Deep Heads Research Articles

The double-headed accessory iliacus muscle: a case report.

Numerous accessory muscles are present in the human body, many of which are clinically significant. We present a case of an anomalous accessory iliacus composed of two heads, whose occurrence and anatomical location indicate a high probability of causing femoral nerve compression. During a routine dissection of the posterior abdominal wall of a xx-year-old cadaver, a double headed accessory muscle was noted, measured and photographed. In addition to the normal anatomy of dissected structures from the posterior abdominal wall, an accessory iliacus muscle composed of superficial and deep heads was identified. In addition, the inferior roots of the divided femoral nerve located between the heads was found to follow an unusual course. It is important to be aware of morphological variability around structures such as double-headed accessory iliacus muscle presented in this study, due to their association with neurovascular bundles and hip joint. The reported atypical morphology is not widely known in the literature but might be of great clinical significance, therefore knowledge of such variability might be regarded in order to diagnose properly and introduce accurate treatment.

A three-headed psoas major muscle: a case report.

Multiple anatomical variations, from anomalous courses to additional structures, have been reported in muscles from different compartments of the human body. We report an extremely rare case of a psoas major muscle presenting as a three-headed structure with variable morphology. During a routine dissection of the posterior abdominal wall of a 82-year-old male cadaver, an anomalous PM muscle with supernumerary head was identified, photographed and subjected to further measurement. Although the anatomy of the dissected posterior abdominal wall structures was typical, a three-headed psoas major muscle composed of superficial, intermediate and deep heads was identified. It is important to be aware of morphological variability of muscles, especially those considered to be constant, since an anomalous structure might interfere not only with their functions, but also lead to further clinical consequences.

Muscle interconnections in the anterior and posterior arm compartment: a cadaveric case series with possible clinical implications

PurposeThe report describes four cases of accessory bundles (ABs) or fibers connecting the muscles of the anterior with the posterior arm compartment. The ABs morphology (pure muscular or musculofascial or musculoaponeurotic) is described emphasizing their attachment points, characterized as muscles’ interconnections.Materials and methodsFour formalin-embalmed donated male cadavers were dissected.ResultsThe muscles’ interconnections were unilaterally identified. In the first case, the two ABs originated from the coracobrachialis muscle (CB), received fibers from the biceps brachii (BB), and were inserted into the triceps brachii (TB) medial head. The ABs created an arch over the brachial vessels and the median nerve (MN). In the second case, an accessory musculoaponeurotic structure was identified between CB and TB medial head and extended over the brachial vessels. In the third case, the myofascial ABs between the BB short head and the upper arm fascia, coursed anterior to the MN, the brachial artery, and the ulnar nerve, with direction to the TB medial head. In the fourth case, the three muscular ABs originating from the CB superficial and deep heads, in common with the BB short head, joined the upper arm fascia and the TB medial head and possibly entrapped the musculocutaneous nerve, the MN, and the brachial artery.ConclusionABs or musculoaponeurotic extensions may predispose to complications due to their potential compression on nerves and vessels. Clinicians should consider the possible existence of such bridging variants between muscles, in the differential diagnosis of a patient presenting with ischemia, edema, or MN palsy symptoms.

Coracobrachialis muscle morphology and coexisted neural variants: a cadaveric case series

PurposeThe current cadaveric case series evaluates the coracobrachialis muscle morphology, the related musculocutaneous nerve origin, course, and branching pattern, as well as associated adjacent neuromuscular variants.Materials and methodsTwenty-seven (24 paired and 3 unpaired) cadaveric arms were dissected to identify the coracobrachialis possible variants with emphasis on the musculocutaneous nerve course and coexisted neural variants.ResultsFour morphological types of the coracobrachialis were identified: a two-headed muscle in 62.96% (17/27 arms), a three-headed in 22.2% (6/27), a one-headed in 11.1% (3/27), and a four-headed in 3.7% (1 arm). A coracobrachialis variant morphology was identified in 37.04% (10/27). A three-headed biceps brachii muscle coexisted in 23.53% (4/17). Two different courses of the musculocutaneous nerve were recorded: 1. a course between coracobrachialis superficial and deep heads (in cases of two or more heads) (100%, 24/24), and 2. a medial course in case of one-headed coracobrachialis (100%, 3/3). Three neural interconnections were found: 1. the lateral cord of the brachial plexus with the medial root of the median nerve in 18.52%, 2. the musculocutaneous with the median nerve in 7.41% and 3. the radial with the ulnar nerve in 3.71%. Duplication of the lateral root of the median nerve was identified in 11.1%.ConclusionsThe knowledge of the morphology of the muscles of the anterior arm compartment, especially the coracobrachialis variant morphology and the related musculocutaneous nerve variable course, is of paramount importance for surgeons. Careful dissection and knowledge of relatively common variants play a significant role in reducing iatrogenic injury.

