Hand Moore

Overall, most wrist movement occurs at the wrist _________ between the radius and articular disc of the distal radio-ulnar joint and the proximal row of carpal bones (primarily the scaphoid and lunate). However, concomitant movement at the intercarpal (IC) joints (especially the midcarpal IC joint) augments these movements.

(radiocarpal) joint

Organization: The muscles and tendons of the hand are organized into five fascial compartments: two radial compartments (_______________) that serve the thumb, an ulnar (__________) compartment that serves the little finger, and two more central compartments that serve the medial four digits(______)

(thenar and adductor), (hypothenar), (a palmar one for the long flexor tendons and lumbricals, and a deep one between the metacarpals for the interossei).

______________ is an uncommon but serious injury that usually results from a fall on the dorsiflexed wrist (Fig. B3.42A). The lunate is pushed out of its place in the floor of the carpal tunnel toward the palmar surface of the wrist. The displaced lunate may compress the median nerve and lead to carpal tunnel syndrome (see clinical box earlier in this chapter). Because of its poor blood supply, avascular necrosis of the lunate may occur. In some cases, excision of the lunate may be required. In degenerative joint disease of the wrist, surgical fusion of carpals (arthrodesis) may be necessary to relieve the severe pain

Anterior dislocation of the lunate

___________ refers to a sprain of the radial collateral ligament and an avulsion fracture of the lateral part of the proximal phalanx of the thumb. This injury is common in individuals who ride mechanical bulls.

Bull rider's thumb

___________ results from any lesion that significantly reduces the size of the carpal tunnel (Fig. B3.32A-D) or, more commonly, increases the size of some of the nine structures or their coverings that pass through it (e.g., inflammation of synovial sheaths). Fluid retention, infection, and excessive exercise of the fingers may cause swelling of the tendons or their synovial sheaths. The median nerve is the most sensitive structure in the tunnel. The median nerve has two terminal sensory branches that supply the skin of the hand; hence, paresthesia (tingling), hypoesthesia (diminished sensation), or anesthesia (absence of sensation) may occur in the lateral three and a half digits. The palmar cutaneous branch of the median nerve arises proximal to, and does not pass through, the carpal tunnel; thus, sensation in the central palm remains unaffected. The nerve also has terminal motor branches: the recurrent branch, which serves the three thenar muscles, and branches to lumbricals 1 and 2 (Fig. 3.85A).

Carpal tunnel syndrome

Fracture of the distal end of the radius (_______ fracture), the most common fracture in people >50 years of age, is discussed in the clinical box "Fractures of Radius and Ulna." Fracture of the scaphoid, relatively common in young adults, is discussed in the clinical box "Fracture of Scaphoid."

Colles

________ is a disease of the palmar fascia resulting in progressive shortening, thickening, and fibrosis of the palmar fascia and aponeurosis. The fibrous degeneration of the longitudinal bands of the palmar aponeurosis on the medial side of the hand pulls the 4th and 5th fingers into partial flexion at the metacarpophalangeal and proximal interphalangeal joints (Fig. B3.30A). The contracture is frequently bilateral and is seen in some men >50 years of age. Its cause is unknown, but evidence points to a hereditary predisposition. The disease first manifests as painless nodular thickenings of the palmar aponeurosis that adhere to the skin. Gradually, progressive contracture of the longitudinal bands produces raised ridges in the palmar skin that extend from the proximal part of the hand to the base of the 4th and 5th fingers (Fig. B3.30B). Treatment of Dupuytren contracture usually involves surgical excision of all fibrotic parts of the palmar fascia to free the fingers (Salter, 1999).

Dupuytren contracture

What motions can occur at the wrist?

Extension-flexion, abduction-adduction, and circumduction occur.

___________________ is common in children because of frequent falls in which forces are transmitted from the hand to the radius (Fig. B3.42B, C). In a lateral radiograph of a child's wrist, dorsal displacement of the distal radial epiphysis is obvious (Fig. B3.42C). When the epiphysis is placed in its normal position during reduction, the prognosis for normal bone growth is good.

