In the course of evolution, the skeleton of the human limbs has undergone significant changes. So, the legs, performing the tasks of movement and support, ensure the preservation of the body in a vertical position, and the hands have become tools of labor. Next, let's take a closer look at the skeleton of the upper limb: the structure and tasks that it performs.
General information
The skeleton of the human upper limbs has acquired significant mobility in the course of phylogenesis. Due to the presence of the collarbone, which provides a connection to the torso, people can perform fairly extensive movements. In addition, the elements included in the skeleton of the free upper limb have a movable articulation with each other. This is especially true for the area of the hand and forearm. The functions of the skeleton of the upper limbs are quite extensive. Hands are adapted to complex types of labor activity. Due to the presence of a large number of bones and joints, fingers can perform different work: from writing to assembling any mechanisms. The leg, acting as an organ of movement and support of the body in space, includes more massive and thicker bones. Their mobility relative to each other is less significant. The skeleton of the upper and lower extremities is drawn up according to the general plan. It includes two parts.
Departments of the skeleton of the upper limb: bones of the belt
This part includes:
Second part
In it, the skeleton of the upper limb consists of a hand, forearm and shoulder element. The last segment is represented by one bone - the humerus. The hand includes the finger phalanges, metacarpus and wrist. There are two elements in the forearm. It is represented by the ulna and radius bones.
Brachial bone
It is presented in the form of a tubular long element. In the bone, a diaphysis (body) and 2 epiphyses (ends) are distinguished: upper and lower. The first is a rounded articular head. It serves to connect with the blade. The upper end is separated from the body with an anatomical neck. Below it on the outer side are tubercles (elevations) - small and large. They are separated by a furrow. The narrowed part in the body, located closer to the head, is called the "surgical neck". Tuberosity is also present on the surface of the bone. It acts as a site for attachment of the deltoid muscle. The lower epiphysis has an extension and passes into the condyle. It serves to connect at the joint with the radius and ulna.
Forearm
In this part, the skeleton of the upper limb includes two elements:
Brush
The skeleton of the upper limb in this zone is represented by the bones of the wrist, metacarpus and fingers. The first zone consists of two rows of spongy short bones (four in each). In articulate. The upper side of the first row has connections with the articular surface. The lower part of the second is attached to the base of the metacarpal elements. The metacarpus is represented by five tubular short bones. Start counting from the thumb. Each has a head, base and body. The first element articulates with the upper phalanx in the corresponding tubular short bone elements. They have a head, base and body. In the first two elements, articular surfaces are distinguished. In the upper phalanges, this segment has an articulation with the head in the corresponding metacarpal bone, in the lower and middle ones, with the phalanx located above (proximally). There are two tubular bones in the thumb, and three in the others.
Age features of development: bones of the belt
All elements included in the skeleton of the upper limb, except for the clavicle, go through the connective tissue stage, cartilage, and bone.
middle part
- Elbow bone. At 7-14 years old, the ossification point is laid in the proximal epiphysis. From it begins the olecranon, in which there is a block-shaped notch. By the age of 3-14, ossification sites are formed in the distal epiphysis. Growing, the bone tissue forms the styloid process and the head. Fusion with the body of the proximal epiphysis occurs in the 13-20th year, the distal - in the 15-25th.
- Radius. By 2.5-10 years, an ossification site is laid in the proximal epiphysis. Fusion with the diaphysis occurs by the age of 13-25.
Development of brush elements
The skeleton of the upper extremities has a complex structure in which each element plays its role.
The skeleton of the upper limb is divided into two sections:
- 1) shoulder girdle ( cingulum membri superioris);
- 2) skeleton of a free limb ( skeleton membri superioris liberi).
The shoulder girdle includes the clavicle ( clavicula) and scapula (scapula). These bones are called a belt because they, covering the chest, attach the upper limb to the body. The free upper limb is divided into three sections:
- 1) shoulder ( brachium);
- 2) forearm ( antebracium);
- 3) brush (manus).
