Chapter 19: The Elbow, Forearm, Wrist and Hand

Elbow Osteochondritis Dissecans

Although osteochondritis dissecans is more common in the knees, it can also occur at the elbow. Cause of injury: Unknown; however, impairment of the blood supply can lead to fragmentation and separation of a portion of the articular cartilage and bone, creating loose bodies within the joint. Signs of injury: The adolescent athlete usually complains of sudden pain and locking of the elbow joint. Range of motion returns slowly over a few days. Swelling, pain and crepitus may also occur. Care: Repeated episodes of locking may warrant surgical removal of the loose bodies. If they are not removed, traumatic arthritis can eventually occur.

Muscles of the elbow

Biceps brachii, brachialis, brachioradialis All flexors of the elbow. Briachialis is the primary elbow flexor. Extension is controlled by the triceps brachii muscle. The biceps brachii and supinator muscles allow supination of the forearm; the pronator teres int he proximal forearm and pronator quadratus, in the distal forearm act as pronators.

Phalanx Fractures

Cause of injury: Phalanx fractures can occur from a variety of actions: the fingers are stepped on, hit by a ball or twisted. Signs of injury: The athlete complains of pain and swelling in a finger. Tenderness is felt at the point of fracture. Care: The finger suspected of fracture should be splinted in flexion around a gauze roll or a curved splint to avoid full extension. Flexion splinting reduces the deformity by relaxing the flexor tendons. Fracture of the distal phalanx is less complicated than fracture of the middle or proximal phalanx.

Wrist Tendinitis

Cause of injury: Wrist tendinitis occurs in wieght lifters, rowers, and participants in other supports that require the athlete to perform repetitive wrist accelerations and decelerations. Signs of injury: The athlete complains of pain with use or pain in passive stretching. There is tenderness and swelling over the tendon. Care: Acute pain and inflammation are managed by ice massage for 10 minutes four times daily for the first 48 to 72 hours, nonsteroidal anti-inflammatory medication, and rest. A wrist splint may protect the injured tendon. When swelling has subsided, range of motion is stressed. When pain and selling have subsided, progressive resistance exercise can be instituted.

Dislocation of the elbow

Cause of injury: high incidence in sports activity and most often is caused by a fall on the outstretched had with the elbow hyperextended or by a severe twist while the elbow is flexed. Signs of injury: The bones of the forearm (ulna and radius) may be displaced backward, forward, or laterally. The appearence of the most common dislocation is a deformity of the olecranon process wherein it extends backward, well beyond its normal alignment with the upper arm. Elbow dislocations involve rupturing and tearing of most of the stabilizing ligamentous tissue accompanied by profuse internal bleeding and subsequent swelling. There is severe pain and disability. The complications of such a trauma may include injury to the major nerves and blood vessels. Check to see whether there is a pulse present in the wrist following elbow dislocation. The absence of a pulse creates a more emergent situation. Care: The primary responsibility is to provide the athlete with an immobilizing splint and to refer him or her to a physician for reduction as soon as possible. In most cases, the physician administers an anesthetic before reduction to relax the muscles. After reduction, the physician often immobilizes the elbow in a position of flexion and applies a splint, which should be used for approximately 3 weeks. A dislocated elbow, like a fracture, may also have possible neurovascular problems.

Lateral epicondylitis

Cause of injury: one of the most common problems of the elbow occuring in sports. Tennis elbow is another name for lateral epicondylitis stemming from a backhand stroke involving overextending the wrist. The cause of lateral epicondylitis is repetitive extension of the wrist, which eventually causes irritation and inflammation to the insertion of the extensor muscle of the lateral epicondyle. Signs of injury: The athlete complains of an aching pain in the region of the lateral epicondyle during and after activity. The pain gradually becomes worse, with weakness in the hand and wrist. Inspection reveals tenderness at the lateral epicondyle and pain on the resisted extension of the wrist and full extension of the elbow. Care: Treatment includes immediate use of PRICE, nonsteroidal anti-inflammatory drugs (NSAIDs), and analgesics as needed. Rehabiliation includes range of motion exercises, deep friction massage, hand grasping while in supination and avoiding pronation movements. Mobilization and stretching may be used within pain free limits. The athlete may wear a counterforce brace or neoprene elbow sleeve for 1 to 3 months. The athlete must be taught proper skill techniques and the proper use of equipment to avoid recurrence of the injury.

