Short Head Research Articles

Coracobrachialis muscle: morphology, morphometry and gender differences.

Coracobrachialis (CBM) is a complex muscle with a wide range of variations in its morphology and innervation. The goal of this study was to elucidate the morphology, morphometry, gender differences of CBM and precise anatomical position of the musculocutaneous nerve (MCN) with reference to surrounding anatomical landmarks in an adult Sri Lankan population. Cadaveric upper limbs (n=312) were examined for the proximal and distal attachments, length, width, thickness of CBM and its relationship with the MCN. The CBM originated from the tip of the coracoid process of the scapula and lateral, posterior and medial aspects of the tendon of short head of biceps brachii. Gender differences were observed in all morphometrical parameters of CBM. In 83.33%, MCN perforated the CBM. In 50% the MCN pierced the middle one-third of CBM while none pierced the lower one-third. The distance from the coracoid process to the point of entry of MCN into CBM (distance P) was 50.62mm. A positive correlation was observed between the arm length and distance P indicating that arm length provides an accurate and reliable means of gauging the distance P of an individual. The present study provides new evidence pertaining to the origin of CBM. Further, it was revealed that the predicted distance P of any upper extremity can be calculated by dividing the arm length by 5. Precise anatomical location of MCN in relation to CBM using unequivocal and well-defined anatomical landmarks will be imperative in modern surgical procedures.

Scapular dyskinesis after Latarjet procedure

Because of detachment of the pectoralis minor and variation of the vector of the conjoint tendons, we hypothesized that the Latarjet procedure may alter scapular position and motion. The purpose of this study was to evaluate scapular position and motion in patients who underwent a Latarjet or a modified iliac crest bone graft transfer (ICBGT) procedure (J-bone graft). Forty-six consecutive patients treated for recurrent anterior shoulder dislocation between 2010 and 2012 were retrospectively enrolled. Twenty-three were treated with a Latarjet and 23 with an ICBGT procedure. Twenty Latarjet and 20 ICBGT patients were available at a mean follow-up of 20 months (min, 12; max, 60). We recorded the Western Ontario Instability Index, the Rowe Score, and the Subjective Shoulder Value. Scapulothoracic position was studied according to the dyskinesis yes/no method. Intraobserver and interobserver reliability of the dyskinesis assessment was assessed. Intraobserver and interobserver reliability of scapula dyskinesis assessment was high (Latarjet: intratester, κ = 0.84; intertester, κ = 0.75; ICBGT: intratester, κ = 0.78; intertester, κ = 0.71). Scapular dyskinesis was observed after 5 of 20 Latarjet and after 0 of 20 ICBGT procedures (P = .047). Patients with dyskinesis had lower scores (Western Ontario Instability Index, P = .043; Rowe, P = .047; Subjective Shoulder Value, P = .046), but no statistically significant difference was found between the Latarjet and ICBGT groups. Two of the 5 scapular dyskinesis patients reached the SICK (Scapular malposition, Inferior medial scapular winging, Coracoid tenderness, and scapular dysKinesis) scapula syndrome definition. Scapular dyskinesis was found in 5 of 20 patients who underwent a Latarjet procedure. Dyskinesis may be related to the detachment of the pectoralis minor, and variation of the vector and the working length of the coracobrachialis and the short head of the biceps.

Sperm size evolution in African greenbuls (Passeriformes: Pycnonotidae)

Sperm morphology is highly diversified across the animal kingdom and recent comparative evidence from passerine birds suggests that postcopulatory sexual selection is a significant driver of sperm evolution. In the present study, we describe sperm size variation among 20 species of African greenbuls and one bulbul (Passeriformes: Pycnonotidae) and analyze the evolutionary differentiation of sperm size within a phylogenetic framework. We found significant interspecific variation in sperm size; with some genera exhibiting relatively long sperm (e.g. Eurillas) and others exhibiting short sperm head lengths (e.g. Phyllastrephus). However, our results suggest that contemporary levels of sperm competition are unlikely to explain sperm diversification within this clade: the coefficients of inter-male variation (CVbm) in sperm length were generally high, suggesting relatively low and homogeneous rates of extra-pair paternity. Finally, in a comparison of six evolutionary or tree transformation models, we found support for both the Kappa (evolutionary change primarily at nodes) and Lambda (lineage-specific evolutionary rates along branches) models in the evolutionary trajectories of sperm size among species. We therefore conclude that African greenbuls have more variable rates of sperm size evolution than expected from a neutral model of genetic drift. Understanding the evolutionary dynamics of sperm diversification remains a future challenge.

