Fascia of forearm and hand

The fascia of the forearm (fascia antebrachii) in the proximal part is thickened, reinforced with fibrous fibers, and distally it is thin, loosely connected to the underlying muscles and their tendons. On the back of the forearm, the fascia is thick, firmly fused to the posterior edge of the ulna. In the proximal part of the forearm, the muscles of the surface layer begin from the fascia. In the anterior region of the forearm on the fascia, 3 furrows are distinguished: radial, median and ulnar. The radial sulcus (sulcus radialis) is bounded by the lateral muscle and lateral and wrist flexor of the wrist - medially. There are radial artery, two veins of the same name and a superficial branch of the radial nerve. The median furrow (sulcus medianus) is located between the radial flexor of the wrist and the superficial flexor of the fingers. In it lies the ulnar artery with adjacent to it two of the same name veins and an ulnar nerve. The ulnar fissure (sulcus ulnaris) from the lateral side is limited by the superficial flexor of the fingers, with the medial - ulnar flexor of the wrist. In the depth of the median groove pass the median nerve and the ulnar artery accompanying it.

From the fascia of the forearm, two intermuscular septums inward - the anterior and posterior ones, attached to the radial bone and dividing the subfascial space into 3 fascial beds: forward, posterior and lateral. The anterior ray intermuscular septum extends along the radial furrow of the forearm, and the posterior septum is along the lateral margin of the brachial muscle.

The anterior fascial bed from the lateral side is bounded by the anterior radial intermuscular septum, and with the medial fascia of the forearm fused with the posterior edge of the ulna. The front wall of this bed is the fascia of the forearm, and the posterior surface is the anterior surface of the ulna and radius bone and the interosseous membrane. The anterior fascial bed is divided into the superficial and deep sections by the deep fascia fascia of the forearm. This plate is located between the superficial and deep flexors of the fingers.

The lateral fascial bed is located between the anterior radial intermuscular septum from the medial side, the posterior radial intermuscular septum posterior and the fascia of the forearm - from the lateral side.

The posterior fascial bed from the lateral side is limited by the posterior radial intermuscular septum. The medial border of this bed is the fascia of the forearm, which is attached to the posterior edge of the ulna. The anterior wall of the posterior fascial bed is the posterior surface of the radial and ulnar bones and the interosseous membrane, the posterior wall is the fascia of the forearm.

In each fascial bed of the forearm are located muscles, as well as nerves and blood vessels. The widest is the anterior fascial bed, in which 8 muscles are arranged in 4 layers. In the surface layer there are 4 muscles: a round pronator, a radial flexor of the wrist, an ulnar flexor of the wrist and a long palmar muscle. In the second layer lies the superficial flexor of the fingers; in the third layer - the deep flexor of the fingers and the long flexor of the thumb of the hand. In the fourth layer there is one muscle - a square pronator, occupying a place in the distal part of the forearm. In the depth of the anterior fascial bed, between the deep flexor of the fingers and the long flexor of the thumb, Pirogov's cell space filled with loose fiber is located. Under the muscles, directly on the interosseous membrane of the forearm, lies the neurovascular bundle formed by the anterior interosseous artery, veins and nerve.

In the lateral fascial bed there are only 3 muscles: more superficially lies the brachial muscle, and under it - the long and short extensors of the wrist.

In the posterior fascial bed there are 10 muscles forming two layers. In the surface layer there are 3 muscles: the radial extensor of the wrist, lateral - the extensor of the little finger, and laterally - the extensor of the fingers (brushes). In the deep layer of the posterior fascial bed, there are 5 muscles: the supine muscle (in the proximal part of the forearm), the long muscle that removes the thumb of the hand (near the ulna), the short extensor of the thumb (near the radius), the long muscle that removes the thumb Brushes (behind the radius and interosseous membranes), and extensor of the index finger (near the ulna). Between the superficial and deep layers of the muscles are the posterior cell space of the forearm and the deep plate of the fascia of the forearm, which is thin in the proximal part, and denser in the distal part. In the distal part, the deep plate fuses with the sagittally oriented partitions under the extensor retainer, separating the tendons of the extensor muscles of the hand and fingers from each other. The front and back cellular spaces of the forearm communicate with each other through the holes in the interosseous membrane, where the interosseous vessels pass. In the depth of the posterior fascial bed, a vascular neural bundle is formed along the interosseous membrane, formed by the interosseous artery, veins and the deep branch of the radial nerve.

