Mikrokosmographia a description of the body of man. Together vvith the controuersies thereto belonging. Collected and translated out of all the best authors of anatomy, especially out of Gasper Bauhinus and Andreas Laurentius. By Helkiah Crooke Doctor of Physicke, physitian to His Maiestie, and his Highnesse professor in anatomy and chyrurgerie. Published by the Kings Maiesties especiall direction and warrant according to the first integrity, as it was originally written by the author.

CHAP. XXXIII. Of the Muscles of Respiration.

THE Chest contayneth the Instruments or Organs of life: Life cannot bee maintayned without Respiration, neither can Respiration bee performed without motion; it followeth therefore that the Chest must needs be mo∣ued for Respiration sake. If it be demanded why Respiration is so neces∣sary, we answere, because of the high and great heat of the Heart, which by the ayre attracted in Respiration is refrigerated and cooled, euen as a mans face in Sum∣mer is cooled by a fan that wafteth fresh ayre vnto it.

Now the Chest is moued either by it selfe or by accident when it followeth the mo∣tion of the spine or Rackbones of the backe, for when the backe is bent the Chest is also bent with it.

It is moued by it selfe and with a proper and peculiar motion for Respiration sake, which Respiration is accomplished by a double motion of the Chest: which is dilated when Inspiration is made, that is, when we draw the ayre into our Longues and so coole the heat of our Hearts; or contracted in Expiration, that is, when the ayre is driuen back through the Rough artery for the generation of the voyce, and the sooty excrements are blowne away least the heart should be suffocaced by them.

In these motions of the chest wee must consider notwithstanding, that in Inspirati∣on the lower parts of the chest are dilated and the vpper angustated or straytned: on the contrary in Expiration the lower are constringed or straytned, the vpper dilated. And this was the reason why the Chest was not made of one bone as was the Scull, But of many, which also are ioyned together by gristles that their motion might be more pliant and easie.

But as the heart is moued with Naturall motion, so the Chest is moued partly with Naturall partly with Voluntary motion: with Natural; because in our sleepe it is moued Naturally not according to our Will. VVith Voluntary, for wee haue read of some that by reteining their breath haue hastned death vpon themselues. As for the Longues they follow the motion of the Chest especially to auoyde vacuity, as well in those that sleepe as in those that are awake.

Philosophers doe differ much concerning these motions, but because we haue alrea∣dy touched vppon their disputation in the tenth question of the sixt Booke, wee will not here Tautoligize though haply we might say something now, because this Volume gro∣weth far beyond that extent which was first limitted for it.

The Chest therefore needed Muscles for Respiration, Respiration is absolued by his Dia∣stole or dilatation when we breath in, & by his Systole or contraction when we breath out. These Muscles are in all 65. on each side 32. that is to say, 22. Intercostal Muscles, 11. inter∣nall and as many externall, and one which is common to both sides called septum trans∣uersum or the Midriffe. Of these we haue spoken before in the fourth and fift Chapters of the sixt Booke.

There remaine yet the proper Muscles of the Chest, sixe on either side, vnlesse it please you to adde three more according to Falopius: Finally, the Muscles of the Abdomen (which helpe also our Respiration) are on each side foure beside the Pyramidals or Spirie Muscles, so that the whole summe will now amount to 7••.

Of these some are Common, as the Muscles of the Abdomen which beside Respiration doe serue also for other purposes, others are Proper and serue for Respiration alone. But Respiration is double, one free or naturall, the other constrayned or violent.

That we call Free which is done gently and easily, that is, when in Inspiration there is without constraint so much ayre drawne in as may suffice for the generation of vitall spy∣rits, and in Expiration when a part of the attracted ayre is againe gently returned for the generation of the voyce, and both these are wrought by the motion of the Midriffe a∣lone.

The first by the Contraction of the Midriffe wherein the end of the bastard ribs are gathered a little vpward, the lower and forward part of the Chest angustated or straitned and the backepart inlarged to the Racke-bones, the seauen lower ribbes parted as it were asunder and so the Chest dilated.

