Electromyostimulation - article 2

Electromyostimulation can represent very important step in the training of soccer players and their recovery.

ADDITIONAL INFO ARE AVAILABLE BY CLICKING ON THIS LINK.

Electromyostimulation

Electromyostimulation takes an important role in the athletes training.

ALL INFO ABOUT ELECTROMYOSTIMULATION ARE AVAILABLE BY CLICKING ON THIS LINK.

Blisters and soccer

Blisters often are a problem in soccer, particularly on the feet. Tight-fitting shoes and aggressive running styles over long periods sometimes encourage blisters to form. Understanding how to treat and prevent blisters will keep you in the game longer.

Cause

Excessive irritation on the skin causes blisters. Stiff, narrow soccer shoes rub on the sides of the feet as soccer players run, causing friction and irritation. Abrasive socks can cause blisters, too, especially if the shoe is too large and allows the foot to slide around. Blisters are more likely to occur in moist environments. Sweat and wet field conditions frequently create moisture in a soccer cleat.

Symptoms

When a blister begins to form, it appears as a red, slightly tender area. Rubbing may produce a burning sensation. As the blister gets worse, a bubble filled with fluid develops -- your body's attempt to cushion the area. If the fluid-filled area is left untreated and you continue to play, the fluid will increase and the bubble will rupture and drain. You may feel slight relief after the blister ruptures.

Treatment

If you catch a blister before it has filled with fluid, treat it with a cushioning bandage or moleskin product and continue to play. You should not attempt to puncture the blister in field conditions because that might lead to infection. If the blister is already filled with fluid, continuing to play will only make the problem worse. If the blister has ruptured, clean the area as you would a normal wound and apply a clean bandage and antibacterial cream.

Prevention

The first step in blister prevention in soccer is choosing a proper shoe. Soccer shoes should fit your foot's length, width and most importantly, volume. When you try on soccer shoes at the store, wear the socks in which you play to achieve a better fit. If you wear shin guards that have ankle guards, bring them. Always break in new cleats slowly to avoid blisters from a stiff new pair. Wear comfortable socks and change them during halftime to help keep your feet dry and comfortable.

References

http://www.usyouthsoccer.org/news/all_there_is_to_know_about_blisters/?story_id=3978

“Handbook of Sports Medicine and Science - Football(Soccer)”, Björn Ekblom

Immediate injury treatment

What to do first few days after an injury occurred?

Rest?

• Rest from painful exercise or a movement is essential in the early injury stage. We call this active rest. "No pain. No gain." does not apply in most cases.  The rule of thumb is - don't do anything that reproduces your pain for the initial two or three days.  After that, you need to get it moving or other problems will develop.

• If you are unsure what to do, please contact your doctor.

Ice or Heat?

Ice

• Ice is preferred for the initial two or three days post-injury.
• Apply ice for 20 minutes each two to three hours for the first few days until the "heat" comes out of the injury.
• Ice should also help to reduce your pain and swelling in traumatic soft tissue injuries, such as ligament sprains, muscle tears or bruising.

Heat

• It is preferable to avoid heat (and heat rubs) in the first 48 hours of injury. The heat encourages bleeding, which could be detrimental if used too early.
• Once the "heat" has come out of your injury, heat packs can be used to stimulate blood flow. We recommend 20 minute applications a few times a day to increase the blood flow and hasten your healing rate. Heat will also help your muscles relax and ease your pain.

• Heat Wheat Packs are an excellent home solution for a multitude of conditions.

Not Sure?

• If you're not sure what to do, please contact your doctor.

Bandage / Support?

• Yes. If it is possible to apply a compressive bandage or elastic support to the injury, it will help to control swelling and bleeding in the first few days.  In most cases, the bandage/support will also help to support the injury as the new scar tissue is laid down. This should help to reduce your pain.

• Some injuries will benefit from more support such as a brace or rigid strapping tape.

• Please contact your doctor if you are unsure what to do.

Elevation?