Which movements occur at the elbow joint?

Flexion and extension occur at the humeroulnar and humeroradial joints. Pronation and supination occur at the radioulnar joint.

Elbow complex joints

Humeroulnar Humeroradial joint Radioulnar joint

Lateral and medial epicondyle tests

The elbow is flexed to 45 degrees and wrist extension is resisted, which increases pain at the lateral epicondyle. When wrist flexion is resisted, pain increases at the medial epicondyle.

Prevention of elbow, forearm and wrist injuries

The elbow, forearm, and wrist are vulnerable to a variety of both acute traumatic injuries and chronic overuse type injuries. Acute injuries usually occur from either a direct blow or falling on an outstretched hand. In contact sports such as football or in high impact collision sports like baseball, wearing appropriate padding can reduce the force of impact, thus minimizing both the likelihood and the severity of the injury. Learning how to fall correctly by landing and rolling without putting the hand out to break the fall can help to prevent many of the injuries that would normally occur in the wrist, forearm or elbow. The chances of developing chronic overuse injuries that typically occur in the elbow or in the wrist may be reduced by using several strategies. The athlete should limit the number of repetitions in throwing a baseball or in hitting a tennis ball. Make certain that the mechanics of throwing or hitting techniques being used are correct and are not creating unnecessary stresses and strains. Select and use equipment that is appropriate for a specific skill level (e.g., tennis racket with the appropriate grip size). The athlete should maintain appropriate levels of strength and endurance in the muscles surrounding these joints by engaging in strength training. He or she should routinely stretch the muscles in the elbow, forearm, and wrist to make certain that they have the necessary flexibility to allow movement through a full range of motion. If a chronic overuse problem seems to be developing, the athlete should take some time off and give the injury a chance to hear so that it won't get worse.

Elbow pain may not be directly associated with an elbow injury but rather may be referred pain from the neck or shoulder.

True

Bones of the forearm

Ulna and radius Ulna: Direct extension of the humerus, is long, straight and larger at its upper end than at its lower end. The radius, considered an extension of the hand, is thicker at its lower end than its upper end.

Collateral ligament sprain

Cause of injury: A collateral ligament sprain of a finger is very common in sports such as basketball, volleyball and football. A common cause of collateral sprains is an axial force to the tip of the finger, producing the "jammed" effect. Signs of injury: Severe point tenderness exists at the joint site, especially in the region of the collateral ligaments. There may be a lateral or medial joint instability when the joint is flexed to 150 degrees. Care: Care of a collateral sprain includes ice packs for the acute stage, x-ray examination, and splinting.

Colles' Fracture

Cause of injury: A colles' fracture among the most common forearm fractures, involves the lower (distal) end of the radius. The cause of a Colles' fracture is usually a fall on the outstretched hand with an extended wrist, forcing the forearm backward and upward into hyperextension. The distal fracture fragment is displaced backward reselting in what is sometimes referred to as a dinner fork deformity. A smith's fracture is similar to a Colles' fracture in that both involve a fall on the hand. But in a Smith's fracture, the wrist is flexed, causing the distal radius fragment to be displaced anteriorly. A smith's fracture is much less common than a Colles' fracture. Signs of injury: In most cases, there is a visible deformity to the wrist. Sometimes no deformity is present, and the injury may be passed off as a bad sprain. Bleeding is profuse in this area, with the accumulated fluids causing extensive swelling in the wrist and, if unchecked, in the fingers and forearm. Ligamentous tissue is usually unharmed, but tendons may be torn away from their attachment, and there may be median nerve damage. Care: The main responsibility is to apply ice, splint the wrist, put the limb in a sling, and then refer the athlete to a physician for x-ray examination and immobilization. Lacking complications, a colles' fracture will keep an athlete out of sports for 1 to 2 months.

