The subclavius posticus muscle is a rare aberrant muscle that traverses from the costal cartilage of the first rib posterolaterally to the superior border of the scapula. We report a patient having persistent paralysis of shoulder abduction with wrist and finger extension after a humeral neck fracture. Electromyography (EMG) examination revealed injuries to several upper extremity peripheral nerves, including the radial, axillary, and musculocutaneous nerves. Magnetic resonance imaging (MRI) performed at 10 months post-injury showed severe entrapment of the left brachial plexus by the subclavius posticus muscle at the thoracic outlet. The diagnosis of brachial plexus injury due to a rare abnormal subclavius posticus muscle was typically delayed until the MRI was performed for unexplained multiple peripheral nerve palsy. Resection of the aberrant muscle and brachial plexus decompression did not yield significant improvement in the patient’s radial nerve palsy until 6 months after surgery. Entrapment of the brachial plexus caused by the subclavius posticus muscle can cause symptoms of acute thoracic outlet syndrome following trauma to the upper extremity. In a case of inexplicable multiple peripheral nerve injuries in the upper extremity that are not proportional to the degree of trauma, MRI imaging along with EMG is required.

Capsaicin, a pungent ingredient of hot pepper, elicits an intense burning pain when applied cutaneously and intradermally. Activation of capsaicin-gated channel in. C-type dorsal root ganglion (DRG) neurons produces nonselective cationic currents. Although electrophysiological and biochemical properties of capsaicin-activated current (ICAP) were studied, the regulatory mechanism and intracellular signaling pathway are still unclear. In the present study, we investigated the modulations of ICAP by DAMGO (micro-opioid agonist) and cholecystokinin octapeptide (CCK-8). In 18 out of 86 cells, the amplitude of ICAP was significantly increased by DAMGO and completely reversed after washout, while ICAP was decreased by DAMGO in 25 cells. In 43 cells, DAMGO had no effect on ICAP. Mean action potential duration was significantly different between 'increased-by-DAMGO' group and 'decreased-by-DAMGO' group. Mean amplitudes of IH were not significantly different between both groups. CCK-8 reversibly enhanced the amplitude of ICAP (5/13). DAMGO also increased ICAP amplitude significantly in the same cells. The amplitude of ICAP was increased in additive manner by combined applications of DAMGO and CCK-8 in these cells. These results suggest that DAMGO and CCK-8 can either increase or decrease ICAP presumably depending on the subtypes of DRG cells and classified by electrophysiological properties.
Action Potentials ; Analgesics, Opioid ; Animals ; Burns ; Capsaicin ; Cholecystokinin ; Diagnosis-Related Groups ; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-* ; Ganglia, Spinal* ; Neurons ; Rats* ; Sincalide ; Spinal Nerve Roots*