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Peripheral Nerve Examination
Published in J. Terrence Jose Jerome, Clinical Examination of the Hand, 2022
J Terrence Jose Jerome, Dafang Zhang
Anterior interosseous nerve syndrome is an isolated lesion to the anterior interosseous nerve fibres, which innervates the flexor pollicis longus, the flexor digitorum profundus to the index finger and middle finger, and the pronator quadratus. The cause of anterior interosseous syndrome is varied and unclear. While direct compression of the anterior interosseous nerve has been reported, a pseudo-anterior interosseous nerve syndrome can arise from a brachial neuritis or Parsonage–Turner syndrome. The etiology of Parsonage–Turner syndrome may be autoimmune, post-viral or post-traumatic, and may involve an interplay of genetic and environmental factors. In the absence of direct compression, the mainstay of treatment of anterior interosseous nerve syndrome is observation before performing surgical decompression, as spontaneous recovery has been reported even after one year of symptoms [8].
Upper Limb
Published in Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno, Understanding Human Anatomy and Pathology, 2018
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno
The anterior (flexor) compartment of the forearm includes a superficial group of forearm flexor muscles and a deep group of forearm flexor muscles (Plate 4.13). The functions, attachments, innervation, and arterial blood supply of these muscles is given in Table 4.5. Therefore, in this paragraph, we will mainly refer to ways for the students to better understand, group, and study these muscles. For instance, textbooks and atlases of human gross anatomy often refer to an intermediate layer of forearm muscles, but this layer has no true developmental and evolutionary—or even anatomical—support. An easier way to study both the superficial and deep layers of forearm anterior (ventral) muscles is to go from lateral (radial) to medial (ulnar). Also, remember that all forearm flexors are innervated by the median nerve or its branch, the anterior interosseous nerve, with only two exceptions: The flexor carpi ulnaris and the part of the flexor digitorum longus that move digits 4 and 5 are innervated by the ulnar nerve. Even these exceptions make sense, because they comprise the most medial (ulnar) muscle structure of the superficial layer—the flexor carpi ulnaris—and the most medial part of a muscle of the deep layer—the ulnar half of the flexor digitorum longus, going to digits 4 and 5. They thus lie much closer to the ulnar nerve than to the more centrally placed median nerve, as explained above.
Practice Paper 1: Answers
Published in Anthony B. Starr, Hiruni Jayasena, David Capewell, Saran Shantikumar, Get ahead! Medicine, 2016
Anthony B. Starr, Hiruni Jayasena, David Capewell
The posterior interosseous nerve is a branch of the radial nerve that runs deep in the forearm to supply the wrist and finger extensors except the extensor carpi radialis longus (ECRL) (which is innervated by a proximal branch from the radial nerve). The posterior interosseous nerve can be damaged in forearm fractures, and this damage results in an inability to extend the fingers and a slight wrist drop. The wrist drop is only slight as the ECRL muscle still provides some wrist extension. There is no sensory loss with these nerve lesions. The anterior interosseous nerve is a motor branch of the median nerve in the forearm. Lesions of this nerve are rare and usually arise from deep lacerations to the forearm. The anterior interosseous nerve provides motor fibres to flexor pollicis longus, the medial part of flexor digitorum profundus and pronator quadratus. Lesions result in a weakness in the thumb and index finger characterized by a deformity in the pinch mechanism between the thumb and index fingers.
AIN to PIN transfer for PIN palsy following distal biceps tendon repair: a case report
Published in Case Reports in Plastic Surgery and Hand Surgery, 2022
Jillian A. Fairley, Parham Daneshvar
Herein, we present the case of a patient who sustained a rare PIN injury after a two-incision distal biceps tendon repair. He subsequently went on to nerve transfer utilizing a novel technique. The donor nerve was the distal extent of the anterior interosseous nerve (AIN) to pronator quadratus (PQ), which is more typically described as a donor option for restoration of intrinsic hand function [10]. However, since sacrifice of PQ leaves little clinical deficit [11], it was a valuable option in this case since its nerve branch provided enough length (Figure 2) to reach the recipient branches of the injured PIN. The distal AIN has been used for transfer in more distal PIN/radial nerve dysfunction, in particular for thumb motion [9]. However, we do not know of any study using the AIN for a more proximal PIN transfer. The transfer more distally is performed to improve thumb function as often there is limited thumb extension recovery with flexorcarpi radialis (FCR) to PIN transfer [9,12]. While FCR is typically used for proximal PIN transfer, this transfer was not performed in our case because the zone of injury was very large and we could only innervate the PIN branches after they had already branched more distally. Thus, the FCR branch was not long enough to allow for the typical median to radial nerve transfer as described by Davidge et al. [13]
An investigation of dynamic ulnar impingement after the Darrach procedure with ultrasonography
Published in Journal of Plastic Surgery and Hand Surgery, 2022
Kuan-Jung Chen, Jung-Pan Wang, Hui-Kuang Huang, Yi-Chao Huang
The patients received surgery under general anesthesia. An incision was made on the dorsal side of the wrist, medial to the extensor carpi ulnaris (ECU). Anterior interosseous nerve (AIN) and posterior interosseous nerve (PIN) neurectomy were routinely performed, excising the distal 1–2 cm section. The extensor retinaculum, periosteum, and the distal part of the pronator quadratus (PQ) muscle were elevated to expose the distal ulna. Then ulnar osteotomy was made in a long-sloped shape, and parallel to the contour of the opposing radius. The edges of the ulnar cut were beveled with the saw. The detached distal part of the PQ muscle was transferred dorsally and sutured onto the periosteum sleeve of the ulnar stump, forming an interposition (Figure 2). In the cases with an attritional tear of the extensor tendons, the tendons were explored and reconstructed using the same incision.
Bilateral Martin-Gruber and Marinacci Anastomoses in the Same Patient: A Case Report
Published in The Neurodiagnostic Journal, 2020
Estimates of the prevalence of crossovers of median and ulnar nerves in the forearm vary greatly in the literature (Smith et al. 2019; Unver et al. 2009). Martin-Gruber anastomosis is the most common, with a reported incidence between 10% (Felippe et al. 2012; Kazakos et al. 2005) to 27% in cadaveric dissections Caetano et al. 2016), and as high as 54% based on some electrodiagnostic studies (Amoiridis and Vlachonikolis 2003). It is unilateral in almost two-thirds of cases with a right-sided predominance (Kazakos et al. 2005), and the connecting branch is usually between the anterior interosseous nerve and the ulnar nerve, supplying the FDI muscle (Roy et al. 2016); the thenar and hypothenar muscles are supplied less commonly (Saba 2017). Marinacci anastomosis (Marinacci 1964; Resende et al. 2000) is much rarer, and most dissection studies either fail to find the anomaly (Duran and Ferreira Arquez 2016; Kazakos et al. 2005; Sarikcioglu et al. 2003) or do so only rarely (only one out of 30 forearms dissections in the study by Felippe et al. 2012). The prevalence in electrodiagnostic studies ranges from 0.7% (Saba 2017) to 4% (Meenakshi-Sundaram et al. 2003). A case of purely sensory ulnar-to-median anastomosis in the forearm has been reported (Hopf 1990). Bilateral Marinacci anastomosis has not been previously described, and we are unaware of any reports of Martin-Gruber and Marinacci anastomoses occurring together, as was the case in our patient.