Development. Limbs appear in the third week of development in the form of tubercles on the sides of the body. Mesenchyme grows in the tubercle, which successively forms a membranous, cartilaginous and bone skeleton.
shoulder blade (scapula)- paired bone of triangular shape. The anterior, or costal, surface adjacent to the chest between the 2nd and 8th ribs is deepened in the middle in the form of a subscapular fossa (fossa subscapularis). The back surface is convex and divided by a ridge (spina scapulae) into two pits - supraspinous (fossa supraspinata) and worthy (fossa infraspinata). The crest of the scapula in the lateral direction ends with the shoulder process (acromion) at the anterior end of which is the articular surface for articulation with the clavicle. In the scapula, the upper, lateral and lower corners and the upper, medial and lateral edges are distinguished. The lateral angle of the scapula is thickened and forms a glenoid cavity (cavitas glenoidalis), which articulates with the humerus. In the region of the upper edge there is a well-defined notch of the scapula (incisura scapulae), next to which there is a strongly protruding curved coracoid process (processus coracoideus).
Development. The scapula develops from cartilage, the main nucleus of ossification emerges from its body near the neck in the 2nd month of uterine life. Additional nuclei for processes appear later (even after 10 years).
Anomalies. The scapular notch can be turned into a hole by a bone bridge. Sometimes the acromion, less often the coracoid processes are independent bones.
Ktchitsa (clavicula)- bent in the form of a letter S a bone located between the sternum and the humeral process of the scapula. It has two ends:
- 1) sternal (extremitas stemalis);
- 2) acromial (extremitas acromialis).
The sternal end is thickened and has a large articular surface for articulation with the sternum. The acromial end is flattened, it has a small articular surface for articulation with the acromial process of the scapula. The upper surface of the clavicle is smooth, and the lower one is rough, on it there is a cone-shaped tubercle ( tuberculum conoidum) and trapezoidal line (linea trapezoidea).
Development. Ossification of the clavicle begins at the 6th week of embryonic life. The sternal end develops as the primary bone, and the humerus develops as the secondary bone.
Anomalies. Anomalies relate to the degree of curvature of the clavicle.
Brachial bone (humerus) forms a shoulder and refers to long tubular bones. It distinguishes the body, or diaphysis, the upper (proximal) and lower (distal) epiphyses. On the lateral surface of the body of the humerus is the deltoid tuberosity (tuberositas deltoidea), and on the back surface - the groove of the radial nerve
(sulcus nervi radialis). The proximal epiphysis forms a thickening in the form of a head (caput humeri) on which there is an articular surface for articulation with the scapula. The articular surface is separated from the body by an oblique groove - anatomical neck (collum anatomicum). Below the head on the body of the humerus there is a narrowed place where bone fractures often occur, therefore this place is called the surgical neck (collum chirurgicum). At the proximal end are well-defined large and small tubercles. (tuberculum majus el minus), from which the crest of a large tubercle descends down (crista tuberculi majoris) and crest of the lesser tubercle (crista tuberculi minoris), between which there is an intertubercular groove (sulcus intertubercularis).
On the distal epiphysis there is a block (trochlea humeri) and head (capitulum humeri) condyle of the humerus. These articular surfaces articulate with the bones of the forearm. Above the articular surfaces are the medial and lateral epicondyles. (epicondylus medialis et lateralis). On the posterior surface of the medial epicondyle there is a groove for the ulnar nerve. On the anterior surface of the distal epiphysis are the coronary (fossa coronoidea) and radial (fossa radialis) fossa, and on its posterior surface - the fossa of the olecranon (fossa olecrani).
The skeleton of the forearm is formed by two bones - the ulna and the radius. Both are long tubular bones and therefore have two epiphyses (proximal and distal) and a diaphysis. The ulna is located on the side of the little finger (i.e., medially), and the radius is on the side of the thumb (i.e., laterally).
Development. secondary bone. The main ossification point appears in the diaphysis, secondary - in the epiphyses, tubercles. The merging of individual parts occurs from 18 years and later.
Anomalies. Over the medial epiphysis sometimes formed rgos. supracondylaris, and below it are the openings of the same name, limited by a ligament or bone bridge, connecting the process with the epicondyle.
Ulna (ulna) forms a thickening on the proximal epiphysis, on which two processes protrude: the ulna (olecranon) behind and coronal (processes coronoideus) front. Between these processes is a block-shaped notch. (incisura trochlearis), which articulates with the block of the humerus. On the radial side of the coronoid process there is a small radial notch (incisura radialis), which serves to connect with the head of the radius. Below the coronoid process in front there is a tuberosity of the ulna (tuberositas ulnae), to which the tendon of the shoulder muscle is attached. On the diaphysis of the ulna there is a sharp interosseous edge (margo interosseus), facing laterally to the radius, to which the interosseous membrane is attached (membrane interossea antebrachii), connects the ulna and radius bones. The head of the ulna lies on the distal epiphysis. (caput ulnae) on which there is an articular circumference (circumferentia articularis) for articulation with the radius and a well-defined styloid process (processus styloideus ulnae).