Subungual hematoma

Cause of injury: A contusion or crushing injury to the distal finger can cause blood to accumulate in the nail bed under the fingernail. Blood that accumulates in a confined space underneath the nail is likely to produce extreme pain and can ultimately cause loss of the nail. Signs of injury: Bleeding into the nail bed may be either immediate or slow, producing considerable pain. The area under the fingernail assumes a bluish purple color, and gentle pressure on the nail greatly exacerbates pain. Care: An ice pack should be applied immediately and the hand should be elevated to decrease bleeding. Within the next 12 to 24 hours, the pressure of the blood under the nail should be released by drilling a small hole through the nail into the nail bed. This drilling must be done under sterile conditions and is best done by either a physician or an athletic trainer. It is not uncommon to have to drill the nail a second time because more blood is likely to accumulate.

Hamate fracture

Cause of injury: A fracture of the hamate bone, and in particular the book of the hamate, can occur from a fall but more commonly occurs from contact when holding a sports implement such as the handle of tennis racket, a baseball bat, a lacrosse stick, a hockey stick or a golf club. Signs of injury: Wrist pain and weakness and point tenderness are experienced. There is possibly tingling, numbness, and weakness in the little and ring fingers because the ulnar nerve may be compromised due to of its close proximity to the hamate. Care: Casting of the wrist is usually the treatment of choice. The hook of the hamate can be protected by wearing a doughnut pad to take the pressure off the area.

Gamekeeper's thumb

Cause of injury: A sprain of the ulnar collateral ligament of the MCP joint of the thumb is common among athletes, especially skiers and tackle football players. It can also occur in baseball and softball players when the thumb is hit by a ball, exerting torque on the joint. The mechanism of injury is usually a forceful abduction of the proximal phalanx, which is occasionally combined with hyperextension. Signs of injury: The athlete complains of pain over the ulnar collateral ligament, with a weak and painful pinch. Inspection demonstrates tenderness and swelling over the medial aspect of the thumb. Care: Because the stability of pinching can be severely reduced, proper immediate and follow up care must be performed. If there is instability in the joints, the athlete should be immediately referred to an orthopedist. If the joint is stable, X-ray examination should be performed to rule out fracture. Splinting of the thumb should be applied for protection over a 3 week period or until it is pain free.

Wrist ganglion

Cause of injury: A wrist ganglion is considered by many to be either a herniation of the joint capsule, of the synovial sheath of a tendon, or a cystic structure. It usually appears slowly, after repeated forced hyperextension of the wrist, and contains a clear, mucinous fluid. The ganglion most often appears on the back of the wrist. Signs of injury: The athlete complains of occasional pain, and there is a lump at the site. Pain increases with wrist extension. There is a cystic structure that may feel soft, rubbery, or very hard. Care: An old method of treatment was first to break down the swelling through digital pressure and then apply a felt pressure pad for a time to encourage healing. A newer approach is the use of a combination of aspriation and chemical cauterization, with subsequent application of a pressure pad. Neither of these methods prevents the ganglion from recurring. Surgical removal is best of the various methods of treatment.

Fractures of the elbow

Cause of injury: An elbow fracture can occur in almost any sporting event and is usually caused by a fall on the outstretched hand or the flexed elbow or by a direct blow to the elbow. Children and young athletes have a much higher rate of this injury than do adults. A fracture can take place in any one or more of the bones that comprise the elbow. A fall on the outstretched hand quite often fractures the humerus above the condyles or the bones of the forearm and wrists. Signs of injury: An elbow fracture may or may not result in visible deformity. There usually is hemorrhage, swelling, and muscle spasm in the injured area. Care: Because of the seriousness of an elbow fracture, careful immediate care must be rendered. Following the application of ice and a sling support, the athlete must be referred immediately for medical attention. A fractured elbow is associated with rapid swelling that may cause a condition called Volkmann's contracture, an extremely serious and often irreversible condition.

