Kimani J K, Mbuva R N, Kinyamu R M
Department of Human Anatomy, University of Nairobi, Kenya.
Anat Rec. 1991 Jan;229(1):103-8. doi: 10.1002/ar.1092290111.
We report the distribution of sympathetic nerves in the hindlimb arterial system of the giraffe based on the histochemical demonstration of monoamines by the sucrose-potassium phosphate-glyoxylic acid method. It is noted that the hindlimb arterial system shows regional variations in its sympathetic innervation with regard to the density and the penetration of the nerves into the tunica media not hitherto described. The femoral and popliteal arteries showed a paucity of sympathetic innervation. Distally the dorsal pedal and great metatarsal arteries showed sparse sympathetic innervation characterized by a tendency toward exclusion of the nerves toward the outer layers of the tunica media. In contrast, the anterior (cranial) tibial artery in the leg revealed a relatively rich pattern of sympathetic innervation and a greater penetration of the nerves into the tunica media. The latter part of the arterial system showed a marked thickening of the tunica media and luminal narrowing, thus suggesting a "sphincteric" function. It is conceivable that this sphincter subserves a dual function, namely, to modulate blood flow to the distal parts of the limbs, and secondly to channel blood to the thigh and crural musculature. Pertinent to this is the fact that the presumptive sphincter occurs immediately after the crural muscular branches are given off.
我们基于磷酸蔗糖 - 钾 - 乙醛酸法对单胺进行组织化学示踪，报告长颈鹿后肢动脉系统中交感神经的分布情况。值得注意的是，后肢动脉系统在交感神经支配方面呈现出区域差异，具体表现为神经密度以及神经向中膜的穿透情况，这些此前尚未有过描述。股动脉和腘动脉的交感神经支配较少。在远端，足背动脉和第1跖背动脉的交感神经支配稀疏，其特点是神经有向外膜外层排斥的倾向。相比之下，小腿的胫前动脉显示出相对丰富的交感神经支配模式，且神经向中膜的穿透性更强。动脉系统的后半部分显示中膜明显增厚且管腔狭窄，因此提示具有“括约肌”功能。可以想象，这种括约肌具有双重功能，即调节流向肢体远端的血流，其次是将血液导向大腿和小腿肌肉组织。与此相关的一个事实是，推测的括约肌在小腿肌肉分支发出后立即出现。