Development. Ossification nuclei appear in the diaphysis and both epiphyses. They merge at the age of 18-20.
Anomalies. Bone may be missing. The olecranon can be an independent bone.
Radius (radius) on the proximal epiphysis has a head (caput radii), on which two articular surfaces are located:
- 1) top - concave (fovea articularis) for connection with the head of the condyle of the humerus;
- 2) along the edge of the head - articular circumference (circumferentia articularis radii) for connection with the radial notch of the ulna.
On the diaphysis of the radius is the interosseous edge, facing medially, to which the interosseous membrane is attached. A thickening forms on the distal epiphysis of the radius, which ends with a well-defined styloid process (processus styloideus radii). On the lower surface of the distal end of the radius there is a carpal articular surface (facies articularis carpea) for articulation with the bones of the wrist and elbow notch (incisura ulnaris), which articulates with the articular surface of the head of the ulna.
Development. The radius develops as a secondary. Ossification points are laid in the diaphysis and epiphyses. The merger of the latter occurs at the age of 18-20 years.
Anomalies. Bone may be missing.
brush consists of three departments:
- 1) wrist (carpus);
- 2) metacarpus (metacarpus)
- 3) fingers (digiti).
The wrist consists of eight small spongy bones that form two rows - proximal and distal. In the proximal row, counting from the thumb, there are bones: scaphoid (o5 scaphoideum), semilunar (os lunatum) trihedral (os triquetrum) and pisiform (ospisiforme). In the distal row, if you also count from the thumb, are located: trapezium (os trapezium), trapezoidal (os trapezoideum), capitate (os capitatum) and hooked (os hamatum) bones. The metacarpus consists of five tubular bones, on each of which a base, body and head are distinguished. Each finger (except the thumb) consists of three tubular bones called phalanges. (phalanges).
There are proximal, middle and distal phalanges. The thumb has only two phalanges - proximal and distal.
Development. In a newborn, all the bones of the wrist are cartilaginous. Ossification points appear before the age of 12 years. In the bones of the metacarpus, ossification nuclei appear during fetal development: one in the diaphysis and one in the epiphyses. The phalanges also have two ossification points each in the diaphysis and epiphysis.
Anomalies. Often the presence of additional bones both in the wrist and in the metacarpus; there are additional fingers of varying degrees of development, fusion of the phalanges.
limb skeleton
In the process of human development, the skeleton of the limbs has changed significantly. The upper limbs acquired greater mobility, began to perform the function of labor organs, to perform complex and extensive movements, and the lower limbs - the function of movement and support, holding the human body in an upright position.
In the skeleton of the upper and lower extremities of a person, a belt and a free part are distinguished.
Upper limb belt consists of the clavicle and scapula. The free part of the upper limb includes the humerus, bones of the forearm (radius and ulna), bones of the hand (carpal bones, metacarpal bones and finger bones - phalanges).
Lower limb belt it is formed with a paired pelvic bone, which articulates with the sacrum and femur of the free part of the lower limb. Skeleton of the free part of the lower limb consists of the femur, the bones of the lower leg (tibia and fibula), the patella and the bones of the foot (tarsus, metatarsal bones and bones of the fingers - phalanges).
Belt of the upper limb. shoulder blade(scapula) - a flat triangular bone, located behind the chest at the level of II-VIII ribs (Fig. 36, 37).
In the scapula, the costal and dorsal surfaces, the upper, lower and lateral angles, as well as the upper, lateral (lateral) and medial (inner) edges are distinguished. The dorsal (posterior) surface of the scapula is divided by the spine of the scapula into the supraspinatus and infraspinatus fossae; The spine of the scapula passes into the shoulder process - the acromion. The scapula also has an articular surface for connecting it with the humerus and a coracoid process directed forward.
Collarbone(clavicula) - an S-shaped curved bone that has a body, acromial and sternal ends with articular surfaces (Fig. 38).
Rice. 38. Right clavicle (view from below):
1- acromial articular surface; 2 - trapezoidal line; 3 - groove of the subclavian muscle; 4 - clavicle body; 5 - sternal end; o - sternal articular surface; 7- depression of the costoclavicular ligament; 8- conical tubercle; 9- acromial end
The first articulates with the shoulder process (acromion) of the scapula, the second with the sternum.
