2 Examination of the upper extremity
Physical examination of the upper extremity consists of inspection, palpation, measurement of length, girth and ranges of motion, assessment of stability, and detailed assessment of the associated nerve and vascular systems.
Thorough understanding of the anatomy, physiology and biomechanics of the upper extremity is essential to perform a physical examination correctly and to make a correct diagnosis of pathologic conditions of the upper extremity.
The patient history can be the most important tool in developing an accurate diagnosis. The history should not only detail the patient’s current complaint, but should also document other elements of the patient’s history which may be of great significance for interpreting the patient’s current problem and choosing between treatment options. A patient history should include information on the patient’s demographics, current complaint, medical history, allergies, medications, and socioeconomic status. The time course of the patient history interview should be documented.
The patient’s name, age, occupation, hand dominance and hobbies should be documented. Information about previous injuries or diseases should be obtained, regardless of whether they seem to be related to the patient’s current complaint.
All information on the patient’s current problem, including symptoms of pain, numbness, tingling (paresthesia), weakness, dislocation, coldness, clumsiness or poor coordination and clicking or snapping, should be documented. Each symptom should be characterized according to its location, intensity, duration, frequency, radiation and associated symptoms. The patient history should include information on activities or treatments that aggravate or ameliorate the symptoms. It is also important to record the time and place at which the initial injury occurred and the mechanism by which it was incurred.
1. The time of the injury and the interval between the injury and the patient’s presentation should be determined. The interval between an injury and revascularization of amputated fingers has a great effect on the outcome of replantation surgery.
The patient’s health status may influence diagnosis and treatment. Before starting treatment, it is essential to determine whether the patient has diabetes, or cardiac, pulmonary and/or renal disease and whether the patient has a history of rheumatologic disease. Documentation on the family’s medical history may be helpful for making an accurate diagnosis and for choosing an appropriate treatment modality if the disease is hereditary. Patients and their families should be questioned about previous problems associated with bleeding and anesthesia. It is also important to determine the course of any prior surgery.
The patient history should include data on any medications that the patient is taking. Previous allergic reactions to foods or medications should be noted. People who are allergic to shellfish are often allergic to contrast media that contain iodine.
Social history includes the patient’s use of tobacco and alcohol. The amount of tobacco and alcohol used should be documented. Substance abuse and infection with hepatitis virus or HIV should also be noted. The patient’s hobbies or sports should be documented because these activities often determine the most appropriate treatment.
Accurate diagnosis of hand problems depends on a systematic, careful physical examination. Physical examination should be performed routinely following a specific protocol. Even if the patient complains of a problem limited to the hand, the physical examination should start at the neck and shoulder region because the hand is suspended by the bones of the forearm, which connect proximally to the elbow joint, which in turn is stabilized by the humerus and the shoulder joint. In addition, numbness of the hand may be associated with cervical problems. The following eight elements (inspection, palpation, measurement of range of motion, stability assessment, musculotendinous assessment, nerve assessment, vascular assessment, and specific tests) should be included in the examination procedure for patients with problems of the upper extremities. An understanding of the interrelationships among these elements is helpful for drawing accurate diagnostic conclusions. Repeated physical examinations reveal how symptoms change over time, which is important for assessing the effectiveness of the treatment.
When inspecting the upper extremities, it is essential to compare the affected extremity with the contralateral extremity because the latter can be used as a normal reference if the injury is unilateral.
An abnormal skin color or a change in the color of the skin of the upper extremity is indicative of a wide variety of problems. Infections often cause swelling and patches of redness with proximal streaking. Vascular problems caused by arterial inflow insufficiency often present as pale colored and the distal part of the upper limb appears to have shrunk, whereas those caused by venous outflow insufficiency present as a purple or dark red discoloration and a swollen limb. The color of a hematoma can be used to estimate the interval since the trauma occurred. A fresh hematoma has purple or blue patches, which then become green and finally yellow.
Fractures, tumors, arthritis and some infectious conditions can cause deformities of the upper extremity. Fractures of the phalanges of the fingers frequently result in angular rotation or malrotation of the fingers. When the fingers are held up, the point at which the long axes of the fingers converge corresponds with the position of the scaphoid tubercle. However, the long axis of a malrotated finger deviates from the position of the scaphoid.
It is important to determine whether atrophied muscles are innervated by specific peripheral nerves. If the atrophic muscles are innervated by a specific nerve, the atrophy may have been caused by a peripheral nerve disorder. Muscular atrophy may occur under systemic neural or muscular pathological conditions; in most of these cases, the atrophy is symmetrical in the bilateral extremities. Generally, neurogenic diseases involve muscles in the distal part of the extremity and muscular diseases involve the proximal part of the extremity. The girths of the arm (a portion measured should be noted, like the arm girth 20 cm distal to the acromion) and forearm (a portion with the maximum diameter of the forearm) of both upper extremities should be measured routinely because this often reveals a loss of muscle mass, which may not be obvious to the eye.
