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Year : 2017 | Volume : 5 | Issue : 2 | Page : 60 - 62  


Original Articles
Variation in shapes of coronoid process in human mandibles

Maria Kala1, Usha Mukkera2, Rajasree TK3, S. Sri Sarada Devi Sattiraju4

1Associate Professor, 3Professor & HOD, 4Professor, Department of Anatomy, Malla Reddy Institute of Medical Sciences,Suraram, Hyderabad 500055, Telangana, India

2Associate Professor, Department of Anatomy, Malla Reddy Medical College for Women, Suraram, Hyderabad

Corresponding Author

Dr. Maria Kala

Email: mariakala.moorthi@gmail.com

ABSTRACT:

Background: Various shapes of coronoid process have been described, they are triangular, rounded and hook shape. The shape and size of the coronoid process is influenced by dietary habit, genetic constitution, hormones and mainly by temporalis muscle activity. The coronoid process is a good auto bone graft. It has advantage of biocompatibility, availability and less operative time for harvesting.

Objective: To study variations in shapes of coronoid process in human mandibles

Methods: About 100 dried human mandibles were taken for study and categorized according to age group and both sexes.

Results: The most prevalent shape was triangular in all age groups and both the sexes. The least prevalent shape was hook in all age groups and both sexes. It was observed that the mandible was triangular in 52.5%, rounded in 38% and hook in 9.5% of coronoid process.

Conclusion: The coronoid process can be used for reconstruction of maxillofacial regions, orbital floors. It is also important to anatomist, anthropologist and forensic researches.

Key words: Coronoid process, triangular shape, rounded and hooks shape.

INTRODUCTION:

The mandible or sub maxilla forms the lower jaw. It has two processes, the condylar process articulating with the temporo mandibular fossa on the base of the skull and the coronoid process of mandible. There is another coronoid process in ulna and coronoid fossa in humerus. In lower animals separate coronoid bones are present which articulate with splenial, angular, supra angular bones etc. to form a common dentary bone which is homologus to mandible in humans.

The coronoid process of mandible and condylar process develop in endochondral ossification while the body of the mandible develops in membrane1. The term coronoid comes from the Greek word korone meaning crown. The coronoid process is flat from side to side, the tip points upwards and forwards2. Two muscles of mastication are attached to coronoid process. The temporalis muscle is attached onto the medial surface and anterior part of the lateral surface3. These two important muscles show morpho-functional dependence.

Various shapes of coronoid process have been described, they are triangular, rounded and hook. The shape and size of the coronoid process is influenced by dietary habit, genetic constitution, and hormone and mainly by temporalis muscle activity. Enlargement of coronoid process is seen in some pathological conditions like osteochondroma, exostosis, osteoma and other developmental anomalies. Hernandez-Alfaro F4 noticed a new joint between enlarged coronoid process and zygomatic bone (Jacobs disease) causing restriction in opening of mouth. Though fracture of mandible is common, fracture of coronoid process is rare. It requires no treatment unless there is impingement on the zygomatic arch.

The coronoid process is a good auto bone graft. It can be removed intraorally without functional deficiency and facial disfigurement. It can be used for reconstruction of orbital floor deformities, alveolar defect, and paranasal augmentation, non union fracture of mandible, osseous defects and in craniomaxilla facial surgeries. It acts as an anthropological marker for detection of races. Mintz et al5 1998, Clauser L. et al6 1995 reported the use of temporal myofascial flap both as a single and as composite flap, as the arteries supplying the coronoid process also supply the muscles attached to it.

MATERIAL & METHODS:

About 100 dried human mandibles were taken for study from study material of various medical colleges, Malla Reddy Institute of Medical Sciences, Malla Reddy Medical College for Women, Osmania Medical College and Kakatiya Medical College from Telangana State.

According to the standard text book description of the determining features, the mandibles were categorized as young, adult and old age groups and as male and female groups1. The 200 coronoid processes were observed for its various shapes like triangular, rounded and hook. The triangular coronoid process has its tip pointing upwards, the rounded coronoid process has its tip rounded and margins wider, the hook shape has pointed tip pointing backwards and outwards. (Figure – 1)

RESULTS:

Out of 100 mandibles observed there were 2 in young age group, 1 male and 1 female; 10 in old age group, 7 male and 3 female; 88 in adult group, 70 males and 18 females. There were 78 male mandibles and 22 female mandibles. Only 1 mandible in male young showed unilaterally triangular shape on left side and hook on right side. All other mandibles showed similar shape bilaterally. The various shapes observed are shown in table1.

