Flexor muscle

“ Four of the muscles, whose uses are to bend the leg, and which compose the internal and external hamstrings; to wit, gracilis, semitendinosus, semimembranosus, and biceps tibiæ, together with that adductor and flexor muscle of the leg called sartorius, were removed at a considerable distance from the thigh-bone on its inferior part, and from the tibia and fibula on their superior parts; by which means a large bed or cavity was formed for containing the extravasation, which consisted partly of a fluid, and partly of a coagulated blood ”

“ This cartilage is perforated by the tendons of several flexor muscles; the distal end of the cartilage attaches to the posteroproximal corner of the tarsometatarsus.
Innervation.—A branch of the medial division of the tibial nerve penetrates the lateral surface.
Individual Variation.—In one leg, a small bundle of fibers separates from the proximal end of the muscle, forming a short accessory head which attaches, separately from the remainder, to the articular capsule posteroproximal to the main origin; a blood vessel passes between the main and accessory heads. ”

“ Extensor indicis (p. 176, and Fig. 85, c) .
34. Pronator teres (p. 179, and Fig. 77, q) .
35. Flexor carpi radialis (p. 179, and Fig. 77, r) . The tendon of the flexor carpi radialis should not be traced to its insertion until the deep muscles of the palm of the hand have been dissected.
36. Abductor brevis pollicis (p. 184, and Fig. 77, w) .
37. Flexor carpi ulnaris (p. 180, and Fig. 77, t) .
38. Palmaris longus (p. 179, and Fig. 77, s) . In dissecting this muscle be careful not to injure the part of the flexor sublimis (Fig. 77, x) that rises from its surface (see flexor sublimis, p. 181) . ”

“ Fig. 53 represents the muscles of the arm after the skin and flesh are removed. They are all in smooth silky cases, laid over each other, and separated both by the smooth membranes that encase them and by layers of fat, so as to move easily without interfering with each other. They are fastened to the bones by strong tendons and cartilages; and around the wrist, in the drawing, is shown a band of cartilage to confine them in place. The muscle marked 8 is the extensor that straightens the fingers after they have been closed by a flexor the other side of the arm. ”

“ That the second condition may be realized, there must be such a development of the extensor muscles on the back of the body as will be sufficient to antagonize the flexor muscles on the front of the body. ”

“ The biceps is a flexor of the forearm on the arm. It also contributes to the movement of extension of the humerus.
Brachialis Anticus (Fig. 68, 22; Fig. 69, 19; Fig. 70, 27; Fig. 72, 12) .—In veterinary anatomy further designated as the short flexor of the forearm, this muscle, which is thick, occupies the musculo-spiral groove, and arises from it, reaching upwards to just below the head of the humerus. But it does not, as in man, extend to the internal surface of the bone. ”

“ The transverse diameter of this joint is long, thus giving it contacting surfaces that are sufficiently extensive to minimize the strain upon the mesial and lateral ligaments (internal and external lateral common ligaments) . Motion is that of flexion and extension; slight rotation is possible when the position is that of flexion. While supporting weight the carpus is fixed in position by a slight dorsal flexion, but undue dorsal flexion is prevented by the flexor muscles and tendons and volar-carpal or annular ligament, together with the superior check ligament. ”

“ A three-headed muscle whose heads arise separately and [123] first unite in the region of the lower leg as a short, strong tendon. Their origins are as follows: (1) As a band from the anterior margin of the ischium, pushing between the ischio-femoralis and the pubi-ischio-femoralis externus muscles; (2) From the posterior margin of the ischium as a narrow, tendinous band near the insertion of the ischio-caudalis muscle; (3) from the portio-dorsalis posterior of the ilium, ventralward, near the origin of the flexor tibialis externus muscle. ”

“ The amount of variation reported by a worker depends in large part on the degree of variation that he considers significant.
[Pg 447]
Individual variation in the muscles and in the nerves will be discussed separately; that of the muscles (excluding innervation) will be considered first.
Muscles
Considering the number, rather than degree, of variations, the most variable muscles are: Mm. flexor digitorum longus, obturator, caudofemoralis, and extensor hallucis longus. The first-mentioned muscle exhibits 14 different variations in the specimens studied. ”

“ So with regard to the muscles. The short flexor of the toes of the Gorilla differs from that of Man by the circumstance that one slip of the muscle is attached, not to the heel bone, but to the tendons of the long flexors. ”

“ This belief is founded on what I regard as an erroneous assumption, viz., that muscles have only the power of shortening, and that when one muscle, say the flexor, shortens, it must drag out and forcibly elongate the corresponding extensor, and the converse. This would be a mere waste of power. Nature never works against herself. There are good grounds for believing, as I have stated elsewhere,14 that there is no such thing as antagonism in muscular movements; the several muscles known as flexors and extensors; abductors and adductors; pronators and supinators, being simply correlated. ”

“ The wasting of these muscles is of little importance to us who have no need to use our toes in detail; but it is far otherwise with the deep flexors of the foot and toes which are attached to the leg-bones, and whose tendons pass under the ankle joint and arch of the foot and form their chief support. It is, indeed, from the wasting or inaction of the deep flexor muscles, coupled with the turning out of the toes which fashion has imposed upon us, that the ankle and arch of the foot give way under the changed position of the limbs in girls at puberty, which I have described ”

“ These pains do not follow the course and distribution of the nerve-trunks, and lack the tender pressure-points of true neuralgias. They are more common in the lower extremities, the knee being especially apt to be affected. When they affect the upper extremity the elbow and shoulder suffer more frequently than the other joints. The flexor muscles are much more frequently attacked than the extensors. The muscles of the back, especially the great masses of long muscles in the lumbar region, whose function is to sustain the equilibrium of the body, are frequently implicated. ”

