Anatomy Week 8

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Questions and Answers

Which bone forms the heel of the foot?

Cuboid

Navicular

Calcaneus (correct)

Talus

What structure do the inferior aspect of the tibia and fibula create in the talocrural joint?

Ligament

Mortise (correct)

Articular surface

Joint capsule

How many cuneiform bones are present in the midfoot region?

3 (correct)

Which of the following is NOT a part of the hindfoot?

Navicular Signup and view all the answers

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

Bear weight and protect tendons Signup and view all the answers

What type of joint is classified as a synovial joint and is involved in the movement of the ankle?

Hinge Signup and view all the answers

Which aspect of the talocrural joint is wider anteriorly than posteriorly?

Mortise Signup and view all the answers

What is included in a 'ray' of the foot?

Metatarsal and its corresponding phalanx Signup and view all the answers

What is the primary adaptation of the epithelium on the plantar surface during weight bearing?

Thicker stratum corneum Signup and view all the answers

What structures are included in the medial compartment of the foot?

Abductor Hallucis and Medial Plantar nerves Signup and view all the answers

Which arteries are derived from the terminal divisions of the posterior tibial artery?

Lateral Plantar Artery and Medial Plantar Artery Signup and view all the answers

What is the primary function of the deep fascia in the plantar surface of the foot?

Partitioning the foot into compartments Signup and view all the answers

Which structure serves as a 'shock absorber' in the hypodermis of the plantar surface?

Adipose tissue pockets Signup and view all the answers

Which of the following components does NOT belong to the central compartment of the foot?

Abductor Digiti Minimi Signup and view all the answers

What is the primary function of the arches of the foot during walking?

To absorb weight and shock during the loading phase. Signup and view all the answers

What role do the thick vertical septae play in the plantar fascia?

Divide the sole into distinct compartments Signup and view all the answers

Which structures contribute to the shape of the arches in the foot?

Bones, plantar fascia, ligaments, and muscular supports. Signup and view all the answers

Where is the Dorsalis Pedis Artery typically palpable?

Medially between the tendons of tibialis anterior and extensor hallucis longus. Signup and view all the answers

Which plantars nerve is responsible for supplying the majority of the medial side of the foot?

Medial Plantar Nerve Signup and view all the answers

Which nerve innervates the skin of the first interdigital space of the foot?

Deep Peroneal Nerve. Signup and view all the answers

Which of the following muscles is NOT an extrinsic muscle of the foot?

Extensor Digitorum Brevis. Signup and view all the answers

What beneficial effect does plantarflexion and inversion have in foot mechanics?

It prevents excessive eversion during stance. Signup and view all the answers

What is the most significant contact area for weight-bearing in the forefoot?

Medial forefoot including the head of the first metatarsal. Signup and view all the answers

During the loading phase of gait, what role do the arches of the foot play?

Absorb and release energy. Signup and view all the answers

Study Notes

Osteology of the Foot and Ankle

Hindfoot
- Calcaneus
  - Largest tarsal bone
  - Forms the heel
  - Calcaneal tuberosity: Posterior projection, site of Achilles tendon attachment
  - Fibular trochlea: Lateral articular surface, articulates with talus
  - Sustentatculum tali: Medial projection, supports talus
- Talus
  - Located between tibia/fibula and calcaneus
  - Head and neck: Articulates with navicular bone
  - Body: Articulates with tibia/fibula
  - Tubercles: Lateral and medial projections
  - Groove for FHL: Accommodates the flexor hallucis longus tendon
Midfoot
- Cuboid: Lateral bone, articulates with 4th and 5th metatarsals
  - Groove for FL: Accommodates the flexor longus tendon
- Navicular: Medial bone, articulates with talus and cuneiforms
  - Tubercle: Dorsal projection
- Cuneiforms: 3 wedge-shaped bones, located between navicular and metatarsals - Medial: Articulates with 1st metatarsal - Intermediate: Articulates with 2nd metatarsal - Lateral: Articulates with 3rd metatarsal
Forefoot
- Metatarsals: 5 long bones forming the arch of the foot
  - 1st metatarsal: Largest and strongest, articulates with medial cuneiform
  - 2nd metatarsal: Articulates with intermediate cuneiform
  - 3rd metatarsal: Articulates with lateral cuneiform
  - 4th metatarsal: Articulates with cuboid
  - 5th metatarsal: Articulates with cuboid
- Phalanges: 14 bones making up the toes
  - Hallux (big toe): Has 2 phalanges (proximal and distal)
  - Other toes: Have 3 phalanges (proximal, middle, and distal)
Sesamoid Bones
- Small, round bones embedded in tendons
- Located within the tendon of flexor hallucis brevis (FHB)
- Protect Flexor hallucis longus (FHL) tendon
Terminology
- Ray: A metatarsal, its related cuneiform, or the cuboid, sometimes including its associated phalange.

