Three‐dimensional study of pectoralis major muscle and tendon architecture

Abstract

A thorough understanding of the normal structural anatomy of the pectoralis major (PM) is of paramount importance in the planning of PM tendon transfers or repairs following traumatic PM tears. However, there is little consensus regarding the complex musculotendinous architecture of the PM in the anatomic or surgical literature. The purpose of this study is to model and quantify the three-dimensional architecture of the pectoralis muscle and tendon. Eleven formalin embalmed cadaveric specimens were examined: five (2M/3F) were serially dissected, digitized, and modeled in 3D using Autodesk Maya; six (4M/2F) were dissected and photographed. The PM tendon consisted of longer anterior and shorter posterior layers that were continuous inferiorly. The muscle belly consisted of an architecturally uniform clavicular head (CH) and a segmented sternal head (SH) with 6-7 segments. The most inferior SH segment in all specimens was found to fold anteriorly forming a trough that cradled the inferior aspect of the adjacent superior segment. No twisting of either the PM muscle or tendon was noted. Within the CH, the fiber bundle lengths (FBL) were found to increase from superior to inferior, whereas the mean FBLs of SH were greatest in segments 3-5 found centrally. The mean lateral pennation angle was greater in the CH (29.4 +/- 6.9 degrees ) than in the SH (20.6 +/- 2.7 degrees ). The application of these findings could form the basis of future studies to optimize surgical planning and functional recovery of repair/reconstruction procedures.

A systematic review and comprehensive classification of pectoralis major tears

“…29,34,39,60 The PM muscle and tendon have a complex musculotendinous anatomy that is often misunderstood by both anatomists and surgeons. 23 As a result, published descriptions of PM ruptures have been inconsistent with the actual musculotendinous morphology. Moreover, the literature lacks an injury classification system that is consistently applied and accurately reflects surgically relevant, anatomic injury patterns.…”

Pectoralis Major Muscle Rupture Repair: Technique Using Unicortical Buttons

“…[1][2][3][4][5] The functions of this muscle include internal rotation, forward flexion, and adduction of the shoulder. 1 The muscle achieves this action through a broad insertion originating from 2 heads, sternal and clavicular.…”

“…2 There is also a well-conserved musculotendinous twist proximal to the bony insertion site, with the sternal limb inserting proximal and deep to the clavicular limb. [2][3][4][5] Surgical repair should ideally reapproximate this anatomy to achieve optimal functional and cosmetic results.…”

Pectoralis Major Repair With Unicortical Button Fixation And Suture Tape

“…1,2 The fibers of the diverging layers of tendon, which make up each individual head, twist from their respective origins before coalescing at the insertion site on the humerus. [2][3][4][5][6] Although the main function of the muscle is adduction, the pectoralis major is also responsible for internal rotation, extension, and forward flexion. 2,5 Pectoralis major injuries are rare and most commonly occur during physical activity.…”

“…[2][3][4][5][6] Although the main function of the muscle is adduction, the pectoralis major is also responsible for internal rotation, extension, and forward flexion. 2,5 Pectoralis major injuries are rare and most commonly occur during physical activity. Typically, the injury mechanism leading to a pectoralis major rupture involves contraction of the muscle with simultaneous external rotation and extension.…”