Riedel's Lobe and Beaver Tail Variant: A Cadaveric Case Report.

Variations of the liver in the form of accessory lobes account for about less than 1%. One of the commonest accessory lobes on the right is Riedel's lobe. An occasional anatomical variant of the left lobe is the beaver tail variant. Both variants are reported to be common in females. We hereby report two cases. A 45-year-old female cadaver was noticed to have Riedel's lobe and beaver tail variant. Riedel's lobe appeared to be a tongue-like projection from the right inferior margin of the liver, almost reaching the level of the iliac crest. It was partially separated from the rest of the liver by a deep fissure. The left lobe was elongated, crossed the midline, and reached the left wall of the abdominal cavity after encircling the spleen. Splenomegaly was noticed, and the left lobe of the liver had a splenic impression. Riedel's lobe was drained by the middle hepatic vein (MHV) and supplied by the right branch of the portal vein (RPV). A similar variation of the beaver tail variant was noticed in an 85-year-old female cadaver. The left lobe of the liver crossed the midline and was related superior to the spleen. The right lobe of the liver and the spleen were normal. The beaver tail variant was drained by the left hepatic vein (LHV) and supplied by the left branch of the portal vein (LPV). These variations are prone to injuries and can be confused with the abdominal mass and could interfere with laparoscopic procedures.

Surgical anatomy of transversus abdominis muscle for transversus abdominis release.

Transversus abdominis release (TAR) is a myofascial release technique which helps in surgical repair of large ventral abdominal wall defects. In this procedure, the medial margin of muscular part of transversus abdominis (TA) is of great importance. Hence, the authors sought to describe the extent of medial margin of TA muscle. The surgical steps of TAR were performed in 10 formalin-fixed cadavers and distance between medial margin of TA muscle, lateral margin of rectus abdominis, to linea alba at five anatomical levels were documented respectively. The distance between the inferior epigastric vessels and the medial border of TA muscle was also noted. The TA muscle was within the posterior rectus sheath in all cadavers, at the xiphisternum (R, 61.6 mm; L, 58.9 mm), and at midway between xiphisternum and umbilicus (R, 25.4 mm; L, 27.1 mm). The TA muscle exited the posterior rectus sheath between this point and the umbilicus. The mean incongruity at the next three levels were -24.6 mm, -24.9 mm, and -22.9 mm respectively on the right and -21.4 mm, -19.9 mm, and -18.9 mm respectively on the left. The mean distance between the medial border of TA and inferior epigastric vessels was 18.9 mm on the right and 17.2 mm on the left. The muscular part of TA was incorporated within the posterior rectus sheath above the umbilicus, and it completely exited the rectus sheath at the umbilicus. This is contrary to the traditional understanding of posterior rectus sheath formation.

Prevalence of the additional head of quadriceps femoris in the South Indian population: a cadaveric and radiological study.

Quadriceps femoris is an extensor muscle in the anterior compartment of thigh and is traditionally taught to be composed of four heads. Recently, there is an increased interest in the occurrence of an additional muscle head of quadriceps femoris. But scientific knowledge regarding its incidence is lacking in the South Indian population. This study was done to confirm the presence of the additional head by routine anatomic dissection and radiological imaging techniques. Forty-one formalin fixed human cadaveric lower limbs were dissected and the morphology of the additional head was noted. Retrospective analysis of 88 MRI images of patients was done. The additional muscle head was present in 43.9% of the cadaveric lower limbs and was consistently located between the vastus lateralis and vastus intermedius. It originated from variable portions of the greater trochanter, intertrochanteric line, lateral lip of linea aspera and lateral surface of the shaft of femur and inserted either as a muscle belly or as an aponeurosis into the vastus intermedius (55.6%), vastus lateralis (22.2%) or directly into the base of the patella. It received its vascular supply from branches of the lateral circumflex femoral artery and was innervated by branches from the posterior division of the femoral nerve. In addition, the additional muscle head was identified by MRI and its incidence was reported to be 30.68% for the first time in living subjects. The result of this study provides additional information in understanding the morphology of the quadriceps femoris muscle.