Metatarsals and Toes

IMAGING ANATOMY

Overview

• In normal weight-bearing stance, all metatarsal heads are at same level and all are weight bearing

Metatarsophalangeal (MTP) joints are slightly extended in standing position
• Each MTP joint is separate synovial cavity

Metatarsal Bones

• 1st metatarsal

Largest metatarsal

Articulates with 1st cuneiform, 1st proximal phalanx, sesamoids

Medially receives attachments from tibialis anterior tendon; plantar side receives peroneus longus tendon

Origin of medial head of 1st dorsal interosseous muscle on its lateral surface
• 2nd-4th metatarsals

Gradually smaller and shorter moving laterally

Receive interosseous muscle on medial and lateral sides
• 5th metatarsal

Insertion of peroneus tertius and brevis

Phalanges

• Distal phalanx is insertion site for tendons from flexor and extensor digitorum longus
• Middle phalanx is insertion site for tendons from flexor and extensor digitorum brevis
• 2nd-4th proximal phalanges are attachments of interosseous muscles on both sides and lumbricals on medial side

1st Metatarsophalangeal Joint

• Dorsiflexion of toe important in push-off phase of gait
• Metatarsal head has 2 concave facets at plantar surface, 1 for each sesamoid, separated by ridge (crista)
• Distal articular surface of metatarsal head may be flat, rounded, or have central prominence
• Base of proximal phalanx has concave contour
• Sesamoids

Either sesamoid may be bipartite or tripartite, medial > lateral

– Bipartite sesamoid typically larger than single sesamoid with irregular opposing contour

Alternatively, either sesamoid may be hypoplastic or aplastic

Medial sesamoid in medial head of flexor hallucis brevis and abductor hallucis

Lateral sesamoid in lateral head of flexor hallucis brevis and adductor hallucis and deep metatarsal ligament

Medial and lateral sesamoids joined by intersesamoid ligament

– Intersesamoid ligament is floor of canal in which flexor hallucis longus tendon runs

Both are partially embedded in plantar plate of joint

Sesamophalangeal apparatus

– Sesamoids fixed in position relative to 1st proximal phalanx, move relative to 1st metatarsal

– Therefore, displaced laterally in hallux valgus
• Plantar plate

Fibrocartilaginous plantar plate extending from metatarsal neck to base of proximal phalanx

Prevents hyperextension

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Apr 9, 2020 | Posted by admin in MUSCULOSKELETAL IMAGING | Comments Off

IMAGING ANATOMY

Overview

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Metatarsals and Toes

Metatarsals and Toes

Metatarsal Bones

Phalanges

1st Metatarsophalangeal Joint

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Radiology Key

Fastest Radiology Insight Engine

Metatarsals and Toes

Metatarsals and Toes

IMAGING ANATOMY

Overview

Metatarsal Bones

Phalanges

1st Metatarsophalangeal Joint

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Related posts:

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