The causes of upper extremity pain can be categorized as neurologic, musculoskeletal, joint-related, and vascular. A thorough history is critical to characterize the pain. Clinicians should ask specific questions about the quality of the pain (eg, aching, stabbing, throbbing, tingling, pins and needles, numbness). Radiologic and diagnostic testing can help the clinician differentiate between the sources of pain, thereby limiting the differential diagnosis. However, because pain is subjective, the objective physical, radiologic, and electrophysiologic findings sometimes correlate poorly with the intensity of the patient’s perceived pain.
Anatomy & Common Terminology
Describing anatomic locations in the hand and the finger can be difficult because of their complex, three-dimensional structures. To avoid confusion and potential errors, standardized terminology should be used. While the surface of the palm can be referred to as either the palmar or the volar surface, palmar is the preferred term to avoid confusion. The back of the hand is referred to as the dorsal surface. The terms “ulnar” and “radial” are used instead of “medial” and “lateral” to describe the sides of the hand because lateral and medial sides can change based on the rotational position of the arm at the time of the examination. The side of the hand toward the small finger is referred to as the “ulnar” side, and the side toward the thumb is referred to as the “radial” side. The fingers should be referred to by name, such as the thumb, the index finger, the middle (or long) finger, the ring finger, and the small finger rather than as the first, second, third, fourth, or fifth fingers. It not infrequent that the index finger is called the first finger and the small finger is called the fourth finger. In truth, however, the thumb is the first finger and the small finger is the fifth finger.
There are 27 bones within the hand: 8 carpal bones, 5 metacarpal bones, and 14 phalangeal bones. The 8 carpal bones are arranged in two rows (a proximal and a distal) that contain 4 bones each. The scaphoid, lunate, triquetral, and pisiform form the proximal row. The distal row is formed by the trapezium (under the thumb metacarpal), the trapezoid, the capitate (which is directly under the middle finger metacarpal), and the hamate (on the ulnar side). The carpal bones are connected to each other by strong ligamentous connections. There are 5 metacarpal bones, and they should be referred to by name rather than by numbers based on the fingers to which they are attached: thumb, index, long, ring, or small metacarpal bones. The phalanges are the bones in the fingers. The thumb has 2 phalanges: the distal and the proximal phalanges. The four other fingers have 3 phalanges: the distal, middle, and the proximal phalanges. To avoid confusion, the phalanges should also be referred to by name (distal, middle, or proximal) rather than by numbers, such as P1, P2, or P3.