Linea Alba
Original Editor - Lucinda hampton
Top Contributors - Vidya Acharya, Lucinda hampton and Kim Jackson
Introduction
The linea alba is a fibrous band of highly organized collagen fibers[1] that runs vertically the entire length of the center of the anterior abdominal wall from the xiphoid process to the pubic bone. It plays an important role in stabilizing the abdominal wall complex[2].
The Linea Alba continues from the rectus sheaths derived from the abdominal muscle aponeuroses and receives the attachments of the oblique and transverse abdominal muscles. The collagen fibers of the linea alba cross in an interwoven pattern from both sides of the abdominal wall muscle sheets ensuring core stability under abdominal muscle tension and allowing the accommodation of intraabdominal volume by chronic separation of the medial borders of the rectus muscles. [3]
Clinical Significance
Changes in Linea Alba during pregnancy
The linea alba tends to lose its strength during pregnancy. The width of the LA is equivalent to the inter-rectus distance. [1] Research shows that the inter-rectus distance, the distance between the rectus abdominis muscles widens in pregnant women by their third trimester. More than half remain abnormally wide 8 weeks after delivery, and, although some recover by 6 months, but many do not at 1 year[1].
Diastasis rectus & Hernia
Diastasis rectus occurs due to hormonal elastic changes of the connective tissues and mechanical stress by the growing fetus on the abdominal wall. Research suggests that the hormonal changes causes reduction in the tensile strength of rectus fascia in pregnant women. Literature studies have reported that the interrectus distance starts to increase at approximately 14 weeks of gestation and continues to increase until delivery with some recovery of the linea alba occuring between delivery and 8 weeks’ postpartum, after which time it plateaus and does not return to normal.[4] Ultrasound studies in postpartum women have demonstrated thinner and wider rectus abdominis muscle[5] Studies state that the failure of abdominal wall correction and containment could be due to the changes in type I and III collagen in the fascia of the abdominal wall, especially the type 1 and type 3 collagen[6]. Strengthening of the core can help restore integrity to the linea alba. See Core Strengthening.
Surgical Incision Site
The transverse, oblique and circular fibers are macroscopically arranged in a circular manner around the umbilical stalk[7]. This anatomical landmark is crucial to laparoscopic surgeons where they find the peritoneum fused to the LA, allowing easy peritoneal entry. Additionally as the linea alba is poorly vascularized, a median incision through the linea alba is a common surgical approach (laparotomy incision).[8]
References
- ↑ 1.0 1.1 1.2 Lee D, Hodges PW. Behavior of the linea alba during a curl-up task in diastasis rectus abdominis: an observational study. journal of orthopaedic & sports physical therapy. 2016 Jul;46(7):580-9.
- ↑ Gueroult P, Joppin V, Chaumoitre K, Di Bisceglie M, Masson C, Bege T. Linea alba 3D morphometric variability by CT scan exploration. Hernia. 2024 Apr;28(2):485-94.
- ↑ Kaufmann RL, Reiner CS, Dietz UA, Clavien PA, Vonlanthen R, Käser SA. Normal width of the linea alba, prevalence, and risk factors for diastasis recti abdominis in adults, a cross-sectional study. Hernia. 2022 Apr 1:1-0.
- ↑ Janes LE, Fracol ME, Dumanian GA. Appreciation of postpartum changes of the rectus muscles in primary and repeated abdominoplasty. Plastic and reconstructive surgery. 2019 Aug 1;144(2):197e-204e.
- ↑ Coldron Y, Stokes MJ, Newham DJ, Cook K. Postpartum characteristics of rectus abdominis on ultrasound imaging. Manual therapy. 2008 Apr 1;13(2):112-21.
- ↑ Blotta RM, Costa SD, Trindade EN, Meurer L, Maciel-Trindade MR. Collagen I and III in women with diastasis recti. Clinics. 2018;73:e319.
- ↑ Merh R, Saunders M, Jenner D. The fibers of the circular junction of the linea alba in normal adult anatomy. Clinical Anatomy. 2021 Sep;34(6):842-4.
- ↑ Varacallo M, Scharbach S, Al-Dhahir MA. Anatomy, anterolateral abdominal wall muscles.