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The hand and the wrist have a higher concentration of joints than any other part of the body.
Terms used to describe the anatomy of the hand:
The terms volar and palmar refer to the palm of the hand.
The term dorsalrefers to the back of the hand.
The radial border refers to the edge of the hand next to the thumb.
The ulnar border refers to the opposite edge, next to the fifth digit.
Each finger is composed of three phalangeal bones that articulate at three joints.
The joints of the finger are: the metacarpophalangeal joint between the metacarpal bone and the proximal phalanx, the proximal interphalangeal joint between the proximal and intermediate phalanges, and the distal interphalangeal joint between the intermediate and distal phalanges.
The thumb has only two phalangeal bones and two joints: the metacarpophalangeal joint and the interphalangeal joint.
The triangular depression on the dorsal radial aspect of the hand and wrist and is an important surface landmark, known as the snuffbox.
The isosceles triangle is formed by the extensor muscles of the thumb.
The base of the triangle is formed by the radial styloid process in the wrist, and the apex is denoted by the carpometacarpal joint at the base of the thumb.
The scaphoid bone, in the floor of the snuffbox, is the carpal bone that is most commonly fractured.
Lister’s tubercle is a small bony prominence palpable on the dorsal radial aspect of the wrist.
Lister’s tubercle is key to locating the distal radius and the scapholunate ligament, which holds together the scaphoid and lunate bones of the wrist.
Just under Lister’s tubercle, on the dorsum of the wrist is the distal ulna.
The distal ulna is the largest prominence in the wrist.
The carpal tunnel is a passageway for the median nerve, tendons, and connective tissue on the palmar side of the wrist.
The carpal tunnel resides just below the transverse carpal ligament when the palm is facing upward.
Swelling of any of the nine tendons within the carpal tunnel can increase compartmental pressure and compress the median nerve, causing the symptoms that are characteristic of carpal tunnel syndrome,
Carpal tunnel symptoms include tingling and pain in the fingers or hand and numbness in the thumb, the second and third digits, and the radial half of the fourth digit.
To assess for carpal tunnel syndrome, initially check for sensation to light touch at the terminal pads of the fingers.
The two-point discrimination, or the ability to discern two distinct points on the skin, is more sensitive.
Assess the patient for Tinel’s sign by firmly percussing the median nerve.
Tinel’s sign is present if the patient reports tingling, “pins and needles,” or any other signs of paresthesia, such as a shooting sensation in the thumb or the second or third digits.
The sensitivity of Tinel’s sign for carpal tunnel syndrome is 36% and the specificity is 75%.
The Durkan’s test is performed by compressing the carpal tunnel for up to 30 seconds with the thumb.
The onset of pain, tingling, or any abnormal sensation in the median nerve distribution constitutes a positive test result.
The Phalen’s maneuver asks the patient to hold the wrist in forced flexion for 30 to 60 seconds.
The Phalen’s maneuver can increase pressure on the carpal tunnel and further irritate the median nerve, causing abnormal sensations that include burning, tingling, or numbness in the thumb or in the second or third digits.
Carpal tunnel syndrome is caused by ischemia of the median nerve, and a decrease in cardiac output during sleep can exacerbate the ischemia, resulting in pain that may cause the patient to wake during the night.
By decreasing external compression of the carpal tunnel, splinting minimizes wrist flexion and extension, and can alleviate symptoms
Persistent symptoms may be an indication for surgical release.
Persistent pain, especially at night, especially if also unresponsive to splinting, the patient should be referred to a hand surgeon.
Prolonged compression or ischemia of the median nerve can lead to irreversible damage.
Stenosing flexor tenosynovitis, known as trigger finger, occurs when a finger becomes stuck in a flexed position and then extends suddenly, often with a painful snap.
Trigger finger is usually caused by inflammation of the flexor tendon, that leads to thickening and subsequent stenosis of the tendon sheath.
The tendon sheath is composed of multiple pulleys that hold the tendon to the bone as the tendon glides during bending and straightening of the finger.
The tendon sheath releases fluid that facilitates the gliding of the tendon during movement.