Arthrology of the Ankle and Foot

Talocrural Joint
- Synovial joint, providing an articulation between the talus and the tibia/fibula.
- Forms the ankle mortise
- Mortise: Shape created by the distal tibia and fibula, into which the talus fits.
- Medial Malleolus: Projection on the tibia, providing medial stability
- Lateral Malleolus: Projection on the fibula, providing lateral stability
- Articular Surfaces: Talus has two articulating facets with tibia (superior and medial) and one facet with fibula (lateral).
- Joint Capsule: Encloses the joint, providing stability and attachment for ligaments.
Arches of the Foot
- Functions:
  - Shock absorption during weight-bearing.
  - Allows for flexible movement during gait.
  - Provide passage for neurovascular structures.
- Weight Bearing: Distributed between the calcaneus and the forefoot
  - Medial Forefoot: Carries most of the weight. (1st metatarsal head and sesamoid bones)
  - Lateral Forefoot: Contributes to balance (lateral 4 metatarsal heads)
- Support: Result of:
  - Shape of the bones.
  - Plantar Fascia.
  - Ligaments.
  - Muscular support.
- Muscular Strength: Plantarflexion/inversion muscles are stronger than dorsiflexion/eversion muscles, in order to compensate, and prevent excessive dorsiflexion/eversion during gait.
Dorsal Surface of the Foot
- Blood Vessels:
  - Dorsalis Pedis Artery: Palpable between extensor hallucis longus and extensor digitorum longus tendons.
    - Continuation of anterior tibial artery.
- Nerves:
  - Superficial Peroneal Nerve: Innervates the skin of the dorsal foot.
  - Deep Peroneal Nerve: Innervates skin of the first interdigital space.
  - Sural Nerve: Innervates the skin of the lateral aspect of the foot.
- Muscles:
  - Extrinsic Muscles: Tendons of muscles originating in the leg:
    - Tibialis Anterior.
    - Extensor Digitorum Longus.
    - Extensor Hallucis Longus.
    - Peroneus Longus.
    - Peroneus Brevis.
    - Peroneus Tertius.
  - Intrinsic Extensors: Muscles originating within the foot:
    - Extensor Digitorum Brevis.
    - Extensor Hallucis Brevis.
Plantar Surface of the Foot
- Skin: Thickened and adapted for weight-bearing forces.
- Deep Fascia (Plantar Fascia):
  - Thickened fibrous band attaching to the calcaneus posteriorly, and splitting anteriorly to insert on the digits.
  - Supports the longitudinal arch of the foot.
- Vascular Supply:
  - Posterior Tibial Artery: Divides into medial and lateral plantar arteries.
- Innervation:
  - Tibial Nerve: Divides into medial and lateral plantar nerves.
- Muscles:
  - Medial Compartment: Abductor Hallucis, Flexor Hallucis Brevis, Flexor Hallucis Longus tendon, medial plantar nerves and vessels.
  - Central Compartment: Flexor Digitorum Brevis, Flexor Hallucis Longus and Flexor Digitorum Longus tendons, Quadratus Plantae, Lumbricals, Adductor Hallucis, lateral plantar nerve and vessels.
  - Lateral Compartment: Abductor Digiti Minimi, Flexor Digiti Minimi Brevis.

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Description

Explore the intricate anatomy of the foot and ankle in this quiz! From the hindfoot anatomy, including the calcaneus and talus, to the midfoot with its complex structure of bones, deepen your understanding of the skeletal components and their functions.