We dissected 72 upper limbs of fresh cadavers and found 17 cases with a Martin-Gruber communicating branch (23.6%). These were classified into 4 types: type I (n = 5, 29.4%): communicating branch between the anterior interosseous and ulnar nn, type II (n = 3, 17.6%): Communicating branch between the median and ulnar nn., type III (n = 3, 17.6%): Communicating branch between the muscular branches to the flexor digitorum profundus m., type IV (n = 6, 35.3%): combination of type I or II and type III. At histologic examination the number and size of the nerve bundles each communicating branch contained proved to be very different. In one case of type II only a single nerve bundle was found. We suggest that the different numbers of nerve bundles innervate different amounts of the intrinsic hand musculature. The communicating branch with a single nerve bundle probably innervated only the first dorsal interosseous muscle.

While numerous situations may produce a traumatic brachial plexus palsy, these injuries are characteristic of young adults aged 18 -20 who have had a motorcycle accident. '-lo Lesions can be situated at any level from the base of nerve roots to the divisions of the brachial plexus in the axillary region, and several types of lesions can be differentiated: Supraclavicular lesions at the root level (75% of cases) Infra-and retroclavicular lesions of secondary trunks and of terminal branches (25% of cases)The lesions are most often due to traction and stretching of the brachial plexus. The seventy of the lesions can be graded from 1 to 5 on the Sunderland scale.' At the root level, medullary avulsion constitutes a particular type.Our experience is based on 8 10 cases operated on from 1975 to 1994 at the H6pital Bichat (Paris, France). PALSIES AT ROOT LEVEL DUE TO SUPRACLAVICULAR LESIONSSupraclavicular lesions which account for 75% of all cases (with 15% occurring at two levels) may be grouped as follows:C5-C6 or C5-C6-C7 palsies which occur in 20-25% C8-T1 palsies which occur in 2-3% of cases C5-C6-C7-CS-T1 lesions which are the most frequent of cases and occur in 75-80% of cases It is important to determine the exact site of the lesion as this will weigh heavily on the prognosis and future of the patient. A careful clinical examination and special investigations should be rapidly undertaken in order to obtain an exact diagnosis and permit intervention within a period of 6 weeks to 2 months after the trauma.

In our series, GUEPAR II total joint arthroplasty of the thumb CMC joint has proven to be efficacious, improving motion, strength, and achieving a high degree of pain relief. Successful outcome appears in our experience contingent upon strict compliance with numerous surgical technique details. Current research focuses on improving bipolar fixation by developing press-fit cementless implants.

An anatomical and biomechanical study of the stabilizing ligaments of the thumb trapeziometacarpal joint was conducted on 32 hand specimens. Five main ligamentous structures could be identified. The mechanical properties (in particular, strength) of the five ligaments using a strain-rate failure test were determined and evaluated quantitatively. The maximum tensile strength of each ligament was correlated with the condition of the trapeziometacarpal articular cartilage. In studying the anterior oblique ligament, maximum strength decreased from Grade 0 to Grade 1 by 51%. With the first intermetacarpal ligament, the drop from Grade 1 to Grade 2 was 53%. With the posterior oblique ligament, the decrease was closely related to the grade of the deterioration of the trapeziometacarpal articular surface. These three ligaments also significantly decreased in strength with age. Our results may suggest that the anterior oblique ligament, intermetacarpal ligament and posterior oblique ligament play a large role in stabilizing the trapeziometacarpal joint and that the decrease in their strength is related to the pathogenesis of trapeziometacarpal osteoarthritis.