Hand & Wrist Movements & Range of Motion
Hand movements include flexion / extension, rotation and adduction / abduction at the MCP joints, while the wrist movements include flexion /extension, in addition to radial and ulnar deviation.
Wrist Movements
The wrist is the key joint of the hand and contains several segments whose combined movements create a total of wrist range of motion that is greater than the sum of its individual parts.
The Wrist Movements are limited to two degrees of freedom: flexion–extension and ulnar–radial deviation
The apparent axial rotation of the palm -called pronation and supination- occurs at the proximal and DRUJs, with the hand moving with the radius, not separately from it.
See Also: Wrist Anatomy
See Also: Hand Anatomy
Wrist Pronation and Supination
The true axis for pronation–supination at the wrist may be situated anywhere between the radial and ulnar styloid, resulting in not one, but many pronation–supination axes.
Approximately 75–90 degrees of forearm pronation is available. During pronation, the concave ulnar notch of the radius glides around the peripheral surface of the relatively
fixed convex ulnar head. Pronation is limited by the bony impaction between the radius and the ulna.
Approximately 85–90 degrees of forearm supination is available. Supination is limited by the interosseous membrane and the bony impaction between the ulnar notch of the radius and the ulnar styloid process.
Congruency of the DRUJ surfaces is maximal at midrange of motion, although the joint is not considered to be truly locked in this position. At this position, the TFCC is maximally stretched and the interosseous membrane is relatively lax. The proximal and DRUJs are intimately related biomechanically, with the function and stability of both joints dependent on the configuration of, and distance between, the two bones.
This configuration and distance maintains ligament and muscle tension. A change in the length of the ulna of as little as 2 mm results in a change in the transmission of forces of 5–40 percent.
Movement of the Hand on the Forearm
Due to the morphology of the wrist, movement at this joint complex involves a coordinated interaction between a number of articulations. These include:
- the radiocarpal joint,
- the proximal row of carpals,
- the distal row of carpals.
All of these joints permit motion to occur around two axes: anterior–posterior in flexion–extension, and transverse in radial and ulnar deviation. Wrist extension is accompanied by a slight radial deviation and pronation of the forearm. Wrist flexion is accompanied by a slight ulnar deviation and supination of the forearm.
A number of concepts have been proposed over the years to explain the biomechanics of wrist motion. The essential kinematics of the sagittal plane involve the mechanism of the carpal bone motions related to the central column of the wrist formed by the series of articulations among the radius, lunate, capitate, and third metacarpal bone. Within this concept:
- the radiocarpal joint is represented by the articulation between the radius and lunate composed of the radius, scaphoid, trapezoid, trapezium, and the column of the thumb;
- the CMC joint is assumed to be a rigid articulation between the capitate and the base of the third metacarpal;
- The ulnar or medial compartment of the midcarpal joint is represented by the articulation between the lunate and capitate. This column strongly supports the movements in the central column, while simultaneously anchoring the wrist to the radius.
Under the column concept, the radial and ulnar columns are proposed to move with the central column due to mutual displacements between the proximal facets of the scaphoid and lunate. In addition, the proximal carpals are considered to move at the radiocarpal and midcarpal levels.
Flexion and Extension Movements of the Wrist
The wrist flexion and extension are shared between the radiocarpal articulation and the intercarpal articulation in varying proportions. The arthrokinematics are based on synchronous convex-on-concave rotations at the radiocarpal and midcarpal joints.
- During wrist extension, most of the motion occurs at the radiocarpal joint (66.5 percent or 40 degrees versus 33.5 percent or 20 degrees at the midcarpal joint) and is accompanied with slight radial deviation and pronation of the forearm.
- During wrist flexion, most of the motion occurs in the midcarpal joint (60 percent or 40 degrees, versus 40 percent or 30 degrees at the radiocarpal joint) and is accompanied with slight ulnar deviation and supination of the forearm.