Swelling can be identified by comparison with the uninvolved extremity. Localized swelling indicates recent trauma or inflammation. Diffuse swelling is often caused by infection. General swelling may originate from a lymphatic or venous obstruction. Swelling of the dorsum of the hand is also common.
Disappearance of skin creases is indicative of loss of motion of the joint under the creases and can be helpful in determining the validity of a complaint of an inability to move the fingers or upper extremities. Clear finger creases over joints that a patient claims he or she is unable to flex or extend indicate that the patient moves the joint. In such cases, the patient may be malingering or may have a psychosis in which he or she cannot recognize motion of the joint.
Palpation is a powerful maneuver for identifying masses, abnormal skin temperature, areas of tenderness, crepitance, clicking or snapping and effusion. Masses in the deep layer can be detected by palpation before they emerge as masses under the skin. When performing palpation, special attention should be paid to differences in hardness or mobility relative to that of the surrounding tissue. For example, subtle palpation can identify a palmar bowstring of a flexor tendon in a patient who complains of lack of finger flexion after an injury of the flexor pulleys.
Both passive and active ranges of motion should be documented. The range of motion of both the contralateral healthy limb and the affected limb should be measured and compared. The range of motion may be affected by the posture of the adjacent joints. For example, active and passive distal interphalangeal (DIP) joint flexion is limited when the proximal interphalangeal (PIP) joint of the same finger is extended. When the wrist joint is flexed, the active range of finger flexion decreases. The range of motion of a joint should be measured in a posture that permits maximum motion.
The passive range of motion is measured by holding the patient’s structures proximal and distal to the joint in question and then moving the joint from one limit of motion to the other in the absence of any muscular contraction by the patient. A limited range of passive motion is associated with joint stiffness and soft tissue contracture.
The active range of motion of a joint is that which occurs when the patient contracts his or her muscles. The active range of motion is affected by tendon excursion, the posture of the hand and fingers, nerve function and muscular strength.
The tightness of the ligaments around a joint, morphology of the surface of a joint and musculotendinous balance around a joint are useful indices of joint stability. When assessing joint stability, the biomechanical and physiological properties of the ligaments should be taken into consideration and the stress forces applied should be appropriate for the ligament in question. For example, the straight portions of the bilateral collateral ligaments of the finger metacarpal (MP) joints tighten when the joint is in the flexed position (Fig. 2.1), whereas those of the PIP joints tighten when the joints are in an extended position. The stability of ligaments is tested by holding the portions distal and proximal to the joint and gently moving the joint passively to stress the ligaments that stabilize the joint. It is useful to measure the opening angle of the affected joint under stress using X-rays and to compare the opening angle of the affected joint with that of the corresponding healthy joint of the opposite hand (Fig. 2.2). The tear of the ulnar collateral ligament of the thumb MP joint is known to be Stener lesion. The radial collateral ligament instability of the thumb MP joint demonstrates palmar dislocation and ulnar deviation of the thumb MP joint. The radial collateral ligament courses from the distal-palmar to proximal-dorsal direction, the line of which is almost perpendicular to the sagittal axial line of the thumb, the MP joint has tendency to be dislocated palmarly, when the ligament is not functioning. Because the force vector of the adductor pollicis muscle is more transverse to the axial line than that of the thumb abductor muscles, which is more parallel to the axis of the thumb, the thumb MP joint with the radial collateral ligament insufficiency demonstrates ulnar deviation. On the other hand, the long-lasting ulnar collateral ligament insufficiency of the thumb MP joint may also show palmar dislocation.
Fig. 2.1 The collateral ligament of the MP joint. The proper portion of the collateral ligament is relaxed when the joint is extended (top) and is tight when the MP joint is flexed (bottom). The smaller accessory portion has the opposite effect.
Fig. 2.2 Rupture of the radial collateral ligament of the index finger PIP joint. Measure the opening angle of the affected joint under the radial and ulnar stress forces on X-ray films and compare the angle with that of the corresponding normal joint of the opposite hand. (A) Affected finger. (B) Normal opposite finger.
Assessment of the stability of wrist joints is complex and difficult. The stability of the wrist joint is determined by the stability of the radiocarpal, ulnocarpal, distal radioulnar and midcarpal joints. Special tests for assessing the stability of specific ligaments or imaging tools such as X-rays, CT or MRI may be helpful in making a diagnosis.
