19 6月
History: A 10-year-old boy presents with left-sided predominantly conductive hearing loss. No pain or tinnitus was elicited on review of symptoms. On otoscopy, patient has a purple retrotympanic mass with decreased tympanic mobility. Patient is othewise healthy and has no family history of neoplasm or hearing loss.(男性、10岁、主要表现为左侧传导性听力丧失。无疼痛或耳鸣。耳镜检查示鼓膜后面紫色肿块,伴鼓膜流动下降。病人健康的,没有肿瘤或耳聋家族史。)


Q1——The foramen ovale (卵圆孔)is abnormal on the left.
A True
B False
Q2——The finding suggests absence of the middle meningeal artery (脑膜中动脉)on the left.
A True
B False
Additional CT images



Q3——What is implied by the appearance of the left internal carotid artery? (左颈内动脉)
A Abnormal course arises from the cervical internal carotid artery.
B Abnormal course arises from the external carotid artery branches.
C There is dehisence of an otherwise normal vessel.
D There will be retrograde flow (逆流)in the horizontal petrous segment.(水平岩段)
Q4——What other finding is present?
A Persistent trigeminal artery 永存三叉动脉
B Persistent otic artery 永存耳动脉
C Middle-ear hemangioma 中耳血管瘤
D Persistent stapedial artery 永存镫骨动脉
Q5——The differential diagnosis for a pulsatile retrotympanic mass includes all of the following, EXCEPT?
A Facial nerve hemangioma 面神经血管瘤
B Aberrant internal carotid artery 异常颈内动脉
C Dehiscent jugular bulb 开裂颈静脉球
D Glomus tympanicum 鼓室球瘤
答案1—5:B B B D A

Findings and diagnosis




The CT images demonstrate distinct anomalies that have been described as often occurring together, although both are relatively rare. First, there is an elongated horizontal petrous carotid canal and absence of the vertical petrous segment. The carotid artery course is through the middle ear as it enters from below at an enlarged tympanic canal. There is no bony covering to the intratympanic segment, and, in this case, the vessel abuts the tympanic membrane and the ossicular chain. Laterally, the artery has a stenotic appearance, typical for this entity.

Second, there is absence of the left foramen spinosum through which the middle meningeal artery enters the extradural space intracranial as it arises from the mandibular branch of the maxillary artery. Absence or hypoplasia of the foramen spinosum is a direct association with the associated second diagnosis. Further evaluation of the CT images reveals an apparent soft-tissue prominence, asymmetric from the right side, along the expected course of the tympanic facial nerve. Infrequently, there may be subtle erosion of the cochlear promontory, which may contribute to sensineural hearing loss.



Differential diagnosis — retrotympanic mass

  • Paraganglioma 副神经节瘤
  • Hemangioma 血管瘤
  • Dehiscent 开裂的 carotid artery 颈动脉
  • Aberrant carotid artery 异常颈动脉
  • Dehiscent jugular bulb  颈静脉球


  • Cholesteatoma 胆脂瘤
  • Schwannoma 神经鞘瘤;

Aberrant internal carotid artery (left) with associated persistent stapedial artery


The stapedial artery is a vestige (遗迹) of which branchial arch (腮弓)?
A First
B Second
C Third
D Fourth
Misdiagnosis of an aberrant internal carotid artery (ICA) prior to biopsy, myringotomy, or other surgery can have disastrous and potentially life-threatening results. This is a relatively rare abnormality, with an incidence of less than 1%. There is agenesis of the first segment of the internal carotid artery with persistent compensatory enlargement of the inferior tympanic artery, which enters below through the inferior tympanic canaliculus and the caroticotympanic artery, which is the vestigial remnant of the hyoid artery arising from the ICA.

With an incidence of less than 0.5%, persistent stapedial arteries are less common than aberrant carotid arteries. Similarly, failure to identify this anomaly can result in dangerous hemorrhage into the middle ear.

The embryologic development of the branchial system produces six paired arches and corresponding arteries. The primitive second arch gives rise to the hyoid artery, which gives rise to the stapedial artery near its origin from the internal carotid artery.

When a stapedial artery persists in postnatal life, the middle meningeal artery arises from it. The foramen spinosum is absent. A persistent stapedial artery arises from the petrous ICA, entering the hypotympanum in an osseous canal. It goes upward between the crura of the stapes. Then, it enters the facial canal and extends a short distance, together with the facial nerve. Behind the geniculate ganglion, it leaves the facial canal, then travels anteriorly and cephalad in the extradural space of the middle cranial fossa.





  1. Botma M, Kell RA, Bhattacharya J, Crowther JA. Aberrant internal carotid artery in the middle-ear space. J Laryngol Otol. 2000;114(10):784-787.
  2. Moreano EH, Paparella MM, Zelterman D, Goycolea MV. Prevalence of facial canal dehiscence and of persistent stapedial artery in the human inner ear: a report of 1000 temporal bones. Laryngoscope. 1994;104(3 Pt 1):309-320.
  3. Roll JD, Urban MA, Larson TC, Gailloud P, Jacob P, Harnsberger HR. Bilateral aberrant internal carotid arteries with bilateral persistent stapedial arteries and bilateral duplicated internal carotid arteries. AJNR Am J Neuroradiol. 2003;24(4):762-765.
  4. Thiers FA, Sakai O, Poe DS, Curtin HD. Persistent stapedial artery: CT findings. AJNR Am J Neuroradiol. 2000;21(8):1551-1554.


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