Innervation of the infrahyoid muscles is handled by______________?
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Answer: A. Branches of cervical plexus
Explanation
Infrahyoid muscles are innervated by branches of the cervical plexus. Specifically, the ansa cervicalis provides motor innervation to most of these muscles. The thyrohyoid muscle receives separate fibers from cervical spinal nerve C1. The infrahyoid muscles comprise the strap muscles located in the anterior neck. They function to depress the hyoid bone and larynx during swallowing. The cervical plexus is formed by the anterior rami of upper cervical nerves.
Thyroid and neck surgeries require identifying these strap muscles for exposure. Preserving ansa cervicalis branches maintains normal laryngeal mobility postoperatively. Physical therapists assess neck muscle function during rehabilitation after trauma. Option B vagus nerve innervates laryngeal and pharyngeal structures rather than strap muscles. Option C glossopharyngeal nerve supplies the stylopharyngeus and posterior tongue. Option D mandibular nerve innervates muscles of mastication instead of infrahyoids.
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