2012 Annual Conference

Loyd, BJ, SPT

Texas Tech University, Lubbock, TX

Mobilization treatment to the first rib is an important technique when managing pain and dysfunction in the cervicothoracic region.  Proper location of the first rib using surface anatomy and palpation is key to providing effective treatment. One method used to locate the first rib requires locating the first thoracic (T1) transverse process (TP) at which the first rib articulates. However, proper palpation of the T1 TP is often challenging.  It has been proposed that the width from the left TP to right TP of T1 (T1 TP span) is closely related to the width from left TP to the right TP of the first cervical vertebrae (C1 TP span).  Location of the more easily palpated TP of the first cervical vertebrae (C1) may provide a reference point for the T1 TP, thus allowing for proper location of the first rib. To test this from an anatomical standpoint, the authors aimed to examine the relationship between C1 TP span and T1 TP span. In addition, the authors aimed to establish that palpation of the first rib at a point equal to the width of the mastoid process would lead the clinician to a point just lateral to the costotransverse joint of the first rib.  This location just lateral to the costotransverse joint is the appropriate location for initiating first rib spring testing and mobilization techniques. Therefore, the purpose of this study was to establish the C1 TP span and mastoid process span and examine how each of these spans relate to the width of T1 TP span in embalmed cadavers. Results of this study provide valuable information regarding the location of the first rib during testing and treatment.

Twenty-eight prone lying cadavers (13 female, 15 male; average age 79 years) were incorporated.

All overlying soft tissues covering the mastoid process, first cervical vertebrae, and first thoracic vertebrae that included the first costotransverse joint capsule, were removed bilaterally. An individual rater, blinded to the measurement outcome, collected all measurement data. Measurements were taken using a Wiha digiMax ® digital caliper and recorded to a precision of 1/10^th of a millimeter (mm). Three consecutive measurements were taken for each structure, where the caliper was returned to the zero point before each measurement. Mean data were established for the three measures of each structure and analyzed using an Intraclass Correlation Coefficient (ICC 3,k) to determine the relationship between the C1 TP span and T1 TP span, as well as between mastoid process span and T1 TP span. Additionally, the mean absolute difference (mm) between the different spans was established for palpation location and accuracy purposes.

Measurement intra-tester reliability was calculated at r=0.99. An ICC of 0.877 was observed between C1 TP span and T1 TP span. The mean (SD) absolute difference between C1 TP span versus T1 TP span was 3.9(+ 2.58) mm. The relationship between mastoid process span and T1 TP span produced a correlation coefficient of ICC=0.709 with a mean (SD) absolute difference of 35.4(+ 6.46) mm. 

The results of this cadaveric study support the use of C1 TP to locate the T1 TP. In addition the results indicate that the mastoid process span is consistently wider than that of T1 TP. This difference indicates that the mastoid process is approximately 1.75 cm farther lateral than the T1 TP process, unilaterally.  Recognition of this relationship may be beneficial to the clinician when locating the first rib during palpation.  Palpation of the first rib at the width of the mastoid process will consistently place the clinician on the first rib at a position lateral to the T1 TP.