Joints of the bones of the shoulder girdle. The sternal end of the clavicle is connected to the sternum with the help of the sternoclavicular joint (Fig. 39). Due to the presence of an intraarticular cartilaginous disc, movement in the joint occurs up and down around the sagittal axis, and forward and backward around the vertical axis. Thus, small circular movements are possible. The acromial end of the clavicle connects to the shoulder process - the acromion, forms the acromioclavicular joint. It is a flat joint, the volume of its movements is small, firmly reinforced by the capsule and ligaments - the acromioclavicular and coracoclavicular.
Rice. 39. sternoclavicular joints:
1 - costoclavicular ligament; 2 - anterior sternoclavicular ligament; 3 - interclavicular ligament;
4 - articular disc.
Skeleton of the free upper limb. Brachial bone(humerus) refers to long tubular bones, has a body and upper and lower ends (Fig. 40, 41).
The upper end, thickened, forms the head of the humerus. A shallow groove runs along the edge of the head - the anatomical neck, near it there are large and small tubercles, separated by a groove. The thinnest part between the head of the humerus and its body is called the surgical neck (the site of frequent fractures). The lower end of the humerus is expanded, forming the condyle of the humerus, on the sides of which there are two processes - the medial and lateral epicondyles. The medial part of the epicondyle forms a block of the humerus for connection with the ulna of the forearm. Lateral from the block is the head of the humerus, which has a connection with the radius. Ligaments and muscles are attached to the large and small tubercles, epicondyles and other formations of the humerus.
The bones of the forearm consist of two long tubular bones - the radius and the ulna (Fig. 42). Each bone has a disc body and two ends - the epiphysis.
Rice. 42. Right radius and ulna (front view):
A - radius: 1 - the head of the radius; 2 - neck of the radius; 3 - tuberosity of the radius; 4-interosseous edge; 5- front surface; 6- Front edge; 7- elbow notch; 8- carpal articular surface; 9 - styloid process; 10- lateral surface; 11 - the body of the radius; 12- articular circumference; B - ulna: 1 - block cut; 2 - coronoid process; 3 - tuberosity of the ulna; 4- Front edge; 5- body of the ulna; 6- styloid process; 7- articular circumference; 8 - head of the ulna; 9 - front surface; 10 - interosseous edge; 11 - supinator comb; 12 - radial notch
Radius(radius) is located on the outer side of the forearm. Its upper end forms a head with a glenoid fossa and an articular circumference, which articulates with the notch of the ulna. The lower end has a concave carpal articular surface for connection with the first row of carpal bones. On the body and epiphyses of the bones of the forearm are elevations to which muscles and ligaments are attached.
Elbow bone(ulna) is located medially, has a trihedral shape: anterior, posterior and medial surfaces. Its upper end is thickened, includes two notches - radial and block-shaped. The latter is limited by the coronal and ulnar processes and is intended for articulation with the block of the humerus. The lower end of the ulna has a head, articular circumference and styloid process.
The bones of the hand are divided into the bones of the wrist, metacarpal and finger bones (Fig. 43).
Rice. 43. Bones of the right hand (back surface):
1 - distal phalanx; 2 - middle phalanx; 3 - phalanx head; 4 - phalanges (finger bones); 5- proximal phalanx; 6 - base of the phalanx; 7-body of the phalanx; 8- metacarpal head; 9- third metacarpal; 10 - metacarpal body; 11- the base of the metacarpal bone; 12 - metacarpus (1-U metacarpal bones); 13- styloid process; 14- trapezoid bone; 15- trapezoid bone; 16- capitate bone; 17- hook-shaped bone; 18 - trihedral bone; 19 - pisiform bone; 20 - lunate bone; 21 - scaphoid
wrist bones(ossa carpi) consist of short spongy bones arranged in two rows, four in each. The upper row consists of the pisiform, trihedral, lunate, and navicular bones, and the lower row consists of the hamate, capitate, trapezoid, and trapezoid bones; The palmar surface of the wrist has a slight concavity and forms a groove through which the ligament passes. The latter transforms the groove of the wrist into a channel through which the tendons of muscles and nerves pass.
metacarpal bones(ossa metacarpi) are five short tubular bones. They distinguish between the base, body and head. On the base and head there are articular surfaces for connection with the bones of the wrist and phalanges of the fingers.
Finger bones(ossa digitorum) consist of short tubular bones - phalanges. Each finger, with the exception of the thumb, has three phalanges: proximal, middle and distal. The thumb has only two phalanges - proximal and distal.