Extra- and intramuscular innervation of the masseter: Implications for facial reanimation

Irreversible facial paralysis results in significant functional impairment. The motor nerve to the masseter is a reconstructive option, but despite its clinical importance, there are few parametric anatomic studies of the masseteric nerve. The purpose of this study was to investigate the extra- and intramuscular innervation of the masseter in 3D to determine the relationship of the nerve to the muscle heads and identify landmarks to aid identification. The nerve was dissected throughout its entire course in eight formalin-embalmed cadaveric specimens (mean age 84.9±12.2 years). The nerve was digitized at 1-2mm intervals using a MicroScribe™ digitizer and modeled in 3D in Autodesk® Maya®. Two or three extramuscular nerves were found to enter the deep head (DH) of the masseter: one main "primary" nerve (n=8) and one (n=4) or two (n=4) smaller primary nerve(s). The main primary nerve supplied both the deep and superficial heads, whereas the smaller primary nerve(s) only supplied the DH. Surgical landmarks for masseter nerve localization were quantified. Comprehensive mapping of the innervation of the masseter muscle throughout its volume revealed neural partitioning that could provide a basis for safety planning for muscle flaps and donor nerve identification and explain why masseter functional loss is not incurred by donor nerve sacrifice. Quantified landmarks correlate to previous studies and support the constant anatomy of this nerve. Our results provide a basis to optimize surgical approaches for donor nerve and muscle flap surgery.

Assessing the influence of the hydraulic boundary conditions on clay slope stability: The Fontana Monte case study

Recent studies have assessed that slope-vegetation-atmosphere, SLVA, interaction may trigger the activity of deep landslides in clayey slopes. In some cases, the presence of an underground aquifer, fed by an upstream hydraulic recharging area, may represent a predisposing factor of such activity, being co-responsible of deep piezometric heads, which can undergo seasonal fluctuations due to the SLVA interaction. In this perspective, the present paper illustrates the results of a scientific research, carried out in a pilot site of the Daunia Apennines, the Fontana Monte slope at Volturino (Foggia, Italy), considered as a prototype of the class of landslide mechanisms controlled by both the rainfall water infiltration and the presence of a water-bearing aquifer in the hillslope.Numerical simulations of the saturated/partially saturated transient seepage flow in the slope have been performed by means of uncoupled hydraulic finite element analyses, with the aim of investigating the sources of large piezometric heads, related to climatic, hydrogeological and hydraulic slope features. The rainfall and evapotranspiration fluxes, the latter defined through the FAO Penman-Monteith method, are both implemented as ground surface input, while seasonal variations of the upstream hydraulic boundary conditions are imposed to predict the seasonal piezometric excursion at shallow and deep monitoring points. The transient seepage results are then used as input for limit equilibrium analyses to assess the influence of the hydraulic settings on the stability of the considered landslide body. The work shows the impact of both climatic and hydraulic factors on the seepage processes, affecting the stability of the slope. Moreover, it is highlighted that the accurate implementation of the upstream hydraulic feeding is fundamental for a reliable prediction of the monitored piezometric regime, strictly related to the recharge of the water-bearing aquifer.

