Pectoralis minor length measurements in three different scapula positions

Abstract

Background: The pectoralis minor (PM) muscle is commonly regarded as a contributor to abnormal scapula positioning. Subsequently, the muscle length of the scapular stabilising muscles may be affected, as these muscles assume a lengthened position, which over time causes weakness. There are inconsistencies regarding PM muscle length values because of the different techniques and positions used when the length of the PM muscle is measured.Objective: To determine the PM muscle length in participants aged 18−24 using a Vernier® caliper and expressed as pectoralis minor index (PMI), with the scapula in three different positions.Method: The PM muscle length of 144 participants was measured with a Vernier® caliper (intraclass correlation coefficient 0.83−0.87). Measurements were made with the scapula in the resting position, in an active and a passive posterior tilt position.Results: Significant differences were observed in PMI between the resting scapula position – 10.04 (confidence interval, CI 9.93–10.14) and active posterior tilt – 10.19 (CI 10.09–10.30) (p 0.001); the resting position – 10.04 (CI 9.93–10.14) and passive posterior tilt – 10.77 (10.66–10.87) (p 0.001) and active – 10.19 (CI 10.09–10.30) and passive posterior tilt 10.77 (10.66–10.87) (p 0.001). The dominant side had lower PMI values than the non-dominant side.Conclusion: The significant differences between the active and posterior tilt positions suggested that optimal muscle length of PM was affected by the inner range strength of the lower fibres of Trapezius.Clinical implications: It is important that in clinical practice not only the length of PM in scapular misalignment but also the strength of the antagonistic muscles is considered.

Factors affecting upper limb function recovery after mastectomy with immediate breast reconstruction: a STROBE study

“…The improvement in muscle tightness is directly related to amelioration in upper limb disability and indirectly related to QoL improvement via PF, RF, and BS (Supplementary Table S2). Given that 10 PMI was regarded as normal in the resting position [35], the pectoralis minor length was not signi cantly shortened after IBR. As reported, the pectoralis minor was not severely shortened after surgery, and returned normal at 4 months postoperatively.…”

Modifiable musculoskeletal factors and their association with shoulder function in adults: A systematic review of risk and association

“…Decreased exibility of the pectoralis minor and the latissimus dorsi was associated with an increase in pain in competitive swimmers [119]. The presence of scapular dyskinesis has also been observed with alterations in the PMm using different measurement methods [30,44,[85][86][87][88][89][90]120]. See (SoF) (Online Resource I) and [41].…”

Modifiable Musculoskeletal Factors and their Association With Shoulder Function in Adults: A Systematic Review of Etiology and Risk.

“…Decreased exibility of the pectoralis minor and the latissimus dorsi were associated with an increase in pain in competitive swimmers [119]. The presence of scapular dyskinesis has also been observed with alteration of the PMm using different measurement methods [30,44,[85][86][87][88][89][90]120]. See (SoF) (Online Resource I) and Table of Characteristics (Online Resource 2).…”