Supinator Syndrome

Supinator syndrome, also referred to as posterior interosseous syndrome or radial tunnel syndrome , is a rare compression neuropathy of the upper limb affecting the posterior interosseous nerve just near or behind the supinator muscle (Spinner 1968). This nerve is vulnerable to injury at the proximal edge of the superficial belly of the supinator muscle that forms a free, strong, fibrous arch, the arcade of Frohse . At this site, the posterior interosseous nerve may be tethered and entrapped by fibrous bands. 

Bodner G, Harpf C, Meirer R et al (2002) Ultrasonographic appearance of supinator syndrome. J Ultrasound Med 21 1289-1293... 

The most important stimulus to the release of ANP from the heart is atrial stretch via mechanosensitive ion channels. ANP release is also increased by volume expansion, changing from the standing to the supine position, and exercise. ANP release can also be increased by sympathetic stimulation via aiA-adrenoceptors, endothelins via the -receptor subtype (see below), glucocorticoids, and vasopressin. Plasma ANP concentration increases in various pathologic states, including heart failure, primary aldosteronism, chronic renal failure, and inappropriate ADH secretion syndrome. 

Ectopia lentis may occur as part of the syndrome of homocystinuria and Marfen s syndrome. Dilate these patients with caution with a weak mydriatic due to the risk of angle closure. Place the patient in a supine position during the fundus assessment.After the examination, confirm that the crystalline lens remains behind the iris and then mydriasis can be reversed by using a miotic, such as 0.5% dapiprazole. 

Cauda equina syndrome occurred in a 55-year-old woman who underwent spinal anesthesia with a 22 G needle in the L4-5 interspace (214). On needle insertion, she felt radiating pain in her right leg. The needle was immediately withdrawn and repositioned. Pain-free intrathecal injection of 2.0 ml of hyperbaric cinchocaine 0.24% with adrenaline 66 micrograms resulted in block to LI. Surgery was carried out in the supine position. Three days postoperatively, she had enuresis and reduced perineal sensation, without bowel dysfunction or lower limb symptoms. There was sensory loss at S2-5. The symptoms persisted, required self-catheterization and systemic steroids, and disappeared on the 19th postoperative day. 

Fig. 5.13. a A premature infant with intestinal dysfunction, so-called meconium ileus-like syndrome. The supine abdominal film shows dilated intestinal loops because of fecal impaction in ileum, b Cross-table radiograph. Meconium-like ileus with dilated intestinal loops without fluid levels. The whole colonic tract and rectum are airless, c Ultrasound of the right lower quadrant of abdomen demonstrates the impacted and inspissated stool in the ileum... 

Fig.4.7a,b. Afferent loop syndrome, a Supine abdominal radiograph shows virtually absent bowel gas because of frequent vomiting, b Sagittal color Doppler sonogram of the upper abdomen shows the dilated third part of the duodenum (D3) anterior to the abdominal aorta and posterior to the superior mesenteric artery (arrows)... 

Epicondylitis is a common elbow problem, generally called tennis elbow if the lateral epicondyle is involved and golfer s elbow if the medial epicondyle is involved. This is an overuse syndrome that is associated with any activity that requires repetitive pronation and supination, such as gripping a tennis racquet, golf club, screwdriver, or doorknob. The wrist extensor muscles are involved in lateral epicondylitis. 

Fig. 8.46a,b. Posterior interosseous nerve syndrome, a Transverse 12-5 MHz US image obtained over the supinator area in patient with a previous radial head fracture and radial nerve deficit demonstrates the posterior interosseous nerve (arrowheads) entrapped within a hypoechoic scar (arrows) in the area of the supinator muscle (s). b Gross operative view shows the main trunk of the radial nerve (asterisks) as it splits into the superficial cutaneous sensory branch (arrowheads) and the deep posterior interosseous nerve (narrow arrows). This latter nerve is irregularly swollen as it passes over the bone (large arrows) as a result of the scar encasement visible in a... 

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