Biomedical subjects

Richard A Yeasting

Publications and source records attributed to Richard A Yeasting.

8 recordsLinked to original sources

PubMed2006

Morphometric analyses of the cervical superior facets and implications for facet dislocation.

The articular facets of the cervical spine have been well addressed; however, little information is available on the relationship of the superior facets of the cervical spine to traumatic dislocation in the literature. Morphometric analyses of the superior facets of 30 dried cervical spines from C3 to C7 were performed to determine any morphological differences. The angle of the superior facet with respect to the transverse plane was also measured on computed tomography (CT) scans of 30 patients having neck injury without fracture/dislocation. The vertical and surface lengths of the superior facet were significantly lower (P < 0.01) at C6-C7 levels than at C3-5 levels. The anteroposterior diameter of the superior facet was smaller (P < 0.05) at C6 and C7 levels compared to C3-5 levels. Although the superior facet joint surface is in a more coronal orientation in lower cervical vertebrae, the inclination of the superior facet is more horizontal relative to the transverse plane when measured in vivo. A combination of lower height, smaller anteroposterior diameter of the superior facet, and a more horizontally oriented superior facet at C6 and C7 levels in vivo may explain the predilection of translation relative to one another in the lower cervical spine.

Adult↗

PubMed2006

Anatomical evaluation and clinical importance of the tibiofibular syndesmosis ligaments.

The aim of this study was to describe the detailed anatomical arrangement of ligaments of the tibiofibular syndesmosis and to highlight the clinical aspects of fracture dislocations. This study was performed on 42 legs of adult human embalmed cadavers. Tibiofibular syndesmosis ligaments attachments and their mutual relationships were described and their dimensions were measured. The anterior tibiofibular ligament is usually composed of three parts. This ligament runs obliquely at laterodistaly direction making 35 degrees angle with horizontal plane and posteriorly 65 degrees angle with sagittal plane. The posterior tibiofibular ligament runs almost horizontally 20 degrees angle with horizontal plane. The mean thicknesses of tibial and fibular attachments are 6.38+/-1.91 mm and 9.67+/-1.74 mm, respectively. The inferior transverse ligament originates from just below the posterior tibiofibular ligament, which has variations on the shape and dimensions due to its attachment points. The average length is 36.60+/-9.51 mm. The network between the fibular notch and the distal fibula has been filled with the interosseous tibiofibular ligament whose fibers follow the laterodistal and anterior direction from the tibia to the fibula. It lies proximally 30-40 mm from the mortise. At the inferior view of the tibiofibular syndesmosis a pyramidal shaped cartilaginous facet was observed which was attached to the fibula. The length of this cartilage was variable. Some of synovial plicas from the ankle joints synovial membrane were observed at this view. We conclude that the results of this study may be useful to both orthopedic surgeons and radiologists for anatomic evaluation of the tibiofibular syndesmosis area.

Aged↗

PubMed2006

Quantitative analysis of changes in cervical intervertebral foramen size with vertebral translation.

STUDY DESIGN: Simulated translation of the C5 vertebra was performed in 20 embalmed cadaveric cervical spines, and cross-sectional areas of the C4-C5 and C5-C6 intervertebral foramina were measured and compared before and after translation of the C5 vertebra. OBJECTIVE: To determine the relationship of cross-sectional intervertebral foraminal areas to the degrees of vertebral translation. SUMMARY OF BACKGROUND DATA: The common feature of clinical instability and adjacent diseases of the cervical spine is malalignment of the cervical spine (i.e., there is ventral and dorsal translation of vertebral body with respect to the adjacent upper and lower vertebral body, respectively). To our knowledge, no previous study has analyzed the quantitative effect of vertebral translation on the size of the intervertebral foramina. METHODS: The cross-sectional areas of the intervertebral foramina at C4-C5 and C5-C6 were measured on computerized tomography. The images were then transferred to the personal computer, where consecutive dorsal translations of C5 vertebrae with a 1-mm increment from 1 to 5-mm displacements were performed using Microsoft paint software (Microsoft, Corp., Redmond, WA). National Institutes of Health (Bethesda, MD) Image J software (V1.33m) was then used to measure the areas of both sides of C4-C5 and C4-C6 foramina at normal and each displacement level in the computer. RESULTS: Following dorsal translation of C5 vertebra, anterolisthesis of C4 relative to C5 and retrolisthesis of C5 relative to C6 was noted. No significant difference was found between the measured values using Aquarius Image software (Microsoft, Corp.) on computerized tomography and National Institutes of Health image J software on the desktop computer (P > 0.05). When compared with normal values, there was an increase in the C4-C5 intervertebral foraminal area (i.e., 6%, 14%, 18%, 21%, and 26% with anterolisthesis of C4 relative to C5 following 1, 2, 3, 4, and 5-mm dorsal translation of the C5 vertebra, respectively). There was a 12% decrease in the C5-C6 intervertebral foraminal area, with each 1-mm incremental retrolisthesis of C5 relative to C6 vertebra. Statistically significant differences were found among residual cross-sectional foraminal areas following different degrees of dorsal translation (P < 0.05). CONCLUSION: There is a significant increase in size with anterolisthesis and decrease in size with retrolisthesis of upper and lower adjacent vertebral intervertebral foramina, respectively.

