Undescended Scapula with an Omovertebral Bone

Abstract

THE subject of this article is an intelligent, male Porto Rican, 23 years of age, who was admitted to the Moses Taylor Hospital, Scranton, Pennsylvania, with an abscess of the left subclavicular region. No cause for it was found. An X-ray examination of this and the adjacent area showed a left omovertebral bone (Fig. 1). Figures 2, 3 and 4 show the deformity of the left shoulder, the short, thick neck, and the inability completely to elevate the left arm. The deformity of the left shoulder and neck and the restricted motion of the left arm are due to an omovertebral bone which connects the upper half of the vertebral border of the left scapula to the cervical spine. The attachment of the omovertebral bone to the scapula is cartilaginous, as there is a definite space, the same width throughout, which does not change upon motion. The superior border of the scapula is bent forward. This forward bending of the superior border of the scapula was shown on roentgenograms made stereoscopically, although the film here reproduced does not show this deformity. Description of the Roentgenogram The left scapula is 2 inches higher than the right. It is 5.75 inches in its widest extent from the margin of the glenoid cavity to the vertebral border, and 7 inches long, being 1.5 inches wider, and 0.5 inch longer than the normal right scapula. This left scapula represents four borders: axillary, superior, vertebral, and oblique, differing from the normal, therefore, in having an oblique border. This border, which extends from the vertebral to the superior border, is 3.75 inches long, occupies the position of the normal superior vertebral angle, and presents a double curve. The vertebral border, therefore, is only 4.5 inches long as compared to 5.5 inches for the normal vertebral border of the right scapula, and is curved with the concavity toward the spine. Attached to the lower half of the oblique border is a triangular bridge of bone 2 inches wide at its base and 3.5 inches long, extending upward to the fifth cervical vertebra. There is a definite space between it and the scapula, which appears like a joint. The superior border of the left scapula is bent forward to form a shelf. The anterior margin of this shelf bends forward and downward so that its outer two-thirds is actually below the spine of the scapula. The first rib on the left side is smaller than on the right. The cervical spine appears to be normal. The figures here given are from a roentgenogram made at a target film distance of 25 inches, and do not, therefore, represent the actual measurements. Figure 5 is a tracing from the roentgenogram. Examination and History of Patient The patient states that there has been no similar deformity in his family or, so far as he knows, among his ancestors. His mother, who did not discover the deformity until he began to walk, knew of no cause for its appearance, such as injury, etc.