The Head is mov'd by the means of fourteen Muscles, seven on each side; of these, two serve to depress it, eight to lift it up, and four to turn it round about.
The two Depressors are call'd Sternoclinomastoidei; they take their Rise in the Sternum, at the Clavicles, and proceed obliquely to join the Apophysis Mastoides.
Of the four Elevators on each side the first is the Splenius, which begins at the five Vertebræ of the Back and the three lower ones of the Neck, and ascending obliquely, cleaves to the hinder part of the Head. The second, named Complexus or Trigeminus, having its beginning as the Splenius, sticks in like manner to the hinder part of the Head, and they form together a figure resembling that of S. Andrew's Cross. The third is the Rectus Major, which proceeding from the second Vertebra of the Neck, shoots forward to join the hinder part of the Head. The fourth is the Rectus Minor, which begins at the first Vertebra of the Neck, and ends likewise in the hinder part of the Head.
The two Muscles on each side, which move the Head circularly, are the Obliquus Major and
Minor; the greater Oblique taking its rise from the second Vertebra of the Neck, goes to meet the first; but the lesser Oblique hath its Origine in the hinder part of the Head, and proceeds to join the other obliquely in the first Vertebra.
How many Muscles are there in the Lower-Jaw, and which be they?
The Lower-Jaw hath twelve Muscles which cause it to move; that is to say, six on each side, whereof four serve to close and two to open it.
The first of the Openers is the Latus, which beginning at the top of the Sternum, Clavicle, and Acromion, cleaves on the outside to the bottom of the Lower-Jaw-Bone. The second of the Openers is the Digastricus, which takes its rise in a Fissure lying between the Occipital Bone and the Apophysis Mastoides, from whence it passeth to the bottom of the Chin on the inside.
The first of the Shutters is the Crotaphites or Temporal Muscle, which hath its Origine at the bottom, and on the side of the Os Coronale, the Os Parietale, and the Os Petrosum, from whence it is extended till it cleaves to the Apophysis Coronoides of the Lower-Jaw, after having passed above the Apophysis of the Zygoma: Its Fibres are spread from the Circumference to the Center, and it is covered again with the Pericranium, which renders its Wounds very dangerous; so that the least Incisions as can be, ought to be made therein.
The second is the Pterygoideus or Aliformis Externus, whose rise is in the Apophysis Pterygoides, from whence it sets forward till it stick between the Condylus and the Coronal of the Lower-Jaw.