Ulnar Nerve Injuries

Cause of injury: Because of the exposed position of the medial humeral condyle, the ulnar nerve is subject to a variety of problems. The athlete with a pronounced outward angle (cubitus valgus) of the elbow may develop a nerve friction problem. The ulnar nerve can also become recurrently dislocated because of a structural deformity or can become impinged by a ligament during flexion-type activities. Signs of injury: Rather than being painful, ulnar nerve injuries usually respond with a paresthesia to the fourth and fifth fingers. The athlete complains of burning and tingling in the fourth and fifth fingers. Care: The management of ulnar nerve injuries is conservative; aggravation of the nerve, such as placing direct pressure on it is avoided. When stress on the nerve cannot be avoided, surgery may be performed to transpose it anteriorly to the elbow.

Dislocations of the phalanges

Cause of injury: Dislocations of the phalanges occur frequently in sports and are caused mainly by a blow to the tip of the finger by a ball. The force of injury is usually directed upward from the palmar side, displacing either the first of second joint dorsally. The resultant problem is primarily a tearing of the supporting capsular tissue, accompanied by hemorrhaging. However, there may be a rupture of the flexor or extensor tendon and chip fractures in and around the dislocated joint. Care: Reduction of the dislocated thumb should be performed by a physician. To ensure the most complete healing of dislocated finger joints, splinting should be maintained for about 3 weeks in 30 degrees of flexion. Inadequate immobilization can cause an unstable joint and/or exessive scar tissue and possibly a permanent deformity. When the athlete returns to activity, the dislocated finger can be "buddy-taped" to the adjacent finger for additional support. Special consideration must be given to the dislocations of the thumb and second or third joints of the fingers. A properly functioning thumb is necessary for hand dexterity: consequently, any injury to the thumb should be considered serious. Thumb dislocations occur frequently at the second joint, resulting from a sharp blow to its tip with the trauma forcing the thumb into hyperextension and dislocating the second joint downward. Any dislocation of the third joint of the finger can lead to complications and requires the immediate care of an orthopedist. All hand dislocations must be xrayed to rule out a fracture.

Forearm splints and other strains

Cause of injury: Forearm strains occur in a variety of sports, most often from repeated static contractions. Forearm splints occur often in gymnastics. The reason for this problem is likely static muscle contractions of the forearm, such as those that occur when an athlete performs on the side horse. Constant static muscle contraction causes minute tears in the deep connective tissues of the forearm. Signs of injury: The main symptom of forearm splints is a dull ache in the extensor muscles crossing the back of the forearm. Muscle weakness may accompany the dull ache. Palpation reveals an irritation of the deep tissue between the muscles. The cause of this condition is uncertain; like shin splints, forearm splints usually appear either early or late in the season, indicating poor conditioning or chronic fatigue. Care: Care of the forearm splints should be focused on treating the symptoms. The athlete should concentrate on increasing the strength of the forearm through resistance exercises. Emphasis should also be placed on rest, cold or heat, and use of a supportive wrap during activity.

Fifth metacarpal fracture (Boxer's fracture)

Cause of injury: Fractures of the 5th metacarpal are associated with boxing and the martial arts and are usually called a boxer's fracture. The cause of metacarpal fractures is commonly a direct axial force caused by punching the wall or another person. Signs of injury: There is point tenderness and likely a palpable defect in the shaft of the 5th metacarpal. When the athlete makes a fist, the knuckle will appear depressed or sunken. Swelling is rapid. Care: An athlete with a suspected boxer's fracture should be referred to a physician for reduction and immobilization for a period lasting 3 to 4 weeks.

