Neck triangles Infrahyoid Suprahyoid regions Infrahyoid muscles Thyroid

Neck triangles

Infrahyoid & Suprahyoid regions

Infrahyoid muscles Thyroid 1. 2. 3. 4. Omo-hyoid Sterno-hyoid Strno-thyroid Thyro-hyoid ORIGIN Scapula, Sternum INSERTION Thyroid cartilage, Hyoid bone ACTION Depresses thyroid cartilage and hyoid bone NERVE Ansa cervicalis nerve (C 1, 2, 3)

• • Omo-hyoid Sterno-hyoid Strno-thyroid Thyro-hyoid ORIGIN: Scapula, Sternum INSERTION: Thyroid cartilage, Hyoid bone ACTION: Depresses thyroid cartilage and hyoid bone NERVE: Ansa cervicalis nerve (C 1, 2, 3)

Suprahyoid muscles 1. 2. 3. 4. Digastric Stylo-hyoid Mylo-hyoid Geni-ohyoid

Digastric ORIGIN Anterior belly: mental, posterior belly : mastoid INSERTION Fibrous loop to hyoid bone ACTION Elevates hyoid in swallowing NERVE Anterior belly: mylohyoid nerve (V). posterior belly: facial nerve (VII)

Stylohyoid ORIGIN Styloid process INSERTION Hyoid bone ACTION Elevates hyoid bone NERVE Mandibular branch of facial nerve (VII)

Mylohyoid ORIGIN Mylohyoid line on mandible INSERTION Hyoid bone ACTION Elevates hyoid bone. supports floor of mouth NERVE Mylohyoid nerve (V)

Geniohyoid ORIGIN Mental spine in mandible INSERTION Hyoid bone ACTION Elevates hyoid bone. Depresses mandible NERVE C 1 fibers

Hyoglossus ORIGIN Hyoid bone INSERTION Tongue ACTION Depresses tongue NERVE Hypoglossal nerve (XII)

Review Anterior

Neck triangles

Posterior triangles

Anterior triangles

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• S: The skin on the head from which head hair grows. • C: Connective tissue. A thin layer of fat. • A: The aponeurosis called epicranial aponeurosis (galea aponeurotica). • L: The loose connective tissue. • P: The pericranium is the periosteum of the skull bones. 22

SCALP 23

aponeurosis 24