Conducting the “Nonshoulder” Shoulder Examination

AARON SCIASCIA W. BEN KIBLER, MD Alterations in the kinetic chain are found in a high percentage of patients Conducting the “nonshoulder” shoulder examination ABSTRACT: Optimal shoulder function is achieved with the kinetic chain. Alterations in this sequenced activation of body segments often are associated with shoulder injury. A screening examination of areas proximal to the shoulder where these alterations often are found can help physicians make the diagnosis. Core stability provides proximal stability for the distal mobility and function of the limbs. Excessive scapular protraction alters the roles of the scapula in shoulder function. Glenohumeral internal rotation deficit creates abnormal scapular kinematics. Many types of tests may be used to estimate or measure core strength. Physical examination of the scapula is designed to establish the presence or absence of scapular dyskinesis. If the examiner detects scapular dyskinesis, corrective ma- neuvers can be applied. (J Musculoskel Med. 2011;28:58-64) Persons performing complex ath- lar dyskinesis is found in a par- BIOMECHANICAL BASIS letic and work tasks achieve opti- ticularly high percentage of pa- The shoulder and core stability mal shoulder function because of tients with shoulder injury. The various body segments play the kinetic chain. This coordinated, The “nonshoulder” shoulder ex- specific roles in the kinetic chain sequenced activation of body seg- amination—a screening examina- activation sequence. The muscles ments places the distal segment in tion of areas proximal to the and joints of the hips, pelvis, and the optimal position at the opti- shoulder that often are associated spine (known collectively as the mal velocity with the optimal tim- with shoulder injury—helps phy- core) are centrally located and can ing to produce the desired task.1 sicians understand the entire perform many of the stabilizing Alterations in the kinetic spectrum of alterations in the ki- functions that the body requires chain—including core instability, netic chain that contribute to the for the distal segments (eg, the scapular dyskinesis (alteration of diagnosis of shoulder injury in limbs) to perform their specific scapular motion), and glenohu- patients who present with chron- functions. Thus, core stability meral internal rotation deficit ic shoulder pain. If alterations are provides proximal stability for (GIRD)—have been associated found, more specific and detailed the distal mobility and function with shoulder injury in 50% to orthopedic examination can pro- of the limbs.6 100% of reported cases.2-5 Scapu- ceed. In addition, the alterations The shoulder acts as a funnel, that are identified can be man- regulating and transferring forces aged as part of treatment of pa- generated from the core struc- Mr Sciascia is program coordinator and tients with shoulder injury. tures to the hand. The scapula Dr Kibler is medical director of the In this article, we describe the (Figure 1) acts as the platform for Shoulder Center of Kentucky in Lexington. biomechanical basis of kinetic the rotator cuff to work from and For this article, the authors have updated chain alterations that are associat- is the stable base of control for their discussion of the “nonshoulder” shoulder examination that first appeared ed with shoulder injury. Then we the arm during activity. in 2006 in The Journal of Musculoskeletal outline the key aspects of the non- Scapular motion has been ex- Medicine. shoulder physical examination. amined in a 3-dimensional con- 58 THE JOURNAL OF MUSCULOSKELETAL MEDICINE | FEBRUARY 2011 www.musculoskeletalnetwork.com text. Studies have shown that it is ward/downward translation on and it must internally/externally a composite of 3 motions: up- the thoracic wall and retraction/ rotate and posteriorly tilt to main- ward/downward rotation around protraction around the ellipsoid tain the glenoid as a congruent a horizontal axis perpendicular to curve of the rib cage. socket for the moving arm and to the scapular plane, internal/ex- In this more complex framework, maximize concavity/compression ternal rotation around a vertical the scapula is shown to have sev- as well as ball-and-socket kine- axis through the plane, and ante- eral additional roles in shoulder matics.8 In addition, it must be sta- rior/posterior tilt around a hori- function: it must posteriorly tilt bilized dynamically in a position zontal axis in the plane.2,7 With an and externally rotate to clear the of relative retraction during arm intact acromioclavicular (AC) acromion from the arm moving in use to maximize activation of all joint, there are 2 translations: up- forward elevation or abduction,3,7 the muscles that originate on it.9 www.musculoskeletalnetwork.com FEBRUARY 2011 | THE JOURNAL OF MUSCULOSKELETAL MEDICINE 59 Conducting the “nonshoulder” shoulder examination Scapular dyskinesis trol of the translation of scapular and nerve injury—and usually are This kinetic chain alteration is a retraction—regarded as a key ele- managed with rehabilitation. combination of