OBJECTIVETo ascertain an accurate approach to inserting the pedicle screw into C3-C7 segments of the cervical vertebra.

METHODSAnatomic morphology of lateral mass and pedicle, and their anatomic relationship with the adjacent tissue were observed on C3-C7 segments of 25 adult embalmed cadavers (50 sides).

RESULTS1) The inferior edge of the base of the posterior tubercle of the transverse process and the inferior edge of the pedicle were connected with each other on 25 adult embalmed cadavers (50 sides). The transverse section which passed through the median point between the superior edge and the inferior edge of the base of the posterior tubercle of the transverse process, and the transverse section which passed through the central axis between the superior edge and the inferior edge of the pedicle, were in the same horizontal plane. The superior and inferior position of placing the pedicle screw was determined by this transverse section, which passed through the median point between the superior and the inferior edge of the base of the posterior tubercle of the transverse process. 2) There was a directed internal-downwards "triangular sulcule" between the base of the posterior tubercle of the transverse process and the anterolateral edge of the inferior articular process. The anterior wall of the triangular sulcule was the base of the posterior tubercle of the transverse process, the posterior wall was the anterolateral edge of the inferior articular process, and the bottom of the sulcule was connected with the interior edge of the pedicle. The vertical length between the top of triangle and the planes of inferior edge of the pedicle was (2.78+/-1.71) mm. The inferior edge of the cervical pedicle could be detected using a blunt probe along the "triangular sulcule" between the base of the posterior tubercle of the transverse process and the anterolateral edge of the inferior articular process in surgical operation. 3) The lateral fovea of the articular process was observed on all lateral masses (50 sides). The internal and external position of the entrance point could depend on anatomic landmarks: the lateral edge of the lateral fovea of the articular process. The horizontal length between the lateral fovea of the articular process and the entrance point was (3.14+/-1.45) mm. 4) The diameter of pedicle screw, about (2.78+/-1.71) mm, was the transverse diameter of the cancellous bone of the greatest narrow part of the cervical pedicle.

CONCLUSIONSThe median point between the superior edge and the inferior edge of the base of the posterior tubercle of the transverse process, the lateral fovea of the articular process, and the triangular sulcule between the base of the posterior tubercle of the transverse process and the anterolateral edge of inferior articular process, are easy to be exposed and identified in surgical operation. The pedicle screw can be precisely inserted through this method.

Adult ; Bone Screws ; Cervical Vertebrae ; anatomy & histology ; surgery ; Humans

Measurement of cervical lordosis is the basic method for evaluating cervical function, and important reference for determine treatment decision. However, how to choose appropriate measurement in accordance with different situation, as well as the relationship among these methods is not clear. An increasing number of studies suggested that different measurements could directly affect the judgment of cervical lordosis. Therefore, comparative study of cervical vertebrae plays an important role in clinical treatment for cervical spondylosis under different cervical curvature conditions.
Cervical Vertebrae ; anatomy & histology ; Humans ; Lordosis ; diagnosis ; pathology

OBJECTIVETo study the relevant position of the pedicle of C1 to the lateral mass of C(2-4), set up an identification technique for the entry point decision of C1 pedicle screw by using the lateral mass of C(2-4) as anatomic landmarks.

METHODSTwenty cadaver specimens were used to measure the distance from the sagittal midline of spine to the medial border, the midpoint and the lateral border of C1 pedicle or the lateral mass of C2, C3 or C4. The anatomic relation between the measurements data of C1 pedicle and that of the lateral masses of the cervical vertebrae were analyzed, and the technique of C1 pedicle screw fixation was established.

RESULTSThe average medial border of the lateral mass of C2, C3 and C4 was 0.37 mm, 0.27 mm and 0.24 mm lateral to that of C1 pedicle, the average midpoint of the lateral mass of C2, C3 and C4 was 1.18 mm, 1.41 mm and 1.74 mm lateral to that of C1 pedicle, and the average lateral border of the lateral mass of C2, C3 and C4 was 1.96 mm, 2.54 mm and 3.24 mm lateral to that of C1 pedicle, respectively.

CONCLUSIONThere is a steady anatomic location relation between C1 pedicle and the lateral mass of C2, C3 or C4. As well as the lateral mass of C2, the lateral mass of C3 or that of C4 could be convenient anatomic landmarks to determine the location of C1 pedicle and the position of C1 pedicle screw entry point.

Adult ; Cadaver ; Cervical Atlas ; anatomy & histology ; surgery ; Cervical Vertebrae ; anatomy & histology ; surgery ; Female ; Humans ; Male ; Spinal Fusion ; methods

OBJECTIVETo compare anatomic difference between spinous process screws and pedicle screws techniques of the second cervical vertebra.