• Elevation of an injury in the first few days is very helpful.

• Think where your injury is and where your heart is. Gravity will encourage swelling to settle at the lowest point.  Try to rest your injury above your heart.

• Obviously some injuries are impossible or it would be detrimental to elevate, so please use your common sense and be guided by your pain.

Treatment - When? 

In most cases, "the early bird gets the worm".  Researchers have found that intervention of physiotherapy treatment for acute soft tissue injuries within a few days has many benefits. 

Prompt Treatment Benefits include:

• Relieving your pain quicker via joint mobility techniques, soft tissue massage, electrotherapy etc

• Improving your scar tissue quality using techniques to guide the direction it forms

• Getting you back to sport or work quicker through faster healing rates

• Loosening or strengthening of your injured region with individually prescribed exercises and techniques

• Improving your performance when you do return to sport, work or simply daily life

• Correct any biomechanical faults that may be affecting your movement, technique or predisposing you to injury

What If You Do Nothing?

Research tells us that injuries left untreated do take longer to heal and have lingering pain. 

They are also more likely to recur and leave you with:

• abnormal scar tissue formation
• joint stiffness
• muscle weakness

It's important to remember that symptoms lasting longer than three months become habitual and are much harder to solve.  The sooner you get on top of your symptoms the better your outcome.

Proprioception

What are proprioceptors?

Proprioceptors are specialized sensory receptors on nerve endings found in muscles tendons joints and the inner ear.

What is Proprioception?

Proprioception is the sense of knowing where your body part is in space.

This can be a difficult concept to grasp until you lose it, because so much proprioception occurs subconsciously.

Your proprioception capabilities can be impaired when joints are injured, such as with ligament sprains.  When you lose proprioception of your joint after a sprain, you may experience an unstable sensation of the joint. Your joint may even give-out. 

The most common symptom of reduced proprioception is poor balance. In this respect, most people can understand the concept that poor balance can be a result of poor proprioception. However, even your spinal posture has a proprioception component telling you whether or not you are sitting or standing upright. Good posture, for example, could be thought of as perfect spinal balance!

Every injury has the potential to decrease your proprioception and subsequently your balance. However, you can quickly improve both your proprioception and balance with proprioception and balance exercises. That's where your coach has to be an expert and can help you if does the job properly.

What are Proprioception / Balance Exercises?

Proprioceptive and balance exercises teach your body to control the position of a deficient or an injured joint. An common example of a  proprioceptive or balance exercise is the use of a balance or wobble board after an ankle sprain.

The unpredictable movements of the balance board re-educates your body to quickly react to the wobbly movements without having to think about these movements.

That is, your natural balance and proprioceptive reactions that we are attempting to retrain make the transition from a conscious to a subconscious state. A quality subconscious proprioception and balance system is important in everyday life and particularly in sport.

Elite athletes are not thinking about how to stay balanced as they pass or kick a ball. That all happens automatically behind the scenes. The best athletes can then elevate their performance by focusing on what they plan to do with the ball and performing that match winning skill rather than wasting their mental power on just staying upright.

How Does Your Proprioception or Balance Improve?

Proprioception exercises are designed to improve your proprioception feedback circle.

In simple terms, your brain sends electrical contract or relax messages to your muscles. Your joint movement response is detected by your sensory nervous system and reported back to your brain for fine tuning and improvement with repetition of the process.

In other words, perfect practice will eventually mean proprioception perfection.

There are hundreds of injury specific proprioception and balance exercises whether your injury is your shoulder, elbow, hip, knee, ankle or spine.

It is possible to commence advanced proprioception or balance exercises too early, which can be detrimental to your rehabilitation outcome. Once you go to the proprioception training, if going after injury, start very light exercises. Make sure to do the gradual increase in your intensity and exercise hardiness, don’t push too hard, listen to your coach and everything will go in the directed path.

The intercarpal joints

The carpal bones are arranged in two transverse rows between which is the important midcarpal joint. For the majority, the joints between the adjacent individual carpal bones are of the plane synovial type, permitting only slight movement between the bones involved. The only bone which moves appreciably is the capitate.

Joints of the proximal row

Plane synovial joints exist between the distal parts of the adjacent surfaces of the scaphoid, lunate and triquetral. However, because these bones are bound together by interosseus, dorsal and palmar intercarpal ligaments there is minimal movement between them.

The interosseus intercarpal ligaments are short bands attaching to the margins of the joint surfaces involved in the radiocarpal articulation. They unite the bones along their whole anteroposterior length. The palmar and dorsal intercarpal ligaments are transverse bands passing from scaphoid to lunate and from lunate to triquetral on the anterior and posterior aspects of the bones respectively.

The pisiform rests on the palmar surface of the triquetral and has a separate synovial joint with it, which is completely enclosed by a thin but strong fibrous capsule. The pisiform is also anchored to the hook of the hamate by the pisohamate ligament, and to the base of the fifth metacarpal by the pisometacarpal ligament. These two ligaments resist the pull of flexor carpi ulnaris, and transfer its action to the hamate and base of the fifth metacarapal. In this way these ligaments form extensions of the muscle.

Joints of the distal row

As in the proximal row, the four bones of the distal row are united by interosseus, palmar and dorsal intercarpal ligaments, with the joints between the individual bones being of the plane synovial type. Because of these ligaments, movements between adjacent bones is minimal.

The interosseus ligaments are not as extensive as in the proximal row, leaving clefts between the bones which communicate with the midcarpal joint proximally, and with the common carpometacarpal joint distally. Occassionally, the midcarpal and carpometacarpal joints communicate with each other between the bones of the distal row. This occurs when one of the interosseus ligaments is incomplete so that communication is around the borders of the ligament, or when one ligament is absent(most commonly that between the trapezium and trapezoid). Dorsal and palmar ligaments generally run transversely across the appropriate surfaces of the bones, uniting trapezium to trapezoid, trapezoid to capitate, and capitate to hamate.

The radiocarpal joint

The radiocarpal joint is formed between the distal surfaces of the radius and the articular disc, and the scaphoid, lunate and triquetral of the proximal row of carpal bones. It is a synovial joint of the ellipsoid type allowing movement in two planes.

Articular surfaces

Distal surface of the radius and articular disc

The radius and articular disc form a continuous, concave ellipsoid surface, being shallower in its transverse long axis than in its shorter anteroposterior axis(a). The articular cartilage on the radius is divided by a low ridge into a lateral triangular and a medial quadrangular area.

Proximal carpal row

The proximal row of carpal bones presents an almost continuous convex articular surface(b). The three carpal bones are closely united by interosseus ligaments which are continuous with the cartilage on the proximal surfaces of the bones. In the anatomical position, the scaphoid lies opposite the medial radial area and the articular disc, and the triquetral is in contact with the medial part of the joint capsule(b).

Joint capsule and synovial membrane

A fibrous capsule completely encloses the joint. It is attached to the distal edges of the radius and ulna anteriorly and posteriorly. Laterally and medially it is attached to the radial and ulnar styloid processes respectively. Distally the capsule is firmly attached anteriorly and posteriorly to the margins of the articular surfaces of the proximal row of carpal bones. Medially it passes to the medial side of the triquetral, and laterally to the lateral side of the scaphoid. Both the anterior and posterior parts of the capsule are thickened and hence strengthened, while at the sides it blends with the collateral ligaments.

Capsular ligaments

The capsular ligaments are distinct bands of fibres passing between specific bones. As well as strengthening the capsule, their arrangement determines that the hand follows the radius in its movements and displacements.

Dorsal radiocarpal ligament. The dorsal radiocarpal ligament extends from the posterior edge of the lower end of the radius to the posterior surface of the scaphoid, lunate and triquetral(a). Its fibres run downwards and medially, principally to the triquetral, and are continuous with the dorsal intercarpal ligaments.

Palmar radiocarpal ligament. The palmar radiocarpal ligament is a broad band of fibres passing downwards and slightly medially from the anterior edge of the lower end of the radius and its styloid process, to the anterior surfaces of the proximal row of carpal bones(b). Some of the fibres are prolonged and extend to attach to the capitate.

Palmar ulnocarpal ligament. The palmar ulnocarpal ligament is formed by fibres extending downwards and laterally from the anterior edge of the articular disc and the base of the ulnar styloid process to the anterior surfaces of the proximal carpal bones(b).

These anterior and posterior capsular ligaments become taut in extension and flexion of the radiocarpal joint respectively.

Synovial membrane

A relatively lax synovial membrane lines the deep surface of the joint capsule attaching to the margins of all the articular surfaces. It presents numerous folds, particularly posteriorly. Because of the presence of the articular disc of the inferior radioulnar joint and the completeness of the interosseus  ligaments uniting the proximal surfaces of the proximal carpal row, the synovial cavity is limited to the radiocarpal space. Only occasionally does it communicate with the inferior radioulnar joint by a perforation in the articular disc, or with the intercarpal joint when one of the interosseus ligaments is incomplete.

Ligaments

At the sides of the radiocarpal joint, collateral ligaments reinforce and strengthen the joint capsule. They are active in limiting abduction and adduction at the joint. In adduction, the radial ligament becomes taut while the ulnar relaxes; in abduction the reverse occurs.

Radial collateral carpal ligament

The radial collateral carpal ligament passes from the tip of the radial styloid process to the lateral side of the scaphoid, immediately adjacent to its proximal articular surface, and to the lateral side of the trapezium.

Ulnar collateral carpal ligament

The ulnar collateral carpal ligament is a rounded cord attached to the ulnar styloid process above and to the base of the pisiform and the medial and posterior non-articular surfaces of the triquetral below. By its attachment to the pisiform the ligament also blends with the medial part of the flexor retinaculum.

Blood and nerve supply

The arterial supply to the joint is by branches from the dorsal and palmar carpal networks, with venous drainage going to the deep veins of the forearm. Lymphatic drainage of the joint follows the deep vessels.

The nerve supply to the joint is by twigs from the anterior interosseus branch of the radial nerve, the posterior interosseus branch of the radial nerve, and the dorsal and deep branches of the ulnar nerve, with root value C7, 8.

Surface making

The position of the joint is indicated by a line, slightly convex proximally, between the radial styloid process and the head of the ulna, so that the concavity of the radius and articular disc face distally, medially and slightly anteriorly.

Movements

Movements of flexion and extension; and adduction and abduction are possible at the radiocarpal joint. However, each of these is also contributed to by movements between the proximal and distal row of carpal bones at the midcarpal joint.

Flexion and extension

Flexion and extension occur about a transverse axis more or less in the sagittal plane such that the hand moves towards the front of the forearm in flexion and towards the back of the forearm in extension. Flexion is freer than extension and has a maximum range of 50°, whereas extension has a maximum range of 35°. The movements are checked by the margins of the radius, and because the posterior margin extends further distally than the anterior, extension is checked earlier than flexion.

In flexion the scaphoid and lunate move within the concave distal end of the radius so that their proximal surfaces face postero-superiorly. In addition the scaphoid twists about its long axis so that its tubercle becomes less prominent in full flexion. During extension the twisting of the scaphoid about its long axis makes the tubercle more prominent in full extension.

Abduction and adduction

Abduction and adduction, also reffered to as radial and ulnar deviation, are lateral or medial movements respectively of the proximal row of carpal bones in relation to the distal end of the radius. The radial styloid process extends further distally than the ulnar styloid process. Consequently, abduction is more limited at the radiocarpal joint having a range of only 7°, whereas adduction has a range of 30°. In adduction the scaphoid rotates so that its tubercle moves away from the radial styloid process, enabling the lunate to move laterally so that it comes to lie entirely distal to the radius. The triquetral lies distal to the articular disc. In abduction the triquetral moves medially and distally to be clear of the radius; the lunate follows so that its centre lies distal to the inferior radioulnar joint. The movement is limited by impact of the scaphoid tubercle on the radial styloid process.

