"Haleem's Hen"; A mnemonic for the anatomy of hindfoot structures at the level of sustentaculum tali on coronal T1-weighted magnetic resonance images

Abstract

Magnetic resonance anatomy of the hindfoot as seen at the level of the sustentaculum tali is intricate due to surrounding muscles, tendons, aponeurosis and ligaments. The objective of this work is to provide a mnemonic with illustrative figures to simplify this complex anatomical region on coronal T1-weighted MR images (T1-MRIs). One hundred and twenty-four patients referred for foot and ankle complaints were scanned utilizing standard MRI imaging protocols for depiction of the hindfoot. Only coronal T1-MRIs of the calcaneus at the level of sustentaculum tali of unremarkably reported patients were selected for this work. Upon viewing the calcaneus with the adjacent anatomical structures on coronal T1-MRIs, the overall appearance resembles a "Hen in the Nest with Four Eggs''. The calcaneus represents the body of the hen, while the sustentaculum tali forms the head and neck. The posterior tibial tendon represents the crest of the hen, and the flexor digitorum longus and flexor hallucis longus tendons represent its beak and wattle, respectively. The peroneus brevis and peroneus longus tendons represent the tail, and the long plantar ligament represents the flexed legs of Haleem's hen. The plantar aponeurosis represents the hen's nest. Whereas the abductor hallucis, flexor digitorum brevis, abductor digiti minimi and quadratus plantae muscles are the four eggs. The mnemonic, "Haleem's Hen in the Nest with Four Eggs", serves as a simplified phrase for radiologists and orthopedic surgeons to easily recall the anatomy of the hindfoot when viewing it at the level of the sustentaculum tali on coronal T1-MRIs.

Keywords: Anatomy; Hindfoot; Magnetic resonance; Orthopedics; Radiology.

Fig. 1

A – Coronal T1-weighted MR image shows calcaneus (body of the hen) at the level of the sustentaculum tali (head and neck of the hen). B – Illustrative figure shows the calcaneus (body of the hen) and sustentaculum tali (head and neck of the hen).

Fig. 2

A – Coronal T1-weighted MR image shows the calcaneus at the level of the sustentaculum tali with the tibialis posterior, flexor digitorum longus and flexor hallucis longus muscles representing the crest, beak and wattle of the hen, respectively. B – Illustrative figure shows the crest (tibialis posterior), beak (flexor digitorum longus) and wattle (flexor hallucis longus) of the hen.

Fig. 3

A – Coronal T1-weighted image shows the peroneus brevis and peroneus longus tendons as the tail of the hen and the long plantar ligament as the flexed legs of the hen. B – Illustrative figure shows the tail made up of the peroneus brevis and peroneus longus tendons and the flexed legs made up of the long plantar ligament.

Fig. 4

Coronal PD MR image with fat suppression shows the long plantar ligament merging with the cortex of the plantar aspect of the calcaneus.

Fig. 5

A bony density reformatted coronal CT image shows the calcaneus and the long plantar ligament, which is seen adjacent to the cortex of the plantar aspect of the calcaneus.

Fig. 6

A – Coronal T1-weighted MR image shows the three components of the plantar aponeurosis (i.e. medial, central and lateral cords), which represent the nest. B – Illustrative figure shows the medial, central and lateral cords of the plantar aponeurosis which comprise the nest.

Fig. 7

Coronal PD MR image with fat suppression shows the nest made up of the medial, central and lateral cords of the plantar aponeurosis.

Fig. 8

A – Coronal T1-weighted MR image shows the four eggs made up of the abductor hallucis, flexor digitorum brevis, abductor digiti minimi and quadratus plantae muscles. B – Illustrative figure shows the four eggs represented by the abductor hallucis, flexor digitorum brevis, abductor digiti minimi and quadratus plantae muscles.

Fig. 9

When viewing the calcaneus with a coronal T1-weighted MR image as the level of the sustentaculum tali, the resulting image resembles “Haleem’s Hen in the Nest with Four Eggs.” This image shows the relevant anatomical structures and their corresponding parts in the mnemonic.

Fig. 10

Pes planus can present with posterior tibial tendinopathy and atrophy of the quadratus plantae muscle component, which is associated with signs of inflammation around the crest of the hen and a small fourth egg, respectively, as shown above in the coronal T1 (left) and PDFS (right) MRIs.

Fig. 11

On coronal T2 fast spin (left), T1 (middle) and T1 FS post-contrast (right), a hemangioma of the flexor digitorum brevis can be visualized as an abnormal, hyperintense mass within the second egg of the hen.

Fig. 12

Baxter’s neuropathy and chronic denervation presents with abductor digiti minimi atrophy on coronal T1 MRI, and this pathology is associated with a small third egg.

Fig. 13

Abnormal inflammation/thickening of the peroneus brevis and longus is typical of peroneal tendonitis, which would relate to enlargement of the tail of the hen. On this coronal PDFS (left) and T1 (right), peroneus brevis inflammation and enlargement can be visualized.