Head and Neck VI Flashcards
A 45 year old man presents with a lipoma located posterior to the posterior border of the sternocleidomastoid muscle, approximately 4cm superior to the middle third of the clavicle. During surgical excision of the lesion troublesome bleeding is encountered. Which of the following is the most likely source?
A. Internal jugular vein B. External jugular vein C. Common carotid artery D. Vertebral artery E. Second part of the subclavian artery
External jugular vein
The external jugular vein runs obliquely in the superficial fascia of the posterior triangle. It drains into the subclavian vein. During surgical exploration of this area the external jugular vein may be injured and troublesome bleeding may result. The internal jugular vein and carotid arteries are located in the anterior triangle. The third, and not the second, part of the subclavian artery is also a content of the posterior triangle
A 34 year old lady undergoes a thyroidectomy for Graves disease. Post operatively she develops a tense haematoma in the neck. In which of the following fascial planes will it be contained?
A. Gerotas fascia B. Waldeyers fascia C. Pretracheal fascia D. Sibsons fascia E. Clavipectoral fascia
Pretracheal fascia
The pretracheal fascia encloses the thyroid and is unyielding. Therefore tense haematomas can develop.
Right and left lobes connected by isthmus
Surrounded by sheath from pretracheal layer of deep fascia
Apex: Lamina of thyroid cartilage
Base: 4th-5th tracheal ring
Pyramidal lobe: from isthmus
May be attached to foramen caecum at the base of the tongue
Relations Anteromedially Sternothyroid Superior belly of omohyoid Sternohyoid Anterior aspect of sternocleidomastoid Posterolaterally Carotid sheath Medially Larynx Trachea Pharynx Oesophagus Cricothyroid muscle External laryngeal nerve (near superior thyroid artery) Recurrent laryngeal nerve (near inferior thyroid artery) Posterior Parathyroid glands Anastomosis of superior and inferior thyroid arteries Isthmus Anteriorly: Sternothyroids, sternohyoids, anterior jugular veins Posteriorly: 2nd, 3rd, 4th tracheal rings (attached via Ligament of Berry)
Blood Supply
Arterial
Superior thyroid artery (1st branch of external carotid)
Inferior thyroid artery (from thyrocervical trunk)
Thyroidea ima (in 10% of population -from brachiocephalic artery or aorta)
Venous
Superior and middle thyroid veins - into the IJV
Inferior thyroid vein - into the brachiocephalic veins
Which of the following is not a content of the anterior triangle of the neck?
A. Vagus nerve B. Submandibular gland C. Phrenic nerve D. Internal jugular vein E. Hypoglossal nerve
Phrenic nerve
The phrenic nerve is a content of the posterior triangle. The anterior triangle contains the carotid sheath and its contents.
A 45 year old man sustains a significant head injury and a craniotomy is performed. The sigmoid sinus is bleeding profusely, into which of the following structures does it drain?
A. Internal jugular vein B. Straight sinus C. Petrosal sinus D. Inferior sagittal sinus E. External jugular vein
Internal jugular vein
The sigmoid sinus is joined by the inferior petrosal sinus to drain into the internal jugular vein.
Cranial venous sinuses
The cranial venous sinuses are located within the dura mater. They have no valves which is important in the potential for spreading sepsis. They eventually drain into the internal jugular vein.
They are:
Superior sagittal sinus Inferior sagittal sinus Straight sinus Transverse sinus Sigmoid sinus Confluence of sinuses Occipital sinus Cavernous sinus
In which of the following cranial bones does the foramen spinosum lie?
A. Sphenoid bone B. Frontal bone C. Temporal bone D. Occipital bone E. Parietal bone
Sphenoid
The foramen spinosum (which transmits the middle meningeal artery and vein) lies in the sphenoid bone.
Foramina of the base of the skull
Foramen Location Contents
Foramen ovale Sphenoid bone Otic ganglion
V3 (Mandibular nerve:3rd branch of
trigeminal)
Accessory meningeal artery
Lesser petrosal nerve
Emissary veins
Foramen spinosum Sphenoid bone Middle meningeal artery
Meningeal branch of the Mandibular nerve
Foramen rotundum Sphenoid bone Maxillary nerve (V2)
Foramen lacerum Sphenoid bone Base of the medial pterygoid plate.
Internal carotid artery
Nerve and artery of the pterygoid canal
Jugular foramen Temporal bone Anterior: inferior petrosal sinus
Intermediate: glossopharyngeal, vagus, and accessory nerves.