An Anatomical Insight into the Morphology of the Brachialis Muscle and its Clinical Implications

Introduction: Being the chief flexor of the elbow joint, brachialis muscle, also known as ‘work horse’ of the elbow or Portal’s muscle is one of the three muscles of the front of arm. Ascertaining the morphology of the muscle is of considerable clinical significance because infrequent mention of the pathologies like tear, rupture, tendinopathies, etc., coupled with the conflicting reports of its morphology may often leads to inaccurate diagnosis of clinical conditions pertaining to it. Aim: To study the origin of the muscle in the form of number of heads and type of fibres at origin, site and manner of insertion, mode of nerve supply and presence of accessory slips. Materials and Methods: The study was carried out in the Department of Anatomy, Parul Institute of Medical Sciences and Research, Parul University, Vadodara on the 82 upper limbs used for routine dissection of first MBBS students. After incising the skin, superficial and deep fascia of the arm and cubital fossa, the biceps was retracted to visualise the origin, insertion and nerve supply of the brachialis muscle. Results: In all 82 (100%) arms, the muscle arose by lateral superficial and medial deep heads. Deep head inserted into the coronoid process and upper part of the ulnar tuberosity by an aponeurosis. In 81 (98.8%) specimens, superficial head was inserted by round tendon on to the ulnar tuberosity distal to the deep head. In one (1.2%) specimen, fibres of the superficial head were merging with biceps tendon and inserted on to the radial tuberosity. In 75 (91.5%) arms, muscle was supplied by musculocutaneous nerve and radial nerves and in four (5%) cases by the musculocutaneous, median and Radial Nerve (RN) whereas in 3 (3.5%) case by median and radial nerves. Accessory slips were present in four (5%) specimens. Conclusion: Considerable difference in the morphology of the brachialis was found with regards to the classical picture and should be kept in mind before undertaking any surgical procedure in the arm and elbow region.

Estudo anatômico da inervação do músculo supinador para reinervar o nervo interósseo posterior

Objective The purpose of this anatomical study was to analyze the possibility of transferring radial nerve branches to the supinator muscle to reinnervate the posterior interosseous nerve (PIN) originating from the C7–T1 roots. Methods Thirty members of 15 cadavers, all male, prepared with an intra-arterial glycerol and formaldehyde solution injection, were dissected. Results All dissected limbs presented at least one branch intended for the superficial and the deep heads of the supinator muscle. These branches originated from the PIN. A branch to the supinator muscle, proximal to the arcade of Frohse, was identified in six members. In addition, 2 and 3 branches to the supinator muscle were found in 11 and 4 members, respectively. In two limbs, only one branch detached from the PIN, but it duplicated itself proximal to the arcade of Frohse. Seven limbs had no branches to the supinator muscle at the region proximal to the arcade of Frohse. The branches destined for the supinator muscle were sectioned at the neuromuscular junction for connection with no tension to the PIN. The combined diameter of the branches for the supinator muscle corresponded, on average, to 53.5% of the PIN diameter. Conclusion The radial nerve branches intended for the supinator muscle can be transferred, with no tension, directly to the PIN to restore thumb and finger extension in patients with C7–T1 brachial plexus lesions.

AN IN VIVO STUDY OF THE MUSCULOAPONEUROTIC ARCHITECTURE OF MASSETER MUSCLE

Ethical Review Approval for this study was received from the Health Sciences Research Ethics Board, University of Toronto (Toronto, ON, Canada). Background The masseter muscle (MM) is affected in conditions with chronic and acute facial pain. It has been suggested that architectural changes occur in the contractile and connective tissue elements of MM in these patients.1 Muscle architecture is defined as the arrangement of the contractile and connective tissue elements in the muscle volume and quantifiable parameters, including fiber bundle length (FBL) and pennation angle (PA). A cadaveric study of detailed 3-dimensional, laminar MM architecture was conducted in our laboratory.2 Cadaveric studies have been used as a basis to develop ultrasound (US) protocols used in in vivo investigations of the architecture of supraspinatus.3,4 US studies investigating MM architecture are scarce, and such parameters as FBL and PA have not been quantified in vivo. To understand the pathologic changes in MM, it is necessary to elucidate the normal musculoaponeurotic architecture. Objective(s) To investigate the in vivo musculoaponeurotic architecture throughout the volume of MM in asymptomatic participants (ages 20–40 years) with US in the relaxed and maximally contracted states. We hypothesize that there will be significant differences in the architectural parameters of each MM lamina in the relaxed and contracted states. Materials and Methods The MM of 24 participants were scanned by using a Logiq E real-time ultrasound scanner (General Electric, Chicago, IL) with 2 linear probes (L10-22 and L4-12t). A microelectromyography (micro-EMG) surface electromyography unit (OT Bioelectronica, Reno, NV), was used to monitor MM activity, throughout scanning, on the contralateral masseter. Axial and coronal scans of the superficial and deep heads of MM were acquired throughout the volume of the masseter muscle to quantify architectural parameters, such as FBL and PA. Results Connective and contractile tissue elements of musculoaponeurotic architecture have been quantified in vivo, and differences have been observed between the relaxed and maximally contracted states. A further study will involve investigating musculoaponeurotic architectural parameters in pathologic MM.