decreased poste- ment in closed-chain coupled Muscle weakness has been dem- rior tilt and decreased external scapulohumeral rhythm2,7,10—and onstrated in the serratus anterior rotation as well as decreased up- of the motion of external rotation. and lower trapezius muscles in ward rotation.2,3 The predominant If control is lost, gravity, forward patients with impingement.3,13 In- finding on clinical examination is arm motion, and muscle activa- flexibility in the pectoralis minor prominence of the medial border tions take the arm and shoulder muscle—an absolute decrease in of the scapula on observation at girdle forward. The biomechani- muscle length and increased mus- rest or on motion of the arm in el- cal result is a tendency toward cle activation in response to ten- evation (Figure 2). The prominence scapular internal rotation and sile loads—is a common finding represents loss of dynamic con- protraction around the rib cage. in these patients.14 A somewhat Excessive scapular protraction rare proximal cause is true nerve alters the roles of the scapula in injury to the long thoracic or shoulder function.11 The normal accessory nerve. Bony proximal timing and magnitude of acromial causes include thoracic kyphosis motion are changed; the subacro- and scoliosis with resultant al- mial space distance is altered; teration in scapular position. the glenohumeral (GH) arm angle Distal causative factors most may be increased, resulting in the often are associated with anatom- “hyperangulated” joint; and max- ical injuries in the AC or GH joints. imal muscle activation may be They also alter muscle activation decreased. patterns or activations by causing There are 2 categories of causes instability of the bones or through Figure 2 – Medial border prominence of scapular dyskinesis: those pain-based inhibition; they often of the scapula is seen in this patient. proximal and those distal to the require surgery to eliminate their This is the predominant finding on scapula.12 Proximal causative fac- effects and provide the basis for clinical examination in patients with scapular dyskinesis, a kinetic chain tors most often include direct al- effective rehabilitation. GH insta- alteration that is common in shoul- teration of muscle properties— bility is associated with altered der injury. inflexibility, weakness, fatigue, serratus anterior activation.15 (continued on page 61) B Figure 3 – This patient presented with glenohumeral internal rotation deficit (GIRD) (A), another common kinetic chain alteration. Side-to-side A comparison (B) is used to demonstrate the asymmetry that is character- istic of GIRD. 60 THE JOURNAL OF MUSCULOSKELETAL MEDICINE | FEBRUARY 2011 www.musculoskeletalnetwork.com Conducting the “nonshoulder” shoulder examination (continued from page 60) GIRD This common distal causative fac- tor—defined as side-to-side asymmetry of greater than 25° or an absolute value of less than 25° (Figure 3)—is thought to be pro- duced by acquired posterior cap- sular contracture and posterior muscle stiffness; it is seen fre- quently in all types of shoulder injuries.16,17 GIRD creates abnormal scapular kinematics as a result of the “windup” effect of the arm on the scapula. As the arm is forward flexed, horizontally ad- ducted, and internally rotated during a throwing or working activity, the tight capsule and mus- B cles pull the scapula into a pro- tracted, internally rotated, and anteriorly tilted position; this Figure 4 – The 1-leg standing balance causes downward rotation of the test (A) is used to assess a patient’s core strength and stability. A positive acromion, thus creating unde- Trendelenburg test result (B) indicates sired scapular positioning. A inability to control the posture and suggests proximal core weakness. THE PHYSICAL EXAMINATION sulting motions in the 3 planes posture and suggests proximal Assessing quality of movement of trunk motion. This method of core weakness. Many types of tests have been de- analysis is difficult to quantify, The 1-leg squat increases load scribed to estimate or measure but it is similar to actual 3-planar and may show deficits that are core strength. Because core core function testing. not seen in stance. The patient as- strength and core stability are One assessment method that sumes the same starting point as composite actions that involve incorporates many of these vari- in the standing balance test; he or many segments, tests of individu- ables is a 3-part protocol: a 1-leg she is asked to perform repetitive al joints and muscles usually are standing balance ability test; a partial (quarter to half) squats not satisfactory. Evaluation of 1-leg squat test; and a standing, and is given no other verbal cues. specific patterns of motion and 3-plane core strength test.6 The Deviations in the quality of the sequences of muscle activation screening part of the evaluation movement similar to those in the and assessment of the result—the includes the 1-leg standing and standing balance test are as- quality of the movement—is most 1-leg squat tests.

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