What is the size of the human spinal cord?
The spinal cord itself is about 45 cm (18 in) in men and 43 cm (17 in) long in women. A spinal cord injury (SCI) can occur anywhere along the spinal cord, and causes a loss of communication between the brain and the parts of the body below the injury. The human spinal cord consists of nerves that connect the brain to nerves in the body.
What is the normal size of spinal canal?
The diameter of the normal lumbar spinal canal varies from 15 to 27 mm. Lumbar stenosis results from a spinal canal diameter of less than 12 mm in some patients; a diameter of 10 mm is definitely stenotic.
What is the length of the spinal cord?
The length of the spinal cord is about 45 cm in men and 43 cm in women. The spinal cord is shorter than the length of the bony spinal column; the spinal cord extends down only to the last of the thoracic vertebrae.
How many mm is the spinal cord?
The spinal cord has a varying width, ranging from 13 mm (1/2 in) thick in the cervical and lumbar regions to 6.4 mm (1/4 in) thick in the thoracic area. Your spinal cord is protected by the vertebral column (spinal column or backbone).
What is the diameter of the spinal cord in MM?
The cord varies in average anteroposterior and transverse diameters from 8.8 mm x 12.4 mm at C2 to 8.7 mm x 14 mm at C4 to 7.4 mm x 11.4 mm at C7.
How thick is the average spinal cord?
The human spinal cord, part of the central nervous system, is around 45 cm (18 in) in men and around 43 cm (17 in) long in women. The spinal cord has a varying width, ranging from 13 mm (1/2 in) thick in the cervical and lumbar regions to 6.4 mm (1/4 in) thick in the thoracic area.
Does the diameter of the spinal cord change?
In summary, the transverse area of the cervical spinal cord area measured on MRI decreased with age, while RAPT remained unchanged. The bony spinal canal would be narrower with age. But there was no significant correlation between the transverse area and the bony spinal canal diameter.
What is the normal spinal canal measurements?
The average sagittal spinal canal diameter in males was 11.99±1.34 mm and that in females was 12.15±1.24 mm.
What has the largest diameter of spinal cord passing through it?
The spinal cord had the largest transverse diameter at spinal cord neuronal segment C5 (13.3 ± 2.2), decreased to segment T8 (8.3 ± 2.1), and increased slightly again to 9.4 ± 1.5 at L3.
Where is the spinal cord the largest?
lumbar vertebraeRelative Length of Vertebral Bony Segments The vertebral bony segments became longer in the caudal direction, with the lumbar vertebrae being the longest.
How many mm is severe spinal stenosis?
A sagittal diameter of 12 mm is considered as narrow (relative stenosis) and a diameter of 10 mm or less is considered a severely narrowed (absolute stenosis) according to Verbiest.
What is considered severe spinal stenosis?
Symptoms of Severe Spinal Stenosis When spinal stenosis progresses to the severe stage, that means there has been substantial narrowing of the spinal canal. This can occur due to several different factors, but is most commonly caused by degeneration of the discs, vertebrae and spinal ligaments.
Is spinal stenosis a normal part of aging?
Lumbar spinal stenosis is a very common condition in the elderly. In most cases it is due to degenerative changes, the changes can lead to symptoms by themselves or decompensate a preexisting narrow canal.
What is the normal diameter of L4 L5?
The AP diameter of the spinal canal at L4-L5 level in male control group are between 14.66 and 16.5 mm and in case group, the same is between 10.92 and 12.29 mm [Table 3].
What part of the spine can paralyze you?
The first thoracic vertebra, T-1, is the vertebra where the top rib attaches. Spinal cord injuries in the thoracic region usually affect the chest and the legs, resulting in paraplegia.
Can you recover from a C4 spinal injury?
Much of the success of a patient's C4 spinal cord injury recovery is dependent on the level of medical care they receive immediately following the incident. The neck and spinal cord must be stabilized as much as possible, and medications or surgery may be necessary to help reduce swelling and inflammation.
Can you recover from a C5 spinal injury?
Damage to the C5 spinal cord often results in paralysis of both the upper and lower body, otherwise known as quadriplegia. By participating in rehabilitative therapies, individuals can learn to adjust, cope, and manage the outcomes of their spinal cord injury.
