title: The relationship between various anatomical landmarks used for localizing the first rib during surface palpation.
abstract: OBJECTIVE
  To assess the relationship between anatomical landmarks used to locate the first rib during surface palpation. One currently cited technique suggests locating the width of the transverse processes (TPs) of the first cervical vertebrae (C1) to determine the estimated width of the first thoracic vertebrae (T1) TP, allowing for subsequent palpation of the first rib laterally to the transverse process of T1. Based on anatomical structural relationships, the authors propose an additional method of locating the first rib, lateral to T1 TP, by palpating through the trapezius muscle at the width of the mastoid process (MP).
  
  
  METHODS
  Overlying tissue of the bilateral MP, C1 TPs, and T1 TPs of 28 cadavers were removed. Measurements of the left to right spans at the following structures were collected using a digital caliper: mastoid process, C1 TP, and T1 TP. Measurements were used to determine the agreement between each anatomical structural span.
  
  
  RESULTS
  The mean absolute difference (standard deviation, SD) between C1 TP span versus T1 TP span was 3.9 (±2.58) mm with an intraclass correlation coefficient (ICC) of 0.88 (95% CI = 2.9-4.9). The mean absolute difference between MP span and T1 TP span was 35.4 (±6.46) mm with an ICC of 0.71 (95% CI = 33.0-37.8).
  
  
  CONCLUSIONS
  This study confirms the anatomical accuracy and feasibility of using the C1 TP span to determine the general width of the T1 TP span while palpating for the first rib just lateral to the T1 TP. Additionally, this study demonstrates that the more easily palpated mastoid process serves as an effective landmark to identify a width sufficiently lateral to the T1 TP, appropriate for first rib palpation through the trapezius muscle.
authors.affiliation: Clinical Anatomy Research Laboratory, Center for Rehabilitation Research, Texas Tech University Health Sciences Center, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Loyd
authors.affiliation: Clinical Anatomy Research Laboratory, Center for Rehabilitation Research, Texas Tech University Health Sciences Center, USA.
authors.forename: Kerry K
authors.initials: KK
authors.lastname: Gilbert
authors.affiliation: Clinical Anatomy Research Laboratory, Center for Rehabilitation Research, Texas Tech University Health Sciences Center, USA.
authors.forename: Phillip S
authors.initials: PS
authors.lastname: Sizer
authors.affiliation: Clinical Anatomy Research Laboratory, Center for Rehabilitation Research, Texas Tech University Health Sciences Center, USA.
authors.forename: Lee T
authors.initials: LT
authors.lastname: Atkins
authors.affiliation: Laboratory of Anatomy, Biomechanics and Organogenesis (LABO), Faculté de Médecine, Université Libre de Bruxelles (ULB), Belgium.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Sobczak
authors.affiliation: Clinical Anatomy Research Laboratory, Center for Rehabilitation Research, Texas Tech University Health Sciences Center, USA.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Brismée
authors.affiliation: Clinical Anatomy Research Laboratory, Center for Rehabilitation Research, Texas Tech University Health Sciences Center, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Pendergrass
keywords: Bone morphology; First rib; Manual therapy; Reliability; Surface anatomy