Proximity of the Carotid Bifurcation to the Laryngeal Prominence: Results of a Cadaver Study and Recommendations for Safe Pulse Palpation.

BACKGROUND/PURPOSE: The carotid bifurcation (CB) is the location of the carotid sinus and the baroreceptors and is also a major site for atherosclerotic plaque formation. Health care providers have therefore been cautioned to avoid the CB during carotid pulse palpation (CPP) to prevent triggering the baroreflex, occluding an artery, or propagating a thrombus. Potential risks of adverse events during CPP may be greater for older adults due to age-related vascular changes and increased risk of baroreceptor hypersensitivity. The exact location of the CB relative to easily identifiable landmarks has, however, not been well-studied. The purpose of this descriptive study was to identify the location of the CB relative to key landmarks in a cadaver sample and to make recommendations allowing clinicians to avoid the CB during CPP. METHODS: The CB and other regional landmarks in 17 male and 20 female cadavers were exposed by dissection and pins were placed at all landmarks. Digital calipers were then used to measure the distance between the CB and all landmarks. RESULTS AND DISCUSSION: The mean vertical distance from the laryngeal prominence (LP) to the CB was 25.14 mm for females and 36.13 mm for males. No CBs were located below the LP. Ninety-four percent of female CBs and 100% of male CBs were located above the LP, and 74% of female subjects and 87% of male subjects had CBs greater than 20.00 mm superior to the LP. No clinically relevant relationships were found between the CB and any of the other measured landmarks. CONCLUSIONS: Based on this cadaver sample, CPP below the level of the LP in a supine individual would be unlikely to compress the CB and thus unlikely to trigger the baroreflex or occlude the region of greatest atherosclerotic buildup. If a pulse is not palpable below the LP, moving vertically up to 1 cm above the LP in a supine individual would be likely to compress the CB in only a small number of cases.

The effects of thoracic spine manipulation in subjects with signs of rotator cuff tendinopathy.

STUDY DESIGN: Controlled laboratory study. OBJECTIVES: To assess scapular kinematics and electromyographic signal amplitude of the shoulder musculature, before and after thoracic spine manipulation (TSM) in subjects with rotator cuff tendinopathy (RCT). Changes in range of motion, pain, and function were also assessed. BACKGROUND: There are various treatment techniques for RCT. Recent studies suggest that TSM may be a useful component in the management of pain and dysfunction associated with RCT. METHODS: Thirty subjects between 18 and 45 years of age, who showed signs of RCT, participated in this study. Changes in scapular kinematics and muscle activity, as well as changes in shoulder pain and function, were assessed pre-TSM and post-TSM using paired t tests and repeated-measures analyses of variance. RESULTS: TSM did not lead to changes in range of motion or scapular kinematics, with the exception of a small decrease in scapular upward rotation (P = .05). The only change in muscle activity was a small but significant increase in middle trapezius activity (P = .03). After TSM, subjects demonstrated decreased pain during performance of the Jobe empty-can (mean ± SD change, 2.6 ± 1.1), Neer (2.6 ± 1.3), and Hawkins-Kennedy (2.8 ± 1.3) tests (all, P<.001). Subjects also reported decreased pain with shoulder flexion (mean ± SD change, 2.0 ± 1.5; P<.001) and improved shoulder function (force production, 2.5 ± 1.4 kg; Penn Shoulder Score, 7.7 ± 9.4; sports/performing arts module of the Disabilities of the Arm, Shoulder and Hand questionnaire, 16.4 ± 13.2) (all, P<.001). CONCLUSION: Immediate improvements in shoulder pain and function post-TSM are not likely explained by alterations in scapular kinematics or shoulder muscle activity. For people with pain associated with RCT, TSM may be an effective component of their treatment plan to improve pain and function. However, further randomized controlled studies are necessary to better validate this treatment approach. LEVEL OF EVIDENCE: Therapy, level 4.