Fracture-separation of the distal radial epiphysis

________ refers to compression of something between the thumb and index finger—for example, handling a teacup or holding a coin on edge (Fig. 3.73E)—or between the thumb and the adjacent two fingers—for example, snapping the fingers.

Pinching

The tendons of the APL and EPB are in the same tendinous sheath on the dorsum of the wrist. Excessive friction of these tendons on their common sheath results in fibrous thickening of the sheath and stenosis of the osseofibrous tunnel. The excessive friction is caused by repetitive forceful use of the hands during gripping and wringing (e.g., squeezing water out of clothes). This condition, called ____________, causes pain in the wrist that radiates proximally to the forearm and distally toward the thumb. Local tenderness is felt over the common flexor sheath on the lateral side of the wrist.

Quervain tenovaginitis stenosans

__________ (historically, gamekeeper's thumb) refers to the rupture or chronic laxity of the collateral ligament of the 1st MP joint (Fig. B3.43). The injury results from hyperabduction of the MP joint of the thumb, which occurs when the thumb is held by the ski pole while the rest of the hand hits the ground or enters the snow. In severe injuries, the head of the metacarpal has an avulsion fracture.

Skier's thumb

The intrinsic muscles of the hand constitute the _________

T1 myotome

The superficial dorsal venous network is commonly used for ___________________

administering intravenous fluids

The vasculature of the hand is characterized by multiple ________ between both radial and ulnar vessels and palmar and dorsal vessels.

anastomoses

Lesions of the median nerve usually occur in two places: the forearm and the wrist. The most common site is where the nerve passes through the...

carpal tunnel

Progressive loss of coordination and strength of the thumb (owing to weakness of the APB and opponens pollicis) may occur if the cause of compression is not alleviated. Individuals with ___________ are unable to oppose their thumbs (Fig. B3.32E). They have difficulty buttoning a shirt or blouse, as well as gripping things such as a comb. As the condition progresses, sensory changes radiate into the forearm and axilla. Symptoms of compression can be reproduced by compression of the median nerve with your finger at the wrist for approximately 30 seconds. To relieve both the compression and the resulting symptoms, partial or complete surgical division of the flexor retinaculum, a procedure called carpal tunnel release, may be necessary. The incision for carpal tunnel release is made toward the medial side of the wrist and flexor retinaculum to avoid possible injury to the recurrent branch of the median nerve.

carpal tunnel syndrome

The __________ joints of the four medial fingers, which share a common articular cavity, have limited motion (especially those of the 2nd and 3rd digits), contributing to the stability of the palm as a base from and against which the fingers operate. • Motion occurs at the CMC joints for the 3rd and 4th digits, mostly in association with a tight grip or cupping of the palm, as during opposition. However, the great mobility of the CMC joint of the thumb, a saddle joint, provides the digit with the major portion of its range of motion and specifically enables opposition.

carpometacarpal (CMC)

Therefore, the ________ joint is key to the effectiveness of the human hand. In contrast to the CMC joints, the metacarpophalangeal (MP) joints of the medial four fingers offer considerable freedom of movement (flexion-extension and abduction-adduction), whereas that of the thumb is limited to flexion-extension, as are all interphalangeal joints.

carpometacarpal (CMC)

The arteries of the upper limb are innervated by sympathetic nerves. Postsynaptic fibers from the sympathetic ganglia enter nerves that form the brachial plexus and are distributed to the digital arteries through branches arising from the plexus. When treating ischemia resulting from Raynaud syndrome, it may be necessary to perform a ___________________ (excision of a segment of a sympathetic nerve) to dilate the digital arteries.

cervicodorsal presynaptic sympathectomy

The location of superficial and deep palmar arches should be kept in mind when examining wounds of the palm and when making palmar incisions. Furthermore, it is important to know that the superficial palmar arch is at the same level as the distal end of the ________ (Figs. 3.77A and 3.81). As mentioned previously, incisions or wounds along the medial surface of the thenar eminence may injure the recurrent branch of the median nerve to the thenar muscles (see the clinical box "Trauma to Median Nerve").

