Head Of Pronator Teres Research Articles

Ultrasound-guided median nerve hydrodissection of pronator teres syndrome: a case report and a literature review.

To describe the sonographic appearance of pronator teres syndrome and the role of ultrasound-guided hydrodissection for its management. Pronator teres syndrome is a well-known compressive neuropathy of the median nerve between the two heads of pronator teres. However, the clinical presentation of this syndrome can be indolent with vague pain at the proximal volar forearm leading to a delay in diagnosis. We describe our experience in the management of pronator teres syndrome in a healthy young badminton player with ultrasound-guided median nerve hydrodissection. We highlight the clinical presentation, the role of dynamic Ultrasound scan (USS) in the diagnosis and effective treatment of pronator teres syndrome. In conclusion, managing PTS can be challenging, and this case highlights the importance of ultrasound-guided hydrodissection, when conservative measures have failed to improve the symptoms. Further studies are required to assess and compare the long-term outcomes of these interventions.

Supracondylar Process of Humerus – Report of Two Cases

Supracondylar process of the humerus is a congenital bone projection seen on the distal humerus on the anteromedial surface. A fibrous band called ligament of Struthers’ connects the supracondylar process of humerus with medial epicondyle. It is mainly asymptomatic but rarely can present as supracondylar process syndrome due to neurovascular compression. Although isolated median nerve injuries are most common they can also present with fractures and vascular complications. The ulnar nerve is rarely involved. The median nerve can be trapped at several sites proximal to the carpal tunnel. Potential sites where the median nerve can be trapped are bicipital aponeurosis, two heads of pronator teres, flexor digitorum superficialis, aponeurotic arch and Gantzer muscle.[1]
 Supracondylar process of the humerus is a hook-like bony process seen about 5 cm proximal to the medial epicondyle and has a pointed apex. It is curved downwards and forwards and is commonly seen in climbing mammals. Vinilla et al. published a comparison of measurements of the supracondylar process of the humerus in different studies. The length of the process varied from 0.3 cm to 1.6 cm, breadth 1cm to 1.5 cm and distance from the medial epicondyle varied from 4.4 cm to 6.5 cm. They concluded that the supracondylar process had to be differentiated from osteochondroma and myositis ossificans.[2]

Median Nerve Passing below the Ulnar Head of Pronator Teres in Cadavers of a Medical College in Western Nepal: A Descriptive Cross-sectional Study.

Median nerve passes between two heads of pronator teres muscle while passing through the elbow. Detailed knowledge of these variations in the course of Median Nerve in relation to pronator teres and its neighboring structure is required for diagnosis of pronator syndrome. The aim of the study is to find out the proportion of Median Nerve passing below the ulnar head of pronator teres in cadavers of a medical college in Western Nepal. A descriptive cross-sectional study was carried out at the Department of Anatomy in a medical college of Nepal from 20th July 2021 to 2nd September 2021 after ethical clearance from the same institution (Reference number: UCMS/IRC/079/21). Variations in the course of the median nerve while passing through pronator teres were observed, recorded and photographed. Convenience sampling method was used. Data were analyzed using Microsoft Excel 2016. Point estimate at 95% Confidence Interval was calculated along with frequency and percentage. Out of 54 prosected specimens of upper limbs, 4 (7.40%) (0.418-14.38 at 95% Confidence Interval) Median Nerve passed below the ulnar head of pronator teres muscle and in 50 (92.60%) specimens Median Nerve passed between two heads of pronator teres. Our study shows that the median nerve passed below the ulnar head of pronator teres muscle is higher as compared to other studies done in similar settings. Thus, knowledge of variations in the course of Median Nerve in elbow has immense importance in the academic and clinical arena.