In the anterior and posterior regions of the wrist, the fascia of the forearm reaches a considerable thickness, forming on the palmar and back sides the tendon restraints that fix them, preventing the dislocation of the tendons with contraction of the muscles moving from the forearm to the wrist and to the fingers. Holders create the most favorable conditions for the manifestation of muscle strength.

The flexor holder, or the transverse ligament of the wrist (retinaculum flexorum, s.lig.carpi transversum-BNA), is tossed in the form of a bridge over the wrist groove, attached medially to the pea-shaped and hook-shaped bones, to the scaphoid and to the bone-trapezium - laterally. Thanks to the holder between it and the bones of the wrist, covered with deep ligaments, the furrow turns into a carpal canal (canalis carpi). In this canal pass 8 tendons of superficial and deep flexor of the fingers, the median nerve and tendon of the long flexor of the thumb of the hand. Tendons of the flexor of the fingers are located in the common synovial vagina of the flexor fingers of the hand (vagina synovialis communis musculorum flexorum). The tendon of the long flexor of the thumb of the hand is in its own synovial vagina of the same name (vagina synovialis tendinis miisculi flexor pollicis longi). Both synovial vaginas extend 2-2.5 cm proximal to the flexor retainer.

In the distal direction, the synovial vagina of the tendon of the long flexor of the thumb of the hand ends at the level of the base of its distal phalanx. The common synovial vagina of the flexor of the fingers ends blindly in the middle of the palm, and from the ulnar side it continues along the tendons of the superficial and deep flexors. Reaching to the V finger and reaching the base of its distal (nail) phalanx. The synovial sheaths of the tendons I, II, III and IV of the fingers are separated from the common synovial vagina and from each other. They go from the level of the metacarpophalangeal joints to the base of the distal (nail) phalanges of the II-IV fingers. At the level of the distal part of metacarpal bones and to the level of metacarpophalangeal joints, the flexor tendons of the II-IV fingers, devoid of synovial vaginas, pass under the palmar aponeurosis in loose fibrous connective tissue.

The dense fibrous connective tissue, which forms the flexor retainer, is stratified in the medial and lateral parts of the flexor. Due to this there are two channels: the radial and ulnar channels of the wrist. In the radial canal of the wrist (canalis carpi radialis) passes the tendon of the radial flexor of the wrist, surrounded by the synovial vagina (vagina tendinis musculi flexoris carpi radialis), which extends 1-2 cm above the flexor retainer. In the ulnar canal of the wrist (canalis carpi ulnaris) is the ulnar nerve, and outside it lie the ulnar artery and veins.

On the back of the wrist is the extensor retinaculum (retinaculum extensorum), which is the thickening of the fascia at the level of the wrist joint. This thickening connects the anterior edge of the distal end of the radius from the lateral side and the styloid process of the ulna, as well as the ulnar collateral ligament of the wrist - from the medial side. The space under the extensor retainer is subdivided by connective tissue septae extending from the restraint into 6 channels, in which the tendons of the extensors of the hand and fingers are surrounded by synovial vaginas. In the first (lateral) canal pass the tendon of the long muscle that leads the thumb of the hand, and the short extensor of the thumb of the hand. In the second canal there are tendons of the long and short radius extensors of the wrist, in the third channel - the tendon of the long extensor of the thumb of the hand, in the fourth channel - the tendons of the extensors of the fingers and the index finger, as well as the posterior interosseous nerve of the forearm, in the fifth channel - the tendon of the extender of the little finger, in the sixth (medial) canal is the tendon of the elbow extensor of the wrist. The synovial vagina of the tendons of the extensor muscles protrude from under the extensor retainer 2-3 cm above the level of the styloid process of the radius bone.