Repetitive gripping motions can cause inflammation and irritation of the tendon. and may cause the formation of a nodule on the tendon.
The nodule formation leads to narrowing of the sheath space preventing the tendon from gliding smoothly.
The clicking or locking seen with trigger finger is related to the inflammation of the smooth tendon or the popping of the nodule in and out of the flexor sheath pulley over the volar side of the metacarpophalangeal joint.
Diabetes or rheumatoid arthritis patients are at increased risk for trigger finger.
Mild cases of trigger finger may be resolved with splinting and the avoidance of repetitive gripping.
Glucocorticoid injections at the tendon sheath may be necessary to reduce inflammation.
The finger has two tendons: the flexor digitorum profundus tendon and the flexor digitorum superficialis,
The flexor digitorum profundus tendon, which is assessed by having the patient flex the distal interphalangeal joint.
The flexor digitorum superficialis, is assessed by flexing the proximal interphalangeal joint of the affected finger while holding the other fingers in an extended position.
Scaphoid fracture may have occurred in a patient who has radial wrist pain after a fall on an outstretched hand.
Examination of the wrist for scaphoid fracture is noted when the thumb is extended and the anatomical snuffbox becomes more apparent, and has pain in this area.
A fracture line in the scaphoid bone is diagnostic of a scaphoid fracture on x-rays.
25% of all scaphoid fractures may not be detectable on the initial radiograph, however.
Nondisplaced scaphoid fractures or fractures that are not visible on radiography can be treated with an orthosis for the thumb or a cast.
Displaced scaphoid fractures may require surgical treatment.
Failure to identify a scaphoid fracture may result in necrosis of scaphoid fragments and can lead to the early onset of arthritis in the wrist.
De Quervain’s disease is tenosynovitis caused by irritation and swelling of the tendons of the first extensor compartment.
De Quervain’s disease tendons of the first extensor compartment. include the extensor pollicis brevis and the abductor pollicis longus at the base of the thumb.
De Quervain’s disease patients may present with pain on the radial side of the wrist, especially when grasping an object or twisting the wrist.
Swelling may also be seen with De Quervain’s disease.
Finkelstein’s Test is used for diagnosis of De Quervain’s disease.
The test is performed by placing the thumb against the hand and closing the fingers to form a fist.
Diverting the wrist in the ulnar direction, If the patient will feels a sharp pain, a positive result in the Finkelstein’s test may be an indication of de Quervain’s disease.
Pain on palpation of the thumb extensor tendons in the first extensor compartment can further confirm the diagnosis.
Nonsurgical treatments for de Quervain’s disease include the use of a splint to immobilize the thumb and administration of nonsteroidal antiinflammatory drugs.
De Quervain’s disease patients should avoid activities that involve repetitive movements of the hand that irritate the thumb.
Glucocorticoids injected into the tendon sheath can reduce inflammation and swelling of the tendon and relieve pain in approximately 80% of patients.
Repeat steroid injections are of questionable value and may have side effects, including tendon injury.
Carpometacarpal arthritis of the thumb is a degenerative disease in which the cartilage between the two bones of the carpometacarpal joint breaks down. causing the two bones rub against each other, and resulting in pain.
A patient with a fracture of the distal radius will present with pain, bruising, and swelling in the area of the distal radius.
Lister’s tubercle may be especially tender on palpation with fracture of the distal radius.
Treatment of distal radius fractures is usually based on radiographic alignment.
Surgical intervention is considered when displacement or angulation is present.
In patients older than 60 years of age who have distal radius malunions still remain functional, and this require population may not require surgical intervention.
The scapholunate ligament may tear with a fall with an outstretched hand.
The scapholunate ligament is. The most commonly injured ligament in the wrist.
It is associated with tenderness over the depression distal to Lister’s tubercle.
Tenderness over the ulnar extensor tendon and the distal divot of the distal ulna may indicate extensor carpi ulnaris tendinitis or injury of the triangular fibrocartilage complex.
The extensor carpi ulnaris tendon allows the wrist to be in extension, with ulnar deviation.
The triangular fibrocartilage of the extensor ulnaris tendon complex stabilizes the wrist during pronation and supination.