The distal radioulnar joint is a uniaxial pivot joint that has one degree of freedom.1 Although the radius moves over the ulna, the ulna does not remain stationary. It moves back and laterally during pronation and forward and medially during supination. The resting position of the joint is 10° of supination, and the close packed position is 5° of supination. The capsular pattern of the distal radioulnar joint is full range of motion (ROM) with pain at the extreme of rotation.

The radiocarpal (wrist) joint is a biaxial ellipsoid joint.1,2 The radius articulates with the scaphoid and lunate. The distal radius is not straight but is angled toward the ulna (15° to 20°), and its posterior margin projects more distally to provide a “buttress effect.”³ The lunate and triquetrum also articulate with the triangular cartilaginous disc (triangular fibrocartilage complex [TFCC]) (Figures 7-1 and 7-2) and not the ulna. The disc extends from the ulnar side of the distal radius and attaches to the ulna at the base of the ulnar styloid process. The disc adds stability to the wrist. It creates a close relation between the ulna and carpal bones and binds together and stabilizes the distal ends of the radius and ulna.^4,5 With the disc in place, the radius bears 60% of the load and the ulna bears 40%. If the disc is removed, the radius transmits 95% of the axial load and the ulna transmits 5%.⁶ Therefore, the cartilaginous disc acts as a cushion for the wrist joint and as a major stabilizer of the distal radioulnar joint.^3,7 The disc can be damaged by forced extension and pronation. The distal end of the radius is concave and the proximal row of carpals is convex, but the curvatures are not equal. The joint has 2° of freedom, and the resting position is neutral with slight ulnar deviation. The close packed position is extension, and the capsular pattern is equal limitation of flexion and extension.

The stability of the carpals (wrist) is primarily maintained by a complex configuration of ligaments (Figure 7-3).⁸ The ligaments stabilizing the scaphoid, lunate, and triquetrum are the most important.⁹ Of these ligaments, the radioscapholunate ligament is one of the most important, because it is commonly injured and, when intact, maintains carpal stability.¹⁰ This ligament is most likely to be injured with a pronated fall on out-stretched hand (FOOSH) injury (wrist extension, ulnar deviation, and intercarpal supination).^9,11 Lunotriquetral injuries are more likely to occur with wrist extension, radial deviation, and intercarpal supination.⁹ The palmar ligaments are much stronger than the dorsal ligaments. The palmar extrinsic ligaments control the movement of the wrist and scaphoid with the radioscapholunate ligament acting as a sling for the scaphoid.¹⁰ This ligament along with the radiolunate ligament allows the scaphoid to rotate around them, and both stabilize the scaphoid at the extremes of motion.¹⁰ On the ulnar side, the ligaments (palmar lunotriquetral, capitotriquetral, dorsal intercarpal, and the fibrocartilaginous disc) control the triquetrum.

The intercarpal joints include the joints between the individual bones of the proximal row of carpal bones (scaphoid, lunate, and triquetrum) and the joints between the individual bones of the distal row of carpal bones (trapezium, trapezoid, capitate, and hamate). Perilunate injuries involve the lunate and its relation with the other carpals as well as the radius and ulna.12 They are bound together by small intercarpal ligaments (dorsal, palmar, and interosseous), which allow only a slight amount of gliding movement between the bones. The close packed position is extension, and the resting position is neutral or slight flexion. The pisotriquetral joint is considered separately, because the pisiform sits on the triquetrum and does not take a direct part in the other intercarpal movements.

The proximal transverse arch (Figure 7-4) that forms the carpal tunnel is formed by the distal row of carpal bones. In this relatively rigid arch, the capitate bone acts as a central keystone structure.¹³

At the thumb, the carpometacarpal joint is a sellar joint that has 3° of freedom, whereas the second to fifth carpometacarpal joints are plane joints.14 The capsular pattern of the carpometacarpal joint of the thumb is abduction most limited, followed by extension. The resting position is midway between abduction and adduction and midway between flexion and extension. The close packed position of the carpometacarpal joint of the thumb is full opposition. For the second to fifth carpometacarpal joints, the capsular pattern of restriction is equal limitation in all directions. The bones of these joints are held together by dorsal and palmar ligaments. In addition, the thumb articulation has a strong lateral ligament extending from the lateral side of the trapezium to the radial side of the base of the first metacarpal, and the medial four articulations have an interosseous ligament similar to that found in the carpal articulation.

