| Kevin Rosenbloom
Author: Kevin B. Rosenbloom, C.Ped, Sports Biomechanist
Lateral rotation at the hip joint may not seem vital at first inspection, but is definitely important in ambulation. This summary will briefly discuss hip lateral rotation, explore the muscle bodies that contribute to this movement and give some insight into the intriguing research about the muscles.
Lateral Rotation Essentials
Hip lateral rotation is the outward rotation of the thigh and leg (along the transverse plane) at the hip joint. The range of motion has been estimated to be between 10-55° with a mean approximately at 32-34° (Roaas & Andersson 1982, Cheatham et al. 2017). The sartorius, pectineus, obturator internus and externus, both gemelli, the gluteal group (maximus, medius, minimus), piriformis and quadratus femoris are the most significant contributors to lateral rotation (Visible Body 2019). It is important to note that other sources have suggested some contribution from the psoas muscles.
The obturator externus’ origins are partially from the obturator membrane and primarily on the medial side of the obturator foramen. Its triangular shape covers the outer surface of the anterior pelvis (main and inferior surface of rami). Its flat body travels along the pelvis, beneath the acetabulum of the hip joint and inserts into the femoral trochanteric fossa.
Recently, variations of the obturator externus have been observed more frequently. A supernumerary muscle that somewhat mimics the external obturator has been found between the adductor brevis and adductor minimus, a portion of a. magnus. This muscle’s origins begin at the upper portion of the inferior pubic ramus and run downwards and laterally. Although its insertion can run into the a. minimus’ aponeurosis, it has been found that it can also insert into the superior pectineal line or the posterior portion of the lesser femoral trochanter (Nakamura et al. 1992). Ontogenetic variations of the external obturator have also begun to be documented (Yatsunami et al. 2004).
Just like the o. internus, the obturator externus is susceptible to abscess growth. In most cases magnetic resonance (MR) imaging is the most efficient way to detect the source of the problem (King et al. 2003, Kumar & Anderson 2008). However, initial scans in a specific case proved to be not provide helpful identification of the complications (King et al. 2003).
It is quite clear that the mechanisms that form the body, especially the portions of the lower extremities, are complex, with even single organisms capable of displaying multiple functions. Several muscles in the pelvic region have multiple functions and have been briefly discussed in other Kevin Orthopedic summaries. In order to avoid monotony, it is suggested to review the summaries below for additional information on other lateral rotator muscles:
Muscle Overview - Hip Lateral Rotators
Figure 1. Sketch of the right hip lateral rotators, anterior view (left) and posterior view (right).
Obturator externus 
Gluteus maximus 
Gluteus medius 
Gluteus minimus 
Superior gemellus 
Obturator internus* 
Inferior gemellus 
Quadratus femoris 
*Lateral rotator during hip extension
References & Works Cited
Barclay, T. 2018. “Anatomy Explorer,” innerbody.com. Accessed 19 Mar 2019. https://www.innerbody.com/anatomy/muscular/leg-foot.
Cheatham, S., Hanney, W. J., Kolber, M.J. 2017. “Hip Range of Motion in Recreational Weight Training Participants: A Descriptive Report,” International Journal Sports Physical Therapy 12(5): 764-773. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5685413/.
Gray, H. 1918. “The Muscles and Fasciæ of the Lower Extremity,” Anatomy of the Human Body, 20th Ed. Lead & Febiger. Philadelphia & New York, USA. 473, 475, 477-478.
King, R. J., Laugharne, D., Kerslake, R. W., Holdsworth, B. J. 2003. “Case report: Primary obturator pyomyositis: A diagnostic challenge,” The Journal of Bone & Joint Surgery (Br) 85-B: 895-8. https://doi.org/10.1302/0301-620X.85B6.13824.
Kumar, A., Anderson, D. 2008. “Primary Obturator Externus Pyomyositis in a Child Presenting as Hip Pain: A Case Report,” Pediatric Emergency Care 24; 2: 97-98. https://journals.lww.com/pec-online/Abstract/2008/02000/Primary_Obturator_Externus_Pyomyositis_in_a_Child.6.aspx.
Moses, S. 2014. “Hip Range of Motion,” Family Practice Notebook. Accessed 27 Mar 2019. https://fpnotebook.com/Ortho/Exam/HpRngOfMtn.htm.
Nakamura, E., Masumi, S., Miura, M., Kato, S., Miyauchi, R. 1992. “A supernumerary muscle between the adductors brevis and minimus in humans,” Okajimas Folia Anatomica Japonica 69(2-3): 89-98. https://www.ncbi.nlm.nih.gov/pubmed/1436954.
Platzer, W. 2004. Color Atlas of Human Anatomy, Vol. 1: Locomotor System 5th Ed. Thieme. New York, USA.
Quinn, E. 2019. “Generally Accepted Values for Normal Range of Motion (ROM) in Joints,” verywellhealth.com. Accessed 19 Mar 2019. https://www.verywellhealth.com/what-is-normal-range-of-motion-in-a-joint-3120361.
Roaas, A., Andersson, G. B. J., 1982. “Normal Range of Motion of the Hip, Knee and Ankle Joints in Male Subjects, 30-40 Years of Age,” Acta Orthopaedica Scandinavica, 53:2, 205-208. https://www.tandfonline.com/doi/abs/10.3109/17453678208992202.
Robinson, P., White, L. M., Agur, A., Wunder, J., Bell, R. S. 2003. “Obturator Externus Bursa: Anatomic Origin and MR Imaging Features of Pathologic Involvement1,” Radiology 228: 230-234. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.652.1877&rep=rep1&type=pdf.
Yatsunami, M., Tai, T., Irie, Y., Ogawa, K., Miyauchi, R. 2003. “A Morphological Study on the Human Obturator Externus Muscle with Reference to Anomalous Muscle and Anomalous Fasciculus Originating from the Obturator Externus Muscle,” Okajimas Folia Anatomica Japonica 80(5-6): 103-114. https://doi.org/10.2535/ofaj.80.103.
Visible Body. 2019. “Muscle Premium,” VisibleBody.com. Purchasable Application. Accessed 21 Feb 2019.
Kevin B. Rosenbloom, C.Ped, Sports Biomechanist
Kevin B. Rosenbloom, founder and president of Kevin Orthopedic, is a renowned certified pedorthist and sports biomechanist practicing in Santa Monica, CA. With his continuing research on the historical development of foot and ankle pathologies, comparative evolution of lower extremities and the modern environmental impacts on ambulation, he provides advanced biomechanical solutions for his patients and clients.