multiple ossified costal cartilages for 1st rib

Int J Anat Res 2014, 2(4):744-47. ISSN 2321-4287 744

Case Report

MULTIPLE OSSIFIED COSTAL CARTILAGES FOR 1ST RIBRaghavendra D.R. *1, Nirmala D 2.

ABSTRACT

Address for Correspondence: Dr. Raghavendra D.R. Post graduate student, Department of anatomy,J J M Medical College, Davangere, 577004, Karnataka, India. E-Mail: [email protected]

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*1 Post graduate student, Department of anatomy, J J M Medical College, Davangere, Karnataka,India.2 Associate Professor, Department of anatomy, J J M Medical College, Davangere, Karnataka,India.

Costal cartilages are flattened bars of hyaline cartilages. All ribs except the last two, join with the sternumthrough their respective costal cartilages directly or indirectly. During dissection for 1st MBBS students in theDepartment of Anatomy, JJMMC, Davangere, variation was found in a male cadaver aged 45 –50 years. Multipleossified costal cartilages for 1st rib were present on left side. There were 3 costal cartilages connecting 1st ribto manubrium. There were two small intercostal spaces between them. The lower two small costal cartilagesfused together to form a common segment which in turn fused with large upper costal cartilage. The large uppercostal cartilage forms costochondral joint with 1st rib. All costal cartilages showed features of calcification.The present variation of multiple ossified costal cartilages are due to bifurcation of costal cartilage. It maycause musculoskeletal pain, intercostal nerve entrapment or vascular compression. Awareness of theseanomalies are important for radiologists for diagnostic purpose and for surgeons for performing variousclinical and surgical procedures.KEYWORDS: Costal cartilage, bifurcation of Rib, Sternum.

INTRODUCTION

International Journal of Anatomy and Research,Int J Anat Res 2014, Vol 2(4):744-47. ISSN 2321- 4287

DOI: 10.16965/ijar.2014.538

Received: 14 Nov 2014Peer Review: 14 Nov 2014 Published (O):31 Dec 2014Accepted: 02 Dec 2014 Published (P):31 Dec 2014

International Journal of Anatomy and ResearchISSN 2321-4287

www.ijmhr.org/ijar.htm

DOI: 10.16965/ijar.2014.538

Costal cartilages are flattened bars of hyalinecartilages, extending from the anterior ends ofribs. They impart elasticity and mobility of thethorax. The costal cartilages are unossifiedanterior parts of embryonic cartilaginous ribs [1].A typical costal cartilage has medial and lateralends, anterior and posterior surfaces, andupper and lower borders [2]. The upper sevencostal cartilages join with the sternum. Theeighth to tenth cartilages articulate with thelower borders of the adjacent upper cartilages;the lowest two cartilages posses free pointedtips in the muscular wall of abdomen. The firstchondrosternal joint is primary cartilaginous, rest

CASE REPORT

of the articulations are synovial. The interchon-dral joints are also synovial, except thatbetween the 9th and 10th cartilages which is afibrous joint [1]. The costochondral articulationsare hyaline cartilaginous joints. Each rib has acup shaped depression in its sternal end intowhich the costal cartilage fits. No movementsnormally occurs at costochondral joints [3].

The present variation was observed during grossanatomy dissection of thoracic region for 1st

MBBS students in the Department of Anatomy,J.J.M. Medical College, Davangere in a malecadaver aged about 40-50 years. It involved

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Raghavendra D.R, Nirmala D. MULTIPLE OSSIFIED COSTAL CARTILAGES FOR 1ST RIB.

multiple ossified costal cartilages for 1st rib onleft side(Figure.1). There were 3 costal cartilagesconnecting 1st rib to manubrium. They werenamed as upper, middle and lower costalcartilages. There were two small intercostalspaces between them. The middle and lowercostal cartilages were small and fused togetherto form a common segment which in turn fusedwith large upper costal cartilage. The large up-per costal cartilage forms costochondral jointwith 1st rib (Figure.2). The remaining all othercostal cartilages were normal on both sides.

Fig. 1: Multiple ossified costal cartilages for 1st rib.

MCC-Multiple costal cartilages; 1R-1st rib;M-manubrium;L-left; R-right.Fig. 2: Formation of multiple ossified costal cartilages

for 1st rib.

UCC-upper costal cartilages; MCC-middle costal carti-lage; LCC-lower costal carti lage; CS-commonsegment;ICS-intercostal space; ICJ- interchondral junc-tion; CCJ-costochondral junction; M- manubrium.

