2 - Ant cervical triangle Flashcards
Posterior Cervical Triangle:
Anterior boundary = SCM
Posterior boundary = Trapezius m.
Inferior boundary = middle 1/3 of clavicle
Anterior Cervical Triangle Boundaries:
Lateral: anterior border of SCM m.
Superior: inferior border of mandible
Medial: midline of neck
Roof – Skin & platysma m. (contained within the skin)
Floor – formed by muscles
Viscera – considered “contents”
Roof” of anterior cervical triangle:
formed by skin & platysma m.
Platysma m. innervation
Cervical Branch of Facial n. (CN VII)
Anterior Cervical Triangle can be subdivided into 4 smaller triangles:
Submental triangle
Submandibular triangle
Muscular triangle
Carotid triangle
Anterior cervical triangle contents:
Muscles Veins Arteries Nerves Cervical viscera
Muscles of anterior cervical triangle can be grouped based upon their
position relative to the hyoid bone
Suprahyoid muscles
Located superior to hyoid bone
Elevate hyoid bone
4 muscles: Stylohyoid m. Digastric m. Mylohyoid m. Geniohyoid m.
Stylohyoid m. Action
Pulls hyoid bone upward in posterosuperior direction
Stylohyoid m. Innervation
Facial n. (CN VII)
Digastric m. Action
Mandible fixed – raises hyoid bone
Hyoid bone fixed – opens mouth (by lowering mandible)
Digastric m. Innervation
Ant. belly – Mandibular division of trigeminal n. (V3) (mylohyoid branch)
Post. belly – Facial n. (CN VII)
Mylohyoid m. Action
Supports & elevates floor of mouth; elevates hyoid
Mylohyoid m Innervation
Mandibular division of trigeminal n. (V3) (mylohyoid branch)
Geniohyoid m. Action
Mandible fixed – elevates & pulls hyoid forward
Hyoid fixed – pulls mandible downward & inward
Geniohyoid m. Innervation
branch from anterior ramus of C1 carried via hypoglossal n. (CN XII)
Infrahyoid mm.
Located inferior to the hyoid bone
Depress the hyoid bone
4 muscles: Omohyoid m. Sternohyoid m. Thyrohyoid m. Sternothyroid m.
Sternohyoid m. action (infrahyoid group)
Depresses hyoid bone after swallowing
Sternohyoid m. Innervation (infrahyoid group)
anterior rami of C1-C3 via ansa cervicalis
Omohyoid m. (infrahyoid group)
two bellies (superior & inferior) connected by an intermediate tendon
Omohyoid m. innervation (infrahyoid group)
anterior rami of C1-C3 via ansa cervicalis
Omohyoid m. action (infrahyoid group)
depresses & fixes hyoid bone
Thyrohyoid m. Action (infrahyoid group)
Depresses hyoid bone
When hyoid is fixed, it raises the larynx
Thyrohyoid m. innervation (infrahyoid group)
fibers from anterior ramus of C1 carried via the hypoglossal n. (CN XII)
Nerve to thyrohyoid m.