Accessory movements

An anteroposterior gliding of the proximal row of carpal bones against the radius and articular disc can be produced by firmly gripping the lower end of the radius and ulna with one hand, and the proximal row of carpal bones with the other. Alternate anterior and posterior pressure elicits a palpable gliding movement at the radiocarpal joint. With the same grip, a longitudinally applied force along the line of the forearm pulls the carpal bones away from the radius and articular disc.

The wrist

Introduction

The wrist joint is not a single joint but comprised of the articulations between the carpal bones(intercarpal joints) and the articulation with the forearm(radiocarpal joint). Functionally, however, the eight carpal bones are arranged and move as two rows of bones; a proximal row, comprising from lateral to medial: scaphoid, lunate, triquetral and pisiform; and a distal row, again from lateral to medial, formed by the trapezium, trapezoid, capitate and hamate. The two rows articulate with each other at what has become known as the midcarpal joint, a sinuous articular area convex laterally and concave medially. The distal surface of the distal row of bones articulates with the bases of the metacarpals.

Because of the functional interdependence of the wrist and hand, all movements of the hand are accompanied by movements at the radiocarpal and intercarpal joints. The wrist complex is capable of movement in two directions. However, when combined with pronation and supination the hand appears to be connected to the forearm by a ball and socket joint, having great intrinsic stability because of the separation of the three axes about which movement occurs.

The inferior radioulnar joint

Articular surfaces

The articulation is between the head of the ulna and the ulnar notch on the lower end of the radius. The joint is closed inferiorly by an articular disc which passes between the radius and ulna thereby separating the inferior radioulnar joint from the radiocarpal joint of the wrist.

Head of the ulna

The head of the ulna is the slightly expanded lower end of the bone. The crescent-shaped articular surface is situated on its anterior and lateral aspects and is covered with hyaline cartilage, which is continuous with that on the distal end of the ulna over a rounded border. The distal end of the head of the ulna articulates with an intra-articular disc.

Ulnar notch of the radius

The ulnar notch of the radius is situated between the two edges of its interosseus border, and faces medially. It is concave anteroposteriorly and plane or slightly concave vertically. The notch is lined by hyaline cartilage.

Articular disc

A triangular, fibrocartilaginous articular disc is the principal structure uniting the radius and ulna. It attaches by its apex to the lateral side of the root of the ulna styloid process, and by its base to the sharp inferior edge of the ulnar notch between the ulnar and carpal surfaces of the radius. The disc is thicker peripherally than centrally, although it is rarely perforated.

It is an essential part of the total bearing surface of the inferior radioulnar joint by its articulation with the distal surface of the head of the ulna. Inferiorly it participates in the radiocarpal joint. Perforation of its central part would therefore lead to a communication between the inferior radioulnar and radiocarpal joints.

Joint capsule and synovial membrane

The relatively weak and loose fibrous capsule is formed by transverse bands of fibres attaching to the anterior and posterior margins of the ulnar notch of the radius, and to the corresponding regions on the head of the ulna. The inferior margins of these bands blend with the anterior and posterior edges of the articular disc. However, superiorly they remain separated.

The synovial membrane is large in relation to the size of the joint, extending upwards above the margins of the joint capsule between the radius and ulna in front of the interosseus membrane, to form the recessus sacciformis.

Blood and nerve supply

The arterial supply to the joint is by branches from the anterior and posterior interosseus arteries, and from the dorsal and palmar carpal networks, which receive branches from the radial and ulnar arteries. Venous drainage is by similarly named vessels into the deep system of veins. The lymphatic drainage of the joint is by vessels accompanying the deeper blood vessels, some of which pass to nodes in the cubital fossa, but most go directly to the lateral group of axillary nodes.