Quantitative Characterization of Cadaveric Pronator Muscles Using 3D Modeling

The pronator muscles of the upper limb, pronator teres (PT) and pronator quadratus (PQ), work together to rotate the radius around the ulna along an axis parallel to the central bands of the interosseous membrane while stabilizing the involved joints. Anatomical variations that affect the rotational efficiency of the PT have been described. Previously, we have described an aberrant PQ with a possible flexor function, and also defined 4 types of anatomical variations in PQ, based on the number of bellies present, and whether it occurred unilaterally or bilaterally, suggesting that PQ is more variable than appreciated. The PT typically has 2 distinct heads of origin (ulnar and humeral) and inserts onto the lateral radius. However, several anatomical variations have been reported, including the number of heads, locations of origin and insertion points, anomalous fiber orientations, and the presence of fibrous bridges and/or arches. In the current study, we sought to determine if there are patterns of anatomical variations in the PT, and whether any such variations occurred in relationship to those of the PQ. Sixteen forearms from 8 embalmed cadavers (4F,4M ages 64–93, mean 82) were dissected, and the PT and PQ muscles observed for muscle shape, fascicle orientation, and attachment points. PT and PQ heads was described, and PT tendon length, width, and distance from the radial head and styloid process measured. Our data revealed that the PT existed as only a single muscle head (humeral), bilaterally, in 25% of the cadavers examined, while exhibiting the traditional two muscle heads (humeral, ulnar) bilaterally in 75% of cadavers. Interestingly, the PT variant with a single humeral head occurred in conjunction with Type II PQ muscles bilaterally (i.e., the presence of 2 muscle bellies). Of the six cadavers with both humeral and ulnar heads of PT, 33.3% had an occurred with Type I PQ (1 head, bilateral), 33.3% with Type II PQ (2 heads, unilateral), and 33.3% with Type III PQ (2–3 heads, bilaterally). Our data suggests that there may be a relationship between the patterns of anatomical variations between PT and PQ muscles, which may provide new insight into the biomechanical relationship between these 2 muscles. The inclusion of additional cadaveric specimens, as well as quantitative comparisons between PT and PQ muscles, including cross sectional area, volume, and line of action, will help to elucidate the potential relationship between PT and PQ muscles.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Presence of Additional Head of Pronator Teres Muscle - Case Report

Presence of Additional Head of Pronator Teres Muscle - Case Report

Effects of Muscle Activities of the Two Heads of Pronator Teres on the Dynamic Stabilizing Function of the Elbow Joint

Effects of Muscle Activities of the Two Heads of Pronator Teres on the Dynamic Stabilizing Function of the Elbow Joint

Anatomical and clinical study of median nerve entrapment at the elbow

Objective To provide anatomic and clinical basis for diagnosis and treatment of median nerve entrapment at the elbow.Methods Microanatomical dissection of the median nerve was done in 10 cadaver upper limb specimens to observe the anatomical factors that cause compression of the median nerve at the elbow and shape of the median nerve.Case analysis was conducted in 14 patients with median nerve entrapment at the elbow who were treated in our department.Results Anatomic studies in the 10 dissected specimens showed three types of relationship between the bicepital aponeurosis and median nerve:complete-covering (2 specimens,20％),partial-covering (1 specimen,10％) and non-covering (7 specimens,70％).Thickened fascia in the superficial layer of pronator teres ulnar head was seen in 9 specimem (90％).Intramuscular tendinous bundles in the anconeus were observed in 2 specimem (20％).The reverse fascia that traversed the median nerve was seen in 6 specimens (60％).The structures of the origins of two heads of the flexor digitorum superficialis (FDS) had three types:intramuscular tendinous bundle (1 specimen,10％),fibrous arch (1 specimen,10％),and conjoined tendinous arch (8 specimens,80％).Of the 14 patients who had median nerve entrapment at the elbow,5 were diagnosed as pronator teres syndrome while 9 were diagnosed as anterior interosseous nerve(AIN) compression.The compression points in the pronator syndrome cases were ulnar side of the thickened and taut bicepital aponeurosis (2 cases),deep tendinous arch of pronator teres (2 cases),and between two heads of pronator teres (1 case).The compression points in the AIN compression cases were deep tendinous arch of pronator teres (2 cases),ulnar head of pronator teres (1 case),between two heads of pronator teres (1 case),and thickened and taut FDS origin (5 cases).Six patients were follow-up.The average follow-up time was 2 years and 4 months.Good to excellent recovery of motor function was achieved in these patients.Condusion The shape of the median nerve,its surroanding tendinous structures and thickened and taut fascia are the anatomic basis of median nerve entrapment at the elbow. Key words: Median nerve; Entrapment; Elbow; Applied anatomy; Case report

