title: Influence of pectoralis minor and upper trapezius lengths on observable scapular dyskinesis.
abstract: OBJECTIVE
  Although a relationship between short pectoralis minor and upper trapezius and scapular dyskinesis has been postulated, no studies have investigated this theory. Understanding the effect of these muscle lengths on observable scapular dyskinesis may aid in determining risks and therefore making treatment decisions. Being aware of the magnitude of this effect would help gauge the significance of risks involved. Our aim was to evaluate the influence of pectoralis minor and upper trapezius lengths on scapular dyskinesis.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Asymptomatic participants (n = 148; 296 arms) were evaluated.
  
  
  METHODS
  Scapular Dyskinesis Test (SDT) was used to identify scapular dyskinesis, Pectoralis Minor Index (PMI) and Upper Trapezius Length Testing were used to determine muscle length.
  
  
  RESULTS
  SDT+ arms had shorter pectoralis minor resting length (PMI: 7.49 ± 0.38) (p < 0.001) and greater incidence of short upper trapezius (ISUT) (66.7%) (p < 0.001) compared to SDT- arms (PMI:8.58 ± 0.75, ISUT:22.5%). With each decrease in PMI, the likelihood of having scapular dyskinesis increased 96% (p < 0.001). Arms with short upper trapezius were 2.049 times more likely to exhibit scapular dyskinesis than those with normal length (p = 0.042).
  
  
  CONCLUSIONS
  Having a shorter pectoralis minor and upper trapezius length substantially increased the likelihood of having visually observable scapular dyskinesis.
authors.affiliation: School of Physical Therapy and Rehabilitation, Dokuz Eylul University, Turkey. Electronic address: sevgi.subasi@deu.edu.tr.
authors.forename: Sevgi Sevi
authors.initials: SS
authors.lastname: Yeşilyaprak
authors.affiliation: School of Physical Therapy and Rehabilitation, Dokuz Eylul University, Turkey. Electronic address: er-tugrl@hotmail.com.
authors.forename: Ertuğrul
authors.initials: E
authors.lastname: Yüksel
authors.affiliation: School of Physical Therapy and Rehabilitation, Dokuz Eylul University, Turkey. Electronic address: s_yuksel_24@hotmail.com.
authors.forename: Serpil
authors.initials: S
authors.lastname: Kalkan
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D003430:Cross-Sectional Studies; D020820:Dyskinesias / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D010369:Pectoralis Muscles / Q000033:anatomy & histology* / Q000503:physiopathology; D012540:Scapula / Q000033:anatomy & histology* / Q000503:physiopathology; D064171:Superficial Back Muscles / Q000033:anatomy & histology* / Q000503:physiopathology; D055815:Young Adult
keywords: Biomechanics/upper extremity; Scapula; Shoulder