Myotomia reformata, or, A new administration of all the muscles of humane bodies wherein the true uses of the muscles are explained, the errors of former anatomists concerning them confuted, and several muscles not hitherto taken notice of described : to which are subjoin'd a graphical description of the bones, and other anatomical observations : illustrated with figures after the life / by William Cowper, Surgeon.

CHAP. XXVIII. Of the Muscles of the four Fingers.

THESE we shall divide into Com∣mon and Proper. The Common Muscles of the Fingers are such as Arise from the External or Internal Protuberances of the Os Humeri, and subdividing themselves, are Inserted into most, if not all the Fingers; namely Perforatus, Perforans, Lumbri∣cales, and Extensor Communis Digito∣rum. The Proper Muscles of the Fingers are such as have their Begin∣nings distinct, and are Inserted with∣out any subdivision into each respe∣ctive Finger; as the Interossei, The Extensor and Abductor Indicis, the Ex∣tensor and Abductor Minimi Digiti: First of the Common Muscles of the Fingers.

Perforatus.

So called because its Tendons are Perforated to admit Those of the following Muscles to pass thorough

Them to their Insertions; It is also call'd Sublimis from its Situation, be∣ing above the Following; and Flexor secundi Internodii Digitorum from its Use. It Ariseth Tendinous from the Internal Extuberance of the Os Hu∣meri (22) between the Flexores Carpi;* 1.1 it also has a Disgregated Fleshy Ori∣gination from the Fore-part of the Radius, between the Pronator Radii Teres and Flexor Pollicis Magnus, com∣posing a Fleshy Belly lessens it self in less then half its progress, where it's divided into Four Fleshy Portions, each of which soon becomes so many Roundish Tendons, and are included in their proper Mucilaginous Mem∣brane as they pass under the Liga∣mentum Transversale Carpi through the Palm; near the first Internode of the Fingers each Tendon is divided to admit those of the following Muscle to pass through them, then joining, and subdividing again, immediately before they are Inserted to the su∣perior part of the second Bone of each Finger (30.)

This and the following Muscle are Accurately exprest by Bidloo, Tab. 67.

Perforans.

Because its Tendons run through those of the Former, it's also called Profundus from its Situation, and Tertii Internodii Digitorum Flexor from its Use. It Ariseth Fleshy from near two Thirds of the Superior and Fore-part of the Ulna (26), as also from the* 1.2 Ligament between the last named Bone and Radius, becoming a Large Thick Bellied Muscle, grows out∣wardly Tendinous before it passes over the Pronator Radii Quadratus, and is divided into Four Round Tendons which march under those of the for∣mer Muscle beneath the Ligamentum Transversale abovementioned, (from each of these Tendons the Musculi Lumbricales are said to Arise) after which they pass through the Fissur's of those of the Former, and proceeding over their extremities, Terminate in the superior and fore-part of the third Bone of each Finger. (30.)* 1.3

The Tendons of the last described Muscle running through those of the Precedent, is a no less Useful then Stu∣pendous Artifice in Nature.

To the end the Fingers (like so many Leavers) should be Bended with great Force, it is absolutely necessary the strongest Muscle should be Insert∣ed nearest their Extremities, and far∣thest from their Fulcimina the Ossa Me∣tacarpi: But in regard every Inter∣node should be attended with a parti∣cular Muscle, the better to accommo∣date them to various Imployments, and the Origination of the superior or Perforatus is confined to the Apex of the Internal Extuberance of the Os Humeri and upper part of the Radius only, wherefore could not be a fit In∣strument for so Strenuous an Action, and that not only in regard to its Magnitude, but by the Approach of its two Extreams when the Cubit or Carpus are Bended; both which would be no small impediments in divers Actions; it's therefore necessary it should be imployed in the Motions of the second Internodes: But since these superior Tendons would be hereby liable to interrupt the Inferior in their Right progress to the Extremities of the Fingers, it seems an Argument of great Counsel in transmitting the Lat∣ter through the Fissures of each of the

Former, whereby the Actions of Both are not only distinctly performed, and the extremities of the Fingers attend∣ed with the Largest Muscle, (whose Origin is below the Os Humeri, where∣fore its Extreams cannot approach in the Flexion of the Cubit) but their Motions are preserved, though the Superior Muscle is totally divided, which indeed is a Provident Contri∣vance of the Author of Nature, and is in it self sufficient to excite our Ad∣miration.

Lumbricales.

* 1.4

So called from their Figure, being not much unlike the Common Earth∣worms; they are also called Flexores Primi Internodii Digitorum from their Use. Anatomists generally derive the Originations of these Muscles from the Tendons of the last treated of; but in a Subject which we lately Dis∣sected I observed part of that Lum∣brical Muscle belonging to the Fore-Finger had a distinct Fleshy Original, and a long slender Tendon lying be∣tween the Two Preceeding; which suggested to me that the other Three

and those of other Subjects have their Beginnings in common with the Per∣forans, and Uniting with its Tendons are afterwards Disunited again, and growing Fleshy pass to their Tendi∣nous Implantations with the Interossei at the first Internode of each Finger externally laterally next the Thumb.

These we suppose perform those Minute Motions of the Fingers when the Second and Third Internodes are Curvated by the two last treated of Muscles; and therefore Used in play∣ing on Musical Instruments, and may be thence Named Musculi Fidicinales.

Extensor Digitorum Communis, seu Digi∣torum* 1.5 Tensor.