Predator-Induced Defenses in Five Species of LarvalAmbystoma

While predator-induced plasticity has been demonstrated in a wide range of organisms, relatively few data exist to compare differences among species. In studies of predator-induced plasticity in amphibians, larval anurans have been widely examined, but there are fewer data for larval salamanders. We sought to examine morphological and behavioral defenses in larvae of five species of Ambystoma salamanders. We raised five species of larval mole salamanders (A. barbouri, A. gracile, A. laterale, A. maculatum, A. tigrinum) in separate lab experiments and exposed them to predator cues from larval dragonflies (Anax junius). Salamanders did not vary in their refuge use during the experiment, but A. gracile, A. laterale, and A. tigrinum reduced their activity in the presence of predators early in development. Dragonfly cues induced relatively few morphological changes across species: A. barbouri developed relatively large heads and deep tails, A. gracile and A. laterale developed relatively shorter heads, and A. ...

Unusual origin of three headed biceps brachii muscle

The biceps brachii is one of the most variable muscles in the human body in terms of the number of heads contributing to the muscle. The most common origin of these supernumerary heads is along the humeral shaft. We document a previously unreported point of origin for a supernumerary head. Routine dissection of a 10% formalin fixed upper extremity of a 72 year old Caucasian male, revealed a tricipital biceps brachii muscle. The third head took its origin from the deep investing fascia of the brachialis muscle and inserted onto the tendon of the short head of the biceps brachii. We believe this to be a previously unreported point of origin for a supernumerary head of the biceps brachii muscle. Supernumerary heads become clinically important as they can be a source of confusion for surgeons operating in this region and may be mistaken for soft tissue tumors when they are unilateral. An understanding of such variations is important. Keywords: biceps third head; elbow; shoulder; supernumerary biceps brachii

Sperm head phenotype and male fertility in ram semen

Although there is ample evidence for the effects of sperm head shape on sperm function, its impact on fertility has not been explored in detail at the intraspecific level in mammals. Here, we assess the relationship between sperm head shape and male fertility in a large-scale study in Manchega sheep (Ovis aries), which have not undergone any selection for fertility. Semen was collected from 83 mature rams, and before insemination, head shapes were measured for five parameters: area, perimeter, length, width, and p2a (perimeter2/2×π×area) using a computer-assisted sperm morphometric analysis. In addition, a cluster analysis using sperm head length and p2a factor was performed to determine sperm subpopulations (SPs) structure. Our results show the existence of four sperm SPs, which present different sperm head phenotype: SP1 (large and round), SP2 (short and elongated), SP3 (shortest and round), and SP4 (large and the most elongated). No relationships were found between males' fertility rates and average values of sperm head dimensions. However, differences in fertility rates between rams were strongly associated to the proportion of spermatozoa in an ejaculate SP with short and elongated heads (P < 0.001). These findings show how the heterogeneity in sperm head shape of the ejaculate has an effect on reproductive success, and highlight the important role of modulation of the ejaculate at the intraspecific level.

Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1

Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients, although with variable extent and severity of lesions. In the upper girdle, the subscapularis muscle was invariably affected. In the lower limbs, all the patients showed a consistent involvement of the flexor hallucis longus, which is very rarely affected in other muscle diseases, and a diffuse involvement of thigh and posterior leg with sparing of gracilis, tibialis anterior and, to a lesser extent, short head of biceps femoris. Mutations in STIM1 are associated with a homogeneous involvement on imaging despite variable clinical features. Muscle imaging can be useful in identifying STIM1-mutated patients especially among other forms of tubular aggregate myopathy.