When musculotendinous units are examined, it should be kept in mind that the muscle strength and ranges of motion of the hand and digits change depending on the posture of the wrist, forearm or digits. For example, the range of motion of the DIP joint of a finger is less when the PIP joint is passively extended than when the PIP joint is flexed.
There are many muscles and tendons in the hand. When the origin and insertion of a muscle are both distal to the wrist joint, the muscle is called an intrinsic muscle. When a muscle extends across the wrist joint, it is called an extrinsic muscle. Other muscles often compensate for a nonfunctioning muscle, in which case the nonfunctioning muscle appears to function. To evaluate muscle function, each muscle should be evaluated in a posture or situation in which the cooperative muscles do not function. For example, the extensor pollicis longus (EPL) can compensate for impaired thumb adduction. Even when the thumb adductors do not function because of ulnar nerve palsy, patients may be able to adduct the thumb using a functional EPL.
The presence of abnormal muscles or an abnormal linkage of tendons should sometimes be considered. The flexion function of the PIP joint of a finger is generally accepted to be independent of that of the other fingers because the flexor digitorum superficialis (FDS) tendon of each finger has its own muscle belly. The motion of the FDS tendon of the small finger is often linked to that of the ring and/or the long finger and the PIP joint flexion of the small finger often coordinates with that of the ring and/or long fingers.1 The extensor digitorum manus brevis is sometimes present in the middle finger and causes dorsal wrist pain.2
Muscle power is classed according to the Medical Research Council scale, which ranges from zero to five (0–5) (Table 2.1).3 Grip strength is a good indicator of the global muscle strength of the upper extremity. Grip strength is measured using a dynamometer with the shoulder and elbow joints stabilized. The patient grips the dynamometer with the elbow straightened beside the trunk in the standing position or flexed 90° in the sitting position.
|Grade||Physical examination findings|
|1||Flicker or trace contraction|
|2||Active movement with gravity eliminated|
|3||Active movement against gravity|
|4||Active movement against gravity and resistance|
Reproduced with permission from: Seddon HJ. Peripheral Nerve Injuries. Medical Research Council Special Report Series, 282. London: HMSO; 1954.3
In clinical settings, it is very important to distinguish nerve palsy from tendon laceration or rupture. The milking test and dynamic tenodesis effects (described later) can be used to distinguish between the two.
This test is used to assess the continuity and muscle power of each of the FDP tendons. The patient’s hand is placed palm upward on a table. The examiner holds the proximal and middle phalanges of the target finger down to keep the MP and PIP joints in extension and asks the patient to flex the DIP joint. The test should be performed on each finger.
This test is used to assess the continuity and muscle power of each of the FDS tendons. The FDS tendons insert on the proximal half of the palmar surface of the middle phalanx of the fingers. Because each FDS tendon has its own muscle belly, its function is independent of the FDS of the adjacent fingers. The patient’s hand is placed palm upward on a table. The examiner holds the distal phalanges of all fingers down except that of the finger to be tested to keep the MP, PIP and DIP joints of the other fingers in full extension. The patient is asked to flex the finger to be tested. Each finger is tested individually. Because the FDP muscles share a common origin, holding the DIP joint of a finger in full extension may prevent motion of all FDPs. However, because each FDS has an individual origin, the FDS moves but the FDP does not when the other fingers are kept fully extended.
The EPB inserts at the dorsal base of the proximal phalanx of the thumb. It is sometimes connected to the EPL. The APL has several tendons and inserts at the dorsolateral base of the thumb metacarpus and trapezium. Both tendons pass through the first dorsal component at the wrist (the APL tendon lies radial to the EPB in the compartment). When the patient abducts the thumb maximally, the EPB and APL tendons as well as the EPL tendon merge under the skin over the radiodorsal side of the wrist and create the snuffbox. The EPB and APL tendons are palpable as taut tendons in the radiopalmar border of the snuffbox.
The ECRL and ECRB tendons insert at the dorsal bases of the second and third metacarpal bones, respectively. The function of these muscles is to extend the wrist joint. Because the functional axis of the ECRL deviates radially, the ECRL extends the wrist dorsoradially. When the ECRB does not function, extension of the wrist deviates radially because of the intact ECRL tendon. The extensor digitorum communis (EDC) tendon also may function as a wrist extensor. To remove the EDC contribution to wrist extension, the patient is asked to make a fist and then extend the wrist. Making a fist eliminates EDC function.
The EPL passes through the third dorsal compartment, turns radially at the Lister’s tubercle and inserts at the dorsal base of the distal phalanx of the thumb. The EPL extends the IP joint of the thumb. The hand is placed palm down on a table with the thumb adducted. The patient is asked to lift only the thumb off the surface of the table, keeping the thumb adducted. The taut EPL tendon is palpable in the radiodorsal aspect of the wrist.