The carpometacarpal articulations of the fingers allow only gliding movement. The second and third carpometacarpal joints tend to be relatively immobile and are the primary “stabilizing” joints of the hand, whereas the fourth and fifth joints are more mobile to allow the hand to adapt to different shaped objects during grasping. The carpometacarpal articulation of the thumb is unique in that it allows flexion, extension, abduction, adduction, rotation, and circumduction. It is able to do this because the articulation is saddle shaped. Because of the many movements possible at this joint, the thumb is able to adopt any position relative to the palmar aspect of the hand.14

The plane intermetacarpal joints have only a small amount of gliding movement between them and do not include the thumb articulation. They are bound together by palmar, dorsal, and interosseous ligaments.

The metacarpophalangeal joints are condyloid joints. The collateral ligaments of these joints are tight on flexion and relaxed on extension. These articulations are also bound by palmar ligaments and deep transverse metacarpal ligaments. The dorsal or extensor hood (Figure 7-5) reinforces the dorsal aspect of the metacarpophalangeal joints while volar or palmar plates reinforce the palmar aspect (see Figure 7-5).³ Each joint has 2° of freedom. The first metacarpophalangeal joint has 3° of freedom, thus facilitating the movement of the carpometacarpal joint of the thumb.¹⁴ The close packed position of the first metacarpophalangeal joint is maximum opposition, and the close packed position for the second through the fifth metacarpophalangeal joints is maximum flexion.¹⁵ The resting position of the metacarpophalangeal joints is slight flexion, whereas the capsular pattern is more limitation of flexion than extension.

The distal transverse arch (see Figure 7-4) passes through the metacarpophalangeal joints and has greater mobility than the proximal transverse arch allowing the hand to form or fit around different objects. The second and third metacarpophalangeal joints form the stable portion of the arch while the fourth and fifth metacarpophalangeal joints form the mobile portion (see Figure 7-27).¹³

The longituginal arch follows the more rigid portion of the hand running from the carpals to the carpometacarpal joints providing longitudinal stability to the hand. The second and third metacarpophalangeal joints are the keystone to both the distal transverse arch and the distal longitudinal arch.¹³

The interphalangeal joints are uniaxial hinge joints, each having 1° of freedom. The close packed position of the proximal interphalangeal joints and distal interphalangeal joints is full extension; the resting position is slight flexion. The capsular pattern of these joints in flexion is more limited than extension. The bones of these joints are bound together by a fibrous capsule and by the palmar and collateral ligaments. During flexion, there is some rotation in these joints so that the pulp of the fingers faces more fully the pulp of the thumb. If the metacarpophalangeal joints and the proximal interphalangeal joints of the fingers are flexed, they converge toward the scaphoid tubercle (Figure 7-6). This is sometimes referred to as a cascade sign. If one or more fingers do not converge, it usually indicates trauma (e.g., fracture) to the digits that has altered their normal alignment.

In addition to the questions listed under the “Patient History” section in Chapter 1, the examiner should obtain the following information from the patient:

Any localized swellings (e.g., ganglion) that are seen on the dorsum of the hand should be recorded (Figure 7-8).²¹ In the wrist and hand, effusion and synovial thickening are most evident on the dorsal and radial aspects. Swelling of the metacarpophalangeal and interphalangeal joints is most obvious on the dorsal aspect.

Any vasomotor, sudomotor, pilomotor, and trophic changes should be recorded. These changes may be indicative of a peripheral nerve injury, peripheral vascular disease, diabetes mellitus, Raynaud disease, or reflex neurovascular syndromes (also called complex regional pain syndrome, reflex sympathetic dystrophy, shoulder-hand syndrome, and Sudeck atrophy). The changes seen could include loss of hair on the hand, brittle fingernails, increase or decrease in sweating of the palm, shiny skin, radiographic evidence of osteoporosis, or any difference in temperature between the two limbs. Table 7-1 illustrates vasomotor, sudomotor, pilomotor, and trophic changes that occur in the hand when sympathetic nerve function has been affected.

The presence of Heberden or Bouchard nodes (Figure 7-9) should be recorded. Heberden nodes appear on the dorsal surface of the distal interphalangeal joints and are associated with osteoarthritis. Bouchard nodes are on the dorsal surface of the proximal interphalangeal joints. They are often associated with gastrectasis and osteoarthritis.

The examiner should note any rotational or angulated deformities of the fingers, which may be indicative of previous fracture. The nail beds are normally parallel to one another. The fingers, when extended, are slightly rotated toward the thumb to aid pinch. Ulnar drift (Figure 7-10) may be seen in rheumatoid arthritis, owing to the shape of the metacarpophalangeal joints and the pull of the long tendons.

The examiner should take time to observe the fingernails. “Spoon-shaped” nails (Figure 7-11) are often the result of fungal infection, anemia, iron deficiency, long-term diabetes, local injury, developmental abnormality, chemical irritants, or psoriasis. They may also be a congenital or hereditary trait. “Clubbed” nails (Figure 7-12) may result from hypertrophy of the underlying soft tissue or respiratory or cardiac problems, such as chronic obstructive pulmonary disease, severe emphysema, congenital heart defects, or cor pulmonale. Table 7-2 shows other pathological processes that may affect the fingernails.

