Lastly, in the Octopoda the shell is represented only by small chitinous rudiments to which the retractor muscles of the head and funnel are attached; these are paired in Octopus, unpaired in other cases as in Cirrhoteuthis.
The superficial origin of its retractor muscles closely applied to the shell and serving to hold the animal in its place.
In the branchial sense-organs of Limulus there are no retractor muscles, and it seems to me that both retraction and protrusion must be brought about by alterations of pressure in the vascular fluids.
Polypide The tentacular crown, alimentary canal, and retractor muscles of a polyzoon-individual.
Polypide stout and short; the tip of the fundus of the stomach capable of very complete constriction; the retractor muscles unusually short and stout.
Retractor muscles The muscles by the action of which the lophophore can be pulled back into the zooecium.
They include the adductor muscle or muscles (one or two in number) that pull the valve together; the muscle or muscles that withdraw the foot, called the retractor pedis, and the protractor pedis that pulls the foot out.
On touching the tip of the foot we find it retract by the contraction of the muscular fibres of which it is composed, aided, perhaps, by the action of one or more retractor pedis muscles with which it is supplied.
When functional it is drawn across the eye by special muscles derived from the retractor bulbi, called the bursalis and pyramidalis.
Among the accessory structures of the eye the retractor bulbi muscle is found in amphibians, reptiles, birds and many mammals; its nerve supply shows that it is probably a derivative of the external or posterior rectus.
Note the large muscle impression just in front of the hinge-teeth; this is the point of attachment of the anterior adductor muscle, while just behind and adjoining it is the impression of the anterior retractor muscle.
Note the projecting muscular foot, the movements of which are governed by the retractor and protractor muscles attached to the impressions just mentioned.
Note two sets of these muscles, one set for thrusting the cardiac portion of the stomach out through the mouth and another for pulling it back, the protractor muscles and retractor muscles, respectively.
Note posterior to the adductor and below the retractor a small impression which affords attachment for the protractor muscles of the foot.
At the other end of the valve, note the large impression of the posterior adductor muscle with the impression of the small posterior retractor muscle just above it.
When it is at rest, the top of the sac in which it lies is pulled in by the retractor muscle r, and looks, as I have said, like the finger of a glove with the top pushed in.
The back of the scoop was used as a retractor for delicate structures.
When the optic nerve is not lacerated and the retractor muscles at the back of the eye are intact, an attempt at reduction is advisable.
This bend is attributable to the fact that the retractor muscles are attached to the penis at this point, and in withdrawing that organ within its sheath they double it upon itself.
The retractor oculi envelops the optic nerve between the brain and the ball of the eye and becomes attached upon the external face of the sclerotic tunic.
Its edge is then drawn slightly outwards by means of a retractor and separated from the underlying deep fascia.
Muller’s retractor is then inserted to retract the wound laterally, the hooks being made to engage the margins of the incision by means of forceps.
The patient is placed in the lithotomy position and a retractor is inserted in the anterior cul-de-sac in order to elevate the anterior vaginal wall: Fig.
The speculum is removed and the eyelid everted and pulled upward by means of a retractor or two silk stitches passed through the substance of the lid.
Axenfeld’s retractor is then inserted in the longitudinal axis of the wound (Fig.
Péan’s retractor is passed into the vagina, and the cervix is seized with a volsella and drawn downwards and backwards.
Body globular in form, mantle having a pedal slit on the abdominal side; two respiratory apertures without retractor muscles; foot mostly uncinate or strap-shaped.
T have shown that these creatures are to be recognized by a discoid groove in the shell, which simply depends upon the mantle, the retractor muscles being wanting.
I have shown, that they are already to be recognized by the uncinate or hook-shaped groove for the mantle in the shell, and which proceeds from the insertion of the retractor muscles.
Body flat, mostly discoidal; there is a large fissure on the abdominal side of the mantle for the passage of the foot, while posteriorly there are two long respiratory tubes with retractor muscles.
The proximal portion forms the retractor muscles of the manubrium, or proboscis, well developed, for example, in Geryonia.
This is a structure which, like the retractor muscle, is not found in the eye of man, but it serves in the lower animals to assist in removing foreign bodies from the front of the eyeball.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "retractor" in a variety of sentences. We hope that you will now be able to make sentences using this word.