Aged↗

PubMed2005

Enlarged perforating branch of peroneal artery and extra crural fascia in close relationship with the tibiofibular syndesmosis.

We found an extremely large perforating branch of peroneal artery in an 89-year-old female cadaver's left ankle. The anterior tibial artery could not reach to supply the ankle and dorsum of the foot. The perforating branch of peroneal artery continued as the dorsalis pedis after giving off an anterior lateral malleolar artery branch. The posterior tibial artery was thinner than usual. On the anterior side of the ankle, there was an extra crural fascia in addition to the regular crural fascia, under the anterior crural muscles. This strong fascia was tightly overlying the perforating branch of peroneal artery and anterior tibiofibular ligament. It is important to know the relationship of these vessels to the surrounding structures. Surgeons must be careful while dissecting this area since the perforating branch of peroneal artery might be anomalously enlarged as well as crossing in front of the tibiofibular syndesmosis in order to prevent vascular injury.

Aged, 80 and over↗

PubMed2005

Lateral femoral cutaneous nerve: an anatomic study.

The purpose of our study was to determine the location of the lateral femoral cutaneous nerve and its branches at the inguinal ligament and proximal thigh. We think that further defining the location of the nerve and its branches based on certain measurements from known anatomic landmarks would enable us to determine a danger zone that could aid in preventing iatrogenic injury to the lateral femoral cutaneous nerve. The anatomic course of the lateral femoral cutaneous nerve was studied in 29 cadaver specimens and distances from various landmarks were recorded. In addition, the branching pattern of the nerves was recorded. We observed variability in the course and branching patterns of the lateral femoral cutaneous nerve. The lateral femoral cutaneous nerve was found to potentially be at risk as far as 7.3 cm medial to the anterior superior iliac spine along the inguinal ligament and as much as 11.3 cm distal on the sartorius muscle from the anterior superior iliac spine. As many as five branches of the lateral femoral cutaneous nerve were found and in 27.6% of cases the lateral femoral cutaneous nerve branched before traversing the inguinal ligament. We used this information to describe a danger zone, which could be used as a guide to help prevent unnecessary injury during certain procedures.

Adult↗

PubMed2003

Dynamic changes in the contact area of the sacroiliac joint.

Thirty adult dry-bone ilium specimens were used in conjunction with computer analysis to determine the average articular contact area between the sacrum and ilium at the sacroiliac joint. Simulating an unstable pelvic injury, the sacroiliac joint was displaced in three directions by moving the ilium posteriorly, superiorly, and posterosuperiorly. After each displacement, the contact area between the sacrum and ilium at the sacroiliac joint was calculated. The data showed that the average articular surface area of the male sacroiliac joint (1138.3 mm2) was approximately 12.8% greater than the average surface area of the female sacroiliac joint (992.5 mm2). The average articular contact area between the sacrum and ilium at the sacroiliac joint was lowest with the ilium displaced posterosuperiorly compared to equal displacements superiorly or posteriorly. This study quantitatively illustrated the loss of contact surface area between the sacrum and ilium during various displacements of the ilium, thus indicating the clinical cross-section area available for open reduction and internal fixation or fusion.