The nerve supply to the joint is by twigs from the anterior and posterior interosseus nerves, with a root value of C7 and 8.

Relations

Passing directly behind the inferior radioulnar joint is the tendon of extensor digiti minimi, enclosed within its synovial sheath, on its way to the little finger. Anteriorly lies the lateral part of flexor digitorum profundus enclosed within the common flexor sheath. Proximal to the joint pronator quadratus passes between the radius and ulna holding them together, and thereby protecting the joint.

Stability

Although the joint capsule is loose, to allow for movement between the radius and ulna, the inferior radioulnar joint is extremely stable and is rarely dislocated. The stability is due primarily to the articular disc, but also to the interosseus membrane and pronator quadratus.

A fall on the outstretched hand with the wrist extended frequently results in a transverse fracture in the lower 2 or 3cm of the radius(Colles’ fracture), with the fragment being displaced posteriorly. The ulna is usually not involved except that its styloid process may be torn off. In a Colles’ fracture the hand is displaced laterally and dorsally. Alternatively, the fall may result in dislocation at the radiocarpal joint, but not at the inferior radioulnar joint.

Movements

The main movement at the inferior radioulnar joint is a rotation of the lower end of the radius around the head of the ulna during pronation and supination. However, because during everyday activities the axis of pronation and supination coincides with the axis of the hand along the middle finger, the radial rotation is accompanied by movement of the head of the ulna. So that while the radius rotates about the ulna, the ulna is displaced with respect to the radius. The ulna displacement observed during rotation is merely the result of two elementary movements: slight extension and medial displacement of the ulna at the elbow. The very slight side-to-side movement possible between the trochlea of the humerus and the trochlear notch of the ulna is mechahically amplified at the lower end of the ulna to become a movement of appreciable magnitude. Both the extension and lateral displacement of the ulna are brought about by the action of anconeus, and therefore occur simultaneously during pronation. The arc of the movement described by the head of the ulna does not involve a rotation of the bone, as it remains parallel to itself throughout, that is, the ulnar styloid process remains posteromedial.

Accessory movements

Gripping the lower ends of the radius and ulna firmly, the head of the ulna can be moved anteroposteriorly with respect to the radius.

Palpation

The line of the inferior radioulnar joint can be palpated on the posterior aspect of the wrist, running vertically between the two bones.

Interosseus membrane

The interosseus membrane stretching between the interosseus borders of the radius and ulna is a strong, fibrous sheet whose fibres predominantly pass obliquely downwards and medially from the radius to the ulna. Being deficient superiorly, it has a free oblique border which is attached 2 to 3cm below the radial tuberosity and passes to a slightly lower level on the ulna. Inferiorly the membrane is continuous with the fascia on the posterior surface of pronator quadratus, attaching to the posterior of the two lines into which the radial interosseus border divides. An opening in the lower part of the membrane enables the anterior interosseus vessels to pass into the posterior compartment of the forearm. On the posterior part of the membrane there are a small number of fibrous bands which pass obliquely downwards and laterally. During pronation and supination, tension in the membrane varies, being greatest in the midprone position.

The oblique direction of the fibres of the interosseus membrane serves to transmit forces from the radius to the ulna. The radius is the forearm bone articulating at the radiocarpal joint, receiving impacts and forces from the scaphoid and lunate. At the elbow, however, it has a rather ineffective articulation with the humerus, whereas the ulna has a large and firm articulation. The membrane serves to transmit forces carried from the hand up through the radius to the ulna and thence to the elbow joint and humerus.

As well as providing a firm connection between the radius and ulna the interosseus membrane separates and increases the area of attachment of the deep muscle of the anterior and posterior compartments of the forearm.

Above the upper free border of the interosseus membrane the oblique cord passes upwards and medially from the radius to the ulna. It is a slender, flattened fibrous band, which is said to represent a degenerated part of flexor pollicis longus or supinator, attached just below the radial tuberosity and to the lateral border of the ulnar tuberosity. In the gap between the oblique cord and the interosseus membrane, the posterior interosseus vessels pass to and form the posterior compartment of the forearm.

