Knee-Chest Position

What Is It, Uses, and More

Author:Georgina Tiarks

Editors:Alyssa Haag,Emily Miao, PharmD,Kelsey LaFayette, DNP, ARNP, FNP-C

Illustrator:Jessica Reynolds, MS

Copyeditor:David G. Walker

What is the knee-chest position?

The knee-chest position is a position involving bringing the knees to the chest and may be useful in certain medical situations. Individuals will be asked to flex (i.e., bend) their hips and knees so that their knees reach their chest; the hips may also be abducted (i.e., away from the midline). An individual who is assuming the knee-chest position can be either prone (i.e., lying on the stomach) or supine (i.e., lying on the back).

Person lying with knees flexed to chest.

What is the knee-chest position used for?

The knee-chest position can be used in various situations. Most often, the knee-chest position is used in obstetrics and gynecology. During malposition of the fetus, or when the fetus is not in the ideal position for delivery (e.g., breech position), the knee-chest position can be used in an attempt to reposition the fetus by increasing the anterior-posterior pelvic space. During delivery, it can allow spontaneous rotation to the correct positioning, and it increases the success rate of vaginal delivery. In cases of umbilical cord prolapse, the knee-chest position can elevate fetal parts and prevent further compression of the umbilical cord. This position can also be helpful for obtaining ultrasound imaging of the fetus’ facial features during the antepartum period. 

Children with tetralogy of Fallot (ToF), a cyanotic congenital heart condition, may also use the knee-chest position to improve oxygen distribution around the body. The underlying cardiac abnormalities seen in tetralogy of Fallot prevent adequate levels of oxygenated blood from circulating systemically, which can cause cyanosis (i.e., bluish discoloration of the lips, fingers, toes, etc). When an individual with ToF becomes agitated, cyanotic spells, also called “tet” spells, can occur. Squatting or assuming the knee-chest position can help increase the systemic vascular resistance (SVR) and venous return, which allows more blood to enter the lungs for oxygenation, temporarily resolving cyanosis and hypoxemia

Other uses of the knee-chest position can include certain surgical procedures as the position can increase pulmonary oxygenation and decrease sedation requirements; and in cases of suspected child abuse, this position may be employed to help complete a pediatric pelvic examination. 

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What are the most important facts to know about the knee-chest position?

The knee-chest position is a position, defined by flexion of the hips and knees, or bringing the knees as close to the chest as possible. This position can be used by healthcare providers in certain medical situations, such as fetal malposition, umbilical prolapse, certain surgical procedures, and pediatric sexual assault examinations. The knee-chest position may also be assumed by children with tetralogy of Fallot during cyanotic, or “tet,” spells to increase systemic vascular resistance and venous return.  

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Related links

Anatomy of the leg
Tetralogy of Fallot

Resources for research and reference

Apitz C, Anderson RH, Redington AN. Tetralogy of Fallot with pulmonary stenosis. Paediatric Cardiology.  Elsevier; 2010:753-773. doi:10.1016/b978-0-7020-3064-2.00039-4

Bennarosh L, Peuch C, Cohen J, et al. Effects of the knee-chest position on cardiac index and propofol requirements during bispectral index (BIS)-guided spine surgery. Annales Francaises D’anesthesie Et De Reanimation. 2008;27(2):158.e1-5. doi:10.1016/j.annfar.2007.10.037

Isaac R. The physical examination of the child when sexual abuse is suspected. Medical Evaluation of Child Sexual Abuse. Elsevier; 2011:63-68.

Lucas JH, Baxley EG. Malpresentation and malpositions. Family Medicine Obstetrics. Elsevier; 2008:500-522.

Moriwaki K, Sasaki H, Kubota M, et al. Knee-chest position improves pulmonary oxygenation in elderly patients undergoing lower spinal surgery with spinal anesthesia. Journal of Clinical Anesthesia. 1991;3(5):361-366. doi:10.1016/0952-8180(91)90176-n

Roy HS, Cheng C. Importance and significance of knee-chest decubitus position of the pregnant women, in the delineation of fetal facial imaging with four-dimensional color Doppler ultrasound. The Open Medical Imaging Journal. 2018;10(1):9-16. doi:10.2174/1874347101810010009