Morphometric Aspects ot the Alba and Lunate Lineas and Correlations with the Physiological Diastasis of the Rectus Abdominis Muscles: Prospective Study

Abstract

IntroductionThe anatomical study of the aponeuroses of the anterolateral abdominal wall (AAW) is described, but the AAW aspects remain without clarification. The decussation of the myoaponeurotic of the external oblique (EO), internal oblique (IO) and transversus abdominis (TA) muscles form the abdominal rectus muscle sheath. Theses muscles are not tangential in their respective lateral margins, then they form the semilunar linea (LS), and on the medial margin of the abdominal rectus muscle they form the alba linea. Even having few citations on the width of the LS and the LA, the literature presents clinical aspects, classifications and proposals for the correction of the pathological width of this line: the diastasis. The measurements of the LA and the LS need reliability for the establishment of criteria for normality or for disorder.ObjectiveThe aim of this study was to measure the width of the LA and LS, the length of the LA, the distance from the umbilicus (CU) to the anterior margin of the lumbar vertebra (VL) in the plane passing through the CU and to establish whether there is a correlation between the measurements of the LS, LA and the distance from the CU to the anterior margin of the VL.MethodTrough the tridimensional reconstruction of computerized tomographies of the AAW in adults, measurements were made of the distances to the LA and LS in five levels from the xifoid process to the pubic symphysis using Osirix MD software.ResultsA total of fifteen individuals were studied as the pilot sample for the calculation of the sample, with the standard deviation for the average and 95%IC. The calculation led to the evaluation of 29 individuals (15 men and 14 women). The analyzed outcomes were: 1. Dpx_sp_reta; 2. Dpx_sp_pela_LA; 3. Dcu+VL; 4. DLA_NSu1; 5. DLA_NSu2; 6. DLA_NSu3; 7. DLS_dir_NSu3; 8. DLS_esq_NSu3; 9. DLA_NU; 10. DLS_dir_NU; 11. DLS_esq_NU; 12. DLA_Niu1; 13. DLS_dir_Niu1; 14. DLS_esq_Niu1; 15. DLA_Niu2; 16. DLS_dir_Niu2; 17. DLS_esq_Niu2. Considering that the DLA – distance from alba linea, DLS – distance from semilunar linea, sp – pubic symphysis; vL – lumbar vertebra; NSu – supraumbilical level; Niu – infraumbilical level. The maximum and average measurements were established for each outcome for men and women and the measurements (DLA_NSu1) e (DLA_Niu1) presented significant differences between men and women.ConclusionThe results may lead to a relevant discussion on the concept and the classifications of diastasis, producing a deeper knowledge of the morphological variations of the abdominal wall and the normal and unnormal functional aspects of these muscles and fáscias. This anthopometric anatomical parameter will fill in a blank with relevant data for the determinations of the criteria of normality, anatomical variation or disorder.