common flexor sheath

Thickening of a fibrous digital sheath on the palmar aspect of the digit produces stenosis of the osseofibrous tunnel, the result of repetitive forceful use of the fingers. If the tendons of the FDS and FDP enlarge proximal to the tunnel, the person is unable to extend the finger. When the finger is extended passively, a snap is audible. Flexion produces another snap as the thickened tendon moves. This condition is called __________ (Fig. B3.31).

digital tenovaginitis stenosans (trigger finger or snapping finger)

Although the radial nerve supplies no muscles in the hand, radial nerve injury in the arm can produce serious hand disability. The characteristic handicap is inability to __________ resulting from paralysis of extensor muscles of the forearm, all of which are innervated by the radial nerve (Fig. 3.61B; Table 3.11). The hand is flexed at the wrist and lies flaccid, a condition known as wrist-drop (see the clinical box "Injury to Radial Nerve in Arm"). The fingers of the relaxed hand also remain in the flexed position at the metacarpophalangeal joints. The loss of the ability to extend the wrist affects the length tension relationship of the wrist and finger flexors. This will drastically reduce grip strength and functional lifting. The interphalangeal joints can be extended weakly through the action of the intact lumbricals and interossei, which are supplied by the median and ulnar nerves (Table 3.13). The radial nerve has only a small area of exclusive cutaneous supply on the hand. Thus, the extent of anesthesia is minimal, even in serious radial nerve injuries, and is usually confined to a small area on the lateral part of the dorsum of the hand.

extend the wrist

Movements: The larger (wider range) and stronger movements of the hand and fingers (grasping, pinching, and pointing) are produced by _______ muscles with fleshy bellies located distant from the hand (near the elbow) and long tendons passing into the hand and fingers. • The shorter, more delicate and weaker movements (typing, playing musical instruments, and writing), and positioning of the fingers for the more powerful movements are accomplished largely by the _______ muscles.

extrinsic, intrinsic

Each segment of the upper limb increases the functionality of the end unit, the hand. Located on the free end of a two-unit articulated strut (arm and forearm) projecting from a mobile base (shoulder), the hand can be positioned over a wide range relative to the trunk. The hand's connection to the flexible strut via the multiple small bones of the carpus, combined with the pivoting of the forearm, greatly increases its ability to be placed in a particular position with the digits able to...

flex (push or grip) in the necessary direction

Acting together with the lumbricals, the interossei ____ the metacarpophalangeal and _____ the interphalangeal joints of the medial four digits (the Z-movement).

flex, extend

Median nerve injury resulting from a perforating wound in the elbow region results in loss of _____________________. The ability to flex the metacarpophalangeal joints of these fingers is also affected because digital branches of the median nerve supply the 1st and 2nd lumbricals. Simian hand (Fig. B3.32F) refers to a deformity in which thumb movements are limited to flexion and extension of the thumb in the plane of the palm. This condition is caused by the inability to oppose and by limited abduction of the thumb. The recurrent branch of the median nerve to the thenar muscles (Fig. 3.84A) lies subcutaneously and may be severed by relatively minor lacerations of the thenar eminence. Severance of this nerve paralyzes the thenar muscles, and the thumb loses much of its usefulness.

flexion of the proximal and distal interphalangeal joints of the 2nd and 3rd digits

People who ride long distances on bicycles with their hands in an extended position against the hand grips put pressure on the hooks of their ______ (Fig. 3.70B), which compresses their ulnar nerves. This type of nerve compression, which has been called handlebar neuropathy, results in sensory loss on the medial side of the hand and weakness of the intrinsic hand muscles.

hamates

The _________ (flexion of the IP joints of the 2nd to 4th digits) resists gravitational (downward) pull with only digital flexion. It is the posture of the hand that is used when carrying a briefcase (Fig. 3.73B). This grip consumes less energy, involving mainly the long flexors of the digits, which are flexed to a varying degree, depending on the size of the object that is grasped.