Pronation and supination

In the supine position, the bones of the forearm lie parallel to one another(a); in the anatomical position the palm of the hand therefore faces forwards. In the prone position, the bones of the forearm cross one another(a), with the radius lying anterior to the ulna; with reference to the anatomical position the palm faces backwards. The movement which causes crossing of the radius and ulna is called pronation, while that causing them to become parallel is called supination. The movements between the radius and ulna occur at the superior and inferior radioulnar joints.

The muscles producing pronation are pronator teres and pronator quadratus, with pronator teres being the more powerful of the two. Flexor carpi radialis, because of its oblique course, can and does assist in pronation. Supination is produced by supinator and biceps brachii, of which biceps is by far the stronger. However, when the elbow is fully extended biceps is unable to act as a supinator because its tendon runs almost parallel to the shaft of the radius, and so cannot produce radial rotation. Of the two movements supination is the more powerful. Because the majority of the population are right-handed, screws have a right-hand thread. If you are trying to move a particularly stubborn screw from a cabinet or door frame, ask a left-handed friend to do it! Both pronation and supination are most powerful when the elbow is flexed to 90°.

The axis of pronation and supination can vary depending about which finger the movement is occurring. It always passes through the centre of the head of the radius, but at the level of the wrist it can pass through any point between the ulnar and radial styloid processes. Nevertheless, it will tend to lie in the medial half of this region in most instances. Therefore, to state that the axis runs between the centre of the radial head and the base of the ulnar styloid process is not strictly correct. When rotation occurs about a more laterally placed centre at the wrist, ulnar movement at the trochlea is insufficient. Consequently, with the elbow flexed the movement is supplemented by rotation of the humerus.

The forearm can be pronated through almost 180°, without medial rotation of the humerus(b). The constraint to further movement comes predominantly from the passive resistance of the opposing muscles, and not from ligamentous ties. However, if the humerus is allowed to rotate then it becomes possible to turn the hand through almost 360°.

Pronation and supination are frequently used movements in many activities. Consequently loss of the ability to pronate and supinate can be a marked disability. When these movements are lost it is less disabling if the forearm is fixed in a midprone position, so that the palm faces medially.

The superior radioulnar joint

The articulation is between the head of radius rotating within the fibro-osseous ring formed by the radial notch of the ulna and the annular ligament.

Head of the radius

The beveled circumference of the head of the radius is covered by hyaline cartilage continuous with that on its upper concave surface, so forming a smooth surface for articulation with the ulna and annular ligament(a). The anterior, medial and posterior parts of the circumference tend to be wider than the lateral part, for direct articulation with the ulna. The head of the radius tends not to be circular but is slightly oval, with the major axis lying obliquely anteroposteriorly. The major and minor axes have a length ratio of approximately 7:6.

Radial notch

The hyaline-covered radial notch is continuous with the trochlear notch of the ulna on its lateral side, being separated from it by a blunt ridge(a,c). It forms approximately one-fifth of the articular fibro-osseous ring, and is therefore concave anteroposteriorly but almost flat vertically.

Annular ligament

The flexible annular ligament forms the remaining four-fifths of the articular surface which encircles the head and neck of the radius. Its flexibility enables the oval head of the radius to rotate freely in pronation and supination. The ligament is a strong, well-defined band attached to the anterior and posterior margins of the radial notch of the ulna. Posteriorly the ligament widens where it attaches to adjacent areas of the ulna above and below the posterior margin of the notch. The diameter between its lower borders is narrower than that above(c), so it cups in under the head of the radius and acts as a restraining ligament preventing downward displacement of the head through the ring.

Superiorly the annular ligament is supported by the firm fusion of the radial collateral ligament and the blending of the lateral part of the fibrous capsule of the elbow joint in front and behind. Inferiorly a few loose fibres attach the ligament to the neck of the radius beyond the epiphyseal line. These fibres are too loose to interfere with movements at the joint, but give some support to a dependent fold of synovial membrane. The upper part of the ligament is lined with fibrocartilage continuous with the hyaline cartilage of the radial notch. The lower part of the ligament is lined with synovial membrane.