METHODSTen human cadaveric of cervical spine (5 male, 5 female) were harvested and had no gross deformities such as scoliosis and/or kyphosis were found in the study. The average age of the subjects was 60.5 years. The specimens were placed in the prone position. Posterior cervical exposure was attained by dissecting all soft tissue off the posterior aspect of the second cervical vertebra. After clear exposure of the lateral mass,the spinous process screw and pedicle screw insertion techniques were performed in this study. Each technique involved ten specimens and 10 screws inserted into C2 bilaterally. The one side of C2 was randomly selected for the spinous process screw and the other side was designate for the pedicle screw. This point then was drilled with a 3 mm drill, and followed by placement of a 4.0 mm cortical screw. The starting point for spinous process screw insertion was located at the junction of the lamina and the spinous process and the direction of the screw was about 0 degrees caudally in the sagittal plane and about O0 medially in the axial plane. The starting point of pedicle screw should be the midpoint of the base of inferior articular facet of the axis. The drilling angle was 15 degrees to 20 degrees in the superior direction and 30 degrees in the medial direction. After screw placement, all the specimens were CT scaned. On the CT scan,the length of the spinous process screw and pedicle screw trajectory were measured. Results were recorded for each screw that violated impinged of the pedicle, spinal canal and transverse process foramen.

RESULTSAll the C2 spinous process screws were successfully placed, without impingement the spinal cord, the vertebral artery and the breakage of the spinous process. There was one pedicle screw breaking the pedicle into the vertebral artery foramen. The trajectory length for the spinous process screws were (21.4 +/- 1.4) mm,compared with the pedicle screws (23.7 +/- 1.0) mm. But there was no significant differences between spinous process screws and pedicle screws techniques (t = -4.387, P > 0.05).

CONCLUSIONThe C2 spinous process screw fixation has the anatomic feasibility and is easier to perform than pedicle screw fixation.

Aged ; Bone Screws ; Cervical Vertebrae ; anatomy & histology ; surgery ; Female ; Humans ; Male ; Middle Aged

Finite element analysis (FEA) is broadly used in engineering, it was initially applied to simulate and solve a variety of engineering mechanics, thermal, electromagnetics, and other physical problems. The principle is a collective to be composed by an infinite number of particles, and an unlimited number of degrees of freedom from the continuum approximation. Brekelmas and Ryblcki firstly applied the finite element method to orthopedic biomechanics research in 1972. The first cervical vertebra finite element model was established in 1982 by Hosey. With the computer and software technology advances in the past 20 years, finite element method in cervical spine biomechanics studies is increased and widespread.
Biomechanical Phenomena ; Cervical Vertebrae ; anatomy & histology ; physiology ; Finite Element Analysis ; Humans ; Models, Anatomic ; Models, Biological ; Movement

INTRODUCTIONThe uncinate process (UP) has an important role because of its relationship with the vertebral artery and spinal roots. Degenerative diseases cause osteophyte formation on the UP, leading to radiculopathy, myelopathy and vertebral vascular insufficiency, which may require surgical management. This study aimed to evaluate the morphometry of this region to shed light on the anatomy of the UP.

METHODSMorphometric data was obtained from 13 male formaldehyde-fixed cadavers. Direct measurements were obtained using a metal caliper. Computed tomography (CT) morphometry was performed with the cadavers in the supine position.

RESULTSDirect cadaveric measurements showed that the height of the UP increased from C3 (5.8 ± 1.0 mm) to C7 (6.6 ± 0.5 mm). On CT, the corresponding measurements were 5.9 ± 1.2 mm at C3 and 6.9 ± 0.6 mm at C7. The distance between the left and right apex of the UP from C3 to C7 also increased on both direct cadaveric and CT measurements (C3: 20.8 ± 1.0 mm and C7: 28.1 ± 2.4 mm vs. C3: 23.7 ± 3.4 mm and C7: 29.0 ± 3.0 mm, respectively). On CT, the distance between the UP and superior articular process at the C3 to C7 levels were 9.8 ± 1.7 mm, 7.9 ± 1.8 mm, 7.9 ± 1.6 mm, 7.8 ± 1.3 mm and 8.2 ± 1.7 mm, respectively.

CONCLUSIONDirect cadaveric and CT measurements of the UP are useful for preoperative evaluation of the cervical spine and may lead to better surgical outcomes.

Cadaver ; Cervical Vertebrae ; anatomy & histology ; physiology ; surgery ; Formaldehyde ; Humans ; Male ; Tomography, X-Ray Computed

OBJECTIVETo offer normal reference of diameter of the cervical spinal cord and available diameter of cervical spinal canal and to screen scientific radiographic criteria to define and quantify cervical spinal cord disease.

METHODSThe magnetic resonance images of 120 normal people had been measured. The data of diameters of cervical spinal cord, CSF, M, the ratio of diameters of cord and CSF, and the ratio of diameters of cord and M had been collected and statistical analysis was made. And the relationships between the data above and each of gender, the length of C-spine and age were evaluated. In addition, the ratio of diameters of cord and CSF, and the ratio of diameters of cord and M was evaluated.

RESULTSThe study showed that in healthy people, the diameters of cervical spinal cord, CSF and M was larger in the males than in the females, decreased with age, and increased with the length of C-spine but the diameter of CSF. And the ratio of diameters of cord and CSF increased with age and not affected by the length of C-spine. However, the ratio of diameters of cord and M was not affected by age and the length of C-spine.