What happens if you break C3 and C4 vertebrae?
Paralysis from the Neck Down A C3 spinal cord injury results in quadriplegia, which refers to paralysis of the arms, trunk, and legs. Depending on the severity of your spinal cord injury, you may be able to move and/or feel sensation below your level of injury.
Why is spinal cord size important?
These case-control studies typically suffer from low power and without population estimates, it can be difficult to determine whether a specific patient should be considered to have a pathologically small spinal cord. Furthermore, many experimental strategies for the treatment of acute and chronic traumatic spinal cord injuries are in different phases of development ( 2 ). In all studies where a premade device, instrumentation, or otherwise physical object needs to be applied to the spinal cord, the population estimates of spinal cord size are of importance because they represent the variation in physical dimensions that will be encountered when operating on patients.
Where are the longest spinal cord segments found?
The longest spinal cord neuronal segments were found in the thoracic spinal cord , and each segment constituted approximately 5% of the whole spinal cord. Multiplying the relative length of a spinal cord neuronal segment in Table 3 with the average length of the spinal cord yielded segments lengths well above 2 cm in the thoracic spinal cord and around 1.5 cm in the cervical spinal cord. The calculated relative lengths of each spinal cord neuronal segment are presented in Table 3.
Why is it important to know the transverse and anteroposterior diameters of the spinal cord?
Continuous population estimates of the transverse and anteroposterior diameters of the spinal cord could be useful in diagnosing and monitoring patients with neurodegenerative and neuroinflammatory diseases. It is known, for example, that patients suffering from multiple sclerosis have a reduced cross-sectional area compared to healthy matched controls ( 1 ), but these studies have low power. Without population estimates, it can be difficult to determine whether a specific patient should be considered to have a pathologically small or large spinal cord.
How to align spinal cord neuronal segments?
To align the spinal cord neuronal segments with the vertebral bony segments, we multiplied all cumulative percentages for vertebral bony segments by 1.29. This scaling factor was calculated by dividing the cumulative percentage of entire spinal cord (100%) with the cumulative percentage of the vertebral column at vertebral bony segment L1. This new scaling of vertebral bony segments set the caudal end of the L1 vertebral bony segment equal to the caudal end of spinal cord neuronal segment S5. As a result, the positioning depends on knowledge of the positions of the C3 and C4 spinal cord neuronal segments relative to the C3 vertebral bony segment presented by Cadotte et al. ( 10) and the level of termination of the spinal cord between vertebral bony segments L1 and L2 ( 11 ).
How to combine cross sectional measurements of the spinal cord?
To combine the cross-sectional measurements of the human spinal cord from all studies into single estimates, we calculated a moving weighted average. First, measurements from all studies were aligned along their correct position on our corrected craniocaudal axis described above and in Figures 1 and 2. Thereafter, starting at the cranial end, four consecutive measurements of spinal cord diameter were combined into a single average, weighted by the number of subjects in the comprising studies for the four included measurements. The average position along the craniocaudal axis of the four measurements was used as the new position for the weighted average. Next, the most cranial of the four measurements was dropped, and the closest measurement caudal to the three remaining measurements was included to create a new group of four measurements, with a new weighted average and a new position along the craniocaudal axis.
Which direction do vertebrae go in?
The vertebral bony segments became longer in the caudal direction, with the lumbar vertebrae being the longest. The lumbar vertebrae constitute almost 6% each of the whole vertebral column, or 3.5 cm per segment. The absolute measurement is naturally highly dependent on the length of torso of the individual. The calculated relative length of each vertebral bony segment is presented in Table 4.
What is the number of subjects measured for a given segment?
The number of subjects measured for a given segment was defined as the total number of subjects included in any study with a calculated craniocaudal position inside the cranial and caudal limits of the segment in question. This was used as an approximation of sample size, as there is no obvious way of calculating exact sample size for different portions of a smoothing function.
What are the normative ranges for the sagittal diameters and areas of spinal canal and spinal cord?
Normative ranges for the sagittal diameters and areas of spinal canal and spinal cord were defined at C1, C3, and C6 levels for men and women.
How to measure the sagittal spinal canal?
