Microanatomical and immunohistochemical study of the human anterior branch of the medial antebrachial cutaneous nerve of forearm at the antecubital fossa and its clinical implications.

PURPOSE: Poor prognosis of nerve repair in patients may be due to changes in intraneural anatomy with age. Also, chances of Complex Regional Pain Syndrome-Type I (CRPS-I) secondary to peripheral nerve injury are comparatively high. The present study is to find the fascicular pattern of the anterior branch of the medial antebrachial cutaneous nerve of forearm (MACN) (at antecubital fossa), microanatomic morphometric characteristics of its connective tissue components (adipose tissue) and changes with age and study of intraneural sympathetic fiber content.

MATERIAL AND METHODS: Sixty six human (37-88-year-old) cadaveric anterior branch of MACN have been collected from antecubital fossa and the study has been performed at magnifications (5x, 10x, 20x, and 40x objective) after routine histological (Hematoxylin & Eosin stain, Masson's trichrome stain) processing was done for morphometric analysis (total cross-sectional, fascicular and non-fascicular area) and immunohistochemical (tyrosine hydroxylase) processing for sympathetic fibers.

RESULTS AND CONCLUSIONS: The anterior branch of the MACN's average total cross section area was 1.150 mm(2) on right side and 1.156 mm(2) on left side. There was significant increase in non-fascicular connective tissue area. In non-fascicular area, there was very less amount of adipose tissue in 86.37% of cases and more adipose tissue in 13.63% (elderly) cases. The average sympathetic fiber area is 0.0109 mm(2) without definite relationship with age. Our study makes an attempt to build a normal data base for MACN which might be helpful during the application of diagnostic and surgical nerve graft procedures.