The _Obturator Externus_ ariseth from the outward Circ.u.mference of the same Hole of one _Ischion_, and is terminated in the side of the other near the great _Trochanter_.
_What are the Motions of the Leg, and what are its Muscles?_
The Leg is mov"d four several ways, that is to say, it is bent, extended, and drawn inward and outward, by the means of eleven Muscles _viz._ three _Flexors_, four _Extensors_, two _Adductors_ and two _Abductors_.
The three _Flexors_ of the Leg are the _Biceps_, the _Semi-nervosus_, and the _Semi-membranosus_.
The _Biceps_ hath two Heads, the longer whereof cometh out of the bottom of the Prominence {51} of the _Ischion_, and the other from the middle and exterior part of the _Femur_, and is terminated in the outward and upper part of the _Epiphysis_ of the _Perone_ or _Fibula_.
The _Semi-nervosus_ hath its Origine in the k.n.o.b of the _Ischion_, and is join"d backward to the top of the _Epiphysis_ of the _Tibia_. These three Muscles are plac"d in the back-part of the Thigh below the b.u.t.tocks.
The four _Extensors_ of the Leg are the _Rectus_, the _Vastus Internus_, the _Vastus Externus_, and the _Crureus_.
The _Rectus_ or streight Muscle of the Leg takes its rise from the fore-part and the bottom of the _Ilion_, and descends in a right Line: It covers with its _Tendon_, which is common to the three following, the whole Knee-Pan, and adheres to the top of the _Tibia_, on the fore-part.
The _Vastus Internus_, being situated on the inside of the Thigh, hath its beginning in the top of the Thigh inwardly, and a little below the lesser _Trochanter_ or _Rotator_: Afterward it is ty"d to the _Tibia_ by a large _Tendon_, common thereto with the preceeding.
The _Vastus Externus_ is plac"d on the outside of the Thigh, springing from the top and the fore-part of the _Femur_, being united by the same _Tendon_ with the two preceeding.
The _Crureus_ proceeds from the top, and the fore-part of the Thigh-Bone, between the two _Trochanters_; then covering the whole Bone, it is also fasten"d to the Leg-Bone with the three preceeding Muscles, after having cover"d the Knee-Pan with their common {52} _Tendon_, which serves likewise as a Ligament to the Knee.
The two _Adductors_ of the Leg are the _Sartorius_ and the _Gracilis_.
The _Sartorius_ or the _Longissimus_ draws the leg inward, deriving its Original from the upper _Spine_ of the _Ischion_; from whence it descends obliquely thro" the inside of the Thigh, and cleaves to the top on the inside of the _Tibia_.
The _Gracilis_ hath its Origine in the fore-part at the bottom of the _Os Pubis_, and its Insertion in the top of the _Tibia_ on the inside.
The two _Abductors_ of the Leg are the _Fascia lata_, and the _Poplitaeus_.
The _Fascia lata_, or the _Membranosus_, is as it were a kind of large Band, which covers all the Muscles of the Thigh. It proceeds from the outward Lip of the _Os Ilion_, is ty"d by a large Membrane to the top of the _Perone_ or _Fibula_ and sometimes descends to the end of the Foot.
The _Poplitaeus_, or _Sub-poplitaeus_, arises from the lower and external _Condylus_ of the Thigh-Bone, pa.s.seth obliquely from the outside to the inside, till it is lost in the upper and inner part of the Leg-Bone under the Ham.
_What are the Motions of the Foot, and what are its Muscles?_
The Foot performs two Motions by the help of nine Muscles, as being bent by two, and extended by seven.
The two _Flexors_ are the _Crureus Anticus_, and the _Peronaeus Anticus_.
The _Crureus_ or _Tibiaeus Anticus_, is plac"d along the _Tibia_, and takes its rise from its upper and fore-part: Afterward it is bound by two {53} _Tendons_ to the first _Os Cuneiforme_, or Wedge-like Bone, and to that of the _Metatarsus_ or Instep, which stayeth the great Toe, after having pa.s.s"d under the annular Ligament.
The _Peronaeus Anticus_ springs from the middle and outward-part of the _Perone_ or _Fibula_, and insinuating it self thro" the Cleft which is under the external _Malleolus_ before, sticks to the Bone of the _Metatarsus_ that supports the little Toe.
The seven _Extensors_ of the Foot are the two _Gemelli_, or the _Soleus_, the _Plantaris_, the _Crureus Posticus_, and the two _Peronaei Postici_.
The _Gemelli_ are the _Interior_ and the _Exterior_; the former having its Source in the inner _Condylus_, and the other in the outward and lower of the Thigh-Bone; from whence they extend themselves till they are fasten"d to the _Talus_ or Ankle-Bone by a _Tendon_ common to them, with the two following.
The _Soleus_ ariseth from the top on the back-part of the Leg-Bone and _Perone_, and confounding its _Tendon_ with that of the _Gemelli_, sticks close to the _Talus_.
The _Plantaris_, which lies hid between the _Gemelli_ and the _Soleus_, hath its Origine from the _Exterior Condylus_ of the Thigh-Bone; then uniting its _Tendon_ with the preceeding, it adheres to them; and this common _Tendon_ is call"d _Chorda Achillis_.
The _Crureus_ or _Tibiaeus Posticus_, springs from the back-part of the Leg-Bone, from whence extending it self downward, it pa.s.seth thro" the Fissure in the _Internal Malleolus_, and cleaves to the inner-part of the _Os Scaphoides_. {54}
The _Peronaei_, or _Fibulaei Postici_, are otherwise call"d the _Longus_ and the _Brevis_, whereof one proceeds from the upper and almost fore-part of the _Perone_, terminating in the upper-part of the Bone, that supports the great Toe in the _Metatarsus_, and the other from the lower part of the _Perone_, adhering in like manner to the Bone with which the little Toe is sustain"d.