Joints of the bones of the upper limb. The joints of the free upper limb connect the bones of this part to each other, as well as to the girdle of the upper limb.
shoulder joint(articulatio humeri) is formed by the head of the humerus, the articular cavity of the scapula, which is complemented by the articular lip (Fig. 44).
The joint capsule covers the head of the humerus on the anatomical neck, and on the shoulder blade is attached along the edge of the articular cavity. The joint is strengthened by the coracobrachial ligament and muscles. The tendon of the long head of the biceps brachii passes through the joint cavity. The shoulder joint is a spherical joint in which movement is possible around three axes: frontal, sagittal and vertical.
elbow joint(articulatio cubiti) - complex, it includes the humeroulnar, humeroradial and proximal radioulnar joints. These three joints have a common joint capsule, which is reinforced by the radial and ulnar collateral ligaments, as well as the annular ligament of the radius. The elbow joint belongs to the block-like joints: flexion, extension and rotation of the forearm are possible in it (Fig. 45).
Distal radioulnar joint(articulatio radioulnaris distalis) is an independent joint, and the proximal radioulnar joint is included in the elbow joint. However, they form a single combined cylindrical (rotational) joint. If the rotation of the radius occurs around the longitudinal axis along with the palmar surface of the hand inward, then such a movement is called pronation, and vice versa - supination.
wrist joint(articulatio radiocarpalis) - a complex elliptical joint formed by the carpal articular surface of the radius and three bones of the first row of the wrist. Two types of movement are possible in it: adduction and abduction, flexion and extension, as well as a small passive circular movement. The joint is surrounded by a common capsule, it is strengthened by powerful ulnar, radial, palmar and dorsal radiocarpal ligaments.
Hand joints include intermetacarpal, carpometacarpal, metacarpophalangeal, and interphalangeal joints. These joints are strengthened by short interosseous ligaments, which are located on the palmar and dorsal surfaces of the hand outside the joint cavities. The carpometacarpal joint of the thumb has a special structure. It is saddle-shaped in shape, it is characterized by two types of movement: flexion and extension, adduction and abduction, and possibly a circular movement, as well as opposing the thumb to the rest. The metacarpophalangeal joints are spherical, and the interphalangeal joints are block-shaped. The structural features of the bones and joints of the hand determine its extreme mobility, which allows you to perform very subtle and varied movements.
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Shoulder blade – a flat triangular bone located on the dorsal side of the chest at the level of II–VII ribs (Fig. 1.20, BUT). The blade has three angle(upper, lower and lateral, or articular), three the edges(superior, lateral and medial) and two surfaces.
Rice. 1.20. Bones of the therapeutic girdle
A - right shoulder blade behind;
B - right clavicle from below;
1 - top,
2 - lower and 3 - lateral angles;
4 - medial,
5 - lateral and 6 - upper edges;
7 - awn;
8 - supraspinous pit;
9 - infraspinatus pit;
10 - acromion;
11 - tenderloin;
12 - coracoid process;
13 - neck;
14 - subarticular tuberosity;
15 - sternal and 16 - acromial ends of the clavicle
The surface of the scapula facing the ribs is slightly concave (subscapular pit). Dorsal surface almost across the running crest - scapular spine - divided into supraspinous and infraspinatus pits. The crest itself is laterally extended into a powerful humeral process - acromion, which articular surface at its free end articulates with the clavicle. The spine and lower angle of the scapula are easy to feel on a living person.
The articular angle bears a concave articular fossa, separated from the rest of the mass of the scapula by a slightly constricted neck. Visible above and below the neck supraarticular and subarticular tuberosity.
On the upper edge of the scapula, a notch is visible, outside of which rises a curved forward and laterally coracoid offshoot.
Collarbone
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The clavicle (clauicula) is curved in the form of a strongly elongated Latin letter S and is easily palpable under the skin (Fig. 1.20, B). The bone, located horizontally, connects the handle of the sternum with the acromion. The articular surfaces are located at the ends of the bone. The functional significance of the clavicle is very high. It keeps the shoulder joint at the proper distance from the chest and thereby determines the freedom of movement of the limb. As a result, the upper limb hangs behind the line of gravity of the body. In humans, the clavicle ossifies before all other bones.
Brachial bone
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The humerus (humerus) is a typical long tubular bone, in which a body and two ends are distinguished (Fig. 1.21).