This has an Acute Tendinous Ori∣gination from the outward Extube∣rance of the Os Humeri (20) between* 1.6 the Extensores Carpi becoming Fleshy, in less than half its progress its di∣vided into three Portions which be∣come so many Tendons (of which the Middlemost is the Longest) passing under their Annular Ligaments be∣tween the Lower parts of the Ulna (23) and Radius (22) march sepa∣rately

over the Dorsum Manus, and remitting. Tendinous Filliaments to each other as they pass the First In∣ternodes of each Finger, and are af∣terwards Inserted to the superior parts of the First, Second, and Third Bones of the Fore, Middle, and Third Fin∣gers. (28.)* 1.7

There being no Force required in the Extension of the Fingers, we need not wonder that the Muscles im∣ployed in that Office are no Larger in Proportion to their Antagonists.

The Proper Muscles of the Fingers now offer themselves to the Knife, which we shall Treat of in the Order they are above Named.

Interossei Manus.

These are Distinguished into Exter∣nal and Internal, They are aptly named from their Situation: Authors disagree in their Number, some reck∣oning Six, others Eight, amongst which they esteem the Abductor Minimi Digiti and Indicis, but we rather incline to the First Opinion, conceiving the Two latter named Muscles do not deserve these Denominations. They Arise Fleshy

Internally in the Palm from the supe∣rior parts of the Metacarpal Bones (28) next the Carpus (27), whence* 1.8 descending between the last named Bones they become Tendinous at the first Internode of each Finger lateral∣ly, and pass to their Insertions with the last Treated of Muscle. Each Interstice of the Metacarpal Bones en∣tertaining Two Muscles Inserted to the sides of the Fingers.

When all these Interossei Act toge∣ther they Draw the Fingers nearer each other, and Assist in their Exten∣sion, as Galen takes notice, at which* 1.9 time they together with the Abductor Indicis and Minimi Digiti are capable of Divaricating the Fingers, which Action cannot without some Difficulty be performed by them when they are Bended; which Contrivance of the Most Wise Architect is also observed by Galen.* 1.10

Extensor Indicis seu Indicator.

* 1.11

It Arises Fleshy from the middle of the External part of the Ulna (23)* 1.12 next the Radius (22), immediately below the Extensores Pollicis, and

descending obliquely becomes Tendi∣nous as it passes under its Annular Ligament at the Lower part of the Radius and Carpus (25), passing over* 1.13 the Os Metacarpi Indicis, and joining with the Tendon of the Extensor Com∣munis, is Inserted with it to the supe∣rior part of the 3d Bone of the Fore-Finger. The Tendon of it is some∣times divided. Its Name Declares its Use.

Abductor Indicis.

* 1.14

This is not to be seen till the Ab∣ductor Pollitis is Raised; by some it is reckoned amongst the Interossei as a∣bove noted. It Arises Fleshy from the Os Metacarpi that sustains the Fore-Finger* 1.15 (28), and descending over the First Internode of the said Finger be∣comes Tendinous, joining with the Tendon of one of the Lumbrical Muscles, and is Inserted with it toge∣ther with the Tendon of the former Muscle. Its Name intimates its Use, in Drawing the Fore-Finger from the rest.

Extensor Minimi Digiti.

* 1.16

This Arises partly Tendinous at the Extremity of the External Apo∣physis of the Os Humeri (20), and* 1.17 partly Fleshy from the superior part of the Ulna (23), between the Ex∣tensor Communis Digitorum and Muscu∣lus Ulnaris Extensor, and becoming Tendinous as it passes under the Li∣gamentum Annulare at the Carpus (25); it is there divided into Two, some∣times three Tendons, which are U∣nited into one at its Insertion to the superior part of the 3d Bone of the Little-finger: Its Name Declares its Action.

Abductor Minimi Digiti.

This Appears in some Bodies divided into Two or Three Muscles, having each a differing Series of Fibres; The First of which seems to be a Flexor primi Internodii Minimi Digiti; The Second an Abductor of the same; The Third Abductor Se∣cundi and Tertii Internodii: But this Division is not Constant, wherefore

we shall Describe it as One Muscle, lest we might appear inclinable to multiply their Number, which has been a Vice amongst some. It Arises Fleshy First from the Ligamentum Transversale, and Fourth Bone of the Carpus; Secondly from the Third Bone of the Carpus; Thirdly and lastly from the superior part of the subjacent Os Metacarpi: The two First continue Fleshy to their Insertions; the Former Terminating at the supe∣rior part of the First Bone of the Little-finger forwards, the Latter end∣ing at the same part of the said Bone laterally; the Third and Last be∣coming Tendinous like the Interossei, is Inserted like them with the Tendon of the Extensor Minimi Digiti at the superior part of the 3d Bone of the Little-finger.

Notes

• * 1.1

  Fig. xvii.
• * 1.2

  Fig. xvii.
• * 1.3

  Fig. xvii.
• * 1.4

  ••id. T. 67. ••MMM.
• * 1.5

  Bid. T. 69. G.
• * 1.6

  Fig. xviii▪
• * 1.7

  Fig. xviii.
• * 1.8

  Fig. xvii.
• * 1.9

  Lib. i. De Us. par. C. 18.
• * 1.10

  Loco supra citato.
• * 1.11

  Bid. T. 70. not let∣ter'd.
• * 1.12

  Fig. xviii.
• * 1.13

  Fig. xviii.
• * 1.14

  Bid. T. 68. H.
• * 1.15

  Fig. xvii.
• * 1.16

  Bid. T. 70. & 71. K, K.
• * 1.17

  Fig. xviii.