ABSTRACT
Neuralgic amyotrophy (NA), also known as Parsonage-Turner syndrome or idiopathic brachial plexopathy, is a multifocal inflammatory neuropathy that usually affects the upper limbs. The classic picture is a patient with acute onset of asymmetric upper extremity symptoms, excruciating pain, rapid onset of multifocal paresis often involving winged scapula, and a monophasic course of the disease.
We present an unusual case of recurrent NA characterized first by right brachial plexitis and then isolated left posterior interosseous nerve palsy.
ABSTRACT
BACKGROUND AND OBJECTIVE:The posterior interosseous nerve (PIN) is vulnerable to injury in the dorsal approach to the proximal radius. The goal of this study is to describe the quantitative relationship of the PIN to the supinator muscle in the context of anatomic landmarks. Knowledge of superficial landmarks related to the PIN would hopefully minimize iatrogenic injury to the posterior interosseous nerve.METHODS: 12 cadavers (22 forearms) were dissected and analyzed. The length of the supinator muscle was determined. The oblique distances of the PIN entry and exit points to the proximal and distal borders of the supinator muscle as well as their perpendicular distances to the lateral epicondyle-Lister's tubercle (LE-LT) reference line were measured and recorded. The number of PIN branches inside the supinator substance was recorded. Mean and median values were determined and subjected to statistical analysis.RESULTS: Mean supinator length was 5 centimeters. Ninety-one percent of the cadaveric forearms had PIN branches inside the supinator muscle substance. Twelve of the 22 forearms (55%) had 2 branches. The mean oblique distances of the PIN from the lateral epicondyle to the entry and exit points in the proximal and distal borders of the supinator muscle was 3.52 and 7.31 centimeters, respectively. The mean perpendicular distances of the PIN from LE-LT reference line to the entry and exit points in the proximal and distal borders of the supinator muscle was 1.13 and 1.26 centimeters, respectively. An imaginary danger-zone 4 centimeters wide overlying the LE-LT reference line depicts the possible area where the PIN and its branches may most likely be located.CONCLUSION: The dorsal approach to the proximal radius may allow a safe exposure without causing iatrogenic injury to the posterior interosseous nerve through the use of superficial anatomic landmarks and reference lines in combination with mean measurements from our study.
Subject(s)
Humans , Forearm , Radius , Anatomic Landmarks , Iatrogenic Disease , Peripheral Nerves , Muscle, Skeletal , Wrist Joint , CadaverABSTRACT
PURPOSE: Cross-sectional sonographic measurements are considered first-line confirmatory tests in diagnosing peripheral nerve entrapment syndromes. Our aim is to establish normal values of cross-sectional area of the posterior interosseous nerve (PIN) at the arcade of Frohse, the most common site of compression of this nerve. METHODS: The PIN was identified with ultrasound on 50 healthy adults and 30 cadavers. Measurements of the cross-sectional area (CSA), antero-posterior (AP) and lateral (L) distances were taken immediately proximal and distal to the arcade of Frohse. RESULTS: The mean AP and L distances of the PIN proximal to the arcade of Frohse were 0.111 cm (0 ± 0.021) and 0.266 cm (±0.058), respectively, while the mean AP and L distances of the PIN distal to the arcade of Frohse were 0.085 cm (±0.019) and 0.343 cm (±0.057), respectively. P squared testing showed a statistically significant difference between the AP and lateral distances of the PIN when comparing proximal and distal to the arcade (p ≤ 0.001). However, the mean CSA of the PIN measured immediately proximal to the arcade of Frohse was 0.022 cm(2) (±0.005); immediately distal to the arcade of Frohse, it was 0.023 cm(2) (±0.004). t test showed no statistical difference between the two regions (p = 0.11). CONCLUSIONS: Our study has provided reference values for the PIN in healthy individuals at the arcade of Frohse. Although, there is a flattening of the nerve as it enters the supinator muscle, this should not be mistaken for nerve entrapment as the size of the nerve remains consistent.
