Middle age diabetic with tooth extraction with ipsilateral swelling over middle one-third of sternocleidomastoid and displacement of tonsils towards contralateral side. Diagnosis is

PARAPHARYNGEAL ABSCESS (Syn. Abscess of pharyngomaxillary or lateral pharyngeal space.) APPLIED ANATOMY :- Parapharyngeal space is pyramidal in shape with its base at the base of skull and its apex at the hyoid bone. AETIOLOGY :- Infection of parapharyngeal space can occur from: 1. Pharynx - Acute and chronic infections of tonsil and adenoid, bursting of peritonsillar abscess. 2. Teeth - Dental infection usually comes from the lower last molar tooth. 3. Ear - Bezold abscess and petrositis. 4. Other spaces - Infections of parotid, retropharyngeal and submaxillary spaces. 5. External trauma - Penetrating injuries of neck, injection of local anaesthetic for tonsillectomy or mandibular nerve block. CLINICAL FEATURES :- Clinical features depend on the compament involved. Anterior compament infections produce a triad of symptoms: (i) prolapse of tonsil and tonsillar fossa, (ii) trismus(due to spasm of medial pterygoid muscle) and (iii) external swelling behind the angle of jaw. There is marked odynophagia associated with it. Posterior compament involvement produces (i) bulge of pharynx behind the posterior pillar, (ii) paralysis of CN IX, X, XI, and XII and sympathetic chain, and (iii) swelling of parotid region. There is minimal trismus or tonsillar prolapse. Fever, odynophagia, sore throat, toicollis (due to spasm of preveebral muscles) and signs of toxaemia are common to both compaments. Ref:- Dhingra; pg num:-267,268