Forearm shaft fractures

Cause of injury: Fractures of the forearm are particularly common among active children and youths. Forearm fractures occur as a result of a blow or fall on the outstretched hand. Fractures of the ulna or the radius singly are much rarer than simultaneous fractures to both. Signs of injury: The break usually presents all the features of a long-bone fracture: pain, swelling, deformity, and nonunion. The older the athlete, the greater the danger of extensive damage to soft tissue and the greater the possibility of paralysis. Care: To prevent complications, a cold pack must be applied immediately to the fracture site, the arm splinted and put in a sling, and the athlete referred to a physician. The athlete usually is incapacitated for about 8 weeks.

Medial epicondylitis

Cause of injury: Irritation and inflammation of the medial epicondyle may result from a number of different sport activities that require repeated forceful flexions of the wrist. It has also has been referred to as Little league elbow, pitchers elbow, racquetball elbow, golfer's elbow, and javelin thrower's elbow. Signs of injury: Pain occurs around the medial epicondyle of the humerus during forceful wrist flexion and may radiate down the arm. There is usually point tenderness and in some cases mild swelling. Passive movement of the wrist seldom elicits pain, although active movement does. Care: Conservative management of moderate-severe medial epicondylitis usually includes use of rest, cryotherapy, or heat through the application of ultrasound. Analgesics and nonsteroidal anti-inflammatory agents may be prescribed by a physician. A counterforce brace applied just below the bend of the elbow is highly beneficial in reducing elbow stress. For more severe cases, elbow splinting and complete rest for 7 to 10 days may be warranted.

Wrist sprain

Cause of injury: It is often very difficult to distinguish between a wrist sprain and a tendon strain in the carpal region. A sprain is by far the most common wrist injury. It can occur from any abnormal, forced movement of the wrist. Falling on the hyperextended wrist is the most common cause of wrist sprain, but violent flexion or torsion can also cause injury. Signs of injury: The athlete complains of pain, swelling, and difficulty moving the wrist. On examination, there is tenderness, swelling and limited range of motion. Care: All athletes who have severe sprain should be referred to a physician for x-ray examination to determine possible fractures. Mild and moderate sprains should initially be given PRICE, splinting and analgesics. It is desirable to have the athlete start wrist strengthening exercises almost immediately after the injury has occurred. Taping or support can benefit healing and help prevent further injury.

Jersey finger

Cause of injury: Jersey finger is a rupture of the flexor digitorum profundus tendon from its insertion on the distal phalanx. It most often occurs in the ring finger when the athlete tries to grab a jersey of an opponent, either rupturing the tendon or avulsing a small piece of bone. Signs of injury: Because the tendon is no longer attached to the distal phalanx, the dip joint cannot be flexed, and the finger is in an extended position. There is pain and point tenderness over the distal phalanx. Care: If the tendon is not surgically repaired, the athlete will never be able to flex the dip joint, causing weakness in grip strength; otherwise, function is relatively normal. If surgery is done, the course of rehabilitation requires about 12 weeks and there is often poor gliding of the tendon, with the possibility of re-rupture.

Elbow sprains

Cause of injury: Sprains to the elbow are usually caused by hyperextension or a force that bends or twists the lower arm outward (valgus force), causing injury to the medial collateral ligament, as occurs during the cocking phase of throwing. Signs of injury: The athlete complains of pain and the inability to throw or grasp an object. There is point tenderness over the medial collateral ligament. Care: Immediate care for an elbow sprain consists of cold and a pressure bandage for at least 24 hours, with sling support fixed at 90 degrees of flexion. A main concern should be to progressively aid the elbow in regaining full range of motion, followed by active exercises. During rehabilitation, throwing activities should be controlled by limiting and gradually progressing the number of throw until full mobility and strength have returned. If the elbow is unstable, a surgical procedure that has been called a "tommy john" procedure is often used to repair the medial collateral ligament and joint capsule.

