Anatomy of Ankle and Talocrural Joint

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Questions and Answers

Which of the following muscles is responsible for toe flexion in the sagittal plane?

Flexor Digitorum Brevis

Abductor Hallucis

Adductor Hallucis

Quadratus Plantae (correct)

Which muscle group includes the plantar interossei and dorsal interossei?

First Layer Intrinsic Muscles

Fourth Layer Intrinsic Muscles (correct)

Third Layer Intrinsic Muscles

Second Layer Intrinsic Muscles

What is the primary function of the lumbricals in the foot?

Toe abduction

MTP joint flexion

Toe adduction

IP joint extension (correct)

Which ligament connects the fibula to the talus in the lateral region of the ankle?

Anterior talofibular ligament Signup and view all the answers

Which of the following is NOT part of the intrinsic muscles of the foot?

Extensor Digitorum Brevis Signup and view all the answers

What is the primary function of sesamoid bones in the foot?

To act as a pulley and alleviate stress. Signup and view all the answers

What motion occurs at a perpendicular angle to the axis of rotation in a joint?

Rotational motion. Signup and view all the answers

What is the normal reported range of dorsiflexion in the ankle?

0°-25°. Signup and view all the answers

Which axis allows for movement in the sagittal plane?

Anterior-posterior axis. Signup and view all the answers

What is the ratio of inversion to eversion movement at the subtalar joint?

2:1. Signup and view all the answers

During dorsiflexion at the talocrural joint, how does the talus move?

It rolls anteriorly and glides posteriorly. Signup and view all the answers

Which coupled motion produces supination of the foot?

Plantarflexion, adduction, and inversion. Signup and view all the answers

What anatomical feature is unique about the axis of the subtalar joint?

It lies about 42° superiorly to the sagittal plane. Signup and view all the answers

What structure is primarily responsible for raising and stabilizing the arch during gait?

Plantar fascia Signup and view all the answers

Which of the following is NOT a common site for fractures of the ankle and foot?

Metatarsal Signup and view all the answers

What imaging technique is rarely needed for diagnosing foot fractures?

Ultrasound Signup and view all the answers

Which ligament is involved in the syndesmosis of the ankle joint?

Superficial component of the posterior tibiofibular ligament Signup and view all the answers

Which tendon is primarily associated with the lateral band of the plantar fascia?

Flexor digitorum longus tendon Signup and view all the answers

What can often cause considerable pain, which worsens with weight on the foot?

Fracture Signup and view all the answers

What is the current understanding of the nature of plantar fasciitis?

It is a degenerative condition. Signup and view all the answers

What is the thickest and strongest band of the plantar fascia, typically involved in plantar fasciitis?

Central band Signup and view all the answers

Which symptom is characteristic of plantar fasciitis?

Intense heel pain during the first steps after waking. Signup and view all the answers

Which of the following best describes the windlass mechanism?

A mechanism for raising the arch during walking Signup and view all the answers

What type of spurs are fibro-cartilaginous triangular projections found on the calcaneum?

Plantar calcaneal spurs. Signup and view all the answers

What common theory explains the etiology of calcaneal spurs?

Degenerative changes and vertical compression. Signup and view all the answers

How can plantar fasciitis pain be treated in patients with heel spurs?

Without the need to remove the spur. Signup and view all the answers

Where does Morton's neuroma most commonly occur?

Third intermetatarsal space. Signup and view all the answers

What percentage of cases does Morton's neuroma occur bilaterally?

21% Signup and view all the answers

Which test is positive in diagnosing plantar fasciitis?

Windlass test. Signup and view all the answers

What is Morton’s neuroma primarily caused by?

Chronic, repetitive trauma Signup and view all the answers

Which of the following symptoms is typically associated with Morton’s neuroma?

Pain in the forefoot Signup and view all the answers

What angle is considered abnormal for hallux valgus?

20° and greater Signup and view all the answers

Which factor is NOT mentioned as a risk factor for developing hallux valgus?

High cholesterol levels Signup and view all the answers

What structural change occurs during hallux valgus?

Medial deviation of the first metatarsal head Signup and view all the answers

What contributes to the development of Morton’s neuroma?

Compression or entrapment of the nerve Signup and view all the answers

Which of the following is a potential cause of pes planus?

Congenital vertical talus Signup and view all the answers

What sensation might someone with Morton’s neuroma experience?

