Anatomy of the muscles that move the fingers

Of the muscles that move the fingers, some are located in the hand and others in the forearm. If they were all gathered in a brush, then the brush would undoubtedly become much heavier due to the abundance of meat.

Since the muscles of the wrist are located far from the fingers, their tendons are necessarily long. As a result, they are reinforced with membranes that go to them from all sides. The tendons of these muscles are designed to be round and strong. They do not expand until they reach the point where they approach the movable organ. Here they expand to cover the movable organ well.

All the muscles that extend the fingers are located on the forearm, as well as those muscles that move the fingers downwards. One of the extensor muscles, located in the middle of the outer forearm, grows from the protruding part of the lower end of the humerus and sends four tendons to the fingers that extend them.

As for the muscles that tilt the fingers downwards, three of them connect next to the mentioned muscle. One muscle grows from the middle part of the outer end of the humerus, between its processes, and sends two tendons - to the little finger and to the ring finger. The other is part of a set of two double muscles that make up two of the three mentioned. They grow from the lower part of the processes of the humerus, on the inside, and from the edge of the lower “flint”, and send two tendons - to the middle finger and to the index finger.

Another muscle, that is, the third of the three, grows from the top of the upper “flint” and sends a tendon to the big toe. Near this muscle there is another muscle - this is one of the two that were mentioned among the muscles that move the wrist. It grows from a place in the middle of the lower “flint”, and its tendon moves the thumb away from the index finger.

As for the flexor muscles, some of them lie on the forearm, and some on the inside of the hand. Those on the forearm are three muscles. They are located one above the other and are in the middle. The most important of them, namely the lower one, is hidden under the others and is adjacent to the bone of the lower “flint”. Since its action is most important, its location should be the most protected. It starts from the middle of the outer head of the humerus, on the inside, and passes further, and its tendon widens and divides into five tendons, each of which goes to the inside of one of the fingers. As for the tendons going to the four fingers, each of them bends the first and third joint of the finger. The first joint bends because the tendon is attached to it by a ligament wrapping around it, and the third because the end of the tendon is adjacent to it and reaches it. As for the muscle passing to the thumb, it bends its second and third joints, because it reaches only these joints.

The second muscle located on this one is smaller than it. It starts from the inner of the two tubercles of the humerus, slightly adjoins the lower “flint” and runs along the common border between the outer and inner sides, that is, along the upper surface of the upper “flint”. When it reaches the area of ​​the thumb, it deflects and sends tendons to the middle joints of the four fingers to flex them. Only a branch of this muscle approaches the thumb, coming not from its tendon, but from another place. In addition to the mentioned beginning, the first muscle grows from the end of the lower and upper “flint”, and the second muscle grows from the end of the lower “flint”. In regard to flexion, the thumb is so constructed that it is limited by one muscle, while the other four fingers are flexed by two muscles, for the most important function of the four fingers is flexion, while the most important function of the thumb is extension and distance from the index finger.

As for the third muscle, it is not used for flexion. This muscle passes with its tendon to the inside of the hand and spreads out on it, expanding to give it a sense of touch and prevent the growth of hair on it, and also to give the inside of the hand strength and strength to carry out the actions that it performs. These are the muscles located on the forearm.

As for the muscles located on the hand itself, there are eighteen of them and they are located one above the other in two rows: the bottom row is inside, the top row is outside, closer to the skin.

There are seven muscles in the bottom row. Five of them point their fingers upward. The muscle related to the thumb grows from the first bone of the wrist, and the sixth is short, wide, with fibers running obliquely. Its end is connected to the metacarpus in the place where it passes opposite the middle finger. The tendon of this muscle is adjacent to the thumb and bends it downwards.

The seventh muscle - at the little finger - starts from the metacarpal bone adjacent to the little finger and tilts the little finger downwards. None of these muscles are used for flexion. Five raise their fingers and two lower them.

As for the muscles of the upper row, under the muscle that extends to the palm, that is, the muscle that Galen alone knew, there are eleven of them. Eight of them are arranged so that each two in pairs reach the first joint of each of the four fingers, one above the other, and bend this joint. As for the lower muscle, it bends the joint, simultaneously lowering and tilting it downwards, and the upper one bends it, slightly lifting and elevating it. When these muscles come together in action, they tilt the finger in a straight direction.

Three muscles are inherent in the thumb; one serves to bend the first joint and two - for the second, as you already know. So, there are five muscles that extend the five fingers, and there are five muscles that lower them - one for each finger except the thumb and little finger, and two for the thumb and little finger. There are four flexor muscles for each finger, one deflector muscle for each finger.