What causes Martin-Gruber anastomosis?

A Martin-Gruber anastomosis (MGA) is a connection from the median nerve to the ulnar nerve in the forearm. An anastomosis occurs when two structures that normally are not connected have a connection. In this case the connection is a nerve.

What is Martin-Gruber syndrome?

It is an anomalous pattern of innervation occurring between the median and ulnar nerves in the forearm. In a Martin-Gruber anastomosis, a crossover of axons from the anterior interosseous nerve (the exclusively motor branch of the median nerve) to the ulnar nerve in the forearm usually occurs.

Does ALS affect the median nerve?

We observed that the median/ulnar nerve CSA ratio was decreased in ALS patient at the upper arm segment. Overall, these findings suggest that there is preferential involvement of the median nerve compared to the ulnar nerve in ALS, which is consistent with the clinical findings of the split hand in these patients.

What is prolonged distal peak latency?

Distal motor latency (DML) prolongation along with sensory nerve conduction velocity (SNCV) slowing or absence of sensory action potential (SAP) is the hallmark of the electrophysiological diagnosis [2].

What does ALS feel like in the hands?

Signs of ALS can appear gradually. You may notice a funny feeling in your hand that makes it harder to grip the steering wheel. Or, you may start to slur your words before any other symptoms show up.

Can ALS start in your thumb?

The split-hand sign, one of the early physical symptoms of ALS, refers to a loss of the pincer grasp due to weakness and wasting of two hand muscles — the abductor pollicis brevis (APB) and the first dorsal interosseous (FDI) muscles — located on the side of the thumb.

What is normal distal latency?

It was found that the median SNAP values were as follows; distal latency, 2.6± 0.3 ms with a range of (2.3-2.9); peak latency, 3.5±0.5 ms (3.0-4.0); amplitude, 47.7±18.0μV (29.7-65.7) and conduction velocity, 53.0±7.8 m/s (45.2-60.8).

What is latency in EMG?

The time it takes for the stimulus to reach the recording electrodes is called as latency. It can be accurately measured and a velocity of transmission calculated. Healthy nerves will transmit the electrical impulse faster than diseased ones. Home.