hook grip

Because the palmar fascia is thick and strong, swellings resulting from hand infections usually appear on the dorsum of the hand, where the fascia is thinner. The potential fascial spaces of the palm are important because they may become _______. The fascial spaces determine the extent and direction of the spread of pus formed by these infections. Depending on the site of infection, pus will accumulate in the thenar, hypothenar, midpalmar, or adductor compartments (see Fig. 3.75A). Antibiotic therapy has made infections that spread beyond one of these fascial compartments rare; however, an untreated infection can spread proximally from the midpalmar space through the carpal tunnel into the forearm, anterior to the pronator quadratus and its fascia.

infected

Intermittent bilateral attacks of _______, marked by cyanosis and often accompanied by paresthesia and pain, are characteristically brought on by cold and emotional stimuli. The condition may result from an anatomical abnormality or an underlying disease. When the cause of the condition is idiopathic (unknown) or primary, it is called Raynaud syndrome (disease).

ischemia of the digits

Fascia and Compartments of Palm Moore, Keith L.. Clinically Oriented Anatomy (p. 241). Wolters Kluwer Health. Kindle Edition.

look at

The _________ nerve is most important to the function of the thumb, and sensation from the lateral three and half digits and adjacent palm, whereas the ulnar nerve supplies the remainder.

median

Laceration of the wrist often causes ___________ injury because this nerve is relatively close to the surface. In attempted suicides by wrist slashing, the median nerve is commonly injured just proximal to the flexor retinaculum. This results in paralysis of the muscles of the thenar eminence (except the adductor pollicis and deep head of the flexor pollicis brevis) and the first two lumbricals. Hence opposition of the thumb is not possible, and fine control movements of the 2nd and 3rd digits are impaired. Sensation is also lost over the thumb and adjacent two and a half fingers.

median nerve

Most nerve injuries in the upper limb affect ______________ (Fig. 3.76). Undoubtedly, injuries to the nerves supplying the intrinsic muscles of the hand, especially the median nerve, have the most severe effects on this complex movement. If the median nerve is severed in the forearm or at the wrist, the thumb cannot be opposed. However, the APL and adductor pollicis (supplied by the posterior interosseous and ulnar nerves, respectively) may imitate opposition, although ineffective.

opposition of the thumb

The ___________ nerves and vessels are dominant, supplying not only the more sensitive and functional palmar aspect but also the dorsal aspect of the distal part of the digits (nail beds).

palmar

The arteries of the hand collectively constitute a peri-articular arterial anastomosis around the collective joints of the wrist and hand. Thus, blood is generally available to all parts of the hand in all positions as well as while performing functions (gripping or pressing) that might otherwise compromise especially the _____ structures.

palmar

The __________ is assumed by an inactive hand—for example, when the forearm and hand are laid on a table (Fig. 3.73F). This position is often used when it is necessary to immobilize the wrist and hand in a cast to stabilize a fracture.

position of rest

The ______________ refers to forcible motions of the digits acting against the palm; the fingers are wrapped around an object with counterpressure from the thumb—for example, when grasping a cylindrical structure (Fig. 3.73A). The power grip involves the long flexor muscles to the digits (acting at the interphalangeal joints), the intrinsic muscles in the palm (acting at the metacarpophalangeal joints), and the extensors of the wrist (acting at the radiocarpal and midcarpal joints). The "cocking" of the wrist by the extensors increases the distance over which the flexors of the fingers act, producing the same result as a more complete muscular contraction. Conversely, as flexion increases at the wrist, the grip becomes weaker and more insecure.

power grip (palm grasp)

The ____________ involves a change in the position of a handled object that requires fine control of the movements of the digits (fingers)—for example, holding a pencil, manipulating a coin, threading a needle, or buttoning a shirt (Fig. 3.73C, D). The wrist and digits are held firmly by the long flexor and extensor muscles, and the intrinsic hand muscles perform fine movements of the digits

precision handling grip

In terms of intrinsic structure, the radial nerve is sensory only via its ______________

superficial branch to the dorsum of the hand.

