The proprioceptive innervation of the lateral pterygoid muscle in man and some other mammals

Rakhawy, M.T.; Shehata, Samir; Badawy, Zaizafon

doi:10.1159/000143665

Cited by 31 publications

(6 citation statements)

References 13 publications

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“…This is compatible with the data given by Rakhawy et al (1971). Although no information about the muscle spindles of the jaw muscles in the alligator is available, it is obvious that the power of the jaw muscles in the alligator is much greater than that in the human being or the rat.…”

Section: Discussionsupporting

confidence: 90%

“…In their study on the muscle-spindle counts, the lateral pterygoid muscle contained between 1 and 184 muscle spindles in man, and between 8 and 34 in the rat. However, the spindle counts for the masseter, temporalis and medial pterygoid muscles in the human being were 160, 217 and 155, while those for the same three muscles in the rat wre 136, 46 and 16, respectively (Rakhawy et al, 1971). …”

Section: Discussionmentioning

confidence: 92%

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Morphometric Comparison of the Motor Trigeminal Neurons

Setoyama

Zhou

Goto

et al. 1997

Okajimas Folia Anatomica Japonica

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Summary: Comparative morphological and morphometric studies of the motor trigeminal nucleus (MTN) were carried out on the brains of an alligator, a human being and a rat for the first time. Differences in neurons regarding sizes, areas, numbers, column volumes, neuropil indices and circularity ratios were found. The results showed that the positions and shapes of the MTN were different, and the shapes of motor neurons were different, too. The average area of motor trigeminal neurons was the largest in the alligator, compared with the area in the human being, and the rat; the number of neurons and the column volume of MTN were the largest in the human being. As for the neuropil indices, the value was in descending order: alligator, human being and rat; whereas for the circularity ratio of neuronal cell bodies, the order was: rat, alligator, and human being. We concluded that the size of motor neurons in the MTN may be related to the power of masticatory muscles, and there may be a connection between jaw sizes and shapes and sizes of the motor neurons in the MTN.The motor trigeminal nucleus (MTN), which supplies motor fibres to the masticatory muscles responsible for controlling the closing and opening movement of the jaw, is an oval column of somatotopically organised cells (Palkovits & Brownstein, 1988), and consists of large motor neurons in the human being Mogoseanu et al., 1993;Palkovits & Brownstein, 1988).There have been reports about the human brainstem nuclei studied by morphometric method (Konigmark & Murphy, 1972;Moatamed, 1966;Monagle, 1974;Tomasch & Etemadi, 1962) and a few comparative studies concerning the motor neuron organization of the MTN in rats , as well as a morphometric study of the MTN in developing human brain (Hamano et al., 1988).In this study, we checked whether there were any morphological and morphometrical differences of the MTN among various animals including humans in relation to different jaw sizes. We chose the alligator, the human being and the rat as large, medium and small jaw samples. The position of the MTN innervating masticatory muscles is considered to be practically the same in various animals such as rats (Card et al., 1986;Limwongse & DeSantis, 1977;Mogoseanu et al., 1993;Weijs et al., 1993), cats (Mizuno et al., 1975), guinea pigs (Hecht et al., 1993;Uemura et al., 1982), rabbits (Matsuda et al., 1978) and macaque monkeys (Mizuno et al., 1981), although there might be slight differences in the MTN depending on the animal considered. No data, however, have been included in the literature concerning the morphometric analysis of neurons in the MTN from a comparative point of view. With the help of an image-analyzer and a computer, it is possible to get detailed data about nuclei of the brain stem. In this study the areas of neuronal cells of the MTN in the alligator, the human being and the rat were carefully measured. The relationship between jaw size and neuronal size of the MTN is discussed. Material and MethodsThe brains used in this study were as follows: a human b...

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 92%

Morphometric Comparison of the Motor Trigeminal Neurons

Setoyama

Zhou

Goto

et al. 1997

Okajimas Folia Anatomica Japonica

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“…LUND et al (1978) found 34 muscle spindles and 6 Golgi tendon organs in the masseter and 74 spindles and 20 tendon organs in the temporalis muscle of a kitten. The lateral pterygoid muscle, a jaw-closing muscle in the cat, contains 7-74 spindles (RAKHAWY et al, 1971), and the medial pterygoid muscles also have spindles (SMITH and MARCARIAN, 1967). Although the actual number of the medial pterygoid spindles has not been counted in the cat, it is generally smaller than that of the masseter or the temporalis muscle spindles in other animals (KUBOTA et al, 1980).…”

Section: Discussionmentioning

confidence: 99%

Diameter spectra of sensory and motor fibers in nerves to jaw-closing and jaw-opening muscles in the cat.

1982

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The masseter and the mylohyoid nerves were examined using electron microscopy after unilateral destruction of the trigeminal motor nucleus by kainic acid injection in order to evaluate the distribution of sensory and motor fibers in masticatory muscle nerves. The surviving axons were counted and their diameters measured, and the results were compared with data for control nerves. The diameters of the control masseter nerve fibers were bimodally distributed with peaks at 2-5 and 7-9 ƒÊm. The nerve fiber diameters on the injected side, i.e., afferent fibers, also showed a bimodal distribution with peaks at 2-4 and 6-9 ,um.

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“…The main conclusion from morphological studies on human spindles is that they are structurally very similar to those of the cat (Cooper and Daniel 1963;Kennedy 1970;Rakhawy et at. 1971;Swash and Fox 1972;Barker 1974a;Harriman et al 1974;Kubota and Masegi 1977;Kucera and Dorovini-Zis 1979).…”

Section: Structural Similaritiesmentioning

confidence: 99%