Joint capsule and synovial membrane

The superior radioulnar joint is continuous with the elbow joint and consequently shares the same joint capsule. The synovial membrane associated with the elbow part of the joint space attaches to the upper margin of the fibrocartilage lining of the annular ligament. From the lower border of the fibrocartilage, and lining the lower part of the annular ligament, the synovial membrane extends below the lower border of the ligament to hang as redundant fold which has a loose attachment to the neck of radius. The membrane lies on the upper surface of the quadrate ligament, which limits and supports it, and passes medially from the radius to attach to the lower border of the radial notch of the ulna. The redundancy of the synovial membrane below the annular ligament accommodates to the twisting of the membrane that accompanies rotation of the radius.

Ligaments

Although the annular ligament provides an important support for the head of the radius, it is not sufficient by itself to provide the only support to the superior radioulnar joint, because of its need to change shape with rotation of the radius. Indeed, this constant need to accommodate to the changing orientation of the head of the radius may lead to stretching of the ligament. Consequently, there are additional structures which provide support to the joint: the quadrate ligament and the interosseus membrane.

Quadrate ligament

The quadrate ligament stretches from the lower border of the radial notch of the ulna to the adjacent medial surface of the neck of the radius proximal to the radial tuberosity. Its fibres run in a criss-cross manner between the two bones, so that, irrespective of the relation of the radius to the ulna, some fibres are always under tension. The overall tension within the ligament thus remains constant in all positions of pronation and supination. Its two borders are strengthened by fibres from the lower border of the annular ligament.

Blood and nerve supply

The arterial blood supply to the superior radioulnar joint is by branches from vessels supplying the lateral part of the elbow joint; namely the middle and radial collateral branches of the profunda brachii, and the radial and interosseus recurrent branches from the radial and common interosseus arteries respectively. Venous drainage is by similarly named vessels draining eventually to the brachial vein. Lymphatic drainage is by vessels traveling with the arteries to small nodes associated with the main arteries and then to the lateral group of axillary nodes.

The nerve supply to the joint is by twigs from the posterior interosseus branch of the radial nerve, the musculocutaneous and median nerves, with a root value of C5, 6 and 7.

Surface marking and palpation

The line of the superior radioulnar joint can be palpated posteriorly. Having identified the head of the radius in the depression on the posterolateral aspect of the elbow, a vertical groove between the radius and ulna can be felt medially. This is the position of the joint line. During pronation and supination, the head of the radius can be felt rotating against the ulna.

Relations

Anteriorly the joint is crossed by the tendon of biceps passing to its attachment of the radial tuberosity; posteriorly is the fleshy belly of anconeus . Medial to the tendon of biceps lies the brachial and then the radial artery from above downwards.

Stability

The joint has a reasonable degree of inherent stability. However, in children, the head of the radius may be pulled from the confines of the annular ligament in traction dislocation. Tears of the annular ligament will also result in dislocation at the joint.

Movement

The main movement that occurs at the superior radioulnar joint is rotation of the head of the radius within the fibro-osseous ring of the annular ligament and radial notch of the ulna(a). The movement is probably limited by tension developed in the quadrate ligament.

In addition to this principal movement, there are four other movements related to the joint. These are:

1)      Rotation of the superior concave surface of the radial head in relation to the capitulum of the humerus;

2)      The beveled ridge of the radial head glides in contact with the capitulotrochlear groove of the humerus;

3)      The head of the radius is displaced laterally because the major axis of the oval head comes to lie transversely(a);

4)      The plane of the radial head becomes tilted laterally and inferiorly during pronation due to the radius moving obliquely around the ulna(b).

Accessory movements

Gripping the head of the radius between the thumb and index finger, it can be moved anteroposteriorly with respect to both the ulna and the capitulum.