Bilateral Three Headed Biceps Brachii Muscle

During routine human cadaveric dissection for the purpose of teaching learning of medical undergraduates inour department, third head of the biceps brachii muscle was found bilaterally in a 67 years old male cadaver. Bilaterally symmetrical third head was found with ß eshy proximal attachment on humerus between the insertionof the coracobrachialis and the upper part of the origin of the brachialis. This supernumerary head was deep tothe other two heads of biceps and was inserted into the bicipital aponeurosis. A branch of musculocutaneousnerve could be traced upto the third head. Long and short heads of biceps were of usual anatomy.doi: http://dx.doi.org/10.3126/mjsbh.v12i2.12931

Human Preferences for Conformation Attributes and Head-And-Neck Positions in Horses.

Human preferences for certain morphological attributes among domestic animals may be entirely individual or, more generally, may reflect evolutionary pressures that favor certain conformation. Artificial selection for attributes, such as short heads and crested necks of horses, may have functional and welfare implications because there is evidence from other species that skull shape co-varies with behaviour. Crested necks can be accentuated by flexion of the neck, a quality that is often manipulated in photographs vendors use when selling horses. Equine head-and-neck positions acquired through rein tension can compromise welfare. Our investigation was designed to identify conformations and postures that people are attracted to when choosing their ‘ideal’ horse. Participants of an internet survey were asked to rate their preference for horse silhouettes that illustrated three gradations of five variables: facial shape, crest height, ear length, ear position and head-and-neck carriage. There were 1,234 usable responses. The results show that overall preferences are for the intermediate, rather than extreme, morphological choices (p=<0.001). They also indicate that males are 2.5 times less likely to prefer thicker necks rather than the intermediate shape, and 4 times more likely to prefer the thinner neck shape. When compared to the novice participants, experienced participants were 1.9 times more likely to prefer a thicker neck shape than the intermediate neck shape and 2.8 times less likely to prefer a thinner neck shape than the intermediate neck shape. There was overall preference of 93% (n=939) for the category of head carriage ‘In front of the vertical’. However, novice participants were 1.8 times more likely to choose ‘behind the vertical’ than ‘in front of the vertical’. Our results suggest that people prefer a natural head carriage, concave facial profile (dished face), larger ears and thicker necks. From these survey data, it seems that some innate preferences may run counter to horse health and welfare.

“Popeye muscle” morphology in OBPI elbow flexion contracture

Background: The pathophysiology of elbow flexion contracture (EFC) in obstetrical brachial plexus injury (OBPI) is not established. In basic science models, neonatal denervation leads to impaired muscle growth. In clinical studies, diminished growth is correlated with extent of denervation, and improved with surgical repair. In EFC, the biceps are clinically short and round vs the contralateral size, termed the “Popeye muscle”. The objective of this study was to determine if the biceps morphology (muscle belly and tendon length) in arms with EFC secondary to OBPI is different vs the contralateral. Methods: This is a retrospective matched-cohort study. Patients with unilateral EFC (>20°) secondary to OBPI were identified (median = 6.6 years, range = 4.7–16.8). A blinded radiologist used computed tomography to measure length of the biceps short head muscle belly, and tendon bilaterally using standardised anatomical landmarks. Results: Twelve patients were analyzed. The biceps muscle belly in the injured arm was shorter in all patients vs contralateral, mean difference = 3.6 cm (80%), p < 0.001. The biceps tendon in the injured arm was longer in all patients vs contralateral, mean difference = 1.13 cm (127%), p < 0.001. The total biceps length in the injured arm was shorter in all patients vs contralateral, mean difference = 2.5 cm (89%), p < 0.001. Conclusions: This is the first human study confirming growth discrepancy of an elbow flexor in EFC. Distinct biceps morphology is demonstrated, with a significantly shorter muscle belly and overall length, but longer tendon vs normal. This is termed the “Popeye muscle” for its irregular morphology. Findings are consistent with impaired limb growth in denervation.

