
Morrey BF, An KN (1990) Biomechanics of the shoulder. In: Rockwood CR, Matsen FA (ed) The shoulder. Saunders, Philadelphia, pp 208–245Google Scholar.
lippitt. clin orthop relat res (1993) Rotator Cuff Tears: causes of shoulder pain: Stabilizing effect of negative intraarticular pressure
L. Kessel, M. Watson Published 1 May 1977 Medicine The Journal of bone and joint surgery. British volume The painful arc syndrome. Clinical classification as a guide to management.
Rotsalai Kanlayanaphotporn, Ph.D. (Health Sciences), M.Appl.Sc. (Physiotherapy), B.Sc. (Physical Therapy) Published:November 04, 2013 Changes in sitting posture affect shoulder range of motion
Sally Raine, PhD, Lance T. Twomey, PhD Head and Shoulder Posture Variations in 160 Asymptomatic Women and Men
Raine S, Twomey LT. Head and shoulder posture variations in 160 asymptomatic women and men. Arch Phys Med Rehabil 1997;78:1215-23.
Journal of Orthopaedic & Sports Physical Therapy Published Online:July 1, 2004 Electromyographic Analysis of the Rotator Cuff and Deltoid Musculature During Common Shoulder External Rotation Exercises
P. Chalmers, G. Cvetanovich, +5 authors G. Nicholson Published 1 February 2016 Medicine Journal of shoulder and elbow surgery. The champagne toast position isolates the supraspinatus better than the Jobe test: an electromyographic study of shoulder physical examination tests.
Andrea J Johnson 1, Joseph J Godges, Grenith J Zimmerman, Leroy L Ounanian The effect of anterior versus posterior glide joint mobilization on external rotation range of motion in patients with shoulder adhesive capsulitis DOI: 10.2519/jospt.2007.2307
Robert C. Manske, PT, DPT*, Matt Meschke, DO, Andrew Porter, DO, Barbara Smith, PhD, PT, Michael Reiman, PT, DPTFirst Published December 22, 2009 A Randomized Controlled Single-Blinded Comparison of Stretching Versus Stretching and Joint Mobilization for Posterior Shoulder Tightness Measured by Internal Rotation Motion Loss
Choo Yeonki, PT, Ph.D Dept. of Rehabilitation Therapy, Guposungshim Hospital, Manager Effects of Mobilization with Movement Combined with Exercise(EMWM) on ADH, ROM and Functional Performance in Patients with Impingement Syndrome of the Shoulder
The effect of shoulder position on inferior glenohumeral mobilization Dexter W. Witt DHS, DPT, MHS, PT, OCS, FAAOMPT *, Nancy R. Talbott PhD, MS, PT, RMSK