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Biomedical subjects

R Yeasting

Publications and source records attributed to R Yeasting.

7 recordsLinked to original sources
PubMed2003

Kinematics of the human pelvis following open book injury.

The objective of this study is to determine the three dimensional kinematics of the human pelvis including both sacroiliac joints following a simulated open book injury induced on cadavers by applying anterior-posterior compressive loads to the pelvis. An electromagnetic digitizing and motion tracking system was utilized to measure the morphology of the pelvis and the relative movements of its bones during this simulated open book fracture. The screw displacement axis method was used to describe the relative motion between the sacrum and each hipbone. Morphologically, it was found that the articular surfaces forming the sacroiliac joints could be approximated with planar surfaces directed from proximal and lateral to distal and medial and from posteromedial to anterolateral. The kinematic data obtained from this study indicate that there is a direct correlation between the opening of the symphysis pubis and the opening of the sacroiliac joint (SIJ) during open book injury. This suggests that the extent of injury of the SIJ maybe estimated from the degree of opening of the symphysis pubis as demonstrated on anteroposterior (A-P) x-rays. The results obtained from this study also indicate that the motion of the hipbone with respect to the sacrum on the side of the sacroiliac joint opening is almost a pure rotation, which translates clinically on the A-P x-rays as pure opening of the SIJ without vertical displacement. The average axis of rotation was found to be almost parallel to the SIJ planar articular surface. Furthermore, the pubic bone on the side of SIJ opening was found to displace inferiorly and posteriorly. One can thus conclude that in open book pelvic injuries, the pubic bone on the side of injury displaces inferiorly on the outlet projection x-rays with no vertical displacement of the SIJ. This is important since the initial assessment of the open book injury in the emergency room includes outlet projection x-rays. From this study, the relative vertical positions of the pubic bones on these x-rays can help the surgeon in differentiating open book fracture injury from other pelvic injuries.

Cadaver↗
PubMed1997

Sacroiliac joint injection: a cadaveric study.

Eleven bony pelves were studied in an attempt to find an ideal approach for needle placement into the sacroiliac joint and to describe the unique anatomy of the sacroiliac joint relative to sacroiliac joint injection. A posterior approach starting 2 cm to 3 cm inferior to the posterior superior iliac spine, angled 20 degrees to 30 degrees laterally, relative to the sagittal plane, and 10 degrees to 20 degrees inferiorly, relative to the transverse plane, was found to be the best approach to the intra-articular portion of the sacroiliac joint.

Aged↗
PubMed1996

Surgical anatomy of the radial nerve in the arm: practical considerations of the branching patterns to the triceps brachii.

Thirty-three cadaveric dissections were performed to identify radial nerve branching patterns to the triceps brachii. Radial innervation of the long head of the triceps originated in the axilla in 88% of the cases and the brachio-axillary angle in 12%. Innervation of the medial head of the triceps originated in the spiral groove in 52% of the cases, the brachio-axillary angle in 39%, and the axilla in 9%. The lateral head was innervated by branches arising in the spiral groove in 70% of the cases, the brachio-axillary angle in 24%, and the axilla in 6%. On average, the radial nerve crossed the midline in the proximal 45% of the arm, 3 cm superior to the level of the deltoid insertion. An intramuscular tendon was present in the medial head of the triceps. The tendon, located medial to the midline of the arm, was seen in all specimens. This tendon serves as an interneural plane with nerve branches descending on either side, but never crossing from one side to the other. Due to the complexity of radial nerve branching, this tendon may be used as a reference plane for longitudinal splitting of the medial head minimizing the risk of nerve damage.

Arm↗
PubMed1995

Anatomy of C7 lateral mass and projection of pedicle axis on its posterior aspect.

A specimen study focused on the measurements of C7 lateral mass and pedicle as well as the projection of pedicle axis on the posterior aspect of the lateral mass was done, based on 56 whole clean, dry, well-preserved spines of skeletally mature adults, 32 males and 24 females. Lateral mass widths averaged 11.7 mm. Lateral mass heights averaged 14.8 mm. The average thickness of the lateral mass was 6.8 mm. The average pedicle widths were 6.2 mm, and the average heights were 7.0 mm. Small, but statistically significant differences were found between the averages of the aforementioned dimensions in the male and female groups. The angulation between pedicle axis and the posterior aspect of the lateral mass averaged 107.0 degrees in the transverse plane and 76.2 degrees in the sagittal plane, respectively. Differences in angulations were not significant when compared according to side or sex of group. Distances from the projection point of pedicle axis to a line passing through the mid-line of the transverse process ranged from 2 mm superior to the line to 4.5 mm inferior, with an average 1.2 mm inferior on right side and 0.3 mm inferior on the left. Distances from the pedicular axial projection point to the outer margin of the lateral mass ranged from 0.0 mm to 5.4 mm, with an average 2.4 mm on the right side and 2.9 mm on the left side. Differences of distance related to left or right side were statistically significant, whereas the distances when related to the sex of the group were not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Morphometric evaluation of the cervico-thoracic junction. Practical considerations for posterior fixation of the spine.

STUDY DESIGN: Linear and angular measurements were performed on 128 vertebrae (16 spines) from C5 to T5. OBJECTIVES: Vertebrae were studied to characterize vertebral shape and size changes in the cervico-thoracic region. SUMMARY OF BACKGROUND DATA: Analysis of vertebral anatomy has been extensive and well characterized. Regions of transitional anatomy necessitate further study due to the often abrupt changes in anatomic relationships. METHODS: Two observers performed linear and angular measurements including pedicle width, height, and length, as well as pedicle-body, pedicle-lamina, lamina-transverse process, and pedicle-lamina angular measurements. Pedicle axis projection on the posterior aspect of the lamina was also calculated. RESULTS: The mean pedicle width ranged from 7.8 mm (T1) to 4.4 mm (T5). The body-pedicle angle decreased > 4 degrees per level in the transverse plane, from 50 degrees (C5) to 11 degrees (T5). The axial projection of the pedicle changed throughout the region (compared with level above) and was significant for T1. CONCLUSIONS: Because of the complexities of the cervico-thoracic junction, additional characterization increases the knowledge of the anatomic relationships in this region.

Adult↗
PubMed1990

Do first- and second-year preclinical course scores predict student performance during the surgical clerkship?

The study proposed to determine if a preclinical basic science index comprised of anatomy, behavioral medicine, biochemistry, microbiology, pathology, pharmacology, and physiology courses or any one of these basic science courses would predict student performance during surgical clerkship. The basic science index demonstrated a correlation of 0.55 and 0.35 with the individual student's written and oral clerkship scores, respectively. A stepwise multiple regression using a backward stepping algorithm was applied; the dependent variables were oral and written clerkship scores, and the independent variables were the basic science courses. Microbiology, pathology, and physiology course scores were predictors of written score (R = 0.60). Pathology course scores were the sole predictor of oral score (R = 0.43). Medical student basic science performance was not a strong forecaster of performance on the surgical clerkship. The pathology basic science score was the only consistent predictor of performance on the written and oral evaluations given at the end of the clerkship.

Clinical Clerkship↗