A complex scalenus muscle variant: Case report

During dissection in a first year dental gross anatomy laboratory, we identified an unusual, complex muscle variant in the left posterior triangle of an 87 year‐old, Caucasian female cadaver. This consisted of the left anterior scalene divided longitudinally into two approximately equal ‘heads', superficial and deep, with the fifth and sixth cervical nerve roots passing between them, along with a small but substantial muscle bundle passing between and attaching to portions of the anterior and middle scalene muscles. This extra muscle bundle passed antero‐medially from the middle of the anterior surface of the middle scalene, to attach inferiorly on the superficial aspect of the deep head of the anterior scalene. This ‘bridging’ muscle also passed anterior to and in contact with the middle trunk (C7) of the brachial plexus. The left subclavian artery was observed to pass as expected between the anterior scalene (both superficial and deep heads) and middle scalene insertions. Scalene muscle anatomy and neurovascular relationships on the right side were observed to be normal. Amidst the numerous reports of morphological variations in scalene muscles, particularly in association with the clinical anatomy of thoracic outlet syndrome, myofascial pain, and upper brachial plexopathies, we were unable to find any accounts of a similar complex scalene muscle variant. Most certainly, our specimen did not fit the accepted morphological descriptions of ‘scalenus anticus', scalenus minimus, or Sibson's muscle variants. Although we had no available clinical records, the muscular variations we described were arranged in configurations that other investigators have recognized as contributing to compression of brachial plexus roots associated with thoracic outlet syndrome.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Anastomose de Riché‐Cannieu: estrutura, função e significância clínica

ObjectiveDefine the anatomy pattern and the incidence of Riché‐Cannieu anastomosis (RCA), i.e., median and ulnar communication in palmar aspect of the hand. MethodsA total of 80 anatomical dissections were performed on 60 limbs of 30 cadavers from 1979 to 1982, and on 20 limbs from 2012 to 2015. All procedures were realized at the Department of Anatomy of this institution. The incidence of Riché‐Cannieu anastomosis and innervation of the thenar muscles were studied. ResultsThe Riché‐Cannieu anastomosis was identified in all dissected hands (100%). Extramuscular Riché‐Cannieu anastomosis was recorded in 57 hands and intramuscular in 19 hands. The association of extra‐ and intramuscular Riché‐Cannieu anastomosis occurred in four. The ulnar component always originated from the deep branch. The anastomotic branch arising from the median nerve originated from the motor thenar branch (recurrent branch) of the median nerve in the majority of the observations. The median‐ulnar double innervation to the deep head of the flexor pollicis brevis alone was identified in 29 of 80 hands. In 12 limbs, the deep head of the flexor pollicis brevis was absent. The double innervation of the superficial head of the flexor pollicis brevis was found alone in 13 hands. The double innervation of the superficial and deep heads of the flexor pollicis brevis in the same hand occurred in 14 hands. The oblique head of the adductor pollicis received double innervation in 12 hands. The deep head of the flexor pollicis brevis and the oblique head of adductor pollicis in the same hand were doubly innervated in nine hands. The transverse head of adductor pollicis received double innervation in two hands. The double innervation of the deep head of the flexor pollicis brevis and the transverse head of the adductor pollicis was found in one limb. ConclusionAccording to this study, the Riché‐Cannieu anastomosis should be labeled as a normal anatomical neural connection and not as an anatomical variation. Knowledge of this anastomosis is essential because the presence of such neural communication can cause confusing clinical, surgical, and electromyographic findings in cases of median or ulnar damage or entrapment.

