Unusual venous plexus on psoas major Satheesha NB et al. Journal of Surgical Academia 2015; 5(1): 58-60 58 An Unusual Venous Plexus on Psoas Major Muscle Connecting the Inferior Mesenteric and Testicular Veins Satheesha Nayak B, Bincy MG, Snigdha M, Srinivasa Rao S, Surekha DS Department of Anatomy, Melaka Manipal Medical College (Manipal Campus), Manipal University, Madhav Nagar, Manipal, 576104 Karnataka State, India. Abstract Knowledge of communication between parietal abdominal veins, testicular vein and mesenteric veins is important for Surgeons, Urologists and Radiologists. These communications can result in varicocele or hemorrhoids and may lead to low success rate in hemorrhoid and varicocele surgeries. During routine dissection classes, we observed an unusual large venous plexus on the left psoas major muscle. The venous plexus was unilateral and was formed by many anastomotic venous channels on the psoas fascia and communicated with the left testicular and inferior mesenteric veins. The testicular and inferior mesenteric veins were significantly enlarged below the level of communication with the venous plexus. Keywords: Psoas muscle, venous plexus, retroperitoneal, inferior vena cava, inferior mesenteric vein Correspondence: Dr. Bincy M George, Department of Anatomy, Melaka Manipal Medical College (Manipal Campus), Manipal University, Madhav Nagar, Manipal, 576104 Karnataka State, India. Tel: +91 820 2922519 Fax: +91 820 2571905 Email: bincyrajakumary@gmail.com Date of submission: 10 July, 2014 Date of acceptance: 11 Feb, 2015 Introduction The psoas major muscle is one of the muscles of the posterior abdominal wall.This muscle is enclosed by a facial sheath known as psoas fascia. The venous channels of posterior abdominal wall are well developed; especially those on the psoas major muscle. Within the psoas major these veins communicate with the intervertebral venous plexus through conjugate vessels. The venous networks of the posterior abdominal wall include iliolumbar, lumbar, gonadal, inferior mesenteric and ascending lumbar veins. The inferior mesenteric vein drains blood from the distal part of the large intestine. It usually terminates into splenic vein.The splenic veinunites with the superior mesenteric vein to form the portal vein. This vein can be dilated in liver diseases. The testicular vein (gonadal vein) is vein draining the testis in males. On right side it drains to the inferior vena cava and the left testicular vein drains into the left renal vein. Each gonadal vein begins as a network of veins, called the pampiniform plexus. There are many vessels contributing to this plexus. It ascends in the spermatic cord, anterior to the vas deferens. These vessels unite to form four veins below the superficial inguinal ring. These veins enter the abdominal cavity, passing through the inguinal canal and the deep inguinal ring. Near the deep inguinal ring these veinsunite to form two veins, which run upwards on the psoas major, behind the peritoneum. These two veins unite to form a single testicular vein. Abnormal enlargement of the pampiniform venous plexus in the scrotum is known as varicocele. Varicoceles are more common in left side, as the left gonadal vein terminates in the smaller left renal vein compared to inferior vena cava at an angle of 90°.We observed an unusual plexus on psoas major that freely communicated with the veins draining the left ureter, testicular vein and inferior mesenteric vein. The testicular and inferior mesenteric veins were found dilated below the level of their communication with the plexus. Case Report