“ The ambiens muscle, long and spindle-shaped, lying immediately beneath the skin, extending from the pectineal process or ilio-pubic spine to the knee, is the most median of the muscles of the thigh. When typically developed its long tendon passes the knee-joint, turning towards its outer side, and lastly, without being anywhere attached to the knee, it forms one of the heads of the flexor perforatus digit, ii. ”

“ The flexor muscles on account of the position in sitting and because of a lack of expansive activity, often become too short. They can be extended only by activity of the extensor muscles. The stretch is the special and instinctive action of the extensor muscles in response to a distinctive demand for freedom of the organs, or harmony of the whole myological mechanism. It is also, as has been said, closely connected with the circulation, and the activity of the vital organs.
There is no more important exercise than stretching. Its neglect is one of the strange things in training. ”

“ It is the opposite that is nearer the truth. Both larger and stronger, and, on the whole, more easily educated muscles exist in the flexor than in the extensor [Pg 124] system. The innumerable capacities of the half-closed hand are representative of this superiority. Still more important, however, is the fact that the flexor system is practically the dominant system in the human body. The hinges of the knee, hip, shoulder, elbow, wrist, and jaw are more often, more strongly, and more readily closed maximally than they are expanded to the full. ”

“ On enrolling, the sternites of all segments are pulled forward and the tergites backward. In straightening out, the reverse process takes place. The areas available for muscular attachment [93] are so disposed as to indicate longitudinal flexor and extensor muscles rather than short muscles extending from segment to segment. Indeed, the tenuity of the ventral membrane is such as to preclude the possibility of enrollment by the use of muscles of that sort, while powerful longitudinal flexors could have been anchored to cephalon and pygidium. ”

“ On the front and inside of the forearm are the flexors, which bend the hand, the wrist, and the fingers. If these muscles are worked vigorously, their tendons can be readily seen and felt under the skin. At the back of the shoulder a large, spread-out muscle passes upward from the back to the humerus. From its wide expanse on the back it is known as the latissimus dorsi (broadest of the back) . When in action it draws the arm downward and backward, or, if one hangs by the hands, it helps to raise the body. ”

“ The yielding of the arch lengthens the foot and puts the tendons of all the flexors on the stretch. All of them have a tendency to bend the toes, and as this action is constant, gradually the tendons of the extensors become over-stretched and these muscles are not capable of exerting their full force in overcoming the action of the flexors. The flexor longus digitorum has a tendency to cause a bending of the small toes, and as it also runs across the foot it pulls the toes somewhat inward, that is, toward the big toe. This crowding leads to hammer toes and over-riding. ”

“ The muscle is enlarged in such a manner that a lateral expansion of its mass is apparent in superficial or dorsal view (compare figures 15 and 16) . This, of course, indicates a muscle with powerful contraction, which has been unable to enlarge its circumference symmetrically because the eye is immediately dorsal to the muscle. Therefore it has expanded laterally. Ventral expansion is blocked by the presence of other muscles, and medially there is no surface for the insertion of additional fibers on the orbital process of the quadrate. ”

“ Insertion.—The attachment is by a short flat tendon to the lateral surface of the femur distal to the trochanter and anterodistal to the insertion of M. piriformis and deep to the proximal part of M. vastus lateralis pars lateralis.
Innervation.—The dorsal division of the femoral nerve penetrates the ventral surface.
Individual Variation.—The dorsal division of the femoral nerve may fuse proximally with either the anterior or middle division. In one leg, there are two separate branches to the muscle. ”

“ Each joint has its accompaniment of muscles, and each lack of alignment of bones and joints provokes discord and lack of harmony in the muscular action.
Muscles are attached to bones, and by their contraction or extension the bones are moved. Very few movements are effected by means of a single muscle. The muscles of the foot in nearly all cases are in combination, and are so complex in their action that the best surgeons find it difficult to describe them satisfactorily. ”

“ They are attached chiefly to bones but also to cartilages, ligaments, and skin, either by means of tendons, which are cords or bands of white inelastic fibrous tissue, or by means of aponeuroses, membranous expansions of the same nature. Most voluntary muscles consist of a belly and two ends or tendons. The origin is the fixed point from which it acts while the movable point upon which it acts is known as its insertion.
Action of the Muscles.—When attached to bones, muscles are distributed in three ways: 1. When it is necessary to produce much motion rapidly, a short muscle is used. ”

“ A fourth muscle exists, which veterinary anatomists include in the study of the three portions of the triceps which we have just been discussing, in giving it the name of small extensor of the forearm. But, as this muscle is no other than the anconeus, and as, in human anatomy, we describe the latter, according to custom, in connection with the forearm, it is when on the subject of the latter that we will concern ourselves with it. ”

“ Usually situated at the extremities of the fleshy fascia, they sometimes however occupy the middle, as we see in the digastric muscle; they are almost always found at the most moveable extremity, that which serves for support having aponeuroses for insertion, as we see especially on the fore-arm and the leg, of which all the muscles inserted above by broad osseous or aponeurotic surfaces, terminate below by a more or less slender tendon. ”

“ Here, alone, at the distal portion of the tendon, occur muscular fibres, but these are unstriped, belonging to the category of cutaneous muscles. We have here the interesting fact that a muscle (portion of the triceps humeri of the reptiles) has been reduced to a tendon, which in a secondary way has become connected with cutaneous muscles, which, when strongly developed, represent its belly. ”