In the distal direction, the synovial vagina continues to the middle of the metacarpal bones. The synovial vagina of the tendon of the extensor of the fingers and the index finger (vagina synovialis tendinum musculorum digitorum et extensoris indicis) is the widest. The synovial vagina of the tendon of the elbow extensor of the wrist (vagina synovialis tendinis musculi extensoris carpi ulnaris) is located on the posterior surface of the distal epiphysis of the ulna, the synovial vagina of the tendon - the extensor of the little finger - on the posterior surface of the elbow-elbow joint. All other synovial vaginas of extensor tendons are located on the posterior surface of the diotonic epiphysis of the radius.

In the palm of the hand under the skin is palmar aponeurosis (aponevrosis palmaris), which is the continuation in this place of the tendon of the long palmar muscle, supported by the longitudinal and transverse tendon fibers of the superficial fascia of the palm. The apex of the palmar aponeurosis is connected to the distal edge of the flexor retainer and to the tendon of the long palmar muscle, and the base is turned towards the fingers. At the level of the metacarpophalangeal articulations, the palmar aponeurosis is divided into 4 strands directed to the fingers and involved in the formation of fibrous vagina of the fingers of the hand (vaginae fibrosa digitorum manus) for the tendons of the superficial and deep flexors of the II-IV fingers. On the palmar surface of the vagina of the fingers, transversely extending bundles of fibers are clearly visible - the annular part of fibrous vaginas and oblique fibers crossing with the analogous fibers of the other side - the cruciform part of the fibrous vagina. Fibrous canals contain tendons of superficial and deep flexor fingers surrounded by synovial vaginas.

Connective tissue bundles of the palmar aponeurosis and fibrous vagina of the fingers of the hand are weaved into the skin, so that grooves are formed on the surface of the palm skin of the hand and fingers. In the medial and lateral directions from the palmar aponeurosis, the superficial fascia covers the muscles of the elevation of the thumb and small fingers (tenar and hypotenar). The superficial fascia forms 3 interfascial cell spaces in the palm of the hand due to two fascial septa extending from the palmar aponeurosis to the III-V metacarpal bone. In the outer interfascial space, located between the synovial vagina of the tendon of the long flexor of the thumb, the third metacarpal bone and the fascial septum extending to it, the muscles of the elevation of the thumb overlap.

The middle interfascial cellular space is bounded on either side by the two fascial septa. It distinguishes between two departments: superficial and deep. In the superficial part there are tendons of the superficial and deep flexor of the fingers, as well as the superficial palmar (arterial) arch. From this arc, the common palmar finger arteries, dividing into their own palmar finger arteries at the level of the metacarpophalangeal arches, depart. Under the superficial palmar arc, the branches of the median and ulnar nerves pass. The deep section of the middle interfascial cell space is located under the tendons of the flexors, between them and the deep plate of the palmar fascia. Here lies a deep palmar artery arc, from which four palpal metacarpal arteries depart. The deep section of the cell space is communicated through the carpal tunnel with Pirogov's cell space, located on the front side of the forearm. In the course of vermiformes and other deep mice, this cellular space is communicated with the fiber of the rear of the III, IV and V fingers of the hand.

The third, medial, interfascial cell space from the lateral side is limited by the medial fascial septum and its own fascia, which also attaches to the metacarpal bone. In this space lie the muscles of the V-finger elevation. The underdeveloped deep plate of the palmar fascia of the wrist (interosseous palmar fascia) covers the interosseous muscles, separating them from the flexor tendons of the fingers. The proximal part of the deep plate of the palmar fascia passes to the palmar surface of the bones of the wrist. On the sides of the interosseous spaces this plate fuses with the periosteum of metacarpal bones and with deep transverse metacarpal ligament. In the area of the tenar and the hypotenar, the thinner fascia forms the fascial beds for the corresponding muscles.

The rear fascia of the hand (fascia dorsalis manus) consists of two plates - surface and deep. The superficial plate, weakly expressed, is located over the tendons of the extensor fingers. At the rear of the fingers this plate fuses with the tendons of their extensors. The more developed deep plate of the dorsal fascia of the hand covers the posterior interosseous muscles and is attached to the periosteum of the dorsal surface of metacarpal bones. At the base of the proximal phalanges of the fingers, a deep plate connects to the palmar fascia.

[1], [2], [3], [4], [5]