Muscle activation patterns in the Nordic hamstring exercise: Impact of prior strain injury.

This study aimed to determine: (a) the spatial patterns of hamstring activation during the Nordic hamstring exercise (NHE); (b) whether previously injured hamstrings display activation deficits during the NHE; and (c) whether previously injured hamstrings exhibit altered cross-sectional area (CSA). Ten healthy, recreationally active men with a history of unilateral hamstring strain injury underwent functional magnetic resonance imaging of their thighs before and after six sets of 10 repetitions of the NHE. Transverse (T2) relaxation times of all hamstring muscles [biceps femoris long head (BFlh); biceps femoris short head (BFsh); semitendinosus (ST); semimembranosus (SM)] were measured at rest and immediately after the NHE and CSA was measured at rest. For the uninjured limb, the ST's percentage increase in T2 with exercise was 16.8%, 15.8%, and 20.2% greater than the increases exhibited by the BFlh, BFsh, and SM, respectively (P < 0.002 for all). Previously injured hamstring muscles (n = 10) displayed significantly smaller increases in T2 post-exercise than the homonymous muscles in the uninjured contralateral limb (mean difference -7.2%, P = 0.001). No muscles displayed significant between-limb differences in CSA. During the NHE, the ST is preferentially activated and previously injured hamstring muscles display chronic activation deficits compared with uninjured contralateral muscles.

Clinical and muscle imaging findings in 14 mainland chinese patients with oculopharyngodistal myopathy.

Oculopharyngodistal myopathy (OPDM) is an extremely rare, adult-onset hereditary muscular disease characterized by progressive external ocular, pharyngeal, and distal muscle weakness and myopathological rimmed vacuole changes. The causative gene is currently unknown; therefore, diagnosis of OPDM is based on clinical and histopathological features and genetic exclusion of similar conditions. Moreover, variable manifestations of this disorder are reported in terms of muscle involvement and severity. We present the clinical profile and magnetic resonance imaging (MRI) changes of lower limb muscles in 14 mainland Chinese patients with OPDM, emphasizing the role of muscle MRI in disease identification and differential diagnosis. The patients came from 10 unrelated families and presented with progressive external ocular, laryngopharyngeal, facial, distal limb muscle weakness that had been present since early adulthood. Serum creatine kinase was mildly to moderately elevated. Electromyography revealed myogenic changes with inconsistent myotonic discharge. The respiratory function test revealed subclinical respiratory muscle involvement. Myopathological findings showed rimmed vacuoles with varying degrees of muscular dystrophic changes. All known genes responsible for distal and myofibrillar myopathies, vacuolar myopathies, and muscular dystrophies were excluded by PCR or targeted next-generation sequencing. Muscle MRI revealed that the distal lower legs had more severe fatty replacement than the thigh muscles. Serious involvement of the soleus and long head of the biceps femoris was observed in all patients, whereas the popliteus, gracilis and short head of biceps femoris were almost completely spared, even in advanced stages. Not only does our study widen the spectrum of OPDM in China, but it also demonstrates that OPDM has a specific pattern of muscle involvement that may provide valuable information for its differential diagnosis and show further evidence supporting the conclusion that OPDM is a unique disease phenotype.

Head morphology of ram spermatozoa is associated with their ability to migrate in vitro and correlates with fertility.

Fertility is a highly complex biological function that depends on several properties of spermatozoa that are necessary for them to overcome various barriers in the female reproductive tract to reach the fertilisation site. This ability has been evaluated in vitro using cervical mucus migration tests. Head morphology has been widely studied, and various studies have reported correlations between head morphology and motility, fertility and DNA fragmentation. In the present study, we first evaluated the relationship between the ability of ram spermatozoa to overcome the mucus surrogate barrier in an in vitro migration test and sperm head morphology. Sperm motility (determined by computer-aided sperm analysis) and the acrosomal status, viability and mitochondrial status (determined by flow cytometry) of control and migrating spermatozoa were assessed. Principal component analysis and clustering analysis of the values for the morphometric parameters assessed defined three cell subpopulations. One of these subpopulations, namely spermatozoa with a short and wide head, was absent from samples collected after conclusion of the migration test. Second, we evaluated relationships among head morphology characteristics, the ability to penetrate the artificial mucus and fertility. We did not find any correlation between fertility and the number of spermatozoa that migrated, whereas there was a negative correlation between the proportion of spermatozoa with a short and wide head in the fresh sperm sample and fertility. In conclusion, the head morphology of spermatozoa was associated with their ability to overcome a mucus barrier in a migration test, and the relative size of the non-migrating subpopulation was negatively related to male fertility.

