Subcoracoid impingment syndrome: the aetiological role of coracoid morphometry

Few studies have analysed the anatomical characteristics of the coracoid process. We studied the morphology and orientation of the coracoid process and measured its clirnn- sions. T0 clauify thc possible role 0f thc ccraccid process in the subcuracnid impingcmcnt syndrome ws: performed a mcrphcmctric anatomical study of 200 scapulac of Cau- casian adult subjects. Materials and methods: The length and thickness of the coracnid process and_ Lhc distance between aha latter and the anterior burdcr 0f thc glcncnid was mc:1%urcd. We also smdiad, in aha coronal pianc, thc inclination of thc cnracoid process and, nn thc horizontal, Lhc rnmphology of thc arch formsd by the pustemlatcral margin 0f the curacuid process and thi: Hntcrusuperior border 0f the glcnuid. This dam was correlated to thc ratio lcngihfwidtli of Bic gienoid and the ratio lcngthfwidth of ihc whclc scapula. Based 0n thc latter ratio, wc identified thrcc groups of scapulacz group I (ratio 1.12-1.34); group II (ratio L35-L50); group H1 \{ratio 1.51-1.75). Results: The three groups included 51.5%, 44.5% and 4% of Lhc scapulac respectively. The nicam icngth of the com- ccid process was 38.2mm (range 34-47) in group I, 39.lmm (range 35-47) in group H, and 44.8mm (rzmgc 38-50) in group III. In all groups, Lhc tip surpassed laterally the imturiur border of the glcnoid, on average, of 14.9mm , 14.7mm and 15.21111;:1, respectively: the SDS were as high as 6mm in auch group. The mean thickness uf Ihr; tip was 7.2m.m (range 5.5-10), 753 (range: 6~l0) and 8.50mm (range 7-10,5) in group I, H and HI, respectively. The shortest mean distance between thc lateral margin nf thc coracoid tip and thc anterior border of thc glcnuid was 16.8mm (range 12-18) in group I, 16.0mm (range 14-22) in group H and 18.5mm (range 15-22\} in group LH. In thc coronal planz, thc coracoid was orientated hor- izontally or was slightly inclined caudally. The tzmgcnt Line K0 thc caudal margin of the tip running parallel to thc auicular surface was located cranially (max. 3mm) or cuudaliy (max. l2mm) tu the Lungcnl line to the cranial and uf Lha glcnoid. In thc horizontal plane, Lhc pustcrulaterai margin 0f the coraccid and Lhc antcmsupcriur border cf the, glcnuid delimited Hl'1 :m:h\emdash like: space. We idantiiicd 3 coudguratiuns of this space: square bracket (33%), round bracket (45%) and Hsh h00k (22%) The configurations were equally distributed in thc three groups. Among thc scapulac with 8. round bracket configuration, those with thc extremities of thc bracket very cicrsc to each other showed thc minimal distance between thc ccraccid tip and thc anterior border of the glcnoid. A round bracket configuration was associated with a considerably lcng and thick coracoid process and a marked prominence of Lhc coracnid beyond thc medial glsnuid border in 4% of Lhc scapulac. None uf thc pzuamctrzrs examined could bc correlated tu the ratio lcngmfwidnh of the glcnoid. Conclusions: N0 comlation was found between thc para- mcurrs analysed. Ccracoid processes with similar length audio; thicimcss 0r cquidistam from aha: anterior border of dt glencrid. may be found in cach of the three groups of scapulac. This study shows what 4% of The scapuiaa have bony morphcmccric charzcamiscics which may pnzdispnse to subcumcoid irnpingcmcnt. Since thc pnzvalcncc uf this condition is not so high, it is ccmccivablc aha: mhcr cnn-