CONCLUSIONThe ratio of diameters of cord and M is not affected by individual variation and can be used to evaluate cervical spinal cord atrophy, compression and impaired in patients with cervical myelopathy and can be important information in looking for clinically critical points.

Adolescent ; Adult ; Aged ; Cervical Vertebrae ; anatomy & histology ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Spinal Canal ; anatomy & histology ; Spinal Cord ; anatomy & histology

OBJECTIVETo provide anatomical data for transoral atlantoaxial reduction plate internal fixation.

METHODMicrosurgical dissecting was performed on 10 fresh craniocervical specimens layer by layer according to transoral approach. Stratification of posterior pharyngeal wall, course of vertebral artery, adjacent relationships of atlas and axis and correlative anatomical parameters of internal fixation to atlantoaxial joint were observed.

RESULT(1) Posterior pharyngeal wall consisted of 2 layers and 2 interspace: mucosa, anterior fascia of vertebrae, posterior interspace of pharynx and anterior interspace of vertebrae. (2) The range from anterior rim of foramen magnum to C3 could be exposed by this approach. (3) The distance between the vertebral artery at atlas and midline was (25.2 +/- 2.3) mm and that between the vertebral artery at axis and midline was (18.4 +/- 2.6) mm. (4) The width of atlas and that of axis could be exposed respectively to (39.4 +/- 2.2) mm and (39.0 +/- 2.1) mm. The distance (a) between 2 atlas screw inserting points (center of anterior aspect of C-1 lateral mass) was (31.4 +/- 3.3) mm. The vertical distance (b) between the connecting line of 2 atlas screw inserting points and that of 2 axis screw inserting points (at the central part of the vertebrae which was 3 - 4 mm lateral to the midline of C-2 vertebrae) was (18.7 +/- 2.7) mm. The odds of a/b was 1.5 approximately 1.7.

CONCLUSIONSAnterior atlantoaxial plate internal fixation through transoral approach is suitable and feasible. The design of the plate should be based on the above data.

Atlanto-Occipital Joint ; anatomy & histology ; surgery ; Bone Plates ; Cervical Vertebrae ; anatomy & histology ; surgery ; Equipment Design ; Humans ; Microsurgery ; Oropharynx ; anatomy & histology ; Spinal Fusion ; instrumentation ; methods

OBJECTIVES: To promote the further research on body stature estimation and the innovative applications based on the distances between the anatomical landmarks on body torso surface. METHODS: A specification for the collection of distances between the anatomical landmarks on body torso surface was established. The data of 933 cases of adult population in Yangtze River Delta region were collected. Multiple linear regression method was used to statistical analyse and establish the regression equation of stature estimation. RESULTS: A regression equation about 5 variables including gender （x₁）, cervical vertebrae-coccyx line （x₂）, sterna-pubis line （x₃）, distance between acromion and iliospinale anterius （x₄） and shoulder breadth （x₅）, and stature （y） was established, y=105.406+5.414 x₁+0.436 x₂+0.286 x₃+0.225 x₄+ 0.193 x₅. CONCLUSIONS The method is suitable for the rapid, simple and accurate estimation of stature for the forensic experts.
Adult ; Body Height ; Bone and Bones/anatomy & histology* ; Cervical Vertebrae/anatomy & histology* ; Female ; Forensic Anthropology/methods* ; Humans ; Linear Models ; Male ; Regression Analysis ; Torso/anatomy & histology*

PURPOSE: All structures of the spine, including the spinal canal, change continuously with age. The purpose of this study was to determine how the spinal canal of the lumbar spine changes with age. The L4/5 is the most common site of spinal stenosis and has the largest flexion-extension motion, whereas the T5/6 has the least motion. Therefore, we measured the spinal canal diameter and vertebral body height at T5, T6, L4, and L5 with age. MATERIALS AND METHODS: This was a retrospective study of aged 40 to 77 years. We reviewed whole spine sagittal MRIs of 370 patients with lumbar spinal stenosis (LSS) (Group 2) and 166 herniated cervical disc (HCD) (Group 1). Each group was divided into four age groups, and demographic parameters (age, gender, height, weight, BMI), the mid-spinal canal diameter, and mid-vertebrae height at T5, T6, L4, L5 were compared. Within- and between-group comparisons were made to evaluate changes by age and correlations were carried out to evaluate the relationships between all parameters. RESULTS: Height, weight, and all radiologic parameters were significantly lower in Group 2 than Group 1. Group 1 did not show any differences, when based on age, but in Group 2, height, weight, and T6, L4, and L5 height were significantly decreased in patients in their 70's than patients in their 40's, except for spinal canal diameter. Age was associated with all parameters except spinal canal diameter. CONCLUSION: Vertebral height decreased with age, but spinal canal diameter did not change in patients with either LSS or HCD. Mid-spinal canal diameter was not affected by aging.
Adult ; Age Factors ; Aged ; Cervical Vertebrae/anatomy & histology ; Female ; Humans ; Intervertebral Disc Displacement/pathology ; Lumbar Vertebrae/*anatomy & histology ; Male ; Middle Aged ; Retrospective Studies ; Spinal Canal/*anatomy & histology ; Spinal Stenosis/pathology