1/28/2024 0 Comments External auditory meatus![]() Grazioli L, Olivetti L, Matricardi L, et al. Sonographic anatomy of the neck: The suprahyoid region. Seminars of ultrasound, CT and MRI 1990 (11) 486-503 The radiological evaluation of the parotid space. Differential diagnosis of head and neck lesions based on their space of origin. MRI is significantly less affected by the relative lack of native fat.neonates and young children have limited amounts of fat within the parotid gland which decreases the amount of natural contrast available on CT, which increases the difficulty to perceive a mass lesion and define its margins.MRI is preferred for imaging the parotid space in children 2.CT is preferred for tender, recurrent parotid masses that are likely to be inflammatory whereas MRI is better for assessment of a painless parotid lump.allows for good visualization of deep lesions as well as reliable assessment of size, location, margins, extracapsular extension, involvement of adjacent structures, and areas of necrosis, hemorrhage, calcification of cysts 5.lower attenuation in comparison to muscle due to the combination of fat and glandular tissue.facial nerve is not visualized on US, but is inferred to be located lateral to the retromandibular vein 8.external carotid artery travels in the same route, however, it is a larger structure and is found in a deeper plane to the retromandibular vein. ![]() retromandibular vein crosses the superficial lobe of the parotid gland and continues longitudinally until it reaches the inferior margin of the parotid gland to join with the external jugular vein.external carotid artery and retromandibular vein will be found posteriorly 7.most frequently located in the preauricular region and they provide lymphatic drainage of the external ear and lateral scalp 3.intraparotid lymph nodes (may number up into the twenties) are also evident as rounded/bean-shaped hypoechoic structures with an echogenic central fatty hilum within the hyperechoic parotid gland 6.with the parotid gland filling around two-thirds of the parotid space, US findings will reflect those of the parotid gland 3.inferior margin: inferior mandibular margin (although the parotid tail can extend further inferiorly below the angle of the mandible) 1.superior margin: external auditory canal apex of the mastoid process 3.The parotid space is circumscribed by the superficial layer of the deep cervical fascia 1: posterior belly of the digastric muscle forms a variable portion of the posteromedial border of the parotid space and at times this muscular band helps to differentiate a deep-lobe parotid space lesion to one arising in the carotid space 2.medial to superficial space and subcutaneous tissue.It is traversed by the external carotid artery, retromandibular vein and facial nerve. Other prophylactic measures such as drying the ears with a hair dryer and avoiding manipulation of the external auditory canal may help prevent recurrence.The parotid space is a roughly pyramidal space, the broad elongated base facing laterally, formed by the superficial layer of the deep cervical fascia overlying the superficial lobe of the parotid gland, and its apex pointing medially. Acidification with a topical solution of 2 percent acetic acid combined with hydrocortisone for inflammation is effective treatment in most cases and, when used after exposure to moisture, is an excellent prophylactic. Thorough cleansing of the canal is essential for diagnosis and treatment, but flushing should be avoided. Excessive moisture and trauma, both of which impair the canal's natural defenses, are the two most common precipitants of otitis externa, and avoidance of these precipitants is the cornerstone of prevention. The most characteristic symptom is discomfort that is limited to the external auditory canal, while the most characteristic signs are erythema and swelling of the canal with variable discharge. Otitis externa is most commonly caused by infection (usually bacterial, although occasionally fungal), but it may also be associated with a variety of noninfectious systemic or local dermatologic processes.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |