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Rajiv Gandhi University of Health Sciences Karnataka, Bangalore Annexure 2 Proforma for registration of subjects for dissertation 1. Name of the candidate and Address: Thuslima M. Postgraduate student, Department of Anatomy St.John’s Medical College, Bangalore-560 034. Residential address: No.2,Vallalar Street, Kosapalayam, Puducherry-605013. 2. Name of the institution: St.John’s Medical College, Bangalore - 560 034. 3. Course of the study and subject: M.D (Anatomy) 4. Date of admission: 15th MAY 2012 5. Title of the topic: “Surgical Anatomy of Axillary Nerve”. 6.1 Need for the study: The Axillary nerve is one of the terminal branches of posterior cord of brachial plexus and contains fibres from c5, c6, ventral rami. It innervates teres minor and deltoid muscles,the skin over the shoulder and the gleno-humeral joint . Injuries to the Axillary nerve make up 6% of all brachial plexus injuries[1] . Injections in and about the shoulder complex are performed routinely for the purposes of vaccination, IM medication administration, deltoid trigger-point injections, and intra-articular and bursal steroid injections. Although such injections are considered routine office procedures, there is increased risk of injury to the subdeltoid/subacromial bursa, anterior branch of the axillary nerve and the radial nerve if performed incorrectly, which reflects the lack of awareness of the anatomical position of these structures in and near this muscle [2]. The nerve injury may occur together with shoulder dislocation and rotator cuff tear,comprising the ‘unhappy triad’ of shoulder joint[6]. Knowledge of the precise relationship of the branches of the axillary nerve, its relationship to the shoulder capsule and its common variations within deltoid muscle, provides morphometric data that could be applied during surgical procedures over shoulder, and reduce the incidence of iatrogenic nerve damage. 6.2 AIMS AND OBJECTIVES: The aim of this study is to determine the distribution patterns of anterior and posterior branches of axillary nerve and to determine the exact anatomical location of the axillary nerve in relation to surface landmarks, specifically the acromion process and the deltoid tuberosity. The specific objectives are To analyse the following measurements: 1. To determine the diameter of the trunk of Axillary nerve on right and left side 2. To determine diameter of Anterior division of the nerve on right and left side 3. To determine diameter of Posterior division of the nerve on right and left side 4. To determine the distance of the nerve from the acromian process on right and left side 5. To determine the distance of the nerve from the Deltoid tuberosity on the right and left side 6. To determine the presence or absence of the pseudoganglion in the posterior division of the axillary nerve. 7. To determine the number of branches given off by the anterior division of the axillary nerve on the left and right side 8. To determine the number of branches given off by the posterior division of the axillary nerve on the right and left side. 9. To determine the percentage of cases where the posterior circumflex humeral artery accompanies the posterior division of the axillary nerve. 10. To determine the caliber of the posterior circumflex humeral artery. 6.3 REVIEW OF LITERATURE: Various authors have studied the distribution patterns of axillary nerve. Marios Loukas et al studied the anatomic variations of the axillary nerve within the deltoid muscle, and found that, In 65% of cases, the axillary nerve split into two branches (anterior and posterior) within the quadrangular space, and in the remaining 35% split within the deltoid muscle. The posterior branch of the deltoid muscle irrespectively of origin gave off a branch to the teres minor and the superior lateral brachial cutaneous nerve in 100% of cases. The branch to the posterior part of the deltoid muscle was present in 90% of cases, and the branch to the middle part of the deltoid was present in 38% of cases. The anterior branch of the deltoid muscle provided a branch to the joint capsule, a branch to the anterior part of the deltoid muscle and the middle part of the deltoid in 100% of cases. In 18% of the cases, the anterior branch of the axillary nerve provided a branch to the posterior part of the deltoid muscle. The middle part of the deltoid muscle received dual innervation in 38% of cases and the posterior part of the deltoid muscle in 8% of the cases [1]. An evidence based protocol for safe vaccine administration into the deltoid muscle was presented by Ian F Cook, which was developed using anthropometric measurements of the surface anatomical landmarks in adults who regularly receive intramuscular injection of vaccines into the deltoid muscle (adults ≥65 y old) and mapping the position of structures potentially injured by injection observed in ultra sonographic and cadaveric studies. The