Biomedical subjects

D J Giurintano

Publications and source records attributed to D J Giurintano.

8 recordsLinked to original sources

PubMed1995

A virtual five-link model of the thumb.

Most researchers have modelled the thumb as three rigid links with connections of two universal joints (carpometacarpal joint and metacarpo-phalangeal joint), and a hinge joint (interphalangeal joint). Although this produces the required number of degrees of freedom, the resulting motion is not anatomically accurate. In this work, the thumb is modelled as a five-link manipulator with the virtual links connected by hinge joints-one for each degree of freedom of the thumb. The axes of the hinges are not orthogonal to one another, in the long axis of the bones or to the anatomic planes. Four static positions of hand function were analysed-key pinch, screwdriver hold, tip pinch, and wide grasp. The virtual five-link model of the thumb predicted similar muscle recruitment patterns to published EMG data. The force at the distal surface of the trapezium is between 6 and 24 times the applied load depending on the posture.

Biomechanical Phenomena↗

PubMed1995

The axes of rotation of the thumb interphalangeal and metacarpophalangeal joints.

The axes of rotation of the thumb interphalangeal and metacarpophalangeal joints were located using a mechanical method. The interphalangeal joint axis is parallel to the flexion crease of the joint and is not perpendicular to the phalanx. This offset of the axis with respect to the phalanx explains the ulnar deviation and pronation that occurs with flexion of the interphalangeal joint. The metacarpophalangeal joint has 2 fixed axes: a fixed flexion-extension axis just distal and volar to the epicondyles, and an abduction-adduction axis related to the proximal phalanx passing between the sesamoids. Neither axis is perpendicular to the phalanges. All physiologic motion for these joints occurs about the axes. These are the mechanical axes of the joints through which the muscles and external forces act. Knowledge of their location should help in constructing prosthetic joints and in planning reconstructive surgery such as tendon transfers.

Finger Joint↗

PubMed1992

The axes of rotation of the thumb carpometacarpal joint.

Two axes of rotation of the carpometacarpal (CMC) joint of seven cadaver thumbs were located using an axis finder. The flexion-extension axis is located in the trapezium and the abduction-adduction axis is in the first metacarpal. These axes are fixed, are not perpendicular to each other or to the bones, and do not intersect. Motion of the first metacarpal on the trapezium can be defined by these two axes. Understanding of the movements of the basal joint of the thumb is essential to the study of its function and reconstruction.

Biomechanical Phenomena↗

PubMed1989

A kinematic model of the flexor tendons of the hand.

The multi-joint model is a kinematic simulation of the long flexor tendons of the fingers. The tendons modeled are the flexor pollicis longus, the flexor digitorum profundus, and the flexor digitorum superficialis. The simulated tendons are displayed on an Evans and Sutherland PS330 color graphics terminal attached to a display of articulated bones of the hand. As a user changes the position of the joints of the simulated hand, the simulation displays the new tendon path and the excursion of the tendon for the new position of the hand. The multi-joint model is one component of a comprehensive model for use in a hand biomechanics computer workstation.

Computer Graphics↗

PubMedDate not supplied

Basic biomechanics.

Explore the source record for details and available documents.

Acceleration↗

PubMedDate not supplied

Thumb movements, motions, and moments.

An understanding of the movements of the thumb is essential for understanding thumb function and pathology and for planning therapeutic interventions. The thumb has three joints, which move about axes of rotation. The carpometacarpal and metacarpophalangeal joints have two offset axes of rotation and the interphalangeal joint has one. The thumb muscles act about these axes, and imbalances resulting from paralysis are explained by this model. The effects of tendon transfers and splints can be predicted by analyzing their effects at each joint and axis.

Biomechanical Phenomena↗

PubMedDate not supplied

Objective measures of joint stiffness.

Objective measures of joint stiffness allow for the evaluation of the effectiveness of treatment modalities. Without this, the effectiveness of therapy is not quantifiable. Presently, joint stiffness can be quantified by either passive range of motion (PROM) measurement or torque range of motion (TqROM) measurement. PROM measurement does not control the force applied, nor does it require that the other joints in the kinematic chain be held fixed. Also, it demonstrates poor interrater reliability. An idealized device melding existing technologies of constant passive motion devices and computerized workstations is proposed to allow for easier measurement of TqROM angles for analysis data for the determination of the effectiveness of treatment modalities.

Diagnosis, Computer-Assisted↗

PubMedDate not supplied

Computer simulation of the upper extremities.

The development of real-time, interactive, three-dimensional, computer graphic simulation of the musculoskeletal system with emphasis on the upper extremities is described. Developments in image analysis, scientific visualization, and interactive computer methods and the continuous improvement in knowledge of musculoskeletal function have combined to provide an exciting new tool for musculoskeletal research. Interactive simulation also has promising applications in medical education and clinical rehabilitation. Only those developments that fit the specific criteria of realism, real-time response, intuitive interaction, three-dimensional structures, and modeling flexibility are discussed. It is hoped that an improved understanding of this emerging tool and an appreciation for its potential applications will be gained.

Arm↗