Pubic arch
Arcus pubicus
Definition
The pubic arch is formed by the convergence of the inferior rami of the pubic bones at the midline, creating an arch-like shape.
In obstetrics, the pubic arch angle (PAA) is an important parameter that can be measured using imaging techniques such as transperineal ultrasound. The PAA has been shown to correlate with other pelvic dimensions like the interspinous diameter (ISD) and the obstetrical conjugate (OC), which are critical for assessing the feasibility of vaginal delivery.[1] A wider pubic arch angle is generally associated with a more favorable outcome for vaginal delivery, whereas a narrower angle may predict the need for operative delivery in cases of prolonged second stage of labor.[2]
References
1.The Birth Canal: Correlation Between the Pubic Arch Angle, the Interspinous Diameter, and the Obstetrical Conjugate: A Computed Tomography Biometric Study in Reproductive Age Women.Perlman S, Raviv-Zilka L, Levinsky D, et al.The Journal of Maternal-Fetal & Neonatal Medicine : The Official Journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians. 2019;32(19):3255-3265. doi:10.1080/14767058.2018.1462322.
2.Pubic Arch Angle in Prolonged Second Stage of Labor: Clinical Significance.Gilboa Y, Kivilevitch Z, Spira M, et al.Ultrasound in Obstetrics & Gynecology : The Official Journal of the International Society of Ultrasound in Obstetrics and Gynecology. 2013;41(4):442-6. doi:10.1002/uog.12304.
