Anat Cell Biol.  2019 Sep;52(3):344-348. 10.5115/acb.19.030.

Morphological variations and accessory ossicles in the peroneal and tibialis muscles

• DeLuca MK
• Boucher LC

• KMID: 2459552
• DOI: http://doi.org/10.5115/acb.19.030

Abstract

This study describes five bilateral anatomical variations in the feet of a 97-year-old male cadaver. Following routine dissection, all variants were measured and documented. Three accessory tendons and two accessory ossicles were identified. Bilateral accessory tendons were present from the tibialis anterior (type II), peroneus tertius (type III), and peroneus brevis muscles. Accessory tendon length was 36-104 mm and width was 1-3 mm each inserting more distally then the main tendon. Accessory ossicles were identified as an accessory navicular and os peroneum, respectively. Individually, each variation has varying prevalence rates in the literature, but to date, no known studies have been published describing the combined presence of all five bilateral variations. The acknowledgement of multi-variant cases such as this one may be helpful in the clinical setting, particularly for patients with pathology or for those undergoing foot and ankle surgery.

Keyword

Accessory ossicles; Accessory tendons; Foot; Peroneus tertius; Tibialis anterior

MeSH Terms

Ankle
Cadaver
Foot
Humans
Male
Muscles*
Pathology
Prevalence
Tendons

Figure

• 

  Fig. 1 (A) Accessory tendon morphology. The accessory tendon of peroneus brevis muscle (PB) (arrowheads) extended from the main tendon of PB to attach laterally on the head of the fifth metatarsal. Also visible are the tendons of peroneus longus (PL), peroneus tertius (PT), and extensor digitorum longus (EDL). (B) The main tendon of the tibialis anterior (TA) inserts on the medial cuneiform and first metatarsal base, while the accessory tendon of TA (arrowheads) inserts at the head of the first metatarsal (**). Also visible is the tendon of extensor hallucis longus (EHL), the tendon of tibialis posterior muscle (TP), and the tendon of flexor digitorum longus (FDL). (C, D) Anomalous bifurcation in the tendon of PT indicated by black arrowheads. Image C demonstrates the lateral view of the tendon, while Image D demonstrates the dorsolateral view of the tendon as it attached to the lateral base of the fourth proximal phalanx. Also visible are the muscle belly of extensor digitorum brevis (EDB), tendon of PB, and tendons of EDL.

• 

  Fig. 2 (A) Ossicle morphology. The os peroneum (OP, *) within the tendon of peroneus longus (PL), adjacent to the cuboid. Arrow indicates the convex facet on the cuboid bone at the site of articulation with the sesamoid bone. Also visible is the tendon of peroneus brevis muscle (PB). (B) Isolated OP, measuring 20 mm long and 13 mm wide. (C) Accessory navicular (AN; indicated by tip of probe) located within the tendon of tibialis posterior muscle (TP), proximal to its division and adjacent to the navicular tuberosity (NT). Also visible are the long plantar ligament (LPL), short plantar ligament (SPL), and spring ligament (SL). (D) Isolated AN, measuring 13 mm long and 7 mm wide.

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