The Effect of the Lateral First Metatarsal Head Shape on Hallux Valgus in Forced Turnout in Pre-Pointe Female Ballet Dancers: A Pilot Study.

BACKGROUND: A rounded lateral first metatarsal head shape is associated with higher rates of hallux abducto valgus recurrence following corrective surgery; however, the effect of the lateral first metatarsal head shape on the hallux abduction angle (HAA) has not yet been explored in a nonpathologic, pre-pointe ballet dancer population. The primary purpose of this study was to investigate the effect of the lateral first metatarsal head shape on the HAA when pre-pointe female dancers force their turnout. METHODS: Seventeen female, pre-pointe ballet students (mean age, 10.8 ± 0.95 years) participated in this study. Fluoroscopic images of each dancer's dominant foot were taken, and the lateral first metatarsal head shape was classified visually. Each dancer performed three consecutive stances of natural double-leg upright posture: both functional and forced turnout. HAAs were obtained by marking medial bony landmarks on paper and were compared to photographic measurements. RESULTS: No significant difference was found between the round and angular lateral first metatarsal head shape for the change in HAA from natural double-leg upright posture to forced turnout. Hallux abduction angle significantly increased by 4.6° (P < .001) in forced turnout compared to the natural double-leg upright posture for the photographic method, whereas the paper method demonstrated an increase of 2.6° (P = .007). No statistical differences were found between the paper and photographic methods in measuring the HAA for all stances. CONCLUSIONS: Our findings suggest no association between the HAA and lateral first metatarsal head shape; however, HAA does increase when a dancer assumes forced turnout. The paper method demonstrated similar reliability to the photographic method and shows the potential for future use as a clinical tool in assessing hallux abducto valgus.

3D printing the pterygopalatine fossa: a negative space model of a complex structure.

PURPOSE: The pterygopalatine fossa is one of the most complex anatomical regions to understand. It is poorly visualized in cadaveric dissection and most textbooks rely on schematic depictions. We describe our approach to creating a low-cost, 3D model of the pterygopalatine fossa, including its associated canals and foramina, using an affordable "desktop" 3D printer. METHODS: We used open source software to create a volume render of the pterygopalatine fossa from axial slices of a head computerised tomography scan. These data were then exported to a 3D printer to produce an anatomically accurate model. RESULTS: The resulting 'negative space' model of the pterygopalatine fossa provides a useful and innovative aid for understanding the complex anatomical relationships of the pterygopalatine fossa. CONCLUSION: This model was designed primarily for medical students; however, it will also be of interest to postgraduates in ENT, ophthalmology, neurosurgery, and radiology. The technical process described may be replicated by other departments wishing to develop their own anatomical models whilst incurring minimal costs.

Benign anlage tumour: a very unusual neck mass.

A 44-year-old woman presented with a slow-growing asymptomatic neck swelling at the left medial clavicle. Haematological and biochemical work up was normal and an ultrasound confirmed the swelling, but needle aspiration was non-diagnostic. As lymphoma was the main differential diagnosis, the swelling was completely excised. Immunohistochemistry yielded a rare lesion, suspected to represent a myoepithelial/mixed cellularity tumour of soft tissue. The extreme rarity of these tumours required a confirmatory secondary opinion, which ultimately led to it being identified as a benign anlage tumour (previously known as an ectopic hamartomatous thymoma) This case highlights the fact that thorough assessment of patients with neck swellings should be undertaken to rule out sinister causes-keeping in mind more rare differentials-helping to guide final management.