Common Hand and Finger Deformities

Ape Hand Deformity.

Wasting of the thenar eminence of the hand occurs as a result of a median nerve palsy, and the thumb falls back in line with the fingers as a result of the pull of the extensor muscles. The patient is also unable to oppose or flex the thumb (Figure 7-13).

Bishop’s Hand or Benediction Hand Deformity.

Wasting of the hypothenar muscles of the hand, the interossei muscles, and the two medial lumbrical muscles occurs because of ulnar nerve palsy (Figure 7-14). Flexion of the fourth and fifth fingers is the most obvious resulting change.

Boutonnière Deformity.

Extension of the metacarpophalangeal and distal interphalangeal joints and flexion of the proximal interphalangeal joint (primary deformity) are seen with this deformity. The deformity is the result of a rupture of the central tendinous slip of the extensor hood and is most common after trauma or in rheumatoid arthritis (Figure 7-15).

Claw Fingers.

This deformity results from the loss of intrinsic muscle action and the overaction of the extrinsic (long) extensor muscles on the proximal phalanx of the fingers. The metacarpophalangeal joints are hyperextended, and the proximal and distal interphalangeal joints are flexed (Figure 7-16). If intrinsic function is lost, the hand is called an intrinsic minus hand. The normal cupping of the hand is lost, both the longitudinal and the transverse arches of the hand (see Figure 7-4) disappear, and there is intrinsic muscle wasting. The deformity is most often caused by a combined median and ulnar nerve palsy.

Drop-Wrist Deformity.

The extensor muscles of the wrist are paralyzed as a result of a radial nerve palsy, and the wrist and fingers cannot be actively extended by the patient (Figure 7-17).

Dupuytren Contracture.

This progressive disease of genetic origin results in contracture of the palmar fascia.22 There is a fixed flexion deformity of the metacarpophalangeal and proximal interphalangeal joints (Figure 7-18). Dupuytren contracture is usually seen in the ring or little finger, and the skin is often adherent to the fascia. It affects men more often than women and is usually seen in the 50- to 70-year-old age group.

Extensor Plus Deformity.

This deformity is caused by adhesions or shortening of the extensor communis tendon proximal to the metacarpophalangeal joint. It results in the inability of the patient to simultaneously flex the metacarpophalangeal and proximal interphalangeal joints, although they may be flexed individually.

Mallet Finger.23

A mallet finger deformity is the result of a rupture or avulsion of the extensor tendon where it inserts into the distal phalanx of the finger. The distal phalanx rests in a flexed position (Figure 7-19).

Myelopathy Hand.

This deformity is a dysfunction of the hand caused by cervical spinal cord pathology in conjunction with cervical spondylosis. The patient shows an inability to extend and adduct the ring and little finger and sometimes the middle finger, especially rapidly, despite good function of the wrist, thumb, and index finger. In addition, the patient shows an exaggerated triceps reflex and positive pathological reflexes (e.g., Hoffman reflex).24

Polydactyly and Triphalangism.

Polydactyly is a congenital anomaly characterized by the presence of more than the normal number of fingers or, in the case of the foot, toes. Triphalangism implies there are three phalanges instead of the normal two as would be seen in the thumb.25

Swan Neck Deformity.

This deformity usually involves only the fingers. There is flexion of the metacarpophalangeal and distal interphalangeal joints, but the real deformity is extension of the proximal interphalangeal joint. The condition is a result of contracture of the intrinsic muscles or tearing of the volar plate and is often seen in patients with rheumatoid arthritis or following trauma (Figure 7-20).

Trigger Finger.26

Also known as digital tenovaginitis stenosans, this deformity is the result of a thickening of the flexor tendon sheath (Notta’s nodule), which causes sticking of the tendon when the patient attempts to flex the finger. A low-grade inflammation of the proximal fold of the flexor tendon leads to swelling and constriction (stenosis) in the digital flexor tendon. When the patient attempts to flex the finger, the tendon sticks, and the finger “lets go,” often with a snap. As the condition worsens, eventually the finger will flex but not let go, and it will have to be passively extended until finally a fixed flexion deformity occurs. The condition is more likely to occur in middle-aged women, whereas “trigger thumb” with a flexion deformity of the interphalangeal joint is more common in young children.²⁷ The condition usually occurs in the third or fourth finger. In adults, it is most often associated with rheumatoid arthritis and tends to be worse in the morning.

Ulnar Drift.