Rice. 1.21. Right humerusA - behind
B - in front;
1 - head;
2 - anatomical neck,
3 - large tubercle;
4 - small tubercle and
5 - its scallop;
6 - intertubercular furrow;
7 - scallop of a large tubercle;
8 - surgical neck;
9 - deltoid tuberosity;
10 - opening of the diaphyseal artery;
11-coronary fossa;
12 - medial epicondyle,
13 - block;
14 - capitate elevation;
15 - lateral epicondyle;
16 - cubital fossa
The proximal end ends head, separated faintly visible anatomical neck from small and large tubercles. The small one is located in front, the large one is laterally, and between them there is an intertubercular groove. From top to bottom, tubercles pass into scallops. The part of the bone narrowed under the tubercles is called surgical neck(this is where fractures occur more often). The scallop of the greater tubercle passes into deltoid tuberosity.
The distal flattened and laterally elongated end of the bone forms two articular surfaces, of which the medial, block-shaped, articulates with the ulna, and the lateral, spherical (capitate elevation), with a beam. Above the block-shaped articular surface in front is coronal fossa, and a big one in the back cubital fossa. During flexion and extension of the arm in the elbow joint, the processes of the same name of the ulna rest against these pits. On the sides of the distal end of the bone, rough lateral and medial(more prominent) epicondyles, serving as attachment sites for muscles.
Radius
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Radius (radius) at the proximal end has head with a glenoid fossa articulated with the capitate eminence of the humerus (Fig. 1.22).
Rice. 1.22. Bones of the right forearm in front1 - olecranon;
2 - block-shaped notch;
3 - coronoid process;
4 - tuberosity of the ulna;
5 - ulna;
6 - its head;
7 and 8 - styloid processes;
9 - radius;
10 - tuberosity of the radius;
11 - neck;
12 - head
Along the edge, the head is surrounded by a sheer rim of the articular surface involved in articulation with the ulna.
The part of the bone narrowed under the head is called the neck, below it the roughness is visible - the tuberosity of the radius. Attached to it is the tendon of the biceps brachii.
The trihedral body of the radius is turned with a sharp edge to the corresponding edge of the ulna. Between these ribs is stretched the interosseous membrane, which forms a large surface for muscle attachment.
The distal end of the radius is thickened and faces the ellipsoidal surface towards the wrist.
On the medial side of the bone there is an articular surface for articulation with the distal head of the ulna, and on the lateral side - styloid process.
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The ulna (ulna) at the proximal end has a large, crescent-shaped block-shaped notch, open forward and sliding when moving along the block of the humerus (Fig. 1.22). This semilunar tenderloin back and top limited olecranon(easily felt under the skin), and in front and below - coronoid process. Laterally from the base of the latter, a concave articular surface is visible - beam notch, articulating with the head of the beam, and below - crest, to which the muscle that suppurates the forearm is attached. On the anterior surface of the diaphysis, under the coronoid process, is tuberosity of the ulna. The distal end of the bone forms head. On the side facing the radius, the head has an articular surface, and on the medial side - styloid process.
Brush
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brush – is divided into three parts: the wrist, metacarpus and phalanges of the fingers (Fig. 1.23). Wrist consists of eight small bones arranged in two rows. In the proximal row, the wrists are located (from the radius to the ulna): navicular, lunate, trihedral and pisiform; in the distal row - large polygonal, small polygonal, capitate and hooked bones.
Rice. 1.23. Bones of the right hand from the back1 - scaphoid;
2 - lunar;
3 - trihedral;
4 - pisiform;
5 - polygonal;
6 - trapezoidal;
7 - capitate;
8 - hooked;
9 - base
III metacarpal;
10 - heads
II–V metacarpals;
11 - main;
12 - medium and
13 - nail phalanx;
I-V - metacarpal bones
The first three bones of the proximal row, except for the pisiform, are part of the radiocarpal joint. The pisiform bone is sesamoid and does not have a cartilaginous stage in development. All the bones of the wrist are firmly fastened together by ligaments that are attached to their back and frankincense sides. Therefore, wrist mobility is kept to a minimum. The bones of the wrist form a vault, concavity facing the palm.
metacarpus
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The metacarpus (metacarpus) consists of five tubular metacarpal bones, which, in addition to the first, lie in the same plane and decrease in length from the 2nd to the 5th. Metacarpals II–V are arranged in a row so that three interosseous spaces remain between them. In each metacarpal bone there are body, base resting on the bones of the distal row of the wrist, and heads, articulating with the main phalanx of the finger. I metacarpal bone set aside. The proximal ends of all bones of the metacarpus are widened at the bases. The base of the first metacarpal has a saddle surface. Her body is wide and flattened.
phalanges
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Phalanges (phalanges digitorum) main(proximal), medium and nail(distal) are in the skeleton of fingers II–V; there is no middle phalanx in the 1st finger (Fig. 1.23). The main phalanges are the longest, and the nail phalanges are the shortest.
