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Ms. Sherry Goldsmith, daughter of a local dentist, was involved in a two-car collision yesterday on Highway 280. She suffered severe facial injuries. Upon observation and inspection at the UAB Hospital Emergency Room, she was found to have the following injuries and accompanying symptoms:
The entire ramus of the left mandible was shattered and displaced medially into the infratemporal fossa. • Both the condyloid and coronoid processes were broken off on the left side. • The impact drove the temporomandibular joint (TMJ) medially and broke off the spine of the sphenoid.
A large sliver of the front window pane passed deeply into the infratemporal fossa, reaching the level of the infratemporal crest of the temporal bone and beyond. • A large hematoma, the specific origin of which was unknown, was noted within the fossa shrouding the other “contents”.
After careful debridement of all the facial wounds, an MRI was performed to determine the total “anatomical” involvement of the injuries. • After a lengthy hospitalization and numerous surgical interventions, Ms. Goldsmith was noted to demonstrate the following neural and/or neuromuscular disorders.
Ipsilateral loss of taste sensations on the anterior part of the tongue. • Ipsilateral loss of general sensations on the anterior part of the tongue. • The intact mandible deviated toward the side of the impact.
There was a cutaneous anesthesia involving a strip of skin extending from the ipsilateral lower lip and chin and proceeding anterior to the ear and superior to the scalp. • There was anesthesia to the ipsilateral lingual gingiva (mandibular region),floor of the mouth and mandibular teeth • There was a reduction of the volume of saliva.
Questions-Temporal and Infratemporal Fossae • What are the bony boundaries of the infratemporal fossa?
Infratemporal fossa-separate from temporal fossa by the infratemporal crest of the greater wing of the sphenoid bone.
Bounded by: • Roof – Inferior aspect of greater wing of sphenoid • Medial Wall – lateral surface of lateral pterygoid plate • Lateral Wall – ramus of mandible • Anterior Wall – posterior surface of maxilla • Posterior Wall – anterior surface of condylar process of mandibule and styloid process
Name the six, usually expected, contents of the infratemporal fossa.
First and second parts of maxillary artery (mandibular and pterygoid parts)
Discuss the specific attachments and actions of the muscles of mastication.
Temporalis O: from temporal fossa and temporalis fascia I: muscle fibers converge to form a thick tendon which passes deep to zygomatic arch and inserts into coronoid process and anterior border of ramus of mandible inferiorly to last molar
Temporalis A: vertical fibers (anterior) – powerful closer of jaw (elevator of mandible) horizontal fibers (posterior)-retract jaw (chief one)
Masseter O: superficial fibers- zygomatic process of maxilla and lower border of zygomatic arch deep fibers-lower border zygomatic arch (posterior 1/3) and entire medial surface of zygomatic arch
Masseter I: lateral surface of coronoid process, ramus and angle of mandible A: elevates and protracts jaw
Lateral Pterygoid – 2 heads Upper head (sphenomeniscus part) O: from infratemporal surface of greater wing of sphenoidd I: articular disc (meniscus) of TMJ and upper part of neck of mandible
Lower head (main part) O: lateral surface of lateral pterygoid plate I: Pterygoid fovea of neck of mandible A (of both heads): protract (chief one) and depresses jaw
Medial Pterygoid-2 heads - occupies same position internal to angel of mandible as does masseter externally
Deep Head (main one) O: medial surface of lateral pterygoid plate and pyramidal process of palatine bone
Superficial Head O: tuberosity of maxilla I (of both heads): medial suface of angel and ramus of mandible (as high as mandibular foramen) A (of both heads): elevates and protracts jaw
Contraction of the intact pterygoid muscles (mainly the lateral pterygoid) “pulls” mandible toward side of lesion when mouth is opened.
Name the foramen through which the mandibular division of the trigeminal nerve (V3) passes into the infratemporal fossa. In which boundary of the infratemporal fossa is this foramen located? Does V3 supply any muscles other than the muscles of mastication?
V3 enters infratemporal fossa through the foramen ovale which is located in the roof of the fossa. V3 supplies all the muscles derived from pharyngeal arch 1. These include not only the four muscles of mastication, but also the mylohyoid, anterior belly of digastric, tensor tympani and tensor palati muscles.
The injury damaged the three cutaneous branches of V3. These include: • mental n.(branch of inf. alveolar n.) • supplies lower lip and chin • buccal n. • supplies cheek • auriculotemporal n • Supplies ear and temple (scalp)
Explain the loss of taste on the anterior part of the tongue.
The ipsilateral chorda tympani nerve (a branch off VII) was lesioned.
By severing the otic ganglion and/or its connections to the parotid gland by way of the auriculotemporal nerve, the ipsilateral saliva is decreased.
Additionally, the innervation of the ipsilateral sublingual and submandibular glands has been destroyed (damage to the chorda tympani n).
Identify the branch of the maxillary artery which enters the middle cranial fossa. From what part of the maxillary artery does it arise?
Middle meningeal a. It arises from the first (mandibular) part.
Discuss the pathway by which this artery enters the middle cranial fossa.
The middle meningeal a. passes superiorly (between the two roots of the auriculotemporal n.) and enters the middle cranial fossa through the foramen spinosum.
It supplies most of the dura mater (but NOT the brain) and some of the skull bones.
Name the condition which results from tearing this artery within the cranial cavity. What will be the consequence if this injury is not repaired immediately?
Epidural hematoma (extradural hemorrhage). Compression of brain resulting in death.