This deformity, which is commonly seen in patients with rheumatoid arthritis but can occur with other conditions, results in ulnar deviation of the digits because of weakening of the capsuloligamentous structures of the metacarpophalangeal joints and the accompanying “bowstring” effect of the extensor communis tendons (see Figure 7-10).

Zigzag Deformity of the Thumb.

The thumb is flexed at the carpometacarpal joint and hyperextended at the metacarpophalangeal joint (Figure 7-21). The deformity is associated with rheumatoid arthritis. A “Z” deformity is due to hypermobility and may be familial (Figure 7-22).

Other Physical Findings

The hand is the terminal part of the upper limb. Many pathological conditions manifest themselves in this structure and may lead the examiner to suspect pathological conditions elsewhere in the body. It is important for the examiner to take the time to view the hands when assessing any joint, especially if an abnormal pattern is presented or the history gives an indication that more than one joint may be involved. For example, if a patient presents with insidious neck pain and demonstrates nail changes that indicate psoriasis, the examiner should consider the possibility of psoriatic arthritis affecting the cervical spine as well as the hand. Some conditions involving the hand include the following:

1. Generalized or continued body exposure to radiation produces brittle nails, longitudinal nail ridges, skin keratosis (thickening), and ulceration.

2. The Plummer-Vinson syndrome produces spoon-shaped nails (see Figure 7-11). This condition is a dysphagia with atrophy in the mouth, pharynx, and upper esophagus.

3. Psoriasis may cause scaling, deformity, and fragmentation and detachment of the nails. Psoriasis may lead to psoriatic arthritis affecting spinal and peripheral joints.

4. Hyperthyroidism produces nail atrophy and ridging with warm, moist hands.

5. Vasospastic conditions produce a thin nail fold and pterygium (abnormal extension) of the cuticle.

6. Trauma to the nail bed, toxic radiation, acute illness, prolonged fever, avitaminosis, and chronic alcoholism produce transverse lines, or Beau lines, in the nails (Figure 7-23).

7. Many arterial diseases produce a lack of linear growth with thick, dark nails.

8. Lues (syphilis) produces a hypertrophic overgrowth of the nail plate. The nails break and crumple easily.

9. Chronic respiratory disorders produce clubbing of the nails (see Figure 7-12).

10. Subacute bacterial endocarditis may produce Osler nodes, which are small, tender nodes in the finger pads.

11. Congenital heart disease may produce cyanosis and nail clubbing.

12. Neurocirculatory aesthesia (loss of strength and energy) produces cold, damp hands.

13. Parkinson disease produces a typical hand tremor known as “pill rolling hand” (Figure 7-24).

14. Causalgic states produce a painful, swollen, hot hand.

15. “Opera glove” anesthesia is seen in hysteria, leprosy, and diabetes. It is a condition in which there is numbness from the elbow to the fingers (Figure 7-25).

16. Raynaud disease produces a cold, mottled, painful hand. It is an idiopathic vascular disorder characterized by intermittent attacks of pallor and cyanosis of the extremities brought on by cold or emotion.

17. Rheumatoid arthritis produces a warm, wet hand as well as joint swelling, dislocations or subluxations, and ulnar deviation or drift of the wrist (see Figure 7-10).

18. The deformed hand of Volkmann ischemic contracture is one that is very typical for a compartment syndrome after a fracture or dislocation of the elbow (Figure 7-26).²⁸

Box 7-1 gives further examples of physical findings of the hand.

Box 7-1

Outline of Physical Findings of the Hand

I. Variations in size and shape of hand

A. Large, blunt fingers (spade hand)

1. Acromegaly

2. Hurler’s disease (gargoylism)

B. Gross irregularity of shape and size

1. Paget disease of bone

2. Maffucci’s syndrome

3. Neurofibromatosis

C. Spider fingers, slender palm (arachnodactyly)

1. Hypopituitarism

2. Eunuchism

3. Ehlers-Danlos syndrome, pseudoxanthoma elasticum

4. Tuberculosis

5. Asthenic habitus

6. Osteogenesis imperfecta

D. Sausage-shaped phalanges

1. Rickets (beading of joints)

2. Granulomatous dactylitis (tuberculosis, syphilis)

E. Spindliform joints (fingers)

1. Early rheumatoid arthritis

2. Systemic lupus erythematosus

3. Psoriasis

4. Rubella

5. Boeck’s sarcoidosis

6. Osteoarthritis

F. Cone-shaped fingers

1. Pituitary obesity

2. Fröhlich’s dystrophy

G. Unilateral enlargement of hand

1. Arteriovenous aneurysm

2. Maffucci’s syndrome

H. Square, dry hands

1. Cretinism

2. Myxedema

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