Boutonniere deformity

Cause of injury: The boutonniere, or buttonhole, deformity is caused by a rupture of the extensor tendon over the middle phalanx. Trauma occurs to the tip of the finger, which forces the DIP joint into extension and the PIP joint into flexion. Signs of injury: The athlete complains of severe pain and inability to extend the dip joint. There is swelling, point tenderness, and an obvious deformity. Care: Care of the boutonniere deformity includes cold application followed by splinting of the pip joint in extension. If this condition is inadequately splinted, the classic boutonniere deformity will develop. Splinting is continued for 5 to 8 weeks. While splinted, the athlete is encouraged to flex the distal phalanx.

Carpal Tunnel Syndrome

Cause of injury: The carpal tunnel is located on the anterior aspect of the wrist. The floor of the carpal tunnel is formed by the carpal bones and the roof by the transverse carpal ligament. A number of anatomical structures course through this limited space, including eight long finger flexor tendons, their synovial sheaths, and the median nerve. Carpal tunnel syndrome results from an inflammation of the tendons and synovial sheaths within this space, which ultimately leads to compression of the median nerve. Carpal tunnel syndrome most often occurs in athletes who engage in activities that require repeated wrist flexion, although it can also result from direct trauma to the anterior aspect of the wrist. Signs of injury: Compression of the median nerve usually results in both sensory and motor deficits. Sensory changes can result in tingling, numbness, and paresthesia in the arc of median nerve innercation over the thumb, index and middle fingers, and palm of the hand. The median nerve innervates the lumbrical muscles of the index and middle fingers and three of the thenar muscles. Thus, weakness in thumb movement is associated with this condition. Care: Initially, conservative treatment involving rest, immobilization in slight wrist extension and nonsteroidal anti-inflammatory medication is recommended. If the syndrome persists, injection with a corticosteroid and possible surgical decompression of the transverse carpal ligament may be necessary.

Contusion

Cause of injury: The forearm is constantly exposed to bruising in contact sports such as football. The ulnar side receives the majority of blows in arm blocks and consequently the greater amount of bruising. Bruises to this area may be classified as acute or chronic. The acute contusion can, on rare occasions, result in a fracture. The chronic contusion develops from repeated blows to the forearm with attendant multiple irritations. Signs of injury: Most often, muscles or bones develop varying degrees of pain, swelling, and accumulation of blood (hematoma). Extensive scar tissue may replace the hematoma, and in some cases a bony callus replaces the scar tissue. Care: Care of the contused forearm requires proper attention in the acute stages by application of PRICE for 20 minutes every 1 1/2 waking hours, followed the next day by cold and exercise. Protection of the forearm is important for athletes who are prone to this condition. The best protection consists of providing a full-length sponge rubber pad for the forearm early in the sports season.

Mallet finger

Cause of injury: The mallet finger is sometimes called baseball finger or basketball finger. It is caused by a blow from a thrown ball that strikes the tip of the finger, jamming and avulsing the extensor tendon from its insertion along with a piece of bone. Signs of injury: The athlete complains of pain at the distal interphalangeal joint. X-ray examination may show a bony avulsion from the dorsal proximal distal phalanx. He or she is unable to extend the finger, carrying it at approximately a 30 degree angle. There is also point tenderness at the site of the injury, and avulsed bone often can be palpated. Care: PRICE is given for the pain and swelling. If there is no fracture, the distal phalanx should immediately be splinted in a position of extension 24 hours a day for a period of 6 to 8 weeks.

Olecranon Bursitis

Cause of injury: The olecranon bursa lying between the end of the olecranon process and the skin, is the most frequently injured bursa in the elbow. The superficial location of the olecranon bursa makes it prone to acute or chronic injury, particularly as the result of direct blows or falling on the tip of the bent elbow. Signs of injury: The inflamed bursa produces pain, marked swelling, and point tenderness. Occasionally, swelling will appear almost spontaneously and will occur without the usual pain and heat. Care: If the condition is acute, ice and compression should be applied for 20 minutes. Chronic olecranon buristis requires a program of protective therapy. In rare cases, aspiration by a physician hastens healing. Although seldom serious, olecranon bursitis can be annoying and should be well protected by padding while the athlete is engaged in competition.

