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Muscles of the neck. Ehab Zayyan, MD, PhD. Platysma. Origin : deep fascia that covers the upper parts of the pectoralis major and deltoid muscles Insertion : lower margin of the mandible and the angle of the mouth Innervation : cervical branch of the facial nerve (CN VII)
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Muscles of the neck Ehab Zayyan, MD, PhD
Platysma • Origin: deep fascia that covers the upper parts of the pectoralis major and deltoid muscles • Insertion: lower margin of the mandible and the angle of the mouth • Innervation: cervical branch of the facial nerve (CN VII) • Action: depresses the mandible and the lower lip and the angle of the mouth.
Sternocleidomastoid muscle • Origin: - sternal head: manibrium sterni - clavicular head: medial upper third of clavicle • Insertion: The two heads unite and insert into the mastoid tip and superior nuchal line
SCM muscle • Nerve supply - The spinal part of the accessory nerve (CN XI) - The anterior rami of C2 and C3 (propriorecetive) • Action • Both muscles acting together: extend the head at the atlantio-occipital joint and flex the cevical part of the vertebral column. - The action of one muscle: turns the face to the opposite side and upward. - Acts as an accessory muscle of inspiration
Digastric muscle • The post belly arises from mastoid process of the temporal bone and inserts into the intermediate tendon. • The intermediate tendon binds to the junction of the hyoid body and greater horn. • The anterior belly binds to the lower border of the mandible.
Nerve supply: post belly: facial nerve, anterior belly by the trigeminal nerve….two cranial nerves for such a small muscle !!!!! • Action: depresses the mandible and elevates the hyoid • Surgeon’s friend
Stylohyoid muscle • Origin: styloid process • Insertion: hyoid bone • Nerve supply: facial nerve • Action: elevates the hyoid bone
Strap muscles(Infrahyoid muscles) • Sternohyoid • Omohyoid • Sternothyroid • Thyrohyoid • Together with the suprahyoid muscles stabilize the hyoid bone to provide movements of the tongue and the larynx during swallowing.
Omohyoid muscle • Inferior belly: originates from the upper margin of the scapula, passes deep to the SCM and ends in the intermediate tendon. • Intermediate tendon: held by the deep fascia of the clavicle and first rip. • Superior belly: inserts into the lower border of the hyoid bone body. • Nerve supply: Ansa cervicalis (C1, 2, 3) • Action: depresses the hyoid bone
Sternohyoid muscle • Origin: manibrium sterni • Insertion: body of the hyoid bone • Nerve: Ansa cervicalis • Action: depresses the hyoid bone
Sternothyroid muscle • Origin: manibrium sterni • Insertion: oblique line of the lamina of the thyroid cartilage • Nerve: Ansa cervicalis • Action: depresses the larynx
Thyrohyoid muscle • Origin: oblique line of the thyroid cartilage • Insertion: hyoid body • Nerve to the thyrohyoid (C1 & C2) • Action: depresses the hyoid and elevates the larynx
Platysma SCM Trapezius Diaphragm Digastric Stylohyoid Mylohyoid Geniohyoid Omohyoid Sternohyoid Sternothyroid Thyrohyoid Name the nerve of each muscle