The Anatomy And Clinical Study Of Recurrent Branch Of The Median Nerve

【Objective】The purpose of the study was to define the surface landmarks of the recurrent branch of the median nerve by explore the course, neighbourhood, variation, and to explore the pathogenetic of the cases which bad motive recovery after neurolysis.【Methods】 20 fresh-adult cadavers upper extremities were dissected under loupe magnification(x5) to define the origin ,the course ,the insertion point with relation to flexor tendons,palmar aponeurosis ,the deep transverse carpal ligament,the thenar muscles and superficial palmar arterial arch,then define the compression along the course . The surface landmarks were defined with reference to the measurement of the origin ,the insertion point ,the highest point ,which were measured by the surface landmarks and the hand's crease.Based on the research result,we improve the method to release the compression completely.【Results】⑴The recurrent branch inserts the thenar muscles across the flexor pollicis brevis.The ulnar edge of the flexor pollicis brevis thickens to a tendinous arch at the origin from the deep transverse carpal ligament. 80% of the recurrent branch run across the arch .There is tendinous fascicle at the ulnar edge of the superficial head of flexor pollicis brevis 2mm far from the tendinous arch.The recurrent branch travels across the tendinous arch, then the tendinous fascicle before insert between the flexor pollicis brevis and the abductor pollicis brevis .There is a high occurrence of these tendinous fascicle counted of 85%(17/20).Among the 17 cases, 70.59%(12cases) are the narrower ones which are 6.03mm in length and 3.03mm in width, 29.41%(5cases) are wider ones which are 4.03mm in length and 6.38mm in width.Somethimes, the superficial head of flexor pollicis brevis originate at the middle point of the deep transverse carpal ligament ulnar to the normal sites. We found 4 such cases in the research.Both the tendinous arch and the tendinous fascicle can compress the recurrent branch especially when the origin of the superficial head of flexor pollicis brevis originates ulnar to the normal one . ⑵Observing the whole course, the recurrent branch runs an arch course from the origin to the hightest point then enter the thenar muscles obliquely at an acute angle.In some times, It has a higher original point which originates at an acute from median nerve,then enter the thenar muscles obliquely, so at this time the origin is just the highest point.11 cases has the higher original point in our research.The insertion point is between the flexor pollicis brevis and the abductor pollicis brevis . Along the course the recurrent branch run across two flexor tendon.One is flexor pollicis longus when the recurrent branch run between the superficial and the deep head of flexor pollicis brevis from the origin to the highest point. Although there is a small distance from the flexor pollicis brevis to recurrent branch,we may damage the recurrent branch when operate around the flexor pollicis longus.The other is flexor tendon of index finger when the recurrent branch run from the highest point obliquely. So the recurrent branch may be damaged during incision of the infective thenar space or operation around the flexor tendon of index finger.⑶70% of the recurrent branch travel through the fibrous tunnel formed by superior and deep of the palmar aponeurosis and thenar fascia which is similar to the report previously. The recurrent branch may be compressed at palmar aponeurosis and may be damaged during operation when the origin is further than normal.⑷Define the point when clench.The origin,A point :We can predicted the vector the third web space longitudinally and vector from the pisiform to ulnar border of the pollicis proximal metacarpophalangeal crease. The highest point B:the apex of middle finger longitudinally and the hamate hook to the ulnar border of the pollicis proximal metacarpophalangeal crease.The insertion point C: the second web space longitudinally and the pisiform...