A close examination of the structure of the hand, like any other department of our musculoskeletal system, rather complicated.It consists of three main structures: bones, muscles and ligaments that hold the bones.The brush has three divisions, namely the wrist, fingers and pastern.
In this article we consider in detail the brush: the structure, muscles, joints of the hand.Let's start with a description of the bones in its different departments.
Bones wrist
Since hands should perform quite precise and intricate movement, bone structure of the hand is also extremely difficult.The wrist - 8 small bones of irregular shape, arranged in two rows.In the figure below you can see the structure of the right hand.
proximal articular surface forms a series of convex to the radius.It consists of bones, if you count from the fifth to the thumb: pisiform, triangular, semilunar and navicular.The next series - distal.It is connected to the proximal joint irregular shape.The distal row consists of four bones: trapezoidal, polygonal, capitate and hamate.
Bones pastern
This department consists of 5 tubular metacarpals, also demonstrates the intricate structure of the hand.The skeleton of the long bones is complex.Each of them has a body, a base and a head.Metacarpal 1st finger shorter than the others and is massive.The second metacarpal bone - the longest.Other decrease in length as the distance from the first and closer to the edge of the elbow.Based on the above metacarpal bones articulate with the bones forming the wrist.The first and fifth metacarpals have reason to saddle-shaped articular surfaces, the other - flat.Heads metacarpals with the articular surface (hemispherical), articulates with the proximal phalanges finger.
finger bone
Each finger, except the first, which consists of only two phalanges and has an average, there are three phalanges: distal, proximal and middle (intermediate).The shortest - distal;Proximal - the longest.At the distal end has a head of the phalanx, and the proximal - its foundation.
sesamoid bones brush
The thicker tendons, other than those bones have sesamoid located between the proximal phalanx of the thumb metacarpal and bone.There are also non-permanent sesamoid bones.They are located between the proximal phalanx of the fifth and second fingers and metacarpal bones.Usually sesamoid bones located on the palmar surface.But sometimes they can be found on the back.Pisiform bone also relates to the aforesaid form.Sesamoid bone and shoulder their processes to increase muscle strength, attached to them.
We have reviewed the structure of the hand and wrist bones, now we come to the ligamentous apparatus.
wrist joint
It consists of radial bone and the proximal row of carpal bones: triangular, semilunar and navicular.The ulna is complemented by the articular disc and does not extend to the wrist joint.The main role in the formation of the elbow ulna plays.While the wrist - beam.Wrist joint shape - elliptical.It is possible abduction, adduction hand, flexion and extension.Small passive rotational movement (10-12 degrees) are also possible in this joint, but is carried out thanks to the elasticity of the articular cartilage.Through soft tissue easy to detect the slit wrist, which is detectable with the ulnar and radial sides.With the deepening of the elbow can be felt between the triangular bone and the head of the ulna.With beam hand - the gap between the navicular bone and the lateral styloid process.
wrist movements are closely linked to the work srednezapyastnogo joint located between the distal and proximal rows.Its surface is a complex, irregular shapes.When flexion and extension mobility volume reaches 85 degrees.Bringing the brush in the aforementioned joint reaches 40 degrees, abduction - 20. The wrist joint can make circumduction, iecircular motion.
This joint is strengthened by numerous ligaments.They are located between the individual bones, as well as on the lateral, medial, and the back of the palmar surface of the wrist.Collateral ligament (radius and ulna) are the most important.On the ulnar and radial sides of the bone between the elevations is the flexor - a special bunch.In fact, it does not apply to the joints of the hands, as thickening of the fascia.The flexor wrist furrow turns into the canal, which hosts the median nerve and flexor tendons of the fingers.We continue to describe the anatomy of the wrist.
carpometacarpal joints
They form a flat, inactive.An exception is the joint of the thumb.Range of motion carpometacarpal joints - no more than 5-10 degrees.They limited mobility, ie. A. Ligaments well developed.Located on the palmar surface, they form a stable palmar ligaments interconnecting the wrist and metacarpal bones.There in the brush arcuate ligament and lateral and radial.Capitate bone is central to the ligaments, it secured a large number of ligaments.Palmar developed much better than rear.The rear ligaments connect the bones of the wrist.They form a thickening capsules which are coated with the joints between these bones.Intercostals are located in the second row of carpal bones.