Table 1: Distribution of different shapes of coronoid process in different age groups & in male and female groups

Age group

Gender

No. Of mandibles

Sides

Triangular

Rounded

hook

Young

Male

1

2

01-left side

Nil

01 – right side

Female

1

2

02

Nil

nil

Old

Male

7

14

04

08

02

Female

3

6

04

Nil

02

Adult

Male

70

140

72

56

12

Female

18

36

22

12

02

The most prevalent shape is triangular in all age groups & both sexes. The least prevalent shape is hook in all age groups & both sexes. The rounded shape is nil in young age group and old female group. It is next to triangular in both adult male & female groups and old male group.

DISCUSSION:

In the year 2001 Isaac B. & Holla S.J.7 have observed in their study triangular in 49%, rounded in 23.6%, and hook in 27.4%. In the year 2014 S. Pradhan et al2 noted in his study triangular in 46.73%, rounded in 35.3%, hook in 17.93%. In the year 2015 Sheela D Kadam et al8 in her study observed triangular in 64.97%, rounded in14.01% and hook in 21.02%. In the year 2015, Varalakshmi et al9 observed in her study triangular in 45.19%, rounded in 21.15% and hook in 33.65%. In the year 2015 Priyanka Bhabhor et al10 noted in their study triangular in 29.65%, rounded in 23.35% and hook in 45%. In the present study we observed triangular in 52.5%, rounded in 38% and hook in 9.5% coronoid process. Gender distribution of shapes of coronoid process in studies by different authors is given in table – 2.

Table: - 2 Gender wise distribution of shapes of coronoid process in their studies by different authors

Name

Year

Gender

Triangular

Rounded

Hook

Isaac B& Holla S.J

2001

Male

46.5%

23.5%

30%

Female

53.5%

23.6%

22.8%

  1. Pradhan et.al

2014

Male

45.83%

32.29%

21.87%

Female

47.72%

38.63%

13.63%

Priyanka Bhabhor

2015

Male

27.27%

27.78%

44.12%

Female

35.37%

19.51%

45.12%

Varalakshmi et.al

2015

Male

46.7%

23.7%

30.5%

Female

43.3%

2.3%

34.4%

Sheela D. Kadam et.al

2015

Male

62.5%

17.26%

20.2%

Female

67.8%

10.27%

21.91%

Present study

2016

Male

49.35%

41.02%

9.61%

Female

63.63%

27.27%

9.09%

Our study is correlating with the study of S. Pradhan et al, both in general incidence and gender distribution of shapes of coronoid process.

CONCLUSION:

The shape of coronoid process was studied in 100 dried mandibles. It was found that the triangular shape dominated over the rounded shape. The hook shape was present in the least number. The coronoid process is a good auto bone graft. It can be removed easily intraorally without any minimal morbidity and without any cutaneous scarring. It can be used for reconstruction of maxillofacial regions, orbital floors, alveolar defects and non union fracture of mandible. As it is an anthropological marker, its study is of importance to anatomist, anthropologist and forensic researches. It also helps in determining buccal vestibule during denture fabrication.

REFERENCES:

  1. Susan Standring. In: Susan Standring, editor. Grays Anatomy – The anatomical basis of clinical practice, 41st Canada: Elseiver;2016. p. 426-427.
  2. Pradhan S, Bara DP, Patra S et al. Mohapatra. Anatomical Study of Various Shapes of Mandibular Coronoid Process in Relation to Gender & Age. J Dental Medical Sci 2014;13(8):9-14.
  3. Dutta AK. In: Datta AK, editor. Essentials of Human Anatomy Head and Neck. Part II, 5th Kolkata: Current Books Intenational;2009. p. 42.
  4. Hernandez-Alfaro F, Escuder O, Marco V. Joint Formation between an Osteochondroma of the Coronoid Process and the Zygomatic Arch (Jacob disease): report of case and review of literature. J Oral Maxillofacial Surg 2000;58:227-32.
  5. Mintz SM, Ettinger A, Schmakel T et al. Contra-lateral coronoid process bone grafts for orbital floor reconstruction: an anatomic and clinical study. J Oral Maxillofacial Surg 1998;56(10):1140-5.
  6. Clauser L, Curioni C, Spanio S. The use of the Temporalis muscle flap in Facial and Craniofacial Reconstructive Surgery. A review of 182 cases. J Cranio Maxillofacial Surg 1995;23(4):203-14.
  7. Issac B, Holla SJ. Variations in the shape of the Coronoid Process in the Adult Human Mandible. J Anatomical Society India 2001;50(2):137-9.
  8. Kadam SD, Roy PP, Ambali MP et al. Variation in the Shape of Coronoid Process in Dry Mandible of Maharashtra Population. Int J Anatomy Res 2015;3(1):895-98.
  9. Varalakshmi KL, Padmavathi G, Sangeeta M. Variations in the Shapes of Coronoid Process of Mandible: An Osteological Study. Int J Current Res 2015;7(1):1653-5.
  10. Priyanka B, Bina K, Paras S. Variations in the Shape of the Coronoid Process in the Adult Human Mandible. Int J Res Med 2015;4(4):87-9.





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