The sagittal spinal canal (cerebrospinal fluid [CSF] column) diameter at C1 level was measured on the midsagittal T2-weighted images as the distance from the tectorial membrane or dura mater to the most anterior point of the posterior atlantic arch on a line from the most anterior point of the anterior atlantic arch to the most anterior point of the posterior atlantic arch ( Fig 1, A ). At the C3 and C6 levels, the sagittal spinal canal (CSF column) diameter was measured on a line drawn from the midpoint between the superior and inferior endplates of the vertebral body and perpendicular to the anterior surface of the spinal cord ( Fig 2, A ). The lines were drawn on the midsagittal T2-weighted images with magnification ×1, and the measurements thereafter were performed with magnification ×3. The sagittal spinal cord diameters were measured along the same lines as described above ( Figs 1, A, and 2, A) at C1, C3, and C6 levels ( Figs 1, B, and 2, B ). The midsagittal diameter measurements were also performed on reformatted transverse 1-mm VIBE images at the C1, C3, and C6 levels. At the C1 level, the spinal canal diameter was measured on a line drawn from the most concave point of the anterior atlantic arch to the most concave point of the posterior atlantic arch ( Fig 3, A ). At the C3 and C6 levels, spinal canal diameters were measured on a line drawn from the midpoint of the vertebral body to the midpoint of the corresponding spinous process ( Fig 3, B ). The lines were drawn on reformatted transverse VIBE images with magnification ×1, and measurements thereafter were performed with magnification ×2. The transverse VIBE images were reformatted on the workstations based on sagittal VIBE images. The transverse images were reformatted parallel to the lines used for sagittal measurements as described earlier.
How to determine difference of areas of spinal canal?
Difference of areas (ie, space around the cord) ( 8) was determined by subtracting the values for the spinal cord from those of the total spinal canal.
What is the CSF column size in VIBE?
Figure 4: Transverse reformatted VIBE image demonstrates the areas of the spinal canal (CSF column, 252.26 mm 2) and the spinal cord (77.93 mm 2) at C1 level in the transverse plane (reformations use the same reference lines as the measurements of Figs 1 and 2 ). Analysis of the areas is performed by manually traced regions of interest.
Why should diameters be used?
Because reliability of our measurements was better for diameters than it was for areas, diameters should be used.
Where are the 19 sagittal images?
The 19 sagittal images were centered on the spinal cord at the C4 level and were obtained from the midpoint of the cerebellum to the second thoracic vertebral level, and they included the entire cervical spine.
Which level of the spinal cord is ellipsoid?
This is because the spinal cord area shape gets broader at the lower levels, from circular at C1 level and ellipsoid at C6 level with a broader right-to-left distance. Within each spinal level, both the diameter and the area of the spinal canal increased with body height.
Which vertebral level is the lumbar canal widest?
However, the dimensions of the lumbar than those in the male subjects. It can therefore be deduced that in males the canal is widest at L1 and in females at L1 and l2 vertebral levels which gradually narrows down at successive subjacent vertebral levels and attains relatively narrowest dimensions at L5 vertebral level.
What is the C/B ratio of the lumbar canal?
In both groups B and Bi the C/B ratio of the canal ranges between 1:2 and 1:4.5. However, in group B 1:2 at Ll(8%) and 1:45 at L3, L4 and L5 (8%, 18% and 38% respectively) with a peak frequency distribution pattern ranging between 15% and 60% where as in group Bl, 1:3 at Li and L2(31% and 8% respectively) and 1:4.5 at 13, L4and L5 (8%,8% and 23% respectively) with a peak frequency distribution pattern ranging betwe:n 15% and 62% (Figure 5A and B).
How long does the canal stay constant?
This indicates that dimensions of the canal remain constant between 25 and 45 years, an indication for the completion of the development of thevertebral canal at the age of 25 years and that the subjects selected were not affected by any disease process leading to stenosis of the canal.
What is the C/B ratio of a female?
The C/B ratio in the female subjects ranges between 1:2.0 and i:4.5with 1:2 at Li and L2 (24% & i4% respectively) and 1:4.5 atL3, L4andL5 (41%,6% & 18% respectively) and a peak frequency distribution pattern ranging between 32% and 48% at all vertebral levels (Figure 3B).