The second, when the Midriffe is relaxed or loosened, for then the Chest doeth ea∣sily fall with his owne waight. We call that Respiration constrained, when the Dilatation

or contraction of the chest is euident, that is, when in Inspiration the breath is drawne with violence or vehemencie, as it happeneth when the heart is too much heated: and in Expiration when the ayre is forcibly blowne out, as when wee would speake or hallow aloude, when we would cough or sneese, or else when vpon expulsion it is retained when we would make vse of the midrife in euacuation of excrements or such like.

This respiration is absolued by sixtie foure muscles assisted by the midriffe, yet so that in Inspiration fewer muscles do labour them in Expiration. In Inspiration, that which is called Subclauius, Serratus maior, Serratus posticus superior & inferior, and Falopius his 3. muscles. The Intercostall muscles doe also conferre to this businesse; but that by accident onely. In Expiration more muscles are required, because we breath out with greater strength then we breathe in; these are called Sacrolumbus, triangularis, and all the Inter∣costalls; for the exteriour doe leade the lower ribs upward, and the interior the vpward ribs downeward. The eight muscles of the Abdomen, and haply in great necessities the muscles of the arm and the shoulder blades do lend their helping hands. The Intercostal muscles we wil here altogether passe ouer, as also the midriff, because we haue spoken of them at large before. The muscles of the Abdomen we referre vnto the next chapter, here we will onely handle the proper muscles of the chest, which grow thereto. These are ac∣counted by Galen eight, and so many they are indeed in Apes; but in men there are but sixe in either side commonly receiued, to which Falopius addes three.

Two of these muscles are seated before, the one called Subclauius, the other Trian∣gularis, one occupieth the sides called Serratus maior, the rest lie vpon the back part, three in the backe, two called Serrati postici, and the third Sacrolumbus; three in the necke, and

[illustration]

Tab. 2 Sheweth the muscles especially of the chest, the head, and of the shoul∣der ••••de.

[illustration]

TABVLA XXV.

• A, The fourth muscle of the Chest or the vpper & hinder Saw-muscle.
• B, the 5 muscle of the chest or the lower and hin¦der Saw muscle.
• a, b, A membranous beginning of the muscle of the Abdomen, descending obliquely downe from the spine of the backe.
• C, the 1 muscle extending the Cubit at c his origi¦nal is from the necke of the arme, and from the lower basis of the blade at d.
• E, the originall of the fourth muscle of the Bone hyois from the blade.
• G, G, the outward intercostal muscles.
• I. the Clauicle or Collerbone bared.
• N the vpper, the 2 muscle of the arme cald Deltois
• Char, 4, 5, the beginning of this muscle.
• N, the third muscle of the arme or the broad mus∣cle separated.
• O, the fourth muscle of the arme or the lower Su∣per Scapularis or bladerider.
• 1, 2, 3 char: His originall at the basis of the shoul∣der blade at 12 and his insertion into the ioynt of the arme at 3.
• Q, the sixt muscle of the arme or the vpper Super-Scapularis.
• X, The fourth muscle of the blade called Leuator or the heauer.
• Z, The second muscle of the chest or the greater sawe muscle.
• 7. 7. Char. The ribs.
• Γ, The sixt muscle of the chest, or the muscle caled Sacrolumbus.
• Λ, The first muscle of the head or the splinter.
• EE, the second muscle of the head or the insertion of the muscles called complex.
• Φ, The 2. muscle of the back or the longest muscle
• Ω. The fourth muscle of the backe called Semi∣spinatus.

these are they which we said before were propounded by Fallopius. But by Vesalius are esteemed to be parts of those muscles which occupy the necke and the back, but we come to the particulars.

The first proper muscle of the chest is called Subclauius. [tab. 17, ^Y. tab. 22, fig. 3, ^Y. The reason of the name is, because it is seated vnder the coller-bone which is called Clauicula, for it filleth that space which is betwixt the clauickle and the first rib.

