STUDY OF VARIANT NERVE SUPPLY OF LONG HEAD OF TRICEPS MUSCLE
Sharadkumar Pralhad Sawant
Professor and Head, Department of Anatomy, K.J.Somaiya Medical College, Somaiya Ayurvihar, Eastern Express Highway, Sion, Mumbai - 400 022, Maharashtra, India.
Aim to study the variant nerve supply of long head of triceps muscle. 100 upper limbs of 50 donated embalmed cadavers (45 males & 5 females) of age group ranging from 70 to 80 years were dissected in the department of Anatomy at K. J. Somaiya Medical College, Sion, Mumbai, India. The variant nerve supply of long head of triceps muscle was observed in 2 specimens. The musculo-vascular pattern in the arm was also observed. The photographs of the variant nerve supply of long head of triceps muscle were taken for proper documentation. The variant nerve supplies of long head of triceps muscle were observed in 2 specimens. We observed the axillary nerve giving the motor branch to the long head of the triceps muscle. The axillary nerve winds backward, in company with the posterior humeral circumflex artery, through a quadrilateral space bounded above by the teres minor, below by the teres major, medially by the long head of the triceps brachii, and laterally by the surgical neck of the humerus, and divides into an anterior and a posterior branch. The anterior branch (upper branch) winds around the surgical neck of the humerus, beneath the deltoid, with the posterior humeral circumflex vessels. It continues as far as the anterior border of the deltoid to provide motor innervations. The posterior branch (lower branch) supplies the teres minor, the posterior part of the deltoid and the long head of the triceps muscle. The finding was noted after thorough and meticulous dissection of the upper limbs of both sides. There were no associated variations documented in the arterial pattern in the same cadaver. The variation in the nerve supply of the long head of the triceps brachii muscle is clinically important for surgeons, orthopaedicians and anaesthetist performing pain management therapies on the upper limb. In the present study the motor branch of the long head of the triceps brachii muscle may arise from the axillary nerve hence while examining patients with traumatic injury involving the axillary nerve, it is important to look for the paralysis of the long head of the triceps brachii muscle. The paralysis of the long head of the triceps brachii muscle is the sign of a severe axillary nerve lesion requiring early nerve repair.
5 , 2 , 2015
85 - 88