Case Report International Ayurvedic Medical Journal ISSN:2320 5091

VARIATION IN MUSCLE FOUND DURING DISSECTION- A CASE REPORT 1Dr. Chhaya Gupta 2Dr. J. Manohar 3Dr. Sandeep M. Lahange 1MD scholar, Dept. of Sharira Rachana, NIA, Jaipur, Rajasthan, India 2Assistant Professor, Dept. Of Sharira Rachana, NIA, Jaipur, Rajasthan, India 3Assistant Professor, Dept. Of Sharira Rachana, NIA, Jaipur, Rajasthan, India ABSTRACT The pectoral region covers the anterior thoracic wall and part of the lateral thoracic wall. There are four muscles in the pectoral region: pectoralis major, , subclavius and ser- ratus anterior. The muscles of the pectoral region attach the upper limb to the axial skeleton. The pectoralis major muscle is positioned immediately deep to the superficial . The pecto- ralis major muscle comprises two heads 1) Clavicular head 2) Sternocostal head. It originates from the , manubrium, , , aponeurosis of external oblique muscle of abdomen and inserted on humerus. The present case is a report of an unusual variation of pectoralis major muscle in pectoral region. Key words: - Clavicular, pectoral, sternocostal.

INTRODUCTION lage, the first to the seven costal cartilages, The pectoral word is originated the sternal end of the sixth rib and the apo- from the latin word ‘pectus’ means chest, neurosis of external oblique. Slight cleft which is found on the exterior of anterior separates the clavicular fibres from the thoracic wall and on the region of the lat- sternal fibres. The muscle tends to become eral thoracic wall1 . Generally, the region a flat tendon, approximately 5 cm across. covering both the walls is termed as the The tendon is bilaminar. Fibres from the pectoral region. Pectoral region consists of manubrium form the thicker anterior lam- four muscles, subclavius, pectoralis major, ina, which are binded superficially by cla- pectoralis minor and serratus anterior vicular fibres and strongly by sternal mar- which are also referred as the anterior gin fibres and the 2nd to 5th costal carti- axio-appendicular muscles or thoraco-ap- lages. Clavicular fibres may be further pendicular or pectoral muscles. These elongated into the deltoid tendon. Sixth muscles are responsible for moving the and frequently seventh costal cartilages pectoral girdle2. The pectoralis major is a and ribs provide fibres to the posterior large and fan-shaped muscle that covers lamina, from the front of the sternal and the major part of the . It originates from the obliqus abdominis externus apo- from the anterior surface of the sternal half neurosis. The costal fibres bind the lamina of the clavical, half the width of the ante- directly without windings. The sternum rior surface of the sternum down to the fibres and aponeurosis fibres curve round level of the sixth or seventh costal carti- the lower border of the remaining muscle,