A sharp, stabbing sensation in the affected area Signup and view all the answers

Study Notes

Bones of the Ankle

Sesamoid bones act as pulleys to reduce stress on tendons.
There are two sesamoid bones in the big toe joint situated within the flexor hallucis brevis tendons.
The axis of rotation in a joint defines the direction of movement.
There are three axes of rotation: anterior-posterior, mediolateral, and longitudinal.
Ankle motion primarily occurs in the sagittal plane, but some movement in the frontal and transverse planes are necessary for complete plantarflexion and dorsiflexion.

Talocrural Joint

The talocrural joint is formed by the tibia, fibula, and talus.
Its axis of rotation is oblique to both the sagittal and frontal planes, requiring multi-planar movement.
Dorsiflexion range typically varies between 0-16.5 degrees or 0-25 degrees, depending on weight-bearing status.
Plantarflexion range is typically around 0-50 degrees.
The talus rolls anteriorly and glides posteriorly during dorsiflexion.
Conversely, the talus rolls posteriorly and glides anteriorly during plantarflexion.

Subtalar Joint

The subtalar joint is defined as a single degree of freedom hinge with a tri-planar axis.
Its axis is located about 42 degrees superior to the sagittal plane and about 16-23 degrees medial to the transverse plane.
Inversion-to-eversion movement ratio is approximately 2:1 or 3:2.
Pronation involves the coupled motion of dorsiflexion, abduction, and eversion.
Supination involves the coupled motion of plantarflexion, adduction, and inversion.
Pronation helps the body absorb forces during walking.

Extrinsic Muscles

Extensor digitorum brevis is located on the dorsum of the foot.
Extensor hallucis brevis is located on the dorsum of the foot.

Intrinsic Muscles

First layer:
- Abductor hallucis
- Flexor digitorum brevis
- Abductor digiti minimi
Second layer:
- Quadratus plantae: assists with toe flexion in the sagittal plane.
- Lumbricals: extend the interphalangeal joint.
Third layer:
- Flexor hallucis brevis
- Adductor hallucis
- Flexor digiti minimi brevis
Fourth layer:
- Plantar interossei
- Dorsal interossei: assist with MTP joint flexion, IP joint extension, and toe abduction and adduction.

Ligaments of the Ankle Joint

The ankle joint is stabilized by ligaments.
The anterior talofibular ligament, calcaneofibular ligament, and posterior talofibular ligament are crucial for ankle stability.

Ankle Instability

Instability can result from ligament damage.

Plantar Fascia

It originates at the medial tubercle of the calcaneus and inserts in three locations on the forefoot: medial, central, and lateral.
The central band, also known as the plantar aponeurosis, is the thickest and most frequently involved in plantar fasciitis.
It helps raise and stabilize the arch during gait via the windlass mechanism.

Plantar Fasciitis

It's a degenerative process affecting the plantar fascia, characterized by:
- Insidious onset of heel pain, especially during the first steps after rest.
- Heel pain that often alleviates with moderate activity but worsens throughout the day or after prolonged standing or walking.
- Risk factors include age, weight, and specific activities.

Calcaneal Spur

Calcaneal spurs are bony projections on the calcaneus.
There are two types: dorsal and plantar spurs.
Their development might be related to degenerative, inflammatory, traction, repetitive trauma, and bone-formers theories.
Calcaneal spurs are not the cause of plantar fasciitis, and removing the spur may not always alleviate pain.

Morton's Neuroma

It's a compression neuropathy affecting the common digital plantar nerve.
Typically occurs in the third intermetatarsal space (66% of cases).
It's not a true neuroma, but a benign fibrotic thickening caused by nerve irritation.
Risk factors include chronic trauma, high arches, tight footwear, nerve ischemia, repetitive impact, intermetatarsal bursitis, and nerve entrapment.

Hallux Valgus

The great toe deviates laterally away from the midline towards the lesser toes.
Angles less than 15 degrees are considered normal, while angles of 20 degrees or greater are considered abnormal.
It causes medial prominence of the first metatarsal head and can lead to inflammation of the overlying bursa and soft tissues.
Predisposing factors: poorly fitting footwear, age, female gender, family history, pes planus, Achilles tendon contracture, and ligamentous laxity.

Pes Planus

Flat feet can be caused by genetics, injury, or underlying medical conditions.
The congenital vertical talus is an example of a genetic factor leading to a rigid flatfoot deformity.

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Description

This quiz explores the anatomy and mechanics of the ankle, focusing on the role of sesamoid bones and the talocrural joint. It covers axes of rotation, motion in different planes, and the ranges of dorsiflexion and plantarflexion. Test your knowledge of these essential concepts in lower limb anatomy.