_With what Motions are the Toes endu"d, how many Muscles have they, and which be they?_
The Toes are bent and extended, as also drawn inward and outward, by the means of twenty two Muscles, of which sixteen are Common, and six Proper.
The former are two _Flexors_, two _Extensors_, four _Lumbricales_, and eight _Interossei_. The first _Flexor_ is nam"d _Sublimis_, and the other _Profundus_.
The _Sublimis_ or _Perforatus_ derives its Original from the lower and inner-part of the _Talus_ and is fixt in its proper place by four cleft _Tendons_, which are inserted in the upper-part of the Bones of the first _Phalanx_ of the four Toes. It is situated under the Sole of the Feet.
The _Profundus_ or _Perforans_ hath its beginning in the top and back-part of the Leg-Bone and _Perone_, slips under the _Malleolus Internus_ thro"
the _Sinus Calcaris_, and makes four _Tendons_ which pa.s.s thro" the Fissures of the _Tendon_ of the _Sublimis_, and cleaves to the Bones of the last _Phalanx_ of the Toes, to bow them.
The first _Extensor_ is call"d the _Common_, and the other the _Pediaeus._
The _Common Extensor_, or the _Longus_, takes its rise from the top and fore-part of the _Tibia_ in the place of its joyning with the _Perone_ or {55} _Fibula_, and divides it self into four _Tendons_, which after having pa.s.s"d under the Annular Ligament, are inserted in the Articulations of every Toe.
The _Pediaeus_ or the _Brevis_, being plac"d over the Foot, proceeds from the Annular Ligament, and the lower-part of the _Perone_, and sends forth four _Tendons_, which are fixt to the first Articulation of the four Toes on the outside, Thus this Muscle, together with the _Longus_, causeth their Extension.
The four _Lumbrical_ Muscles of the Toes arise from the _Tendons_ of the _Profundus_, and a Ma.s.s of Flesh at the Sole of the Feet. They are joyn"d by their _Tendons_ with those of the _Interossei Interni_, and adhere inwardly to the side of the first Bones of the four Toes, to incline them toward the great Toe.
The _Abductors_, or those Muscles that remove the Toes from the great Toe, are the eight _Interossei_, whereof four are call"d _Externi_, and as many _Interni_. The former take their rise in the s.p.a.ces between the Bones of the _Metatarsus_, and are terminated outwardly in the side of the first Bones of the Toes. The Internal lie in the bottom of the Foot, and take up the s.p.a.ces between the five Bones of the _Metatarsus_. They arise from the Bones of the _Tarsus_, and the Intervals between those of the _Metatarsus_, and are implanted with the four _Lumbricales_ inwardly, in the upper-part of the Bones of the first _Phalanx_ of the four Toes.
Of the six Proper Muscles of the Toes, there are four appointed for the great Toe, which cause it to perform the Motions of Flexion, {56} Extension, and drawing forward or backward. The two others are the _Adductor_ of the second Toe to the great Toe, and the _Abductor_ of the little Toe, call"d _Hypothenar_.
The Proper _Flexor_ of the great Toe, arises from the top of the _Perone_ or _Fibula_, on the back part, pa.s.seth thro" the Ancle-Bone on the inside to the sole of the Foot, and is fasten"d to the Bone of the last _Phalanx_.
The Proper _Extensor_ of the great Toe springs from the middle of the fore-part of the _Perone_, pa.s.seth over the Foot, and hath its Insertion in the upper-part of the Bone of the great Toe.
The Proper _Adductor_ of the great Toe, or the _Thenar_, taking its rise inwardly on the side of the _Talus_, the _Ossa Schaphoidea_ and _Innominata_, extends it self over the outward-part of the Bone of the _Metatarsus_, which stayeth the great Toe, and adheres to the top of the second Bone of the great Toe, which it draws inward.
The proper _Abductor_ of the great Toe, or the _Ant.i.thenar_, draws it toward the other Toes. It derives its Origine from the Bone of the _Metatarsus_, which supports the little Toe, slides obliquely over the other Bones, and cleaves to the first Bone of the great Toe on the inside.
The _Adductor_ appropriated to the second Toe hath its Source in the first Bone of the great Toe, on the inside, and sticks close to the Bones of the second Toe, which it draws to the great Toe. {57}
The _Abductor_ of the little Toe, or the _Hypothenar_, proceeds from the outward part of the Bone of the _Metatarsus_, that stayeth the little Toe, and is inserted in the top of the little Toe, on the outside, to remove it from the others.
_A List of all the Muscles in the Humane Body._
The Fore-head hath two Muscles 2 The hinder-part of the Head 2 The Eye-Lids 4 The Eyes 12 The Nose 7 The Ears on the outside 8 The Ears on the inside 6 The Lips 13 The Tongue 8 The _Uvula_, or Palate of the Mouth 4 The _Larynx_ 13 The _Pharynx_ 7 The _Os Hyoides_ 10 The Lower Jaw 12 The Head 14 The Neck 8 The _Omoplatae_ or Shoulder-Blades 8 The Arms 18 The Elbows 12 The _Radii_ 8 The Wrists 12 The Fingers 48 The Breast, or the Parts of Respiration 57 The Loins 6 The _Abdomen_ or lower Belly 10 The t.e.s.t.i.c.l.es 2 The Bladder 1 {58} The _p.e.n.i.s_ 4 The _c.l.i.toris_ 4 The _a.n.u.s_ 3 The Thighs 30 The Legs 22 The Feet 18 The Toes 44 Total 425
CHAP. XII.