Study On Applied Anatomy Of The Suboccipital Triangle

Objective: To investigate the microsurgical anatomy of the suboccipital triangle area and to confirm the course ,distribution and the relationship with the abut structure of the nerve and blood vessel of the suboccipital triangle and analyse the important structure quantitatively.To approach the protection and location mark of the nerve and blood vessel of the suboccipital triangle and provide an anatomic basis for clinic surgery .Method: The suboccipital triangle of 20(13 of them are male,7 of them are female) antiseptic adult skulls were microanatomized with 5-times operation microscope ,the feature of the first and second rami posteriores nervorum cervicalium,the feature and the courser of the occipital artery of which the relationships with abut structures were observed .The corpse essays are intact,no abnormalities and coloboma.The artery of essay is filled with emul within red colorant. The venous system is filled with emul within blue colorant.Results:1.The two triangle areas,which is made of the outsides and insides of vertebraoccipital muscular, are (663±21.10)mm2,(138±12.63)mm2.2.Vertebral artery consist of two parts: perpendicular segement and level segement. The longth of vertebral artery perpendicular segement: the left is (24.58±3.61)mm, the external diameter is ( 3.52±0.52 ) mm; the right is (23.25±3.96)mm, the external diameter is (3.28±0.41)mm; The longth of vertebral artery level segement: the left is (30.62±5.02)mm, the external diameter is (5.24±0.74)mm; the right is (28.48±3.95)mm, the external diameter is (4.68±0.42)mm. In this investigate, there are 20 muscular branches in perpendicular segement, the external diameter is (0.48±0.05) mm. There are 21 radicular arteries in perpendicular segement, the external diameter is (1.18±0.20)mm。There are 10 muscular branches in level segement, the external diameter is (0.42±0.22) mm.There are 24 arteriae meningea posterior in level segement, the external diameter is (0.91±0.35)mm.3.The point,which the occipital artery prick the deep fascia located in the under arcuate line of occipital bone(5~10)mm. the everage distance is (8.23±1.68)mm;The distance from linea mediana posterior to point is (25.32~38.26)mm,the everage distance is (33.42±0.68)mm.The distance of Occipital artery and vertebral artery in the mastoid groove is (10.32to25.26)mm,average:(15.36±0.75)mm. The branches of Occipital artery are the sternocleidomastoid muscle branch, the descending branch of the occipital artery, and the occipital branch of occipital artery.4.The branching patterns of occipital artery in scalp are main stem type(32/40),two(9/40),three branch type(4/40)and Short-stem plexiform(5/40).5.When the first cervical nerve root cross over the atlas posterior arch,the first cervical dorsal rami nerve originated from the C1 root,the terminal branches of first cervical dorsal rami dominate rectus capitis posterior major,muscle oblique capitis superior,and muscle oblique capitus inferior. the second cervical dorsal rami nerve originate from C2 root in the atlanto-axial joint,the branches of the second cervical dorsal rami nerve are medial branch,lateral branch,supra-communicating branch,infer-communicating branch and obliquus capitis inferior branch.Medial branch namely major occipital nerve,the distance from major occipital nerve which cross from deep structure to external occipital protuberance is (25.26±5.12)mm,the distance from major occipital nerve which cross from deep structure to the arcuate line of occipital bone (17.34±3.54)mm.Conclusion:1.The suboccipital triangle is made up of the larger posterior straight muscle of head,obliquus capitis superior and obliquus capitis inferior,including the triangle area of the vertebraoccipital muscle covering.2.The caliber of vertebral artery in the perpendicular segement and the level segement enlarged obviously.3.To protect vertebral artery in operation,we should turn attention to the following aspects:(1).when we dissociate vertebral artery,we should abscise its branches in electric coagulation ,in case haemorrhage. (2).There is much variation in coursering direction of the vertebral artery between C1 cervical foramen and C2 cervical foramen,in this location,the vertery artery have conspicuous twist,bulging outside.In case injury. (3).Scleroma is formed in the groove for vertebral artery only in a few cases.When we dissociate the vertebral artery level segement ,the operation should be carefully. If there is scleroma in the vertebra,we should exsect the scleroma first,and then dissociate the vertebral artery. 4.In the site appearance of greater occipital nerve--obliquus capitis inferior outer margin,the greater occipital nerve,the occipital vein and the occipital artery are entrapped by pachyntic obliquus capitis inferior.If the obliquus capitis inferior irriated or spasm,the greater occipital nerve is entrapped by obliquus capitis inferior.5.In the site appearance of greater occipital nerve—the cucullaris aponeurosis and deep fascia in the occipitalia,there are thick fiber bundle and fascial bundle in the round of the greater occipital nerve, the occipital vein and the occipital artery,this location can be emerged the entrapment of greater occipital nerve.