Adult↗

PubMed2002

Extensor hallucis longus innervation: an anatomic study.

Thirty legs from skeletally mature embalmed cadavers were dissected to define the most common pattern and the variants of innervation of the extensor hallucis longus muscle and its clinical significance. Twenty-seven muscles had only one innervating branch (90%). Only three muscles had two innervating branches (10%). Twenty-one of the branches entered the muscles from the fibular side (63.6%), six entered the muscles from the tibial side (18.2%), and six entered the muscles from the anterior edge (18.2%). The branches innervating the extensor hallucis longus from the fibular side had a closer relation with the fibular periosteum than those entering the muscle from the tibial side or the anterior edge. The mean length of these branches between their points of origin and entry in the extensor hallucis longus was 5.0 +/- 1.5 cm. The high risk zone for the iatrogenic injury to the muscular branch of the extensor hallucis longus was located between 5.9 +/- 1.7 and 10.9 +/- 1.7 cm inferior to the most distal palpable point of the fibular head. The current study confirmed that the extensor hallucis longus was supplied mostly by one nerve that usually entered the muscle from the fibular side and had a close relation to the fibular periosteum in the dangerous zone.

Cadaver↗

PubMedDate not supplied

Value of intraoperative true lateral radiograph of C2 pedicle for C1-2 transarticular screw insertion.

BACKGROUND CONTEXT: Transarticular C1-2 screws are widely used in posterior cervical spine instrumentation. Injury to the vertebral artery during insertion of transarticular Cl-2 screw remains a serious complication. Use of a computer-assisted surgery system decreases this complication considerably. However, this system encounters problems in ensuring complete accuracy because of positional variations during preoperative and intraoperative imaging generation. Therefore, intraoperative fluoroscopy still is one of the commonly used methods to guide insertion of transarticular Cl-2 screw. Evaluation of a true lateral radiographic view of the C2 pedicle for screw trajectory during C1-2 transarticular screw insertion may help to minimize this potential complication. PURPOSE: To evaluate the value of intraoperative true lateral radiograph of the C2 pedicle for screw trajectory during C1-2 transarticular screw insertion. STUDY DESIGN: To compare the height of the C2 pedicle area allowing instrumentation on true lateral view radiograph of the C2 pedicle and computed tomographic (CT) scan with multiplanar reconstruction. METHODS: Twenty embalmed human cadaveric cervical spine specimens were used to insert a total of 40 C1-2 transarticular screws using Magerl and Seemann technique. One side of the C2 transverse foramen was filled with radiopaque material (lead oxide) to simulate the artery and to demarcate the danger zone for better visualization on radiography. Measurements and calculation of the mean and standard deviation of the height of the area allowing instrumentation of the C2 pedicle were done on true lateral view radiograph of the C2 pedicle, the sagittal and 30 degrees sagittal views relative to the frontal plane passing exactly through the center of the C2 pedicle of CT scans. Student t test was applied to calculate the statistical significance of measured values. Statistical significance was defined as p or=.36. Using sagittal CT scan views, the height of pedicles was 7.71+/-0.7 mm (right) and 7.58+/-1.01 mm (left), p>or=.23. On 30 degrees sagittal CT scan views, the height of pedicles was 7.84+/-1.00 mm (right) and 7.76+/-1.02 mm (left), p>or=.27. The p value was >or=.78, >or=.56, and >or=.49 for true lateral radiographic view and sagittal CT scan view, true lateral radiographic view and 30 degrees sagittal CT scan view, and sagittal CT scan view and 30 degrees sagittal CT scan views, respectively. On lateral view of cervical spine, the decline angle of the transarticular screw was 51.3+/-0.50 degrees (right) and 50.68+/-0.41 degrees (left), p>or=.17. Mean decline angle was 51+/-0.43 degrees . On the anteroposterior (AP) view, radiograph median angle was 6.87+/-0.53 degrees (right) and 6.0+/-0.59 degrees (left), p>or=.25. Mean median angle was 6.44+/-0.62 degrees. CONCLUSIONS: True lateral radiographic views of the pedicles provide useful information for defining screw trajectory intraoperatively. Using this view along with AP and lateral view of cervical spine and preoperative three-dimensional CT scan may narrow the margin of error in this delicate area.

Aged↗