Morphology and relationships of the biceps brachii and brachialis with the musculocutaneous nerve.

Major anatomical textbooks generally state that the biceps brachii muscle (BB) is composed of long and short heads, whereas the brachialis muscle (BR) consists of a single head. However, the numbers of heads comprising the BB and the BR are very variable. The purpose of this study was to investigate how the branching patterns of the musculocutaneous nerve (MC) influence the number of heads of the BB and the BR. Morphological examinations of the BB and MC were conducted using cadavers of 22 Japanese individuals, and morphological examinations of the BR and the MC were conducted in 9 of those 22 individuals. A three-headed BB was observed in 7 of the 22 specimens (31.8%). Most of these specimens showed a Type III branch pattern (after penetrating the long head or the short head, the MC innervated the supernumerary head or communicated with the main root again). The number of BR heads was categorized into three types: Type A, two heads (superficial and deep heads, 22.2%); Type B, three or four heads (two or three superficial heads and one deep head, 44.4%); and Type C, multiple heads (33.3%). Among these categories, branches of the MC in Type A specimens were most simple. A supernumerary head of the BB seemed to be present if the MC penetrates it. The BR basically consists of superficial and deep heads, and the number of superficial heads is affected by branches of the MC.

The human medial pterygoid muscle: Attachments and distribution of muscle spindles.

Published descriptions about the sites of origin of the human medial pterygoid muscle vary and there are few reports on the distribution and density of muscle spindles in this muscle. We aimed to: (1) determine the extent of anatomical variability in the origins and insertions of the superficial and deep heads of the human medial pterygoid muscle and (2) determine the extent of variation in the distribution of spindles in the two heads of the muscle. Thirty-nine human cadaver hemi-heads were dissected and the attachments of the medial pterygoid muscle examined. The whole muscle was removed, weighed, cut into segments and embedded in wax for light microscopy. Sections were stained with Weigert-Van Gieson stain and scanned into digital images. Spindles were manually counted. In seven specimens, the deep head of the muscle arose from the medial surface of the lateral pterygoid plate and the pterygoid fossa. In 28 specimens, the origin extended onto the lateral surface of the medial pterygoid plate. There were abundant muscle spindles in the middle of the muscle, slightly fewer 1 cm toward the insertion, significantly fewer 1 cm toward the origin, and few or no spindles near the origins of the superficial and deep heads or near their insertion. In conclusion, firstly, this study shows that in 72% of the specimens examined, the origin of the medial pterygoid is wider than conventionally described in anatomical textbooks. Secondly, the segmental distribution of muscle spindles is described for the first time. Clin. Anat. 30:1064-1071, 2017. © 2017 Wiley Periodicals, Inc.

An anatomic study of the structure and innervation of the pronator quadratus muscle.

The pronator quadratus muscle is composed of the superficial and deep heads. However, to date there is no consensus on the variations of each head. To add to this enigma, the innervation patterns of each head have not been thoroughly studied. The present study was conducted to clarify the structure and innervation of the pronator quadratus muscle by minute dissection of 46 forearms from 26 cadavers. The origin, insertion, shape, and direction of the muscle fascicles in each head were observed. The intramuscular distribution and the innervation patterns to each head were investigated. The attachment of the deep head was examined using Masson's trichrome staining technique. Each head consisted of various muscle fascicles which differed in shape and direction. The most distal muscle fascicle extended toward the head of the ulna. On microscopic study, this most distal fascicle was observed to reach the base of the ulnar styloid process. The nerves innervating the superficial head penetrated through the deep head and ran on the anterior surface of the radius from medial to lateral. This tendency was common to all of the forearms studied. We confirmed that each head of the pronator quadratus muscle consisted of various muscle fascicles. The attachment to the base of the ulnar styloid process is considered to be an important structure that prevents the head of the ulna from impacting against the carpal bones. Knowledge of the innervation pattern to each head is critical for preserving the function of the pronator quadratus muscle during surgery for distal radial fracture.

