Vastus medialis: anatomical and functional considerations and implications based upon human and cadaveric studies.

OBJECTIVE: To provide an electrophysiological and functional description of the vastus medialis (VM) and contrast it to an anatomical description. METHODS: Motor points of all superficial portions of the quadriceps were identified on the dominant side of 8 human subjects and electrically stimulated to achieve a light contraction to trace and measure the orientation of the fibers. Electromyography of the VM was then recorded over 2 motor points during isometric and isokinetic maximum knee extensions. An independent laboratory dissected 39 cadaveric specimens focusing on fiber orientations and distal insertions of the VM. RESULTS: Results revealed 5 motor points for the quadriceps: 1 point for the vastus lateralis, 1 point for the rectus femoris (RF), and 3 points for the VM. The 3 VM motor points suggest 3 separate groups of fibers: proximal (pf), median (mf), distal (df). Fiber orientations ranged from 45 degrees for VMpfs to 55 degrees for VMdfs. Motor point stimulation and anatomical dissection clearly showed that the VMpfs and VMmfs were inserted on a tendon common to the RF, whereas VMdfs were attached directly to the medial aspect of the patella. Furthermore, the VMpfs were more active (P < .05) than VMdfs during maximum knee extensions. CONCLUSION: The anatomy, motor points, and electromyography clearly support an important distinction between the VMpfs and VMdfs. The role of the VMpfs would be one of assisting the RF in knee extension, whereas the VMdfs would track the patella medially without participating in knee extension. Because of these anatomical and functional differences, the VMpfs and VMdfs should be addressed very differently during quadriceps rehabilitation in patellofemoral dysfunctions.

Integrating feedback from a clinical data warehouse into practice organisation.

A patient oriented hospital information system (ARIANE) was inaugurated at the Sherbrooke University hospital (CHUS) in 1990 and a clinical data warehouse (CDW) completed 2004. The CDW is updated from ARIANE every 24h and includes ICD discharge diagnosis data, visit DRG and SNOMED encoding. The data is encrypted on storage. Data is accessed according to institutional approval. To facilitate data access two levels of tool have been made accessible using a web-browser. The first level consists of a 'dashboard' that has a defined design and enables a set of pre-determined dynamic queries about a patient population. This level can be operated with minimal training. The second level uses a convivial database query tool, which requires some prior training. Two prototype dashboards have been designed and evaluated for acceptability. The first for the emergency department enables analysis of patient occupancy. The second for the biochemistry department enables quality assurance evaluation. In most cases worldwide the clinical data warehouse is only beginning to be exploited, often impeded by lack of connection between different enterprise databases. Our CDW is expected rapidly to create a culture change so that clinical practice can be continuously evaluated using compiled data readily available from the electronic health record/hospital information system.

Reliability of the motor evoked potentials elicited through magnetic stimulation at three sites.

BACKGROUND: Motor evoked potentials (MEPs) obtained from magnetic stimulation allow the measurement of the excitability of motor nerve cells. Although this technique is becoming widely used, its reliability has yet to be established. OBJECTIVE: To determine the reliability of MEPs and evaluate their stability. DESIGN: Subjects received magnetic stimulation at 3 different sites: cranial, cervical, and peripheral. Three stimulations were given at each site. Stimulations were given under 4 conditions: eyes open or closed and with or without controlled mental activity. SETTING: The study was performed in a research laboratory setting. PARTICIPANTS: Nine healthy subjects (mean age = 21 years +/- 0.9), asymptomatic of any neural or musculoskeletal dysfunctions. MAIN OUTCOME MEASURES: Normalized peak-to-peak amplitude of MEPs at the opponens pollicis muscle. RESULTS: Intraclass correlations were high for all conditions (R > 0.90). The amplitude of the MEPs elicited from the transcranial site during the controlled mental activity condition was increased by 26.6% (P =.017). No other significant differences (P >.05) were obtained among the other conditions. CONCLUSION: Intraclass correlation results reveal that MEP measurements are highly reliable in a controlled environment. The increase of MEPs during the controlled mental activity condition could be attributed to an elevation of neural activity of different nonmotor areas of the brain increasing corticospinal excitability.