A case of double Gantzer's muscle and its possible role in nerve entrapment

Department of Anatomy and Biology, Osaka Medical College, Takatsuki, Osaka, JapanAnomalous variants are essential for teaching bothanatomists and surgeons. Muscle anomalies of theupper extremity are recognized causes of periph-eral nerve disorder (Jones et al., 1997; Pai et al.,2008). Gantzer’s muscle (GM) or accessory head offlexor pollicis longus (FPL) has been implicated inKiloh-Nevin (i.e., ‘‘anterior interosseous’’ nerve)syndrome (Rask, 1979; Oh et al., 2000; Mahakka-nukrauh et al., 2004; Pai et al., 2008). Moreover,both GM and fibrous arch of flexor digitorum sub-limes (FDS) are considered as possible anatomicalfactors for median nerve (MN) entrapment neurop-athy (Lee and LaStayo, 2004; Bilecenoglu et al.,2005). Two GMs (Fig. 1) were detected in the rightforearm of an old Japanese male cadaver duringpractical anatomy course for undergraduate medi-cal students at Osaka medical college. Thesemuscles were present at two different anatomicalplanes. One of them, the deep GM (DGM), waslarger, voluminous in shape, and originated fromthe medial epicondyle of humerus and inserted intothe ulnar side of FPL muscle at the junctionbetween proximal and middle thirds of forearm.The second one or superficial GM (SGM) wassmaller and fusiform in shape and arose from theundersurface of humeroulnar head of FDS muscleand terminated distally into the FPL close and lat-eral to insertion of DGM. The MN passed superficialto the deep head of pronator teres (PT) musclewhere it gave the anterior interosseous nerve(AIN) just distal to the lower border of the crossedmuscle. The AIN arose from the lateral side of MNand both nerves coursed distally between twomyo-fibro-tendinous layers; the fibrous arch of FDSand SGM superficially and the DGM deeply. It hasbeen reported that the arcuate ligament of Fearnand Goodfellow is the fibrous tissue that blends to-gether from the PT and FDS muscles and can catchboth the AIN and MN in some patients sufferingMN compressive neuropathy (Rask, 1979). In ourcase, the origin of AIN from the radial side of MNwas reported by Ashworth et al. (1997). The AINdescended radial to the DGM, gave branches toboth SGM and FPL, sank deep to the tendon ofSGM and then passed deep to FPL where it reap-peared again medial to the latter muscle on theinterossous membrane. The manner of proximaland distal attachments, the shape as well as theinnervation of GMs, have been reported by others(Oh et al., 2000; Mahakkanukrauh et al., 2004;Pai et al., 2008). It seems that both MN and AINwere caught in intermuscular tunnel roofed by theSGM and FDS and floored by the DGM. The pres-ence of both DGM and SGM in addition to fibrousarch of FDS may be involved in MN and AIN com-pressive neuropathy. Moreover, the presence oftwo GMs may result in restricted movement of FPLand subsequent pain in lower forearm as reportedby others (Ryu and Watson, 1987; Pai et al.,2008). On the other hand, the GMs may be impor-tant in local transfers for restoring function in mul-tiple nerve palsies (Pai et al., 2008). The accessoryheads of the flexor muscles have been described inprimates and other mammals (pigs, foxes, andmarmots) as a muscle belly that connects themedial epicondyle origin of the FDS with the moreor less differentiated deep flexors muscle. Theflexor muscles of the forearm that develop fromthe flexor mass divide into two layers, superficialand deep. The FDS, FPL, and flexor digitorum pro-fundus originate from the deep layer. The existenceof accessory muscles connecting the flexor musclescould be explained by the incomplete cleavage ofthe deep layer of the flexor mass during develop-ment (Jones et al., 1997). This is the first report inthe literature regarding the presence of two GMsarising from different proximal attachments at two

Anatomic study and clinical analysis of anterior interosseous nerve compression syndrome

Objective To investigate the anatomic factors that cause anterior interosseous nerve entrapment and analyze the clinical results of decompression. Methods Twelve fresh cadaver upper limb specimens were dissected. The anatomic characteristics of the anterior interosseous nerve and the possible compression factors along its course were observed. Fifteen cases of anterior interosseous nerve compression syndrome were treated between May 1997 and December 2007. One underwent conservative treatment and 14 had surgical decompression of the anterior interosseous nerve. The tendinous structures that compressed the nerve were resected. In 7 cases the vessels that run across the nerve were ligated. Postoperative fo].low up time ranged from 6 months to 4 years. Results Anatomic studies in the dissected 12 specimens showed 91.7% occurrence ( 11specimens) of tendinous structures of the deep head of pronator teres. The anterinor interosseous nerve was almost always sandwiched between the two heads of pronator teres. The tendinous arch of flexor digitorurn superficialis of the index and middle fingers occurred in 41.7% (5 specimens). Accessory head of flexor pollicis longus occurred in 58.3% (7 specimens). The incidence of abnormal vessels across the median nerve and the anterior interosseous nerve was 66.7% (8 specimens). The 7 cases treated with additional ligation of the abnormal vessels running across the anterior interosseous nerve had better results than those treated only with nerve decompression and resection of the tendinous or fibrous structures. Conclusion Anterior interoaseous nerve compression syndrome is the result of multiple factors. All the structures that can cause entrapment of the nerve on its anatomic course should he released in order to achieve satisfactory results. Key words: Nerve compression syndromes; Anatomy, regional; Anterior interosseous nerve