This muscle ariseth fleshy from the inner and lower part of the clauickle which is next to the rib, runneth obliquely forward, and is fleshily implanted into the vpper part of the first rib which is ioyned to the brest bone. His fibres are very oblique, yea almost trans∣uerse. The vse of it is to draw the first rib vpward and outward, and so the cauity of the chest is dilated.

The second muscle is called Serratus maior or the greater saw-muscle. [tab. 10, 17, 25. ^•.] It is a large muscle, situated in the side of the chest, broade also and euery way fleshy. His originall is large and fleshy from all the inner basis of the blade, and towards the ribs it is dilated, coucheth vpon them, is tyed to the by fibres, and is inserted as it were diui∣ded into fingers into the eight vpper, sometimes also into the ninth rib, before they do de∣termine into their gristles. And these insertions of thes muscles are acute or sharp because of the tendons which descend obliquely with points like the teeth of 2 Saw, to meet with the teeth of the oblique descendent muscles of Abdomen, with which they are finger-fan∣ged as also is the lower and backeward Saw.

The vse of this muscle is by the collection of his fibres in great and violent constraintes or endeuours to draw the eight ribbes outward, and so to dilate the chest. But in dogs and Apes it is not onely inserted into the eight ribs, but implanted also in the transuerse processes of the fourth, fifth, sixt and seauenth rackbones of the necke, or if you please it ariseth therefrom.

The third proper muscle of the chest is called Serratus posticus superior [tab. 25, ^A] the vpper backe-saw. It lyeth in the backe vnder the muscle called Rhomboides or the thirde muscle of the blade, betwixt both the blades and aboue the first muscle of the head. A lit∣tle muscle it is, and ariseth broade and membranous from the spines of the three lower rack-bones of the necke and the first of the chest. Afterward it passeth a little obliquely vnder the blade, becommeth fleshy, and being diuided into three parts is inserted into the three distances of the foure vpper ribs.

The vse of it is to draw the ribs vpward, to which it is implanted by contracting his fibres, and so the chest is dilated and the hinder cauity thereof inlarged.

The fourth is called serraetus posticus inferior, the lower backe saw [tab. 25, ^B] and seated almost in the middle of the backe vnder the broade muscle that is the third muscle of the arme. It ariseth membranous, neruous, broade and almost quadrangular like a combe as the other, but broader then it from the spines of the two lower rack-bones of the chest, sometimes of the three, sometimes also from the vpper rackes of the loynes. Afterward it passeth ouerthwart and lyeth vpon the muscles of the backe, and beeing increased with fleshy fibres is inserted at the distances of the foure lower ribs before they determine into gristles. The insertion is made into the ribs themselues, and the muscle at the insertion diuided as it were into fingers. It is much broader in men then in apes and dogs and in dogs larger then in apes.

The vse of this muscle is to draw the three or foure lower ribs outward, and so doth dilate the lower part of the chest as we saide the second muscle did dilate the vpper part.

The fift muscle is called Sacrolumbus [Tab. 10, [〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉] sayeth Laurentius it ariseth from the Oss sacrum and the spines of the Lumbi or loynes. This muscle may be thought to be common as well to the chest as to the backe. It lyeth vnder the former, and ariseth fleshy from the backe part of the holy-bone, and the vpper and inner part of the haunch bone. Af∣terward it creepeth vpward fastening it selfe to the transuerse processes of the rackes of the loynes, and as farre as to the lower racke of the chest, is mixed with the long muscle of the backe, [tab. 10, at φ] so that a skilfull hand can very hardly separate them, and therfore it is esteemed but a portion thereof. [tab. 10, α, β.] A little aboue the lower rack-bone of the chest it departeth from the other muscles to which it did grow, and becomming by degrees more slender, is inserted obliquely with round tendons not altogether fleshy pro∣duced from the outward side [ta. 10, ^yy.] into sixe protuberations of the lower ribs which are their rootes. From thence as Fallopius rightly obserued, are produced sixe new fleshy

