Examination Paper: Anatomy, by Walter Reed, [February 8, 1875] |
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Anatomy I. Enumerate as minutely, as you can, the
muscles concerned in prehension & mastication,
showing the function of each muscle of group, & the
nerve supply of each. The The following are the muscles of
prehension & mastication; To wit: 1. maseteric, con-
sisting of a superficial and a deep portion-
the superficial part arising from the malar process
of Supr maxillary, outr surface of malar & outr part of
infr border of Zygoma & being inserted into angle
& ramus of lower jaw-: the deep part arising from
postr part of infr border of Zygoma & being inserted
into ramus of lower jaw. 2. Buccinator a brand
muscle, arising from alveolar process of sup t
Max. bone, the Extl ridge of Infr maxillary, & the
pterygo-maxillary ligament (the latter being & ten-
dinous raphe between buccinator & Sup t r Constructor
of pharynx)- its fibres converging to be inserted
into, the or rather blended , with the various muscles
of [at] the angle of the mouth- 3. Expl Pterygoid.
arising by two heads: one from the pterygoid
ridge on infr & extl surface of greater wing
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sphenoid bone & from the ptery smooth surface of
bone just below the ridge - the other arising
from tuberosity of supr max. & tubersity of palate
bone & [outer surface of] extl pterygoid plate-these two heads join
& are inserted into neck of lower jaw.
4. Intl Pterygoid-arising from s the fossa between
the intl & extl pterygoid plates & being inserted
into ramus of lower jaw- 5. Temporal- aris-
ing from temporal ridge (whole length) - from the
whole of temporal fossa & from a dense fascia
covering it- is inserted into Coronoid process
(its apex) of infr max- bone. As regard the action of these muscles;
The buccinator forms the side of the cavity of the
mouth & serves to prevent the food from getting into
accumulating between the teeth & side of mouth.
In cases of Facial Paralysis, when this muscles is
paralized, the food accumulates in the above mentioned
location & the loss of the action of the buccinator is
at once seen. The remaining four muscles
may be grouped together in their action. They
serve to bring the teeth of the two jaws in
apposition & also carry the lower jaw from
side to side, thereby grinding the food into |
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small particles. They are sometimes called the "grinders". Each muscle receives its nerve
supply from the extl division of the Inferior
Maxillary branch of the 5th or Trifacial nerve.
The infr maxillary branch of 5th, just after passing through
foramen ovale, divides into an intl & extl branch,
the latter containing most of the motor fibres of
the nerve it is distributed to [the] Buccinator, Mass-
teric, Intl & extl pterygoid, & temporal muscluse. II. What difference exists between the right &
left recurrent laryngeal nerves? The right-left recurrent or infr laryngeal nerves
are branches given off by the Dueumogastric
Nerve after it has entered the chest- The
right nev recurrent nerve passes upwards,
& beneath & behind the right subclavian
Artery, passes & thence behind the Com-
mon Carotid Artery to the groove between
the Trachea & Oesophagus- thence passes
upward & pieces enters the larynx near
the articulation of horn of hyoid bone with
the thyroid Cartilage. The left recurrent nerve |
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passes beneath & behind the Arch of the
Aorta & thence to groove between trachea
&oesophagus to its point of entrance
into the larynx. III. Give the muscles of the larynx & show
what part each plays in vocalization.
The following are the muscles of the larynx:
to wit: 1. Crico-thyroid arising from antr & [lateral] surface
of crycoid cartilage & inserted into postr border
[extl] Surface of thyroid cartilage near [the] postr border-
2. Crico-arytenoideus posticus-arising [from] postr
surface of Crycoid & inserted into infr & outer
angle of arytenoid Cartilage. 3. Cryco-arytenoid-
deus lateralis-arising from extl surface of Crycoid
(anterior to former muscle) & inserted into outer
& lower angle of arytenoid Cartilage. 4.
Arytenoideus-arising from postr surface
of one arytenoid & inserted into the postr
surface of the other. 5th Thyro-arytenoideus
arising from s the receding angle formed by the
thyroid cartilages & passing backwards
to be inserted into antr Surface of the
Arytenoid Cartilage- (The above enumerated
muscles are in pairs) There are, in |
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addition to those given, a supr & Infr Thyro-
ro-Epiglotideus and a Hyo-Epiglotideus; but
these muscles take no part in vocalization. The Cryco-Arytenoideus postice by then ac-
tion serve draw the arytenoid cartilages apart
& at the same [time] turn them slightly outwards on
their axes, thus opening the glottis.
The Cryco-thyroid by their action render the vocal
cords tense. The Thyro-arytenoid by their action
relax the vocal Cords- The arytenoideus closes
the glottis. Dr Dalton, in his physiology, states
that the Cryco-arytenoider postici open the
glottis & all the other muscles of the larynx
close it. Respectfully submitted,
Walter Reed |