Injuries such as a puncture of a finger by a rusty nail can cause infection of the digital synovial sheaths (Fig. 3.81A). When inflammation of the tendon and synovial sheath occurs (________), the digit swells and movement becomes painful. Because the tendons of the 2nd, 3rd, and 4th fingers nearly always have separate synovial sheaths, the infection is usually confined to the infected finger. If the infection is untreated, however, the proximal ends of these sheaths may rupture, allowing the infection to spread to the midpalmar space (Fig. 3.75B). Because the synovial sheath of the little finger is usually continuous with the common flexor sheath (Fig. 3.81B), tenosynovitis in this finger may spread to the common flexor sheath and through the palm and carpal tunnel to the anterior forearm, draining into the space between the pronator quadratus and the overlying flexor tendons (Parona space). Likewise, tenosynovitis in the thumb may spread via the continuous synovial sheath of the FPL (radial bursa). How far an infection spreads from the fingers depends on variations in their connections with the common flexor sheath.

tenosynovitis

The interossei produce multiple movements: ____________________________. Both movements occur at the metacarpophalangeal joints.

the dorsal interossei (and abductors pollicis and digiti minimi) abduct the digits, whereas the palmar interossei (and adductor pollicis) adduct them

Motion at the wrist moves the entire hand, making a dynamic contribution to a skill or movement, or allowing it to be stabilized in a particular position to maximize the effectiveness of the hand and fingers in manipulating and holding objects. Complexity as well as flexibility of the wrist results from....

the number of bones involved

Bleeding is usually profuse when ______________. It may not be sufficient to ligate only one forearm artery when the arches are lacerated, because these vessels usually have numerous communications in the forearm and hand and thus bleed from both ends. To obtain a bloodless surgical operating field for treating complicated hand injuries, it may be necessary to compress the brachial artery and its branches proximal to the elbow (e.g., using a pneumatic tourniquet). This procedure prevents blood from reaching the ulnar and radial arteries through the anastomoses around the elbow (Fig. 3.67, palmar view).

the palmar (arterial) arches are lacerated

The palmar aspect of the hand features a central concavity that, with the crease proximal to it (over the wrist bones), separates two eminences: a lateral, larger and more prominent _____ eminence at the base of the thumb and a medial, smaller ______ eminence proximal to the base of the 5th finger (Fig. 3.72A).

thenar, hypothenar

Muscles: The greatest mass of intrinsic muscles is dedicated to the highly mobile _________. Indeed, when extrinsic muscles are also considered, the thumb has eight muscles producing and controlling the wide array of movements that distinguish the human hand.

thumb

The science of studying ridge patterns of the palm, called dermatoglyphics, is a valuable extension of the conventional physical examination of people with certain congenital anomalies and genetic diseases. For example, people with trisomy 21 (Down syndrome) have dermatoglyphics that are highly characteristic. In addition, they often have a single _____________ (Simian crease); however, approximately 1% of the general population has this crease with no other clinical features of the syndrome.

transverse palmar crease

Compression of the _______ nerve may occur at the wrist where it passes between the pisiform and the hook of the hamate. The depression between these bones is converted by the pisohamate ligament into an osseofibrous tunnel, the ulnar canal (Guyon tunnel) (Fig. 3.70B). Ulnar canal syndrome (Guyon tunnel syndrome) is manifest by hypoesthesia (reduced sense of touch or sensation) in the medial one and a half fingers and weakness of the intrinsic muscles of the hand. "Clawing" of the 4th and 5th fingers (hyperextension at the metacarpophalangeal joint with flexion at the proximal interphalangeal joint) may occur, but—in contradistinction to proximal ulnar nerve injury—their ability to flex is unaffected, and there is no radial deviation of the hand.

ulnar

The arteries to the digits are also characterized by their ability to ____ during exposure to cold to conserve heat and to _____ (while the hand becomes sweaty) to radiate excess heat.

vasoconstrict, dilate

Innervation: Unlike the dermatomes of the trunk and proximal limbs, the zones of cutaneous innervation and the roles of motor innervation are __________, as are functional deficits.

well defined