Wrist Extension
At the radiocarpal joint, extension occurs as the convex surface of the lunate rolls posteriorly (dorsally) on the radius and simultaneously slides anteriorly (palmarly). Rotation directs the lunate’s distal surface in an extended, posterior (dorsal) direction. At the midcarpal joint, the head of the capitate rolls posteriorly (dorsally) on the lunate and simultaneously slides in an anterior(palmar) direction.
When the wrist is extended, the radiolunotriquetral and radiocapitate ligaments are stretched and tension develops within the wrist and finger flexor muscles. Tension within the structures stabilizes the wrist in its close-packed position of extension.
Loss of active wrist extension in the wrist constitutes a considerable functional impairment, including the following:
- A reduction in grip strength.
- Changes in muscle length-tension relationships, which has serious implications when considering the action of the extrinsic muscles of the hand. For example, the strength of the thumb and finger flexors requires normal motion and function of wrist extension.
Wrist Flexion
The arthrokinematics of wrist flexion are similar to those described in wrist extension, but occurs in a reverse fashion.
Frontal Lateral Movements of the Wrist
Like flexion and extension, the movements of ulna and radial deviation of the wrist are shared between the radiocarpal articulation and the intercarpal articulation in varying proportions. The amount of deviation is approximately 40 degrees of ulnar deviation and 15 degrees of radial deviation. There is a physiological ulnar deviation at rest, which is easily demonstrated clinically and radiographically.
Ulnar Deviation
Ulnar deviation occurs primarily at the radiocarpal joint. When the hand is observed at rest, there is a physiological ulnar deviation. During ulnar deviation, the radiocarpal and midcarpal joints contribute fairly equally to the overall motion.
At the radiocarpal joint, the scaphoid, lunate, and triquetrum roll ulnarly and slide a significant distance radially. Ulnar deviation of the midcarpal joint occurs primarily from the capitate rolling ulnarly and sliding slightly radially. Ulnar deviation is limited by the radial collateral ligament.
Although ulnar deviation brings the triquetrum into contact with the TFCC, the lack of direct ulnar-triquetral articulation permits a greater range of ulnar deviation. The muscle with the best biomechanical advantage to produce ulnar deviation of the wrist in pronation is the ECU.
Radial Deviation
Radial deviation at the wrist occurs through similar arthro-kinematics as described for ulnar deviation. Radial deviation occurs primarily between the proximal and the distal rows of the carpal bones. The motion of radial deviation is limited by impact of the scaphoid onto the radial styloid and the UCL. The APL and EPB are best suited to produce radial deviation of the wrist.
Extension of the wrist is accompanied by radial deviation, and flexion of the wrist is accompanied by ulnar deviation. The wrist also allows relatively extensive traction and gliding accessory movements.
A number of studies have examined the necessary wrist range of motion to perform functional activities. These studies report that at least 5 degrees of wrist flexion, 35 degrees of wrist extension, 10 degrees of radial deviation, and 15 degrees of ulnar deviation are needed to perform common personal care activities comfortably. Less motion is required for 90 percent of personal care activities: 5 degrees of flexion, 6 degrees of extension, 7 degrees of radial deviation, and 6 degrees of ulnar deviation.
Wrist Movements and the Digits
The position of the wrist in flexion or extension influences the tension of the long or “extrinsic” muscles of the digits. The position of the wrist also has important repercussions on the position of the thumb and fingers. Neither the flexors nor the extensors of the fingers are long enough to allow maximal range of motion at the wrist and the fingers simultaneously.
Due to the restraining action of the long antagonistic muscles, complete flexion of the fingers is possible only if the wrist is in approximately 20 degrees of extension, which corresponds to the optimal position for hand function. Thus the wrist movements reinforce the action of the extrinsic muscles of the fingers, and are synergistic with the more powerful digital flexors.
In order for grip to be effective and have maximal force, the wrist must be stable and positioned in slight extension and ulnar deviation.
Thumb Movements
The first CMC joint is a saddle joint. The characteristic feature of a saddle joint is that each articular surface is concave in one diameter and convex in the other. Within the thumb CMC joint, the longitudinal diameter of the articular surface of the trapezium is generally concave from an anterior (palmar) to posterior (dorsal) direction, while the transverse diameter is generally convex along a medial to lateral direction.
