| Objective:Anatomical study of cadaveric head to determine and observe the course and structure of the occipital artery in the suboccipital far-lateral approach;and measure the external diameter accurately of the different segments of occipital artery and the relative anatomical distance of the occipital artery.How to obtain the occipital artery safely as the blood supply artery in the posterior circulation bypass surgery to provides the clinical data for the posterior circulation bypass surgery.Methods:1.10 specimens of 20 sides of adult cadaver head with neck were soaked with medical alcohol.Clear water repeated washing out arteriovenous system.After rinsing,the red and blue perfused solution will be used separately for the perfusion of the arteries and veins.2.Microscopically dissected and treated cadaveric head,the suboccipital far lateral approach was used in this experiment.Dissecting muscles and arteries,observing the course and branches of the occipital arteries.The diameter of each segment of occipital artery was measured,and the distance from adjacent structure was measured.Results:1.Anatomy of muscles:The occipital muscles are divided into three layers?The first layer of muscle in the occipital region: the trapezius muscle and the sternocleidomastoid muscle.The second layer consists of the semispinalis capitis muscle,splenius capitis muscle and the longissimus capitis muscle.The third layer of muscle includes superior oblique muscle,inferior oblique muscle,rectus capitis posterior major muscle and rectus capitis posterior minor muscle.2.Occipital artery : It is separated from the posterior wall of the external carotid artery,about 2 cm below the transverse process of atlas,to reach the sulcusof the occipital artery through between the lateral rectus capitalis muscle and the posterior ventral part of the bigaster muscle.The sulcus consists of longissimus capitis muscle and the superior oblique muscle.A few people have not this sulcus,at this time,the OA is across the fascia covering the longissimus capitis muscle.The OA travels below the splenius capitis muscle after sulcus of the occipital artery out,the deep fascia covers it,and it turns upward on the medial margin of splenius capitis muscle and the lateral side of the scalp semitrachis muscle.It is concomitant with the greater occipital nerve.It's the terminal branch terminates in the suboccipital skin and anastomoses with the contralateral occipital artery branches.Three main branches of the occipital artery are the midline branch,the inferior occipital triangular branch and the sternocleidomastoid muscle branch.The length from the transverse process of the atlas across lineae nuchae superior is defined as the effective length of the occipital artery.The effective length of the occipital artery to the left is 88.05~96.10mm(92.52±2.35mm),the right is87.8~97.5mm(93.08±3.18mm);The left distance between the occipital artery and the occipital protuberance at the point of occipital protuberance is 19.70 ~22.50mm(21.58±0.86mm),the right is 20.90~22.90mm(21.76±0.52mm);The furthest distance from lineae nuchae superior at the suboccipital segment to the left is 21.70~25.00mm(23.86±0.96mm),the right is 22.90~25.60mm(23.73±0.88mm);The distance from the posterior central line to the left occipital artery is 31.00~33.20mm(32.32±0.64mm),the right is 31.00~33.60mm(32.33±0.64mm)?Distance from midpoint of occipital sulcus to V3 segment of VA,the left is 29.35~41.36mm(34.22±4.03mm),the right is 26.39~41.06(34.10±4.47mm);Distance from the OA to the PICA,the left is 29.57~42.26mm(35.38±4.74mm),the right is 26.69~46.99mm(36.79±5.87mm)?The diameter of the occipital artery was measured as follows:The external diameter of the occipital artery at it's origin of the left is 2.00~3.30 mm(2.44±0.39mm),the right is1.80~2.90mm(2.49±0.38)mm;The external diameter of the occipital artery at the point of the transverse process of atlas of the left is 1.80~2.80mm(2.19±0.31mm),the right is 1.80~2.60mm(2.15±0.24mm);The external diameter of the occipital artery at lineae nuchae superior ofthe left is 1.60~2.10 mm(1.79±0.16mm),the right of1.40~2.10mm(1.84±0.23mm)?By statistical analysis,the value of P > 0.05,left and right side has no statistical difference,occipital artery is more constant.The data can be used to identify the anatomical location of the occipital artery.3.Osseous markers associated with occipital artery:The nearest distance from the occipital artery at lineae nuchae superior to the occipital protuberance is about2 cm.Most of the lower travel of the occiput is approximately parallel to the lineae nuchae superior.The furthest distance from it to the lineae nuchae superior is about 3 cm.The mastoid tip is an important anatomic marker for identifying the posterior ventral part of the bigaster muscle.also is the marker to find occipital artery.The occipital artery enters the sulcus of the occipital artery above the transverse process of atlas.Conclusions:1.Familiar with the hierarchical relationship between different tissues through the far-lateral suboccipital approach.Occipital artery can be separated and identified by anatomical markers such as occipital protuberance,splenius capitis muscle,sulcus of occipital artery and transverse process of atlas.2.The position of the occipital artery is shallow,the movement is large,the effective length is longer,and the diameter of the canal is not changed much.It is suitable for blood flow reconstruction in ischemic diseases or aneurysms of posterior cranial fossa and is the first choice of blood supply artery for posterior fossa bypass grafting.3.Through the observation of suboccipital soft tissue,the measurement of relevant data to provide a clinical basis for the separation and protection of blood supply arteries in posterior fossa bypass surgery. |
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