Posterior: sigmoid sinus (becoming the internal jugular vein) and some meningeal branches from the occipital and ascending pharyngeal arteries.
Foramen magnum Occipital bone Anterior and posterior spinal arteries
Vertebral arteries
Medulla oblongata
Stylomastoid foramen Temporal bone Stylomastoid artery
Facial nerve
Superior orbital fissure Sphenoid bone Oculomotor nerve (III)
trochlear nerve (IV)
lacrimal, frontal and nasociliary branches of ophthalmic nerve (V1)
abducent nerve (VI)
Superior and inferior ophthalmic vein
A 44 year old lady is recovering following a transphenoidal hypophysectomy. Unfortunately there is a post operative haemorrhage. Which of the following features is most likely to occur initially?
A. Cavernous sinus thrombosis B. Abducens nerve palsy C. Bi-temporal homonymous hemianopia D. Inferior homonymous hemianopia E. Central retinal vein occlusion
Bi-temporal homonymous hemianopia
The pituitary is covered by a sheath of dura and an expanding haematoma at this site may compress the optic chiasm in the same manner as an expanding pituitary tumour.
Which of the following cranial foramina pairings are incorrect?
A. The foramen lacerum and internal carotid artery. B. Foramen ovale and mandibular nerve. C. Optic canal and ophthalmic artery. D. Optic canal and ophthalmic nerve. E. Foramen rotundum and maxillary nerve.
Optic canal and ophthalmic nerve.
The optic canal transmits the optic nerve. The ophthalmic nerve traverses the superior orbital fissure.
A young child undergoes a difficult craniotomy for fulminant mastoiditis and associated abscess. During the procedure the trigeminal nerve is severely damaged within Meckels cave. Which deficit is least likely to be present?
A. Anaesthesia over the ipsilateral anterior aspect of the scalp B. Loss of the corneal reflex C. Weakness of the ipsilateral masseter muscle D. Anaesthesia of the anterior aspect of the tongue E. Anaesthesia over the entire ipsilateral side of the face
Anaesthesia over the entire ipsilateral side of the face
The angle of the jaw is not innervated by sensory fibres of the trigeminal nerve and is spared in this type of injury.
Remember the trigeminal nerve provides motor innervation to the muscles of mastication.
Nerve lesions
A variety of different procedures carry the risk of iatrogenic nerve injury. These are important not only from the patients perspective but also from a medicolegal standpoint.
The following operations and their associated nerve lesions are listed here:
Posterior triangle lymph node biopsy and accessory nerve lesion.
Lloyd Davies stirrups and common peroneal nerve.
Thyroidectomy and laryngeal nerve.
Anterior resection of rectum and hypogastric autonomic nerves.
Axillary node clearance; long thoracic nerve, thoracodorsal nerve and intercostobrachial nerve.
Inguinal hernia surgery and ilioinguinal nerve.
Varicose vein surgery- sural and saphenous nerves.
Posterior approach to the hip and sciatic nerve.
Carotid endarterectomy and hypoglossal nerve.
There are many more, with sound anatomical understanding of the commonly performed procedures the incidence of nerve lesions can be minimised. They commonly occur when surgeons operate in an unfamiliar tissue plane or by blind placement of haemostats (not recommended).
Which of the following is not a branch of the external carotid artery?
A. Facial artery B. Lingual artery C. Superior thyroid artery D. Mandibular artery E. Maxillary artery
Mandibular artery
External carotid artery branches mnemonic:
‘Some Angry Lady Figured Out PMS’
Superior thyroid (superior laryngeal artery branch) Ascending pharyngeal Lingual Facial (tonsillar and labial artery) Occipital Posterior auricular Maxillary (inferior alveolar artery, middle meningeal artery) Superficial temporal
Which of the following statements relating to the basilar artery and its branches is false?
A. The superior cerebellar artery may be decompressed to treat trigeminal neuralgia B. Occlusion of the posterior cerebral artery causes contralateral loss of the visual field C. The oculomotor nerve lies between the superior cerebellar and posterior cerebral arteries D. The posterior inferior cerebellar artery is the largest of the cerebellar arteries arising from the basilar artery E. The labyrinthine branch is accompanied by the facial nerve
The posterior inferior cerebellar artery is the largest of the cerebellar arteries arising from the vertebral artery.