How to cite this URL: Dr. Chhaya Gupta et; al: Variation In Pectoralis Major Muscle Found During Dissection- A Case Report. International Ayurvedic medical Journal {online} 2016 {cited 2016 May} Available from: http://www.iamj.in/posts/images/upload/870_872.pdf Dr. Chhaya Gupta et; al: Variation In Pectoralis Major Muscle Found During Dissection- A Case Report the lower turning successively behind was appearance of this muscle with those cranial to them so that this part of the vertical fibres. muscle is winded on itself and the ab- Materials and Methodology- dominal fibre rise highest upon the tendon. Materials- The posterior lamina of the tendon reaches For literary study:- higher on the humerus then the anterior, 1. Available literature regarding pectoralis giving off an expansion which covers the major muscle from Modern texts. intertubercular sulcus and blends with the 2. Research Journals or papers presented on capsular ligament of the . the relevant topics. From the deepest fibre of this lamina, at its 3. Confirmed World Wide Web sources. insertion, an expansion is given off which For cadaveric dissection Study:- lines the intertubercular sulcus, while from 1. Cadaver: female the lower border of the tendon a third ex- 2. Dissection kit pansion passes downwards to the fascia of Methodology: The anatomical variation in the upper arm3. supply- It is sup- pectoralis major was identified during plied by lateral and medial pectoral ; routine cadaveric dissection of a female clavicular head (C5, C6), sternocostal head cadaver of 55 years old embalmed, in the 4 (C7, C8, T1) . Main action of pectoralis department of Sharira Rachana of Na- major muscle- Adducts and medially ro- tional institute of Ayurveda, Jaipur (Raja- tates humerus; draws anteriorly sthan). On careful dissection, the muscle and interiorly acting alone, clavicular head attachments were identified and recorded flexes humerus and sterno-costal head ex- by using digital camera and photographs tends it from the flexed position5. were taken. Case report: During routine dissection, *Literature Study: All the information re- unusual variation of pectoralis major mus- garding pectoralis major muscle was col- cle has been found on right side of an old lected from modern texts, research journals female cadaver. Usually the abdominal slip or papers presented on the relevant topics from the aponeurosis of the external and authentic internet sources. oblique is sometimes absent but the num- DISCUSSION ber of costal attachments and the extent to The presence of rectus sternalis is rare which the clavicular and costal parts var- last normal anatomical variant in the chest ies. A superficial vertical slip may ascend wall in cadaver of Indian origin. It has ra- from the lower costal cartilages and rectus cial and regional variations based on the sheath to blend with sternocleidomastoid study which has been conducted in 2008, it or to attach to the upper sternum or costal revealed the incidence to be 4-7% in white cartilages. This is sternalis or rectus ster- population,11% in Asian population, 8.4% nalis. in black population, 1% in Taiwanese but The in Indian population is 5-8% equal in both muscle genders6. In present study there was a uni- may be lateral rectus sternalis. In Grays anatomy partially this muscle is described as superficial ver- or com- tical slip which ascend from lower costal pletely cartilages and to blend with absent. sternocleidomastoid muscle or to attach to The unique feature of present case study the upper sternum or costal cartilages. It 871 www.iamj.in IAMJ: Volume 4; Issue 05; May- 2016

Dr. Chhaya Gupta et; al: Variation In Pectoralis Major Muscle Found During Dissection- A Case Report may represent the remains of ‘panniculus 4. Clinically oriented anatomy by Keith carnosus’, which is superficial to pectoral L. Moore, Arthur F. Dalley and Anne fascia and has a nerve supply from anterior M. R. Agur, seventh edition, page cutaneous branches of intercostals nerve7. no.698. It is a rare muscle encountered in the sub- 5. Clinically oriented anatomy by Keith cutaneous plane so it is important for a L. Moore, Arthur F. Dalley and Anne surgeon and an anatomist to identify it for M. R. Agur, seventh edition, page an appropriate dissection plane. no.698. CONCLUSION 6. Sarikcioglu L,Demirel BM,Ucar A part from anatomical variations or Y.Three sternalis muscles associated additional slip of muscle fibres which is with abnormal attachments of found in this case study, it is having keen pectoralis major muscle importance for surgeons while doing re- [J.Exp.Clin.Anat.(Internet);2008 [cited constructive surgery of breast. The loca- 2013 Sep 23] 2; 67-71. tion of rectus sternalis and direction of fi- 7. Barlow RN ,the sternalis muscle in bres suggest that this may help in elevating American Whites and Negroes.Anat lower chest wall. Record.1935:64:413-26 REFERENCES 1. Grant’s dissector by Lippincott Wil- CORRESPONDING AUTHOR liams & Wilkins, fifteenth edition, Dr. Chhaya Gupta page no.26. MD scholar, Dept. of Sharira Rachana, 2. Clinically oriented anatomy by Keith NIA, Jorawer Singh Gate, Amer road, L. Moore, Arthur F. Dalley and Anne Jaipur, Rajasthan, India- 302002 M. R. Agur, seventh edition, page Email- [email protected] no.697. 3. Gray’s anatomy-the anatomical basis of clinical practice, fortieth edi- Source of support: Nil tion.page no.807-808. Conflict of interest: None declared

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