ultrasound

Morton's Neuroma

Definition

 

Benign enlargement of the common digital branch

- usually 3rd webspace

 

Mortons Neuroma Common Site

 

Anatomy

 

Found at level of or just distal to MT heads

- deep to the deep transverse MT ligament

 

Epidemiology

 

Classically women between 40 and 60

Non Union

Definition

 

Non-union

- arrest of progression to union at fracture site 

- > 6-9 /12

- no visible progressive signs of healing for at least three consecutive months

- individualise for each fracture

- when the surgeon believes the fracture has little or no chance to heal

 

Delayed union

- failure of fracture to unite within expected time

- still may spontaneously unite

 

Ultrasound

Physics

 

Very high frequency sound waves

- 3 - 15 MHz

 

Production

 

Piezoelectric effect

- run electric current through a crystal

- produces ultrasound waves

 

Theory

 

Density of substance determines velocity of the US

- reflected back to the probe at different velocities

- converted into 2D image on monitor

 

 

Basic Science

Pathogenesis

 

Virchow's Triad

1. Venous stasis

2. Hypercoagulability

3. Endothelial damage

 

Starts as platelet nidus at valves

- thrombogenic materials elaborated by platelets

- leads to development of fibrin thrombus

- thrombus grows

 

Thrombus may 

- detach as embolus

- be completely dissolved / recanalise

- organise with valve incompetence

De Quervain syndrome

Definition

 

Stenosing tenosynovitis of the first dorsal compartment of wrist

 

Epidemiology

 

Most are middle aged women

 

Aetiology

 

Repetitive thumb movements

- abduction & extension

- combined with RD & UD movements

 

Any mechanical irritation

- foreign body

- prominent bony surface

- restricted fascial compartment

Background

Definition

 

Full thickness tear (FTT)

- variable amount retraction from insertion

 

Rotator Cuff Tear Large

 

Partial thickness tear (PTT)

- incomplete

- bursal or articular sided

Thoracic Outlet Syndrome

Definition

 

Symptoms & signs due to compression of brachial plexus & /or subclavian vessels at root of neck

 

Epidemiology

 

80% 30-50 years 

 

F:M = 2:1 

 

Incidence

 

Uncommon

 

Anatomy

 

Thoracic Outlet forms communication at root of neck 

- for passage of nerves and vessels from mediastinum to axilla 

Achilles Tendon Rupture

AnatomyAchilles tendon anatomy

 

Gastrocnemius tendon 10-25 cm long

- soleus 3-10 cm

- inserts superior calcaneal tuberosity

- fibres spiral 90°

- fibres that lie medially in proximal portion become posterior distally

- allows elastic recoil & energy storage

 

Plantaris present in 90% population

- medial to T Achilles

 

Poor blood supply midportion

- mesotenal vessels