A thorough understanding of upper limb anatomy plays a critical role in elucidating the etiology of CTS. Osteopathic structural examination serves to detect somatic dysfunctions, defined as altered or impaired body structures that involve skeletal, arthrodial, myofascial, vascular, lymphatic, and neural components. Diagnostic criteria are tenderness, asymmetry, restriction, and tissue texture changes, or TART.
42 For patients with CTS, osteopathic structural examination would focus on somatic dysfunction in the hand, wrist, and upper limb. Palpatory examination should focus on the following anatomic components:
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Carpal Tunnel—First, the carpal tunnel contents should be examined using modified range-of-motion procedures reported by Sucher,
43 which were designed for the assessment of somatic dysfunction. Restrictions of motion are graded from 0 to 5 according to the following scale: 0, no restriction; 1, mild restriction; 2, moderate restriction; 3, moderate to marked restriction; 4, marked restriction; and 5, extremely marked restriction.
43 Patients are assessed in the seated position with the wrist flexed to approximately 90° (
Figure 5 and
Figure 6).
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Carpal and Metacarpal Bones—Second, the carpal and metacarpal bones should be examined by assessing for restriction of motion. Dislocation or displacement of the lunate bone can compress the median nerve and lead to CTS; attention should focus on this carpal bone. Additionally, the lunate bone is surrounded by other carpal bones, and the TCL, which contributes to the tunnel, is attached to 4 carpal bones (ie, hamate, pisiform, scaphoid, and trapezium). Hence, each carpal bone should be evaluated because any degree of displacement can affect carpal tunnel anatomy and may therefore increase intratunnel pressure. Subsequently, as a result of carpal bone articulation with the metacarpals, assessment of the metacarpal bones must be included in the examination. These bones articulate with the distal carpal bones, and any metacarpal restriction can thus influence carpal bone alignment.
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Distal Radius and Ulna—Third, because the distal radius and ulna also influence carpal bone position and motion, particularly the lunate bone, evaluation of the radiocarpal and ulnocarpal joints must be performed (
Figure 7 and
Figure 8).
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Anterior Forearm Muscles and Interosseous Membrane—Fourth, the anterior forearm muscles and interosseous membrane stabilize the radius and ulna in the forearm. Dysfunction in these supporting tissues affects the position of the radius and ulna, which alters the anatomic position of the carpal bones and tendons traversing the carpal tunnel. Palpation of the interosseous membrane and anterior forearm muscles may reveal areas of a taut fibrous band, pain, or ease-bind tissue elasticity asymmetry.
The osteopathic palpatory findings, imaging findings, and results of electrodiagnostic studies should be correlated with clinical symptoms and subjective patient reports of suspicious pain, tenderness, paresthesia, or restrictions in active range of motion to more definitively diagnose CTS.