大鼠副神经脊髓核在中枢内的定位

THE LOCATION OF THE SPINAL NUCLEUS OF ACCESSORY NERVE IN ALBINO RAT

用HRP逆行追踪法,研究了大鼠副神经脊髓核在中枢内的定位。在同侧延髓锥体交叉平面至脊髓C_(6)节段内,见到HRP标记细胞主要位于C_(2)和C_(3)节段(占61.15%)。标记的副神经脊髓核似为复合体,可细分为4个纵列亚核,即前角外侧核、前角前核、前角背内侧核和前角中央核等。在脊髓前角内,C_(1)主要见于前角背内侧核;C_(2)和C_(3)见于前角外侧核;C_(4)、C_(5)和C_(6)见于前角前核。自C_(1)至C_(4)节段,标记细胞从内侧趋向外侧分布,C_(5)、C_(6)则又趋向前方。据1例大鼠脊髓连续切片观察,在前角内测量49个标记的副神经脊髓核胞体,其大小约34~68μm。属α运动神经元(直径大于37.5μm)占65.3%;属γ运动神经元(直径小于37.5μm)占34.7%。

Six adult albino rats were studied with HRP crystal smeared,at the proximal cut end of spinal part of accessory nerve near its entrance to the sternomastoid muscle in the carotid triangle.Sections were processed with TMB method.The labeled cells were found ipsilaterally extending from the decussation of pyramids to the sixth cervical segment of the spinal cord,61.15%of the labeled cells being located in the second and third cervical segments.The location of the labeled cells in the anterior horn of the spinal cord was different from C_(1)to C_(6)segments:mainly found in posteromedial nuclear group at C_(1);in lateral nuclear group at C_(2)and C_(3);in anterior nuclear group at C_(4)to C_(6).Through C_(1)to C_(4)seg-ments,a tendency of the labeled cells to shift from medial to lateral was observed.Thus the spinal accessory nucleus could be divided into four nuclear columns:lateral,anterior,posteromedial and central.The size of forty-nine labeled cells(from 34μm to 68μm)were measured in one animal.Alpha motoneurons(diameter>37.5μm),showing light,scattered and small granules and gamma motoneurons(diameter<37.5μm),showing heavy,dense and large granules were observed in 65.3%and 34.7%respectively.