The phalanges are represented by elongated bones, expanded at the ends. Their proximal end has a concave surface corresponding to the metacarpal head. The distal end of the main and middle phalanges has a block-like articular surface.
Upper limb skeleton consists of the shoulder girdle and the skeleton of the free upper limbs (arms). Part shoulder girdle includes two pairs of bones - the clavicle and the scapula. To bones of the free upper limb include the humerus, forearm bones and hand bones. The bones of the hand, in turn, are subdivided into the bones of the wrist, metacarpus and phalanges of the fingers.
Skeleton of upper limb, right. A - front view; B - rear view; 1 - clavicle (clavicula); 2 - scapula (scapula); 3 - humerus (humerus); 4 - ulna (ulna); 5 - radius (radius); 6 - bones of the wrist (ossa carpi); 7 - metacarpal bones (ossa metacarpi); 8 - bones of the fingers (ossa digitorum)
Collarbone(clavicula) - an S-shaped curved paired bone, having a body and two ends - the sternal and acromial. The sternal end is thickened and connects to the handle of the sternum. The acromial end is flattened, connected to the acromion of the scapula. The lateral part of the clavicle bulges backwards, and the medial part forwards.
Clavicle, right(front view, bottom): 1 - body of the clavicle (corpus claviculae); 2 - acromial end (extremitas acromialis); 3 - sternal end (extremitas sternalis)
shoulder blade(scapula) - a flat bone on which two surfaces (costal and dorsal), three edges (upper, medial and lateral) and three corners (lateral, upper and lower) are distinguished. The lateral angle is thickened, it has a glenoid cavity for articulation with the humerus. Above the glenoid cavity is the coracoid process. The costal surface of the scapula is slightly concave and is called the subscapular fossa; from it begins the muscle of the same name. The dorsal surface of the scapula is divided by the spine of the scapula into two pits - supraspinatus and infraspinatus, in which the muscles of the same name lie. The spine of the scapula ends with a protrusion - the acromion (shoulder process). It has an articular surface for articulation with the clavicle.
Shoulder blade, right. A - rear view; B - right side view; B - front view; 1 - upper edge (margo superior); 2 - medial edge (margo medialis); 3 - lateral edge (margo lateralis); 4 - upper corner (angulus superior); 5 - lateral angle (angulus lateralis); 6 - lower corner (angulus inferior); 7 - infraspinatus fossa (fossa infraspinata); 8 - spine of the scapula (spina scapulae); 9 - supraspinous fossa (fossa supraspinata); 10 - acromion (acromion); 11 - coracoid process (processus coracoideus); 12 - notch of the scapula (incisura scapulae); 13 - subscapular fossa (fossa subscapularis); 14 - neck of the scapula (collum scapulae); 15 - articular cavity (cavitas glenoidalis)
Brachial bone(humerus) - a long tubular bone, consists of a body (diaphysis) and two ends (epiphyses). At the proximal end there is a head, separated from the rest of the bone by an anatomical neck. Below the anatomical neck, on the outside, there are two elevations: a large and small tubercles, separated by an intertubercular groove. Distal to the tubercles is a slightly narrowed section of the bone - the surgical neck. This name is due to the fact that bone fractures occur more often in this place.
The upper part of the body of the humerus is cylindrical in shape, and the lower part is trihedral. In the middle third of the body of the humerus, the furrow of the radial nerve spirally passes behind. The distal end of the bone is thickened and is called the condyle of the humerus. On the sides, it has protrusions - the medial and lateral epicondyles, and below are the head of the condyle of the humerus for connection with the radius and the block of the humerus for articulation with the ulna. Above the block in front is the coronary fossa, and behind - a deeper fossa of the olecranon (the processes of the same name of the ulna enter into them).