The thumb carpometacarpal joint is formed by the base of the first metacarpal bone and polygonal.The articular surfaces have a saddle shape.This joint can perform the following actions: abduction, adduction, reposition (retrograde motion), opposition (opposition) and circumduction (roundabout).Volume grasping movements, due to the fact that the thumb is opposed to all the others, is greatly increased.45-60 degrees of mobility carpometacarpal joint of the thumb when bringing and abduction, and the reverse movement and the opposition - 35-40.
structure of the hand: metacarpophalangeal joint
Said joints are formed brush heads metacarpals with the participation of the bases of the proximal phalanges.They are spherical, have a three mutually perpendicular to the rotation axis around which the extension and flexion, abduction and adduction, and circular movements (circumduction).These and possible diversion by 45-50 degrees, and flexion and extension - at 90-100.These joints are collateral ligaments, located on the sides, which strengthen them.Palm, or extensions, are located on the palm side of the capsule.Their fibers interwoven with fibers deep transverse ligament that prevents the divergence in different directions heads metacarpals.
interphalangeal joints of the hand
They trochlear shape and their axis of rotation extend transversely.Extension and possible bending around these axes.The proximal interphalangeal joints are the amount of flexion and extension, equal to 110-120 degrees, distal - 80-90.Interphalangeal joints very well strengthened by collateral ligament.
synovial and fibrous tendon sheath
retainer finger extensors, as well as the flexor, plays an important role in strengthening the position of the muscle tendons that pass under them.This is especially true when using a brush: in its extension and flexion.Nature conceived very competent structure of the hand.Tendons are finding support in conjunction with the aforementioned inner surface thereof.Department of tendon from the bone to prevent tie.This allows for intensive work and a strong contraction of the muscles to withstand a lot of pressure.
reduce friction and sliding tendons coming from the forearm to the wrist, promote special tendon sheath, which are bone-fibrous or fibrous feeds.They are synovial sheath.The largest number (6-7) is located under the extensor retinaculum.Radius and ulna are sulcus, which correspond to the location of the tendons of the muscles.Also, so-called fibrous bridges that separate the channels from each other and extend to the bones of the extensor retinaculum.
Palmar synovial sheath of the flexor tendons are the fingers and hands.Total synovial sheath extends to the center of the palm and reaches the distal phalanx of the fifth finger.Here are the tendons of superficial and deep flexor digitorum.The thumb has long flexor tendon is located in the synovial vagina apart and passing on the finger with a tendon.The synovial sheath in the palm deprived tendons that go to the fourth, second and third fingers.Only the tendon of the fifth finger has a synovial sheath, which is an extension of the total.
muscles brush
the figure below you can see the muscles of the hand.The structure of the wrist is shown in more detail.
muscles in the hand only on the palm side.They are divided into three groups: medium, large and small fingers.
Since finger movements require great accuracy in the brush is a significant number of short muscles complicating the structure of the hand.The muscles of the hand of each of the groups discussed below.
average muscle group
Her form worm-like muscles, starting from the deep flexor tendons of the fingers and attached to the proximal phalanx, or rather their bases, the second to fifth toe, if we consider the structure of the hand.The muscles of the arms also come from the back and palmar interosseous, located in between the metacarpal bones, attached to the base of the proximal phalanx.The function of this group is that the muscles involved in bending the said proximal phalanges of the fingers.Thanks palmar interosseous muscles may bring finger to the middle finger brush.With the rearmost intercostals is their breeding side.
Muscles thumb
This group forms the elevation of the thumb.The muscles surrounding the start around the pastern bone and wrist.As for the thumb of his short flexor mounted near the sesamoid bone, which is located near the base of the proximal phalanx.Opposes the thumb muscle goes to the first metacarpal bone, and leads the thumb is on the inner sesamoid bone.
small finger muscles
This group of muscles forms the inside of the palm of the elevation.These include: the little finger abductor muscle opposes the little finger, short palmar and short flexor.
they originate from the nearby bone in the wrist.These muscles are attached to the bottom of the fifth finger, or rather its proximal phalanx, and the fifth metacarpal bone.Their function is reflected in the title.
In this article we have tried to present the most accurate structure of the hand.Anatomy - is a fundamental science that requires, of course, a more thorough study.Therefore, some questions remained unlit.The structure of the hand and wrist - a topic that interests not only of physicians.Knowing it is also necessary to athletes, fitness instructors, students and other categories of people.The structure of the hand, as you have noticed, is rather complicated, and it can be studied for a long time, relying on a variety of sources.
