depressor muscle
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2021 ◽  
Vol 19 (2) ◽  
pp. 133-137
Author(s):  
N.J. Plang ◽  
I.J. Gosomji ◽  
J.O. Omirinde ◽  
S.A. Hena ◽  
I.A. Azeez ◽  
...  

Congenital abnormalities are common among avian and mammalian species. They could be partial or total drift from the normal structural organization of the organ-systems. This article is aimed at reporting the occurrence of multiple abnormalities in a 3-week-old broiler chick. Ante mortem, post-mortem, radiological and osteological investigations were carried out, to ascertain the number and form of abnormalities present in the chick. A total of four different congenital abnormalities were discovered in this chick. These include: polymelia (presence of supernumerary or accessory limb which is usually malformed); double vents (vent duplex); double cloacal bursae (bursa duplex) and triple caeca. Radiological and postmortem examinations revealed the attachment of the accessory limb to the caudal depressor muscle as a form of synsarcosis, via a tendon that originated from the deep fossa of the modified femoral head of the accessory limb. The right vent was patent whereas the left was not. The two cloacal bursae were almost the same size, while the three caeca showed slight variation in length but typical features of the avian caecum (base, middle (body) and apex) were clearly visible. However, most cases of congenital anomalies in the avian species occur as multiple defects, with the most common being polymelia. The latest finding in this report is the discovery of double cloacal bursae (bursae of Fabricius), which has not been reported in the avian species.


2019 ◽  
Vol 4 (1) ◽  
pp. 31
Author(s):  
Darma Setiawan Putra ◽  
Yuril Umbu WW

The facial electromyograph (FEMG) signal is a signal that occurs in the muscles of the contracted human face. This FEMG signal is one of the techniques used to study human speech recognition. It can be acquired by placing an electrode surface on the skin around the facial articulation muscle. Three types of muscles in this study are the masseter, risorius and depressor muscle. This study aims to extract and analyze the features in the FEMG signal. The extraction method is the discrete wavelet transform (DWT). The type of wavelet transform is Daubechies2 with level 5. After extraction and analysis of FEMG signals, the FEMG signal pattern for each spoken word indicated by differences in the approximation and detail coefficient of the FEMG signal. In addition, the level of difference in the FEMG signal pattern is also indicated by the histogram of the approximation coefficient of the FEMG signal. Thus, the discrete wavelet transform method can be used as one of the methods for extracting the FEMG signal feature in a human facial electromyograph (FEMG) signal.


2018 ◽  
Vol 120 (4) ◽  
pp. 1807-1823 ◽  
Author(s):  
Sasha N. Zill ◽  
Chris J. Dallmann ◽  
Ansgar Büschges ◽  
Sumaiya Chaudhry ◽  
Josef Schmitz

Many sensory systems are tuned to specific parameters of behaviors and have effects that are task-specific. We have studied how force feedback contributes to activation of synergist muscles in serially homologous legs of stick insects. Forces were applied using conventional half-sine or ramp and hold functions. We also utilized waveforms of joint torques calculated from experiments in freely walking animals. In all legs, forces applied to either the tarsus (foot) or proximal leg segment (trochanter) activated synergist muscles that generate substrate grip and support, but coupling of the depressor muscle to tarsal forces was weak in the front legs. Activation of trochanteral receptors using ramp and hold functions generated positive feedback to the depressor muscle in all legs when animals were induced to seek substrate grip. However, discharges of the synergist flexor muscle showed adaptation at moderate force levels. In contrast, application of forces using torque waveforms, which do not have a static hold phase, produced sustained discharges in muscle synergies with little adaptation. Firing frequencies reflected the magnitude of ground reaction forces, were graded to changes in force amplitude, and could also be modulated by transient force perturbations added to the waveforms. Comparison of synergist activation by torques and ramp and hold functions revealed a strong influence of force dynamics (dF/d t). These studies support the idea that force receptors can act to tune muscle synergies synchronously to the range of force magnitudes and dynamics that occur in each leg according to their specific use in behavior. NEW & NOTEWORTHY The effects of force receptors (campaniform sensilla) on leg muscles and synergies were characterized in stick insects using both ramp and hold functions and waveforms of joint torques calculated by inverse dynamics. Motor responses were sustained and showed reduced adaptation to the more “natural” and nonlinear torque stimuli. Calculation of the first derivative (dF/d t) of the torque waveforms demonstrated that this difference was correlated with the dynamic sensitivities of the system.


2012 ◽  
Vol 108 (5) ◽  
pp. 1453-1472 ◽  
Author(s):  
Sasha N. Zill ◽  
Josef Schmitz ◽  
Sumaiya Chaudhry ◽  
Ansgar Büschges

The regulation of forces is integral to motor control. However, it is unclear how information from sense organs that detect forces at individual muscles or joints is incorporated into a frame of reference for motor control. Campaniform sensilla are receptors that monitor forces by cuticular strains. We studied how loads and muscle forces are encoded by trochanteral campaniform sensilla in stick insects. Forces were applied to the middle leg to emulate loading and/or muscle contractions. Selective sensory ablations limited activities recorded in the main leg nerve to specific receptor groups. The trochanteral campaniform sensilla consist of four discrete groups. We found that the dorsal groups (Groups 3 and 4) encoded force increases and decreases in the plane of movement of the coxo-trochanteral joint. Group 3 receptors discharged to increases in dorsal loading and decreases in ventral load. Group 4 showed the reverse directional sensitivities. Vigorous, directional responses also occurred to contractions of the trochanteral depressor muscle and to forces applied at the muscle insertion. All sensory discharges encoded the amplitude and rate of loading or muscle force. Stimulation of the receptors produced reflex effects in the depressor motoneurons that could reverse in sign during active movements. These data, in conjunction with findings of previous studies, support a model in which the trochanteral receptors function as an array that can detect forces in all directions relative to the intrinsic plane of leg movement. The array could provide requisite information about forces and simplify the control and adaptation of posture and walking.


Author(s):  
Haifa Ashraf

ABSTRACT Introduction Mastication is a highly coordinated neuromuscular function involving fast effective movements of the jaw and continuous modulation of force. In older subjects these mechanisms act with marked differences. They have a reduced capacity in various functions of stomatognathic system. Objectives To evaluate the elevator and depressor muscle activity with and without complete denture prosthesis. Materials and methods For the purpose of the study 12 patients between the age of 40 and 70 years were selected. Surface electrodes from the electromyographic unit were placed in the region of right and left anterior temporal muscles, Masseter muscle and depressor muscle at the region of anterior belly of digastric and the electromyographic activity was recorded. Results and discussion The obtained values were subjected to statistical analysis. A paired t- test was performed to determine the difference between the subjects with and without denture prosthesis. Conclusion The elevator muscles showed higher activity in subjects wearing the denture prosthesis when compared to those without denture prosthesis. No significant change in muscle activity was seen on maximal opening of the depressor muscle between the subjects with and without denture prosthesis.


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