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Division of nerves close to their origin and muscular entrapments by nerves in the limbs is not very common. Femoral nerve is the largest branch of the lumbar plexus and arises from dorsal divisions of ventral rami of L2 to L4 spinal nerves. During routine cadaveric dissection for first year medical students at Melaka Manipal Medical College (Manipal Campus), Karnataka, India, we observed a variation in the division and course of left femoral nerve in about 65-year-old male cadaver. The femoral nerve was split into two divisions above the inguinal ligament after its origin from the lumbar plexus. The lower division of the nerve passed deep to the iliopsoas muscle fibres and the upper division ran superficial to iliacus muscle deep to fascia iliaca. Both the divisions joined just above the inguinal ligament to form the trunk of the femoral nerve. Further course and distribution of the nerve was normal. The reports have shown that compression neuropathies of femoral nerve in the limbs are caused by neoplastic masses, vascular abnormalities and also by different anomalous muscles. Such neuropathies may also result from indirect compression of femoral nerve between the fibres of psoas major muscle and lateral pelvic wall. The potential clinical importance of above mentioned variations in the division of femoral nerve would emphasize the surgeons to diagnose the neuromuscular entrapments and consequent alterations of sensation in the anterior and medial aspects of the thigh. [ABSTRACT FROM AUTHOR]

Background: The foramen ovale is an oval opening in the greater wing of sphenoid bone transmitting the mandibular nerve as its major content. It serves as an important landmark for neurosurgeons in certain procedures as to gain access to trigeminal nerve. Therefore, its topographic position in relation to adjacent bony landmarks provides useful tool during these procedures. Aim: To analyse the morphometric measurements of the foramen ovale among South Indian population. Material and Methods: Morphometric analysis was carried out on 104 foramina ovalia of 52 dry human skulls from South India. Following dimensions of foramen ovale were measured: anteroposterior length, transverse width, distance (d1) from tubercle of root of zygoma to the centre of the foramen (CF) and distance (d2) from the midline of the base of the skull to CF. Results: The mean antero-posterior length was 7.0±2.17mm on right side and 6.8±1.40mm on left side, mean transverse width was 5.0±0.42mm and 4.70±0.91mm on right and left side respectively. Mean d1 was 32.58±1.72mm on right side and 32.75±1.76mm on left side. Mean d2 was 25.83±1.26mm on right side and 25.08±1.31mm on left side. Conclusion: Regional variations in the morphometric measures may be useful in neurosurgical procedures like administration of anaesthesia involving the mandibular nerve. [ABSTRACT FROM AUTHOR]

Dorsal and ventral divisions of ventral rami of lower lumbar and sacral spinal nerve were found to pass ventral and dorsal to the piriformis muscle respectively. These divisions joined each other below the piriformis muscle to form sciatic nerve. This low formation of sciatic nerve was observed in distal part of left gluteal region of a 50-year-old male cadaver. The sciatic nerve thus formed passed caudally into back of thigh and divided into tibial and common peroneal nerves in the upper part of popliteal fossa. In addition, a communicating nerve from the sciatic nerve was found to join the common peroneal nerve in the popliteal fossa. Such variations may lead to piriformis syndrome or non-discogenic sciatica. [ABSTRACT FROM AUTHOR]