midpoint of the muscle (midway between the acromion and the deltoid tuberosity) with the arm abducted to 60° is a safe site for injection [2]. Ozgur Cetik et al, studied the distance of the axillary nerve from the acromion and its relation to arm length ,and identified a safe area above the axillary nerve which is quadrangular in shape, with the length of the lateral edges being dependent on the individual's arm length. The axillary nerve was not found to lie at a constant distance from the acromion at every point along its course [3]. Kontakis GM et al studied the position of axillary nerve within deltoid muscle and found that, the vertical distances from the upper deltoid border to the nerve in 17 of 67 cadavers was less than 4 cm in both shoulders. The minimal distance, measured from the mid-middle portion of the deltoid to the axillary nerve, was 2 cm. There was a significant negative correlation between the deltoid ratio (width/length) and the vertical distance, measured in all examined sites. The shorter the deltoid length the greater the danger of damaging the nerve in the short distance during surgical splitting of the muscle [4]. In a study done by Nakatani T et al , the course of the axillary nerve was determined from the skin covering the deltoid muscle in order to safely administer intramuscular injection into the muscle without injuring the nerve. In this study, the course of the axillary nerve projected on the skin covering the deltoid muscle was the transverse line situated at the lower 1/3 between the supero-lateral margin of the acromion and the antero-posterior axillary line. The intramuscular injection in the deltoid muscle can be safely performed using these landmarks without risking injury to the axillary nerve [5]. 7 MATERIAL AND METHODS: 7.1 SOURCE OF DATA: Thirty adult cadavers from the department of Anatomy, St John’s Medical College, Bangalore. SAMPLE SIZE: The sample size was calculated using n Master software. The values for sample size estimation were obtained from literature and a pilot study conducted at the Department of Anatomy at St.John’s Medical College. The standard deviation of the distance of the nerve from acromian was 0.6. The sample mean (from the pilot study) and population mean were 5.7 and 6 respectively. The alpha error and power were set at 5% and 80%.The required sample size was calculated to be thirty. 7.2 INCLUSION CRITERIA: Specimens without any grossly evident shoulder pathologies or surgical procedures. 7.3 EXCLUSION CRITERIA: Specimens with grossly evident shoulder pathologies or surgical procedures. 7.4 STUDY DESIGN: Analytical study- cross sectional type. 7.5 Protocol of the Procedure The cadavers will be dissected and the parameters mentioned in the objective will be measured with the help of digital vernier callipers accurate to 0.01mm. The values so measured will be analysed using SPSS 16. Paired sample t test will be used to compare means. A P value of ≤ 0.05 will be considered significant. 7.6 Does the study require any investigations or interventions to be conducted on patients or other human or animals? If so please describe briefly No interventions or investigations will be done. 7.7 Has ethical clearance obtained from your institution in case of 7.3? Ethical clearance has been obtained. 8 REFERENCES: 1) Marios Loukas, Joanna Grabska, Shane Tubbs, Nihal Apaydin, Robert Jordan. Mapping the axillary nerve within the deltoid muscle. Surgical and Radiologic Anatomy. 2009; 31(3):43-47. 2) Ian F Cook. An evidence based protocol for the prevention of upper arm injury related to vaccine administration. Human Vaccines. 2011; 7(8): 845-84. 3) Cetik O, Uslu M, Acar HI, Comert A, Tekdemir I, Cift H. Is there a safe area for the axillary nerve in the deltoid muscle? Journal of Bone and Joint Surgery. 2006; 88-A. 4) Kontakis GM, Steriopoulos K, Damilakis J, Michalodimitraskis E. The position of the axillary nerve in the deltoid muscle. Acta Orthop Scand.1999; 70(1): 9-11. 5) Nakatani T, Kitagawa A, Kitayama Y, Tanaka A, Yamazaki M, Konya C, Tanaka S. The course of the axillary nerve projected on the skin covering the deltoid muscle of a cadaver for safely administering intramuscular injection in the deltoid muscle. Journal of the Tsuruma Health Science Society. 2003; 27(1): 33-37. 6) Nihal Apaydin, Shane Tubbs, Marios Loukas, Fabrice Duparc. Review of the surgical anatomy of the axillary nerve and the anatomic basis of its iatrogenic and traumatic injury. Surgical and Radiologic Anatomy.2010; 32(3): 193-201. 9. Signature of candidate 10. Remarks of Guide: 11. Name and designation 11.1 Guide : Dr. Roopa Ravindranath Professor and Head of Department, Department of Anatomy, St.John’s Medical college. 11.2 Signature: 11.3 Co-guide: Dr.Lakshmi T.A, Lecturer, Department of Anatomy, St.John’s Medical college. 11.4 Signature: 11.5 Head of the Department: Dr. Roopa Ravindranath 11.6 Signature 12.1 Remarks of the chairman & Principal; 12.2 Signature