Non-surgical aesthetic techniques, p. 332).

•   Blepharospasm: 25 units in 10 divided doses to medial and lateral lids.

•   Frey’s syndrome: 5 units intradermally at 1cm distances.

•   Masseteric hypertrophy: 25 units into masseter.

•   Sialorrhoea/drooling: to submandibular/parotid glands up to 70 units total.

•   TMJ pain dysfunction/dislocation: into lateral pterygoid muscles ± temporalis, up to 80 units each side.

•   Post-operative sialocoele: parotidectomy—emerging evidence.

•   Migrainous headaches.

•   Cervical dystonia (torticollis).

•   Doses relate to Botox^® (Allergan).

Statistics

Sensitivity and specificity

Sensitivity

How good a test is at identifying those who have the disease.

Specificity

How good a test is at identifying those who do not have the disease.

Useful terms

•   True positives: those with a positive test result who do have the disease.

•   True negatives: those with a negative test result who do not have the disease.

•   False positives: those with a positive test result who do not have the disease.

•   False negatives: those with a negative test result who do have the disease.

•   A sensitive test will therefore have few false negatives.

•   A specific test will have few false positives.

For example, MRI of the neck in detection of nodal metastasis:

•   Sensitivity is 75–80% (i.e. not very sensitive). It therefore has a significant number of false negatives. These are the nodes with micrometastasis that do not show up on MRI.

•   Specificity is 90–100%. It has few false positives, i.e. those nodes that fit the radiological criteria for metastatic disease nearly always show disease at histology.

    Sensitivity = No. true positives/(No. true positives + No. false negatives)

    Specificity = No. true negatives/(No. true negatives + No. false positives)

•   The positive predictive value is the proportion of patients with positive test results who are correctly diagnosed:

    PPV = No. true positives/(No. true positives + No. false positives)

The infratemporal fossa

•   The infratemporal fossa is an irregularly shaped cavity, situated below and medial to the zygomatic arch.

•   Previously called the pterygomaxillary space.

Boundaries

Consist of the following structures:

•   Anteriorly: by the infratemporal surface of the maxilla and the ridge, which descends from its zygomatic process.

•   Posteriorly: by the articular eminence of the temporal bone and the spinal angularis of the sphenoid bone.

•   Superiorly: by the greater wing of the sphenoid below the infratemporal crest and the under-surface of the squamous temporal bone.

•   Inferiorly: by the alveolar border of the maxilla.

•   Medially: by the lateral pterygoid plate.

•   Laterally: by the ramus of mandible.

•   It has no floor.

Contents

Muscles

•   The lower part of the temporalis muscle.

•   Lateral and medial pterygoid muscle.

Vessels

•   The internal maxillary vessels, consisting of the maxillary artery originating from the external carotid artery and its branches.

•   Internal maxillary branches found within the infratemporal fossa including:

    •   middle meningeal artery;

    •   inferior alveolar artery;

    •   deep temporal artery;

    •   buccal artery;

    •   pterygoid venous plexus.

Nerves

Mandibular nerve, inferior alveolar nerve, lingual nerve, buccal nerve, chorda tympani nerve, and otic ganglion.

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