The prevalence of the optic canal anatomical variants across the sphenoid sinus varies widely among different ethnic groups. This study aimed to analyse the anatomical variants of the optic canal and their relationship to sphenoid sinus pneumatisation in a Hispanic population.

A review of 320 sphenoid sinuses by high-resolution computed tomography was performed. DeLano's classification of the optic canal, presence of dehiscence, septa insertion, sphenoid sinus pneumatisation and presence of Onodi cells were established.

Dehiscence of the optic canal was observed in 4.7 per cent (n = 15) of the analysed sinuses. Type 4 and 3 optic canals were significantly more frequent among postsellar sphenoid sinuses than other patterns of sphenoid sinus pneumatisation (p = 0.002 and p = 0.018). A type 4 optic canal has a higher tendency to present inserted septum than other optic canal types (p = 0.014).

This study described the optic canal variants in a Hispanic population, which complements existing literature addressing other ethnicities.

Poor response to injection of botulinum toxin (BoNT) into the flexor digitorum longus (FDL) muscle has been reported especially in patients with claw foot deformity. We previously advocated BoNT injection into the flexor hallucis longus (FHL) muscle in such patients. Here, we determined the functional and anatomical relationships between FHL and FDL.

Toe flexion pattern was observed during electrical stimulation of FHL and FDL muscles in 31 post-stroke patients with claw-foot deformity treated with BoNT. The FHL and FDL tendon arrangement was also studied in five limbs of three cadavers.

Electrical stimulation of the FHL muscle elicited big toe flexion in all 28 cases examined and second toe in 25, but the response was limited to the big toe in 3. FDL muscle stimulation in 29 patients elicited weak big toe flexion in 1 and flexion of four toes (2nd to 5th) in 16 patients. Cadaver studies showed division of the FHL tendon with branches fusing with the FDL tendon in all five limbs examined; none of the tendons was inserted only in the first toe. No branches of the FDL tendon merged with the FHL tendon.

Our results showed coupling of FHL and FDL tendons in most subjects. Movements of the second and third toes are controlled by both the FDL and FHL muscles. The findings highlight the need for BoNT injection in both the FDL and FHL muscles for the treatment of claw-toe deformity.

To evaluate the prevalence of variations in the anatomical route of the spinal accessory nerve from the base of the skull to the point where it enters the trapezius muscle. A case report is used to demonstrate an example of a rare but clinically important anatomical variant of this nerve.

An independent review of the literature using Medline, PubMed and Q Read databases was performed using combinations of terms including ‘spinal accessory nerve’, ‘anatomy’, ‘surgical anatomy’, ‘anatomical variant’, ‘cranial nerve XI’ and ‘shoulder syndrome’.

Our report demonstrates marked variation in spinal accessory nerve anatomy. At the point of crossing over the internal jugular vein, the spinal accessory nerve passes most commonly laterally (anterior) to the internal jugular vein. The reported incidence of this lateral relationship varies from 67 to 96 per cent. The nerve can also pierce the internal jugular vein, as demonstrated in our case study, with incidence ranging from 0.48 to 3.3 per cent.

Anatomical variations of the spinal accessory nerve are not uncommon, and it is important for the surgeon to be aware of such variations when undertaking surgery in both the anterior and posterior triangles of the neck.