Structures of The Neck

Structures of The Neck

Major Divisions and Bones

Posterior triangle

• Is bounded by the posterior border of the sternocleidomastoid muscle, the anterior border of the trapezius muscle, and the superior border of the clavicle.
• Has a roof formed by the platysma and the investing (superficial) layer of the deep cervical fascia.
• Has a floor formed by the splenius capitis and levator scapulae muscles and the anterior, middle, and posterior scalene muscles.
• Contains the accessory nerve, cutaneous branches of the cervical plexus, external jugular vein, transverse cervical and suprascapular vessels, subclavian vein (occasionally) and artery, posterior (inferior) belly of the omohyoid, and roots and trunks of the brachial plexus.
• Also contains the nerve to the subclavius and the dorsal scapular, suprascapular, and long thoracic nerves.
• Is further divided into the occipital and subclavian (supraclavicular or omoclavicular) triangles by the omohyoid posterior belly.

Anterior triangle

• Is bounded by the anterior border of the sternocleidomastoid, the anterior midline of the neck, and the inferior border of the mandible.
• Has a roof formed by the platysma and the investing layer of the deep cervical fascia.
• Is further divided by the omohyoid anterior belly and the digastric anterior and posterior bellies into the digastric (submandibular), submental (suprahyoid), carotid , and muscular (inferior carotid) triangles.

Hyoid bone

• Is a U-shaped bone consisting of a median body , paired lesser horns (cornua) laterally, and paired greater horns (cornua) posteriorly.

Body

• Provides for attachments for the geniohyoid, mylohyoid, omohyoid, and sternohyoid muscles.

Greater horn

• Provides attachments for the middle constrictor, hyoglossus, digastric (anterior and posterior) bellies, stylohyoid, and thyrohyoid muscles.

Lesser horn

• Provides attachment for the stylohyoid ligament , which runs from the styloid process to the lesser horn of the hyoid bone.

Styloid process

• Is a slender projection of variable length and extends downward and forward from the temporal bone.
• Gives origin to three muscles (stylohyoid, styloglossus, and stylopharyngeus) and two ligaments (stylohyoid and stylomandibular).

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