Pre-Reading & Videos for Forefoot Masterclass

Abbreviations

MT        Metatarsal

STJ       Subtalar Joint

TMTJ    Tarsometatarsal Joint

MTPJ    Metatarsophalangeal Joint

PIPJ      Proximal Interphalangeal Joint    

DIPJ      Distal Interphalangeal Joint   

AbH       Abductor Hallucis

FHL       Flexor Hallucis Longus

FDB       FH Brevis

FDL       Flexor Digitorum Longus

FDB       FD Brevis

pink = a link to click on

Terminology / Definitions / Biomechanics

The key movement of the ankle joint complex are

• Plantaflexion and dorsiflexion, occurring in the sagittal plane

• Abducation and adduction, occurring in the transverse plane and

• Inversion-eversion, occurring in the frontal plane

Combinations of these motions across both the subtalar and tibiotalar joints create three-dimensional motions called supination and pronation. Both terms define the position of the plantar surface of the foot (sole). During supination, a combination of plantarflexion, inversion and adduction causes the sole to face medially. In pronation, dorsiflexion, eversion and abduction act to position the sole facing laterally.  www.sciencedirect.com

Supination is a combined movement consisting of:

- adduction of the hindfoot

- inversion of the forefoot

- plantarflexion

Pronation 

- abduction

- eversion

- dorsiflexion

There are two axes of the forefoot, across the metatarsal heads:

- transverse axis across MT heads 1 & 2  (high gear propulsion)

- the oblique axis across MT heads 2 - 5  (low gear propulsion)

Arch Apex (Apex of the foot) is the highest point of the medial longitudinal arch. The navicular should be the bone at the apex of the foot.

Good overview: Chan and Rudins (1994) Foot Biomechanics During Walking and Running

Foot deformities:

When observing a foot you can describe the medial longitudinal arch as being reduced or increased, but when there is a large deformity we use:

Pes planus = very flat foot

Pes cavus = very high arched foot

Lesser toe deformities:

Hammer toe

Claw toe

Mallet toe

Functional Anatomy

• The 1st toe (the hallux) has 2 phalanges

• Toes 2-4 have 3 phalanges

• The 5th digit has 3 Phalanges

• The shape of the bone surfaces of the MTPJs are not inherently stable

• The IPJ are hinge joints, stabilised by the collateral ligaments and plantar capsular thickenings.

  • The collateral ligaments provide varus/valgus stability

  • The plantar plate and plantar fascia resist upwards displacements

Soft tissues of interest

• Plantar fascia (AKA aponeurosis) origin and insertions + the windlass mechanism of the foot.

• Extensor expansion

  • is where the FDL originates from distally

  • and where the lumbricals insert

Ligaments

Calcaneal ligaments

Navicular ligaments

Phalangeal ligaments

Muscles & their tendons

• Muscles are either Extrinsic (originating from lower leg) or Intrinsic  (originating from within the foot) & muscle imbalance can lead to toe deformity.

• There are 4 layers of muscles in the foot:

Intrisic muscles

• Interossei

• Lumbricals

Bones

***Sesamoids (and review their function)

Including the crista (a bony ridge on the plantar aspect of the 1st MT head). Skip to 0:53 seconds in this video.

Neurological

When you see a pes cavus foot or clawed toes ensure to rule out an underlying neurological causes, neuromuscular disorders (NMD's) and motorneurone disorders (MND's).

These will present as bilateral foot shape changes.

For example (this list is not exhaustive):

• Progressive muscular atrophy

• Amyotrophic Lateral Sclerosis

• muscular dystrophy

• spinal muscular atrophy

• hereditary neuropathy

  • Charcot-Marie-Tooth disease

• congenital myopathy

• Friedreich's ataxia

• myasthenias

• myotonic syndromes

• metabolic myopathies

• inflammatory myopathy

• Poliomyelitis

• MS

• Stroke 

• Spinal tumour

• Brain tumour

• CP

• Peroneal muscle atrophy

• Myelopathy

• Myelomeningocele

BEWARE OF A UNILATERAL PES CAVUS FOOT CHANGE - THIS IS A RED FLAG AND A SPINAL TUMOUR WILL NEED TO BE RULED OUT