The supinator muscle: anatomical bases for deep branch of the radial nerve entrapment

Our goals were to carry out an anatomical description of the internal architecture of the supinator muscle in order to describe potentially compressive structures for the deep branch of the radial nerve (DBRN) and to establish reference landmarks for the surgical treatment of radial tunnel syndrome. Thirty upper limbs were dissected. The pennation angle of proximal and distal arcades of the supinator to the radial shaft axis was measured. Possible compressive structures of both superficial and deep heads of supinator were recorded. Proximal and distal arcades of the superficial layer of the supinator were classified according to their fiber content as tendinous, musculo-tendinous, muscular or membranous. The distances of superficial layer of the supinator muscle to the humeroradial joint line and lateral epicondyle were measured. Pennation angle was 33.6° (±4.2°) for the superficial layer and 50.2° (±6.6°) for the deep layer. The difference was statistically significant (p<0.0001). The proximal arcade was purely tendinous in 20 cases (66.7%). The distal arcade was mainly tendinous or musculo-tendinous (70%). The average distance between the lateral epicondyle and the proximal arcade was 41.6mm. We did not find any other potentially compressive structure within DBRN course between both layers. Our anatomical results about pennation angle could be used as a basis for a thorough functional study about the supinator. Both proximal and distal arcades appeared as the two zones ables to compress the DBRN. Their localization should help the surgeon for the DBRN neurolysis.

Storm Water Runoff and Deep Groundwater Drainage in Two Closed Basins

Closed basins dotting the landscape of south and central Florida have aroused the interest of numerous hydrologists in the past. Lacking surface water drainage features such as creeks and natural streams, closed basins drain internally through the subsurface during storm events. Little is known, however, about the magnitude and role of subsurface drainage fluxes to deep groundwater aquifers. In this study, instruments were deployed to monitor the surficial and deep aquifer heads at groundwater discharge points in two urbanized closed basins. The purpose of the study was to develop and apply field methods to estimate rapid subsurface runoff following rainfall events and evaluate the effectiveness of internal drainage in urban drainage planning. The two sites were in Hillsborough County, Florida, and one location was a 6-m-deep sinkhole that receives urban runoff from the rest of the basin. The data captured rapid subsurface drainage exceeding 25 cm/day at these discharge locations following rainfall. The two locations collected subsurface runoff rapidly and released the runoff gradually into the deep aquifer system. Results have practical implications for urban drainage in closed basins.

Limb Salvage in the Treatment of Total Muscle Necrosis of the Leg Due to Compartment Syndrome

Prolonged high intracompartmental pressures, whether due to external causes or intracompartmental pathology, can lead to severe, if not total, necrosis of the muscle in the affected compartment(s). Aggressive treatment may reduce systemic complications and can help to improve the function as well as the survival of the patient. The treatment for acute compartment syndrome is early fasciotomy1. In the presence of severe crush injury, however, fasciotomy may lead to infection if any necrotic muscle remains after debridement and if wound and antibiotic therapies are not managed appropriately. Uncontrolled infection may lead to sepsis, amputation, and death. Currently, there is no objective method to predict the potential for the viability of compartment muscles prior to surgical release. Once the compartment has been released, the increased intracompartmental pressure usually returns to normal, and muscle viability is assessed by its response to physiologic stimuli (electrical or mechanical) and by its texture (turgor and rebound to normal following a forceps pinch). Any muscle that is found to be necrotic should be debrided immediately. Repeat returns to the operating room are necessary to reassess marginally surviving muscle and to look for further progression of necrosis. In some patients who have renal failure and/or multiple organ failure, radical debridement of marginally viable muscle or an amputation may be necessary to prevent worsening of the systemic inflammatory response, which could lead to death. In this report, we present the removal of all four compartments (anterior, lateral, superficial, and deep posterior, including both heads of the gastrocnemius muscle in all three patients) in a single session, resulting in a leg consisting of skin, the neurovascular bundles, and bone. Our long-term experience with this technique has shown that it is associated with low morbidity, and it reduces the initial complication rate as well as the time in …