muscles neruous both in their originall and insertion, and are implanted into the sixe vp∣per ribs: so that from the twelfth rib where this muscle is inserted there ariseth a certaine tendon, which becomming fleshy and climing vpward looseth his flesh againe and is in∣fixed into the sixt rib, carrying the resemblance of a slender muscle. In like manner from the eleuenth rib proceedeth another Tendon which is inserted into the fift rib, and one al∣so from the tenth which is inserted into the fourth, one from the ninth into the third; fi∣nally, from the eight and the seauenth which are implanted into the first ribs.

All these Tendons doe resemble distinct Muscles, yet they are so commixed together and with the Sacrolumbus in the surface that they seeme to bee partes thereof whereas in∣deed they are not, so sayth Falopius in his obseruations. VVherefore when as the Sacro∣lumbus draweth the sixe inferior ribs backward and therewith downward, it moueth also together with them the sixe vpper foresayde additaments which are called ansulae or the handles, and so constringeth the Chest.

The sixt proper Muscle of the Chest hath his name from the forme and is called Triangularis or the triangular Muscle, because it consisteth of two long sides & one short. It is seated within the cauity of the Chest vnder the breast-bone: little it is and slender, & in some men especially if they bee leane, there appeareth nothing fleshy in it. In some parts it is like a neruous Membrane stuffed with flesh.

It ariseth from the lower part of the Breast-bone and passeth obliquely vpward and outward, growing to the gristles of the true ribs euen vnto the second: and this is the rea∣son why the Intercostall Muscles and those which are called Intercartilaginei, that is, be∣twixt the gristles doe appeare diuers, because of their diuers fibres. The vse of this mus∣cle is to leade the gristles of the ribs together, and so to constringe the Chest or to presse down the forepart therof so much as is necessary for Respiration, but in Dogs it is whol∣ly fleshy and occupyeth the whole side of the Breast-bone.

Falopius is of opinion that the first and third Muscle are too weake to suffice for the e∣leuation of the Chest, for hee esteemeth the second rather to bee a moouer of the blade; and therefore he sayth that there are three other muscles which performe this office pla∣ced in the necke, which Vessalius in his Apology accounteth for partes of these Muscles which occupy the necke and the backe.

The first of these three ariseth with a neruous beginning from the inside of the trans∣uerse processes of the 3. 4. 5. and sixt Racke-bones of the necke; then becomming more fleshy it is infixed into the first ribbe which it lifteth vp, and together with it the whole Chest.

The second is called Scalenus, because his figure is vnequally triangular, [Ta. 29. Λ Table 13. CC.] It ariseth fleshy from the transuerse processes of all the racke-bones of the neck, the first and the second being sometimes excepted, and hath a fleshy insertion into the first rib, sometimes also into the second. This also serues to lift vp the chest.

The third and last ariseth from the transuerse processes of the fourth and fifth racks of the necke, and is implanted with a fleshy termination into the second ribbe sometimes into the third, and lifteth vp the rib into which it is implanted.

By these three Muscles therefore and the vpper back saw, Falopius conceiueth that the chest is eleuated. And thus much shall suffice to haue sayde concerning the muscles of chest. Now follow the Muscles of the Abdomen.

Notes

• Why the chest moueth.
• His different motions.
• Why not bo∣ny.
• The kinde of motion.
• How respira∣tion is made The number of the muscles of respiration.
• 2. kinds of re∣spiration.
• Free.
• Violent.
• How the mu∣scles moue.
• The position of the mu∣scles.
• 1. subclauius.
• 2 Serratus maior.
• 3. Serratus posticus sup.
• 4. Serratus posti. infer.
• 5. Sacrolum∣bus.
• Fallopius his 6. new muscles.
• The 6 proper muscle.
• His originall.
• Falopius his 3. muscles.