The upper costal cartilage situated horrizontallymeasures 3.5 cms length from manubrium to 1st

costochondral joint and 6cms in circumference.The middle costal cartilage situated horizontallymeasures 0.5 cms length from manubrium tocommon segment formed by middle and lowercostal cartilages and 2cms in circumference. Thelower costal cartilage inclined upwardsmeasures 0.5 cms length from manubrium tocommon segment formed by middle and lowercostal cartilages and 2cms in circumference. Thecommon segment formed by union of middle andlower costal cartilages inclined upwardsmeasures 3.5 cms length and 5cms maximumcircumference. The common segment fused withlower border of upper costal cartilage and formsinterchondral junction. All costal cartilagesshowed features of calcification.The intercostal spaces between costal cartilagesmeasures 2mm in vertical length and filled withconnective tissue.The fibres of pectoralis major had taken originfrom anterior surfaces of all costal cartilages.The lower border of lower costal cartilage alongwith lateral border of common segment hadgiven attachment to internal intercostal muscleand external intercostal membrane. Theposterior surface of all costal cartilages weresmooth and normal.The 2nd intercostal space was narrow below thelower costal cartilage and 2nd costal cartilagemeasuring 5mm in vertical length. Radiologically,

Fig. 3: X-ray of multiple ossified costal cartilages for 1st

rib.

ICJ- interchondral junction; CCJ-costochondral junction;L-left; R-right.


DISCUSSION


normal costochondral junction with ossifiedbridges surrounding the junction noted. Therewas evidence of additional ossified cartilagesextending from the lower part of the manubriumto first costal cartilage forming interchondraljunction (Figure.3).

The first costal cartilage inclines downwards andmedially [1]. The manubrium and the first ribsare fixed to each other and move together asone [4].In thoracic vertebra the costal elements undergoindependent growth and form the ribs. As theribs grow outwards through the segmentalmyotomes of the body wall, they describe thecostal arches. At first each arch is completelychondrofied. The ventral ends of upper sevenor eighth arches unite on each side to form acartilaginous sternal plate. Finally the sternalplates are fused in the middle and form therudiment of the sternum. A typical rib is ossifiedfrom one primary centre which appears close tothe posterior angle of the shaft during theseventh week. From there the ossificationproceeds dorsally and ventrally. At birth ventralpart of the costal arch remains cartilaginous,since ossification has to extend for longerdistance, and this persists as such throughoutlife to establish elastic recoil of the thoracic wall[5]. During this process multiple bifurcations ofthe 1st costal cartilage medially and thenforming the sternal plate explains the possiblecourse of this variation.Anatomic rib variants include developmentaldeformities, cervical rib, and short rib which maymimic true rib diseases. Apart from this theremay be rare occasions where unusual variationsare encountered; for example, the costalcartilage and adjacent portions of the body ofthe rib may be occasionally replaced by fibroustissue, two adjacent ribs may be completelyfused, or the bodies of two or more ribs may bejoined by fusion [6].A bifid rib or bifurcated rib is an unusualmalformation and is rarely observed in theclinical scenario. It is a congenital abnormalityof the rib cage and associated muscles andnerves in which the sternal end of the rib iscleaved into two. It is usually unilateral and

CONCLUSION

asymptomatic but it can present as an isolatedabnormality or be associated with pathologicmalformations such as jaw cysts and basal cellnevus syndrome [7]. In the current casebifurcation of costal cartilage is mediallytowards the sternum instead of usual bifurcationof costal cartilage, which is lateral and inassociation with the bifid rib. Moreover thebifurcated common segment bifurcates againbefore forming the sternal plate, forming middleand lower costal cartilages, showing multiplebifurcations of costal cartilage.In elderly people, the costal cartilages lose someof their elasticity and become brittle; they mayundergo calcification, making them radiopaque[3]. In the current case there is a radiologicalevidence of age related calcifications.Bifid ribs associated with pathologicmalformations such as Gorlin–Goltz syndrome[8,9] and malignancy in childhood usually occurin the young[10] , and might be characteristicof multiplicity of the bifid rib on the same side.In older people, the bifid rib when it is notassociated with other disease may present fewclinical problems. However, knowledge of bifidribs is necessary for the differential diagnosiswith other diseases, such as tumors of the chestwall or costal fracture, because the varioustypes of bifid rib present with diverseappearances on normal chest X-rays [11].The ribs and the intercostal spaces provideimportant surface marking for various physicalexamination procedures and clinical procedures.Hence it is imperative that the radiologists andclinicians be familiar with normal rib anatomy,rib variants, and the radiologic appearance ofthe ribs to prevent misdiagnosis [12].

The present variation of multiple costalcartilages are due to bifurcation of costalcartilage.In the present case bifurcation of costal cartilageis not associated with bifid rib and it showingmultiple bifurcations. It may cause musculo-skeletal pain, intercostal nerve entrapment orvascular compression. Awareness of theseanomalies are important for radiologists fordiagnostic purpose and for surgeons for perfor-


Conflicts of Interests: None

REFERENCES


How to cite this article:Raghavendra D.R, Nirmala D. MULTIPLE OSSIFIED COSTALCARTILAGES FOR 1ST RIB. Int J Anat Res 2014;2(4):744-747.DOI: 10.16965/ijar.2014.538

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multiple ossified costal cartilages for 1st rib

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