Anatomical feasibility of transferring supinator motor branches to the posterior interosseous nerve in C7–T1 brachial plexus palsies

In C7-T1 palsies of the brachial plexus, shoulder and elbow function is preserved, but finger motion is absent. Finger flexion has been reconstructed using tendon or nerve transfers. Finger extension has been restored ineffectively by attaching the extensor tendons to the distal side of the dorsal radius (that is, tenodesis). In these types of nerve palsy, supinator muscle function is preserved because innervation stems from the C-6 root. In the present study, the authors investigated the anatomy and the feasibility of transferring the supinator motor branches to the posterior interosseous nerve. Sacrifice of the supinator motor branches does not abolish supination because biceps muscle function is preserved in lower-type injuries of the brachial plexus. The posterior interosseous nerve was dissected in 20 formalin-fixed forearms. Through posterior forearm access, the posterior interosseous nerve and its motor branches to the supinator muscle were dissected. Specimens were removed for histological study. In the vicinity of the supinator muscle's proximal margin (that is, the Frohse arcade), 2 nerve branches arose laterally and medially from the posterior interosseous nerve to innervate the superficial and deep heads of the supinator muscle, respectively. The supinator motor nerves, when divided, could be coapted directly to the posterior interosseous nerve. The number of myelinated fibers in the supinator motor branches corresponded to 70% that of the posterior interosseous nerve. The supinator motor nerves can be transferred directly to the posterior interosseous nerve to restore thumb and finger extension in patients with C7-T1 brachial plexus lesions.

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Singapore

The National University Hospital (NUH) Tissue Bank was established in October 1988. The National University of Singapore (NUS) was officially appointed by IAEA to be the IAEA/NUS Regional Training Centre (RTC) for RCA Member States for training of tissue bank operators on September 18, 1996. In the first five years since its establishment the National University Hospital Tissue Bank concentrated its work on the sterile procurement and production of deep frozen femoral heads and were used in patients for bone reconstruction. The cost of producing these tissues were about SGD$ 250 per femoral head although cost fees were initially charged at SGD$ 50 per femoral head. The most important activity carried out by Singapore within the IAEA was training. Between November 1997 and April 2007, a total of nine courses were conducted by RTC with a total of 180 tissue bank operators registered, 133 from Asia and the Pacific region (13 countries, including 2 from Iran), 14 from Africa (Zambia, Libya, Egypt, Algeria, and South Africa), 6 from Latin America (Brazil, Chile, Cuba, Peru, and Uruguay), 9 from Europe (Greece, Slovakia, Poland, and Ukraine), and 2 from Australia. The last batch (ninth batch) involved 20 students registered in April 2007 and will be due to sit for the terminal examination in April 2008.

Electromyographic activity and strength during maximum isometric pronation and supination efforts in healthy adults

There exists a lack of quantitative data in the literature related to the torque produced during axial forearm rotation and the electromyographic (EMG) activity of the muscles involved. Therefore, the purpose of this study was to compare the relative EMG activity of four forearm muscles during resisted forearm rotation. A custom-built device capable of measuring torque in the absence of grip was employed. Fourteen healthy volunteers performed maximum isometric voluntary contractions in five positions of axial forearm rotation for both pronation and supination. EMG data were collected simultaneously from the supinator, biceps, pronator quadratus (deep and superficial heads), and pronator teres muscles using fine-wire bipolar electrodes. Data were analyzed to determine the contributions of each muscle to pronation and supination torque over five positions of forearm rotation. In the absence of grip no significant difference was found between supination and pronation torque in neutral position. Supination torque generation was greater in the pronated forearm positions, and pronation torque was greater in the supinated positions ( p<0.05). A root-mean-square EMG analysis verified the major contributions of the pronator teres and both heads of the pronator quadratus muscle to pronation torque, and supinator and biceps to supination torque. The deep head of the pronator quadratus was active during both pronation and supination, lending support to the theory that it may act primarily as a dynamic distal radioulnar joint stabilizer. This information may be helpful in upper extremity modeling, surgical treatments, and rehabilitation strategies.