The EDC tendons pass through the fourth extensor compartment and insert at the dorsal base of the middle phalanges of the fingers. They mainly extend the MP joint, while the intrinsic extensors extend the PIP and DIP joints. EDC function is examined by asking the patient to lift the MP joints of four fingers (the index to the small finger) keeping the PIP and DIP joints flexed.
The EIP tendon passes through the fourth extensor compartment at the wrist deep to the EDC tendon and merges with the ulnar side of the index finger EDC tendon over the MP joint. The function of the EIP is to extend the MP joint of the index finger, which is isolated from the extension of the MP joints of the other fingers. The EIP is functional if the patient can straighten the index finger completely when the other fingers are flexed in a fist.
The EDM tendon passes the fifth extensor compartment and merges with the ulnar side of the small finger EDC tendon at the MP joint level. Because the EDM tendon is usually divided into two tails distally, both tails of the tendon must be transected when the tendon is transferred. This tendon is evaluated by asking the patient to straighten the small finger when the other fingers are flexed into a fist.
The ECU tendon passes through the sixth extensor compartment and inserts on the dorsal base of the fifth metacarpal bone. The function of this tendon is ulnar deviation of a wrist that is held extended. The wrist cannot be extended dorsally only by the ECU. This tendon is evaluated by asking the patient to make a fist and to lift and deviate the wrist ulnarly. The tendon is palpable radial to the ulnar styloid process.
The thenar muscles cover the metacarpal of the thumb and consist of three muscles: the abductor pollicis brevis, the flexor pollicis brevis and the opponens pollicis. The muscles move the thumb into opposition, enabling the thumb to touch the fingertips when the nails are parallel. These muscles are evaluated by asking the patient to place the dorsum of the hand flat on a table and to raise the thumb until it is perpendicular to the palm. The patient is then asked to resist a downward force by the examiner on the thumb.
The ADP muscle arises from the third metacarpal and inserts to the ulnar base of the proximal phalanx of the thumb. Some fibers of the ADP extend dorsally to form an extensor apparatus for the thumb. Together with the first dorsal interosseous muscle, the ADP approximates the thumb to the second metacarpal.
The interosseous and lumbrical muscles flex the MP joints and extend the PIP and DIP joints of the fingers. In addition, four dorsal interosseous muscles abduct the thumb and the radial three fingers and three palmar interosseous muscles adduct the fingers. The second and third dorsal interosseous muscles are evaluated by asking the patient to place the hand flat on a table and then to stretch the long finger upward (i.e., to hyperextend it) and to deviate it radially and ulnarly. Patients with ulnar nerve palsy cannot do this because of loss of power in the interosseous muscles (the Pitres–Testut sign). The first palmar interosseous and the second dorsal interosseous muscles are tested by the “crossing fingers” sign. The patient is asked to cross a flexed long finger over the index finger or to cross a flexed index finger over the long finger when the palm and the ring and little fingers are placed flat on a table. (Finger abduction refers to movement away from the long finger; finger adduction refers to movement toward the long finger.)
Evaluation of peripheral nerves should include both motor and sensory function. To evaluate the motor function of the hand, it is necessary to understand not only the anatomy and biomechanics of the muscles of the upper extremity but also the peripheral innervation of the muscles. An understanding of the order in which branches of the nerve trunk innervate muscles is important for assessing nerve recovery after a nerve injury or a compression neuropathy.
Sensibility testing also relies on knowledge of peripheral nerve anatomy. It is essential to understand which parts of the hand are innervated by which peripheral nerves. Peripheral nerve palsy should be diagnosed using motor and sensory evaluation. When the outcome of a motor assessment does not coincide with that of a sensory assessment, abnormal innervation of muscles or an unusual anastomosis between peripheral nerves should be considered. The Martin–Gruber connection is an abnormal innervation of the median nerve to the motor branch of the ulnar nerve. Patients with cubital tunnel syndrome and this nerve connection may have a sensory palsy of the ulnar nerve without motor palsy.
Comprehensive sensibility evaluation includes static and dynamic two-point discrimination (2 PD) testing, Semmes–Weinstein monofilament testing, vibrotactile threshold testing, and cold-heat testing. The 2 PD test evaluates the tactile sensation of the skin and assesses density of the perception receptors in the skin. Stimuli generated by the static 2 PD test are mainly sensed by Merkel cells (slow-adapting mechanoreceptors), while the main receptors of stimuli generated by the moving 2 PD test are Meissner corpuscles (quick-adapting receptors). In the static 2PD test, a caliper is applied longitudinally to the digit and the smallest distance between the tips of the caliper that the patient can distinguish is measured.4 The moving 2PD test is the smallest perceived distance between the tips of a caliper that is moved longitudinally along the ulnar or radial aspect of the finger.5