Modulation of motor unit activity in biceps brachii by neuromuscular electrical stimulation applied to the contralateral arm.

The purpose of the study was to determine the influence of neuromuscular electrical stimulation (NMES) current intensity and pulse width applied to the right elbow flexors on the discharge characteristics of motor units in the left biceps brachii. Three NMES current intensities were applied for 5 s with either narrow (0.2 ms) or wide (1 ms) stimulus pulses: one at 80% of motor threshold and two that evoked contractions at either ∼10% or ∼20% of maximal voluntary contraction (MVC) force. The discharge times of 28 low-threshold (0.4-21.6% MVC force) and 16 high-threshold (31.7-56.3% MVC force) motor units in the short head of biceps brachii were determined before, during, and after NMES. NMES elicited two main effects: one involved transient deflections in the left-arm force at the onset and offset of NMES and the other consisted of nonuniform modulation of motor unit activity. The force deflections, which were influenced by NMES current intensity and pulse width, were observed only when low-threshold motor units were tracked. NMES did not significantly influence the discharge characteristics of tracked single-threshold motor units. However, a qualitative analysis indicated that there was an increase in the number of unique waveforms detected during and after NMES. The findings indicate that activity of motor units in the left elbow flexors can be modulated by NMES current and pulse width applied to right elbow flexors, but the effects are not distributed uniformly to the involved motor units.

A new genus of Dictyopharidae (Homoptera) from Chile

Chondrophana gen. n. with the type species Cixius gayi Spinola, 1852 (= Chondrodera chilensis Melichar, 1912, syn. n.) is described from Chile. The new genus differs from Chondrodera Melichar in a short head, fully developed intermedial carinae on the metope (clearly not reaching the clypeus in Chondrodera), in the presence of granules on the humeral and pectoral areas of the prothorax and also on the lateral lobes of the metope from the apical callus to the clypeus (in Ch. granicollis, granules and also the intermedial carinae in the lower half of the metope are absent), in multidentate apices of the 1st and 2nd segment of the hind tarsus, in a petiolate ScRM, and in the pterostigma closing the anteroradial area.

Bilateral Three Headed Biceps Brachii Muscle: A Case Report

&lt;p&gt;During routine human cadaveric dissection for the purpose of teaching learning of medical undergraduates in our department, third head of the biceps brachii muscle was found bilaterally in a 67 years old male cadaver. Bilaterally symmetrical third head was found with fleshy proximal attachment on humerus between the insertion of the coracobrachialis and the upper part of the origin of the brachialis. This supernumerary head was deep to the other two heads of biceps and was inserted into the bicipital aponeurosis. A branch of musculocutaneous nerve could be traced upto the third head. Long and short heads of biceps were of usual anatomy.&lt;/p&gt;

