Volume 64 (2014) Issue: 2014 No#3

Creation nerves of the lumbar and sacral plexus in California Sea Lions (Zalophus californianus) and Northern Elephant Seals (Mirounga angustirostris)

Author(s): Mihelić Damir, Smodlaka Hrvoje, Tkalčić Suzana, Palmer Lauren, Mršić Gordan, Špiranec Katarina, Špoljarić Daniel, Popović Maja, Mihelić Draga

Keywords:elephant seal, Mirounga angustirostris, nerve, pinnipedia, sea lion, sea mammals, Zalophus californianus

The lumbosacral plexus was investigated in the California sea lion and Northern elephant seal. In 9 California sea lions and 2 Northern elephant seals the femoral nerve rises from the ventral branches of the 3rd and 4th lumbar nerves, whilst in one male and two specimens of the Northern elephant seal the 5th lumbar nerve was also involved. Ventral branches of the 3rd and 4th lumbar nerves comprised the obturatorius nerve in 7 specimens; in 3 specimens the 5th lumbar nerve additionally supplements the obturatorius nerve. In Northern elephant seals the obturatorius nerve originates from the ventral branches of the 3rd, 4thand 5th lumbar nerves. The ischiadic nerve originates from the ventral branches of the 4th, 5th lumbar and 1st sacral nerves in 8 specimens California sea lions and in 2 North elephant seals. In 2 specimens of both species the 2nd sacral nerve also participates. The gluteal nerve created ventral branches of the 5th lumbar and 1st sacral nerves in three specimens; however in one specimen the 4thand 5th lumbar nerves gave rise to the same nerve in the Northern elephant seal. In California sea lions the gluteal nerve originates from the ventral branches of the 5th lumbar nerve in seven specimens, nonetheless in 3 specimens the 4th lumbar nerve also participates in its formation.