The Anatomic And Clinical Research Of The Influence Of Atlantoaxial Joint Misalignment On Nerves And Muscles

The pilot study of anatomy relationship between atlanto-axial joint misalignment with sternocleidomastoid and trapezius muscles painObjectiveTo observe the anatomic relationship of atlanto-axial joint with the accessory nerve and the second cervical nerve,and to observe the innervation of sternocleidomastoid and trapezius muscle,providing the anatomy basis of sternocleidomastoid and trapezius muscles’pain caused by atlanto-axial joint misalignment.MethodThree adult cadaver neck specimens(6 sides) underwent dissection.The anatomic relationship of atlas transverse process with accessory nerve and lateral atlantoaxial joint with the anterior branch of second cervical nerve,the antomy of atlanto-axial joint’extraforaminal ligament,and the innervation of sternocleidomastoid and trapezius muscle were observed.The minimum distance between atlas transverse process tip and accessory nerve was measured.Result(1) Accessory nerve entered the sternocleidomastoid muscle at its anterior deep surface,divied a nerve branch innvervating the sternocleidomastoid muscle. Accessory nerve piercinged out the sternocleidomastoid muscle posterior edge at the its 1/3 and 2/3 intersection point,and then entered the posterior neck triangle,and then entered the anterior edge of trapezius muscle,dividing several nerve branchs innervating the muscle.(2)Accessory nerve lays anteriorly to the transvers process of the atlas,with a close anatomic relations between both. The minimum distance between atlas transverse process tip and accessory nerve are 4.84-7.60mm(left side) and 3.22-6.80mm(right side).(3)Atlanto-axial joint intervertebral foramen exists extraforaminal ligament,which attachs the second cervical nerve and adheres to atlas transverse process.(4)The second spinal nerve pass through the space of atlas and axis vetebral,and divided as the anterior and posterior nerve branchs. The anterior branch of second cervical nerve crosses forward againsts with lateral atlantoaxial joint,and participated in the composition of cervical plexus.ConclusionAtlanto-axial joint misalignment may stimulate the accessory nerve and the second cervical nerve or its anterior branch,that may cause sternocleidomastoid,trapezius muscle tension and pain.The clinical research of the relationship of Atlanto-axial joint misalignment with the sternocleidomastoid and trapezius pain and structure changeObjectiveComparing the difference of bilateral sternocleidomastoid and trapezius muscle tenderness scores,ultrosound echo intensity(EI),muscle cross-sectional area(CSA),T2 signal intensity between the deviation side and opposite side of spinous process by using muscle tenderness palpation,B ultrsound scan and magnetic resonance image,to further study the relationship of atlantoaxial joint misalignment with there nerves and muscle lesion.MethodAll patients who were included in study accepted muscle tenderness palpation and X-ray examination,with some of tnat accepted B ultrosound or MRI examination.Muscle tenderness scores were graded 0-3.X-ray examiation included mouth-open and lateral radiographs,index of which concluded LADI,ADI, spinous process diviation values and its direction.LADI was defined as shortest distance between the isthmian of dens process lateral margin and atlas lateral mass.AADI was defined as shortest distance between the posterior edge of atlas anterior arch and anterior edge of oodontoid process.Draw 3 line on the open-moth radiographs: odontoid process axis line:a line which is go through the central axis line of odontoid process;Lateral line:a line which is go through the lateral border of odontoid process and paralleled with the odontoid process axis line;Sideline:bisector between dontoid process axis line and Lateral line.Maked a asterisk sign at the point of spine bifurcate.Measured the vertical distance between asterisk and odontoid process axis line that was defined as spinous process deviation value.According to the odontoid process relative position with this 3 lines,it is divided mild,moderate,severe spinous process deviation.The ultrosound probe was placed at the midpoint of sternal head and mastoid when examinating the sternocleimastoid,while the probe was placed as midpoint of seventh cervical spinous process and acrominon. The probe was vertical on the surface of the muscle.The images were saved when the images were clear.Each muscle was saved 2 images,which were DCOM and then imported to personal computers.The images were analysied by Adobe Photoshop.Manualy choosed a region of interst(ROI),and then calculated the echo intensity(EI) using the histogram function module.During MRI scanning, the patient was on supine position. MRI scan sequence included conventional T2W1, T2W sagittal and T2 coronal scanning, neck T2WI cross-sectional scan and C2 spinal nerve STIR sequence.AADI measurement was on the sagittal MR image while LADI on the coronary MR image.AADI and LADI measurement method was the same as it’s measurement on the X-ray.Selected entire muscle edage as interest area on T2WI cross-sectional image and the computer could automatically calculate the CSA and SI of interest area.A experienced doctor observed both sides C2 spinal nerve image difference after maximum density projection (MIP) reconstruction of STIR scan images.Statistical analysisAll of the data were analysised by SPSS 19.0 statistical software. All measurement data were expressed as mean± standard deviation (M±SD).Both sides muscle palpation scores, CSAs, muscle SIs were compared by matching t test.P value<0.05 was as a statistically significant.Result1、19 atlanto-axial joint misalignment patients included in this study.All patients were accepted muscle palpation and X-ray examination,10 of who also accepted B ultrsound examination and 14 of who also accepted MRI examination.2、The sternocleidomastoid and trapezius tenderness score on the side of C2 Spinous process deviation were respectively 2.40±0.63、2.47±0.64,while respectively 0.80±0.67、1.20±0.68 on the opposite side.The The difference is statistically significant(P<0.05).3、The ultrasonic gray-scale analysis results showed that the sternocleidomastoid and trapezius El on the side of C2 Spinous process deviation were respectively 45.70±10.23、53.64±10.42,while respectively 41.21±10.62、42.29±7.86 on the opposite side.The The difference was statistically significant(P<0.05).4、The bone edage, odontoid process,atlas lateral mass and LADI couled be clearly showed.All patients AADI<3mm were showed on the coronal plane of MRI. Local increased signal of facets joints were seen in some patients. LADI and AADI measurement on the MR imaging were larger than that on the X-ray. The The difference was statistically significant(P<0.05).But LADI difference value were not statistically significant(P> 0.05)5、The MRI results showed that the sternocleidomastoid and trapezius CSA on the side of C2 Spinous process deviation were respectively 347.89±63.61mm2、 133.14±21.68 mm2,while respectively 315.03±55.83、105.76±14.97. The sternocleidomastoid and trapezius SI on the side of C2 Spinous process deviation were respectively 125.25±20.89、170.00±40.93,while respectively 101.25±18.99、 132.85±33.29.The muscle CSA and SI on process deviation and opposite sides were significantly difference.6、Conventional MRI:C2 spinal nerve could be showed a a small piece at the intervertebral foramen on the conventional T1WI and T2WI images,surrounded by high signal’fat,with equisignal or low signal.On on STIR images,C2 spinal nerves were high signal,while vertebral body and the surrounding muscles were low signal.7 of 10 patients C2 cervical nerve were innormal and 1 of 8 was nomal.The side of innormal nerves were the same as the side of spinous process deviation in 5 patients,while on the opposite side in 1 patient. The remaining 1 patient of cervical nerve display not clear.Conclusion1、The muscle tendness scores,muscle echo intensity,muscle CSA and MRI T2 signal intensity of atlantoaxial misalignment patients were highter on the spinous process side than the opposite side,that may relate with ipsilateral C2 cervical nerve stimulated by misalignment.2、The changes of related nerves and muscles with Atlantoaixal joint misalignment could be observed on MRI, which is important in clinical use.