Shoulder arthroplasty and its effect on strain in the subscapularis muscle

BackgroundIncreasing the thickness of the prosthetic humeral head on subscapularis strain in patients undergoing total shoulder arthroplasty has not been elucidated. The optimal postoperative rehabilitation for total shoulder arthroplasty that does not place excessive strain on the subscapularis is not known. We hypothesize that the use of expanded non-anatomic humeral heads during shoulder replacement will cause increased tension in the repaired subscapularis. We identified a recommended passive range of motion program without invoking an increase in tension in the repaired subscapularis, and determined the impact of the thickness of the humeral head on subscapularis strain. MethodsEight fresh-frozen, forequarter cadaver specimens were obtained. An extended deltopectoral incision was performed and passive range-of-motion exercises with the following motions were evaluated: external rotation, abduction, flexion, and scaption. An optical motion analysis system measured strain in the subscapularis. The same protocol was repeated after performing a subscapularis osteotomy and after placement of an anatomic hemiarthroplasty of three different thicknesses. FindingsFor abduction and forward flexion, we observed a trend of decreasing strain of the subscapularis, as the laxity is removed with increasing humeral head component thickness. With the short humeral head, strain was similar to native joint with passive scaption and flexion but not with external rotation or abduction. InterpretationThe passive range of motion that minimizes tension on the subscapularis is forward flexion and scaption. Therefore, passive forward flexion or scaption does not need to be limited, but external rotation should have passive limits and abduction should be avoided.

Accessory head of biceps brachii muscle in North Indian cadavers

Background and aims : The biceps brachii is the large muscle of flexor compartment of arm. Normally it arises by two heads (long head and short head) and gets insertion in two parts (tendinous part and aponeurotic parts). The biceps brachii muscle is well known for variation in its origin.These variations can cause compression of brachial artery and median nerve which may pass deep to the accessory head of biceps brachii muscle, and can create problems for surgeons. So the surgeons should keep in mind such variations of biceps brachii muscle.The present study is to find out the variations in the origin of biceps brachii muscle. Material and methods: The present study was conducted in the department of anatomy of Gian Sagar Medical College, Ramnagar, Rajpura district Patiala (Punjab). In this study 32 human cadaveric limbs which were embalmed and fixed in 10% formaldehyde solution were used and these limbs were dissected and variations in origin of the biceps brachii muscle were noted. Results : Out of 32 limbs, 3 limbs (9.38%) were having three heads of biceps brachii muscle in its origin. The variations were found in the right limbs only. Conclusions : The knowledge of accessory head of biceps brachii muscle is important for the surgeons and troumatologists because there can be iatrogenic injury to the third head of biceps brachii muscle.

Unusual Variation of the Biceps Brachii with Possible Median Nerve Entrapment

The biceps brachii is one of three muscles of the anterior compartment of arm. Variations of the biceps brachii are not rare. The most frequent is the existence of a third head called the humeral head by Le Double (1897) (Rodríguez-Vázquez et al., 1999). Our article is based on the unexpected result of a routine dissection class held for medical students. Dissection was performed according to the guidelines accepted by the anatomy department (Seichert, 1999). We describe a third (accessory) head of the biceps brachii. In addition of two regular heads, the third head originated together with the short head from the coracoid process and had three insertions on the humerus after enfolding the median nerve and the brachial artery. This particular variation is important from a clinical perspective as the third head may cause entrapment syndrome of the median nerve and hypoperfusion of the upper limb due to compression of the brachial artery.

Accessory head of biceps brachii muscle in North Indian cadavers

Abstract Background and aims : The biceps brachii is the large muscle of flexor compartment of arm. Normally it arises by two heads (long head and short head) and gets insertion in two parts (tendinous part and aponeurotic parts). The biceps brachii muscle is well known for variation in its origin. These variations can cause compression of brachial artery and median nerve which may pass deep to the accessory head of biceps brachii muscle, and can create problems for surgeons. So the surgeons should keep in mind such variations of biceps brachii muscle. The present study is to find out the variations in the origin of biceps brachii muscle. Material and methods: The present study was conducted in the department of anatomy of Gian Sagar Medical College, Ramnagar, Rajpura district Patiala (Punjab). In this study 32 human cadaveric limbs which were embalmed and fixed in 10% formaldehyde solution were used and these limbs were dissected and variations in origin of the biceps brachii muscle were noted. Results : Out of 32 limbs, 3 limbs (9.38%) were having three heads of biceps brachii muscle in its origin. The variations were found in the right limbs only. Conclusions : The knowledge of accessory head of biceps brachii muscle is important for the surgeons and troumatologists because there can be iatrogenic injury to the third head of biceps brachii muscle.