Paper - Fusion of cervical vertebrae (1932)

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Pan N. Fusion of cervical vertebrae. (1932) J Anat. 66: 426-429. PMID 17104384

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This historic 1932 paper by Pan describes abnormal development of the axial skeleton.

Modern Notes: axial skeleton

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Fusion of Cervical Vertebrae

By N. Pan

Anatomy Department, Medical College, Calcutta

In the collection of bones in the Anatomy Museum of the Medical College, Calcutta, there are eight specimens of fusion of cervical vertebrae. These fusions are nonpathological, as there is an absence of any inflammatory thickening or other evidence of disease in the bones. These fused vertebrae are not traceable to the spinal columns. of which they were parts, and hence they offer no clue to the condition of the vertebrae in other regions of the same axial column. There are five specimens of fusion of the 2nd and 3rd cervical vertebrae. There is one specimen each of fusion of the 4th cervical with the 5th, of the 6th cervical with the 7th and of the 7th cervical with the 1st thoracic vertebra. A detailed description of the specimens is given below.

Fusion of the 2nd and the 3rd cervical vertebrae

Front view. Left lateral view. Specimen No. 1.

Specimen No. 1. There is complete fusion of the under surface of the body of the 2nd cervical vertebra with the upper surface of that of the 3rd. The laminae, the spinous processes and the adjacent articular processes are completely fused and only faint grooves indicating the lines of fusion are seen. The fusion of the spinous processes is so complete that no trace of the line of fusion is visible. The transverse processes, however, have not fused and are quite separate on both sides.

Specimen No. 2. Left lateral view.

Specimen No. 2. The fusion of the parts is the same as in specimen No. 1, and if anything more complete except in the case of the spinous processes where faint grooves are visible indicating the line of fusion.

Front view. Left lateral view. Specimen No. 3.

Specimen No. 3. The odontoid process is slightly deflected to the right. The fusion of the parts is like that of the specimen No. 2. The spinous process of the 2nd cervical is not bifid and the gap between the adjacent transverse processes on the left side is greater than that on the right side owing to the greater depth of the body and the articular pillar of the left half of the 2nd cervical vertebra.

Front view. Left postero-lateral view. Specimen No. 4.

Specimen No. 4. The odontoid process is stunted and conical. The anterior surface of the body of the 3rd cervical vertebra is much prolonged inferiorly like that of a normal 2nd cervical vertebra. The fusion of the parts is like that of the specimen No. 3. The spinous process of the 2nd cervical is also not bifid. The superior articular processes of the 2nd cervical vertebra have fiat surfaces looking upwards.

Front view. Left lateral view. Right lateral view.

Specimen No. 5.

Specimen No. 5. The fusion of the bodies of the two. vertebrae is incomplete in the right three-quarters of the segment. The fusion of the right laminae is also incomplete. The left laminae are completely fused, a groove indicating the line of fusion. There is no fusion of the spinous and transverse processes. The right foramen transversarium is incomplete in the 2nd cervical vertebra.

Fusion of the 4th and 5th cervical vertebrae

Front view. Left lateral view. Specimen No. 6.

Specimen No. 6. In this specinien the fusion of the bodies anteriorly is incomplete, a cleft on this aspect being visible. The anterior surface of the body of the lower vertebra is much prolonged inferiorly. The adjacent articular processes are fused but the laminae, transverse and spinous processes are not fused.

Fusion of the 6th and 7th cervical vertebrae

Front view. Right postero-lateral view. Left lateral view. Specimen No. 7.

Specimen No. 7. The fusion of the bodies is incomplete in front where a cleft is visible. The adjacent articular and spinous processes, and the laminae of the left side are fused. But on the right side the fusion between the laminae and between the articular processes is incomplete. The laminae and the corresponding halves of the spinous processes of the two sides have not fused in the middle line. Moreover, the right half of the spinous process of the 7th cervical vertebra is on a lower level than its counterpart.

Fusion of the 7th cervical and 1st thoracic vertebrae

Right lateral view.

Specimen No. 8.

Specimen No. 8. The fusion of the parts is exactly like that seen in specimen No. 7. The costal process of the 7th cervical vertebra on the left side is not connected laterally with the transverse process, and hence there is no foramen transversarium on this side. There are two such foramina on the right side of the same vertebra.


Many instances of fusion of the occipital bone with the atlas (1), (8), (4) and of the atlas with the axis (2) have been reported, though they are not very common. Fusion of the axis and the 3rd cervical vertebra (4) is still rarer, although five specimens of such fusion are reported in this paper. The tendency to fusion of the segments is greater towards the cranial and caudal ends of the vertebral column. The occipital bone is formed by the fusion of at least three such vertebrae, the body of the atlas is normally fused with that of the axis and the tendency to fusion persists in the succeeding vertebrae, and it is possible that the tendency diminishes as we proceed caudalwards towards the lumbar region. Instances of non-pathological fusion of the vertebral elements towards the lower cervical region and in the thoracic and upper lumbar regions are very rare. It is difficult to infer from the specimens at which stage of development fusion actually occurred and whether these are instances of incomplete cleavage of the segments. It is noteworthy that the fused segments are associated with other developmental anomalies such as stunted growth and deflection to one side of the odontoid process (Specimens 3, 4), nonunion of the two halves of the vertebral arch (Specimens 7, 8) and marked projection inferiorly of the anterior surface of the body of the 8rd cervical vertebra (Specimen 4). .


(1) Exxiorr Surru, G. (1908). “The significance of fusion of the atlas to the occipital bone and manifestation of occipital vertebrae.” Brit. Med. J. vol. 11.

(2) Caves, A. J. E. (1930). “Fusion of atlas and axis vertebrae.” J. Anat. vol. LxIv, pt. 3.

(3) Green, H. L. H. H. (1930). “An unusual case of atlanto-occipital fusion.” J. Anat. vol. LXV, pt. 1.

(4) Nyax, U. V. (1931). “A case of abnormal atlas and axis vertebra.” J. Anat. vol. Lxv, pt. 3.

Cite this page: Hill, M.A. (2020, August 12) Embryology Paper - Fusion of cervical vertebrae (1932). Retrieved from

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