Humerus, right. A - front view; B - rear view; B - right side view; 1 - head of the humerus (caput humeri); 2 - anatomical neck (collum anatomicum); 3 - large tubercle (tuberculum majus); 4 - small tubercle (tuberculum minus); 5 - intertubercular furrow (sulcus intertubercularis); 6 - surgical neck (collum chirurgicum); 7 - body of the humerus (corpus humeri); 8 - deltoid tuberosity (tuberositas deltoidea); 9 - groove of the radial nerve (sulcus n. radialis); 10 - coronal fossa (fossa coronoidea); 11 - medial epicondyle (epicondylus medialis); 12 - block of the humerus (trochlea humeri); 13 - head of the condyle of the humerus (capitulum humeri); 14 - lateral epicondyle (epicondylus lateralis); 15 - radial fossa (fossa radialis); 16 - olecranon fossa (fossa olecrani)
Forearm bones: the radial is located laterally, the ulna occupies a medial position. They are long tubular bones.
Bones of forearm, right. A - front view; B - rear view; B - right side view; 1 - body of the ulna (corpus ulnae); 2 - the body of the radius (corpus radii); 3 - olecranon (olecranon); 4 - coronoid process (processus coronoideus); 5 - block-shaped notch (incisura trochlears); 6 - radial notch (incisura radialis); 7 - tuberosity of the ulna (tuberositas ulnae); 8 - head of the ulna (caput ulnae); 9 - articular circumference (circumferentia articularis); 10 - styloid process (processus styloideus); 11 - head of the radius (caput radii); 12 - articular circumference (circumferentia articularis); 13 - neck of the radius (collum radii); 14 - tuberosity of the radius (tuberositas radii); 15 - styloid process (processus styloideus)
Radius(radius) consists of a body and two ends. At the proximal end is the head, and on it is the articular fossa, with the help of which the radius articulates with the head of the condyle of the humerus. On the head of the radius there is also an articular circle for connection with the ulna. Below the head is the neck, and below it is the tuberosity of the radius. There are three surfaces and three edges on the body. The sharp edge is turned to the edge of the ulna of the same shape and is called interosseous. At the distal extended end of the radius, there is a carpal articular surface (for articulation with the proximal row of carpal bones) and an ulnar notch (for articulation with the ulna). Outside at the distal end is the styloid process.
Elbow bone(ulna) consists of a body and two ends. The thickened proximal end has the coronal and ulnar processes; they are limited block-shaped notch. On the lateral side, at the base of the coronoid process, there is a radial notch. Below the coronoid process there is a tuberosity of the ulna.
The body of the bone is trihedral in shape, and three surfaces and three edges are distinguished on it. The distal end forms the head of the ulna. The surface of the head facing the radius is rounded; on it is located the articular circumference for connection with the notch of this bone. On the medial side, the styloid process descends from the head.
Hand bones divided into carpal bones, metacarpal bones and phalanges (fingers).
Bones of hand, right; palmar surface. 1 - trapezoid bone (os trapezoideum); 2 - trapezium bone (os trapezium); 3 - navicular bone (os scaphoideum); 4 - lunate bone (os linatum); 5 - trihedral bone (os triquetrum); 6 - pisiform bone (os pisiforme); 7 - capitate bone (os capitatum); 8 - hook-shaped bone (os hamatum); 9 - base of the metacarpal bone (basis metacarpalis); 10 - the body of the metacarpal bone (corpus metacarpalis); 11 - head of the metacarpal bone (caput metacarpalis); 12 - proximal phalanx (phalanx proximalis); 13 - middle phalanx (phalanx media); 14 - distal phalanx (phalanx distalis); 15 - sesamoid bones (ossa sesamoidea)
wrist bones- ossa carpi (carpalia) arranged in two rows. The proximal row is made up (in the direction from the radius to the ulna) of the navicular, lunate, trihedral, and pisiform bones. The first three are arcuately curved, forming an elliptical surface for connection with the radius. The distal row is formed by the following bones: trapezium, trapezius, capitate and hamate.
wrist bones they do not lie in the same plane: on the back side they form a bulge, and on the palmar side - a concavity in the form of a groove - a groove of the wrist. This groove is deepened medially by the pisiform bone and the hook of the hamate bone, laterally by the tubercle of the trapezoid bone.
metacarpal bones in the amount of five are short tubular bones. In each of them, a base, a body and a head are distinguished. The bones are counted from the side of the thumb: I, II, etc.
Phalanges of fingers belong to tubular bones. The thumb has two phalanges: proximal and distal. Each of the other fingers has three phalanges: proximal, middle and distal. Each phalanx has a base, body and head.
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