The proximal articular surface of the first metacarpal is reciprocally shaped to that of the trapezium. This articular relationship produces the following Thumb Movements:
Thumb flexion and extension occur around an anterior–posterior axis in the frontal plane that is perpendicular to the sagittal plane of finger flexion and extension. In this plane, the metacarpal surface is concave, and the trapezium surface is convex.
- Flexion is accompanied by a conjunct rotation of internal rotation of the metacarpal.
- Extension is accompanied by a conjunct rotation of external rotation of the metacarpal.
- A total range of 50–70 degrees is available.
Thumb abduction and adduction occur around a medial– lateral axis in the sagittal plane that is perpendicular to the frontal plane of finger abduction and adduction. During thumb abduction and adduction, the convex metacarpal surface moves on the concave trapezium.
- Abduction is accompanied by a conjunct rotation of internal rotation.
- Adduction is accompanied by a conjunct rotation of external rotation.
- A total range of 40–60 degrees is available.
Opposition of the thumb involves a wide arc motion comprising sequential anterior (palmar) abduction and flexion from the anatomic position, accompanied by internal rotation of the thumb. Retroposition of the thumb returns the thumb to its anatomic position, a motion that incorporates the elements of adduction with extension and external rotation of the metacarpal.
Normal Ulnar Inclination of the Fingers
A normal ulnar inclination of the fingers occurs at the MCP joints due to a number of factors:
- Asymmetry of the metacarpal heads and the collateral ligaments.
- Tendon factors: the extrinsic tendons, extensors, and flexors cross into the hand on the ulnar side of the longitudinal axis of the MCP joint.
- Muscle factors: the intrinsic muscles have a predominantly ulnar inclination and predominate over those with a radial inclination.
- The physiologic action of the thumb, which in lateral grip pushes the fingers in an ulnar direction.
The inclination is most marked in the index finger, less in the middle and little fingers, and almost nonexistent in the ring finger. The ulnar inclination is normally limited by the capsuloligamentous resistance at the MCP joints and by the action of the interosseous muscles, which act in a radial direction. The weakness of these stabilizing elements, particularly in rheumatoid arthritis (RA), allows the ulnar inclination to be accentuated, resulting in pathologic ulnar deviation.
References
- Neumann DA: Wrist. In: Neumann DA, ed. Kinesiology of the Musculoskeletal System: Foundations for Physical Rehabilitation. St. Louis, MO: Mosby, 2002:172–193.
- Carpener N: The hand in surgery. J Bone Joint Surg Br 38B:128, 1956.
- Kapandji AI: Physiologie Articulaire. Paris: Librairie Maloine, 1963.
- Nelson DL: Functional wrist motion. Hand Clin 13:83–92, 1997.
- Palmer AK: The distal radioulnar joint. Hand Clin 3:31, 1987.
- MacConnail MA, Basmajian JV: Muscles and Movements: A Basis for Human Kinesiology. New York: Robert Krieger Pub Co, 1977.
- Kapandji IA: The Physiology of the Joints, Upper Limb. New York: Churchill Livingstone, 1991.
- Brumfield RH, Champoux JA. A biomechanical study of normal functional wrist motion. Clin Orthop Relat Res. 1984 Jul-Aug;(187):23-5. PMID: 6744724.
- Brumfield RH, Champoux JA. A biomechanical study of normal functional wrist motion. Clin Orthop Relat Res. 1984 Jul-Aug;(187):23-5. PMID: 6744724.
- Palmer AK, Werner FW, Murphy D, Glisson R. Functional wrist motion: a biomechanical study. J Hand Surg Am. 1985 Jan;10(1):39-46. doi: 10.1016/s0363-5023(85)80246-x. PMID: 3968403.
- Sarrafian SK, Melamed JL, Goshgarian GM. Study of wrist motion in flexion and extension. Clin Orthop Relat Res. 1977 Jul-Aug;(126):153-9. PMID: 598105.
- Tubiana R, Thomine J-M, Mackin E: Examination of the Hand and Wrist. London: Mosby, 1996.
- Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
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