Spinous injury caused by a sea urchin

Area of Science:

• Marine Biology
• Histology
• Biomineralization

Background:

• Marine environments harbor diverse species with unique biological structures.
• Injuries from marine fauna can occur, necessitating accurate identification of the causative agent.
• Sea urchin spines are distinct biomineralized structures with characteristic morphology.

Purpose of the Study:

• To identify the causative agent of a finger injury sustained by a bather in Kenya.
• To characterize the morphology of foreign bodies recovered from a skin biopsy.
• To differentiate between sea urchin spines and other similar marine structures.

Main Methods:

• Microscopic examination of skin biopsy specimen.
• Embedding of recovered spines in plastic resin for sectioning.
• Light microscopy with crossed polarisers to analyze spine structure.

Main Results:

• Skin biopsy contained black spines (0.5 mm diameter, up to 1.5 cm length).
• Microscopy revealed ornate, symmetrical structures characteristic of sea urchin spines.
• Spines composed of calcite crystals with epithelial covering, distinct from chitinous sea mouse spines.

Conclusions:

• The injured bather was likely injured by a sea urchin spine.
• Microscopic analysis of biomineralized structures is crucial for identifying marine-related injuries.
• Distinct morphological features differentiate sea urchin spines from other marine calcified structures.