Scaphoid fracture

Cause of injury: The scaphoid bone is the most frequently fractured carpal bone. The injury is usually caused by a fall on an outstretched hand, which compresses the scaphoid bone between the radius and the second row of carpal bones. Signs of injury: The signs of a recent scaphoid fracture include swelling in the area of the carpal bone and severe point tenderness over the scaphoid bone in the anatomic snuffbox. Care: In an athlete with these signs, cold should be applied, the area should be splinted, and the athlete should be referred to a physician for an x-ray study and casting. It is not uncommon for a scaphoid fracture to be missed on an initial x-ray. In most cases, cast immobilization lasts for approximately 6 weeks and is followed by strengthening exercises coupled with protective taping. Immobilization is discontinued for rehabilitation. The wrist needs protection against impact loading for an additional 3 months. In many cases, the scaphoid does not heal properly, and surgery is often necessary.

Joint articulations in the forearm

The forearm has three articulations: the superior, middle and distal radioulnar joints.

Muscles of the forearm

The forearm muscles consist of flexors and pronators, positioned anteriorly and attached to the medial epicondyle, and of extensors and supinators, which lie posteriorly and are attached to the lateral epicondyle. The flexors of the wrist and fingers are separated into superficial muscles and deep muscles.

Functional evaluation

The joint and muscles are evaluated for pain sites and weakness through passive, active, and resistive motions consisting of elbow flexion and extension and forearm pronation and supination. Range of motion is particularly noted in passive and active pronation and supination.

Elbow ligaments

The ulnar (medial) collateral ligament is most important for stability to a valgus force of the elbow and extends from the medial epicondyle to the proximal ulna. The annular ligament extends from the ulna, forming a sling around the radial head and thus allowing free rotation of the radius while providing instability and and preventing radial head luxation. The radial (lateral) collateral ligament, which provides stability to a varus force, extends from the lateral epicondyle and attaches primarily to the annular ligament.

Muscles of the wrist

The wrist and hand are a complex of extrinsic muscles (which originate outside of the hand) and intrinsic muscles (which originate in the hand) muscles. In general, both the extrinsic and intrinsic muscles located on the medial aspect and front of the wrist and hand flex the wrist and fingers. The muscles on the posterior and lateral aspect of the wrist and hand flex the fingers. Intrinsic muscles of the hand also abduct, adduct and in the thumb create opposition of the metacarpals.

Ligaments of the wrist

The wrist is comprised of a complex series multiple ligaments that bind the carpal bones to one another, to the ulna and radius and to the proximal metacarpal bones. Of major interest in wrist injuries are the ulnar collateral ligament and radial collateral ligament. Crossing the volar (anterior) aspect of the carpal bones is the flexor retinaculum. This ligament serves as the roof of the capral tunnel, in which the median nerve is often compressed. The interphalangeal joints have medial and lateral collateral ligaments and a thickened joint capsule on the palmar surface that is referred to as the volar plate.

Bones of the wrist

The wrist is formed by the distal aspect of the radius and the ulna with a proximal row of four carpal bones and a distal row of four carpal bones that articulate with five metacarpals. The metacarpal bones join the carpal bones above the phalanges below, forming metacarpophalangeal (MCP) articulations. The four fingers each have a proximal, middle and distal phalanx, whereas the thumb only has two phalanges.

Elbow complex

humerus, radius, ulna The distal end of the humerus forms the medial and lateral epicondyles. The olecranon process of the ulna articulates with the trochlea and olecranon fossa on the posteiror humerus. The radial head articulates with the capitellum of the ulna.