Journal of anatomy
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The lumbar intervertebral discs are supplied by a variety of nerves. The posterior aspects of the discs and the posterior longitudinal ligament are innervated by the sinuvertebral nerves. The posterolateral aspects of the discs receive branches from adjacent ventral primary rami and from the grey rami communicantes near their junction with the ventral primary rami. ⋯ Some rami communicantes cross intervertebral discs and are embedded in the connective tissue of the disc deep to the origin of psoas. Such paradiscal rami are likely to be another source of innervation to the discs. The anterior longitudinal ligament is innervated by recurrent branches of rami communicantes.
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In the lumbar region the longissimus thoracis and iliocostalis lumborum are separated by the erector spinae aponeurosis and its ventral reflection--the lumbar intermuscular aponeurosis. Lumbar fibres of the longissimus arise from the ilium and the lumbar intermuscular aponeurosis and insert into the accessory processes and proximal ends of the transverse processes of the lumbar vertebrae. ⋯ The lumbar intermuscular aponeurosis is homologous to the lumbar intermuscular septum in the dog, cat and monkey. The details of attachment of the lumbar fibres of the erector spinae and of the lumbar intermuscular aponeurosis should be taken into account in biomechanical analyses of the lumbar vertebral column.
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A cutaneous branch of the suprascapular nerve was observed in 6 arms from 5 (4 male and 1 female) out of 61 Japanese cadavers. The suprascapular nerves with a cutaneous branch arose from essentially normal brachial plexuses. ⋯ In one case, the peripheral distribution was very carefully dissected, the nerve supplied the proximal third of the lateral aspect of the arm within the territory of the axillary nerve. A cutaneous branch of the suprascapular nerve is obviously not uncommon, at least in Japanese.
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Lateral ventricular coarctation and fusion of the choroid and ependyma was studied in prenatal and postnatal mice. Coarctation of the lateral ventricle was preceded by the presence of a large quantity of extracellular glycogen embedded in an electron-dense, amorphous matrix lying between the ventricular walls. ⋯ The presence of cilia seems necessary for coarctation to occur. Fusion of the choroid plexus with the ependyma appears to be due simply to entanglement of choroidal microvilli and ependymal cilia without any specialised cell to cell connexions being present.
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The lumbosacral dorsal rami of the cat were studied by gross dissection. The L1-6 dorsal rami form three discrete branches - lateral, intermediate and medial. The lateral branches supply the iliocostalis lumborum and become cutaneous over the back. ⋯ The S1 and S2 dorsal rami form three branches, the middle of which form the ascending sacral trunk and accessory ascending sacral trunk. The ascending sacral trunk is derived from S1 and S2, the accessory ascending sacral trunk from S2. Both nerves are the exclusive nerve supply of lumbococcygeus.