L25. GA - Organization of the Neck & Neck Triangles

The neck region is bordered by the base of the skull superiorly, the clavicles inferiorly, and the anterior and posterior midline structures of the neck.

The neck plays a crucial role in supporting the head, enabling movement, and providing passage for vital structures such as airways, blood vessels, and nerves.

The skeletal framework of the neck comprises the cervical vertebrae (C1-C7), the hyoid bone, and the mandible. It provides structural support, attachments for muscles, and protection for crucial structures.

Fascial compartments are spaces created by layers of connective tissue (fascia) that separate and organize structures in the neck. These spaces are important clinically because they can become sites of infections or tumors.

The Platysma muscle is a thin sheet-like muscle that covers the superficial neck region. It can help with facial expressions and can be used as a landmark in procedures.

The superficial veins of the neck include the external jugular vein and the anterior jugular vein. These veins receive blood from the head and face.

The posterior triangle of the neck is bordered by the trapezius, sternocleidomastoid, and clavicle. It contains the brachial plexus, the accessory nerve, and the subclavian artery.

The neck is a region that connects the head and the chest, aiding in head positioning and supporting vital blood vessels, nerves, and airways.

The superior border of the neck is the lower edge of the jawbone (mandible) at the front and specific skull features (mastoid process and superior nuchal line) at the back.

The inferior neck border stretches from the upper part of the breastbone (sternum) along the collarbone (clavicle) to the shoulder bone (acromion) at the front. The back border isn't as defined but can be visualized as a line between the shoulder bone and the prominent C7 vertebrae.

There are seven cervical vertebrae (C1-C7) in the neck, providing the skeletal framework.

The first cervical vertebra (C1) is known as the 'atlas' and lacks a body and a spinous process. It articulates with the second cervical vertebra (C2) and the skull.

The second cervical vertebra (C2) is named 'axis' due to its unique function allowing the head to rotate. It articulates with the atlas (C1) and has a prominent projection called the odontoid process.

Cervical vertebrae have small bodies (except C1), forked (bifid) spinous processes (except C1), and transverse foramina which house the vertebral arteries and veins.

The foramen transversarium is a passage through the transverse processes of cervical vertebrae, which accommodates the vertebral arteries and veins.

The unique articulation of the atlas (C1) with the axis (C2) and the skull enables the head's pivoting movement.

A facial muscle that pulls the lower lip and corners of the mouth downwards.

The vein formed behind the angle of the mandible by the posterior auricular vein and the retromandibular vein.

A variable vein that begins as small veins on either side of the neck midline, descending towards the subclavian vein.

The space in the neck behind the sternocleidomastoid muscle, between the trapezius muscle and the clavicle.

The layer of deep fascia found in the neck, covering the muscles and structures of the posterior triangle.

The large muscle of the neck, extending from the sternum and clavicle to the mastoid process.

The division of the posterior triangle with the clavicle and trapezius as its borders.

The part of the posterior triangle that lies towards the back of the head, bounded by the trapezius and the sternocleidomastoid.

The motor nerve responsible for innervating the sternocleidomastoid muscle.

The nerve fibers carried by the spinal nerves that provide sensory information about position and movement.

A muscle that helps move the hyoid bone and mandible. It originates from the inferior mental spine of the mandible and inserts on the anterior surface of the hyoid bone. It is innervated by a branch from the anterior ramus of C1 that travels with the hypoglossal nerve.

A large salivary gland located in the submandibular triangle. It is shaped like a hook and wraps around the posterior margin of the mylohyoid muscle.

A tough fascial sheath found in the neck that encloses important vessels and nerves. It contains the common carotid artery, internal jugular vein, and vagus nerve.

The point where the common carotid artery divides into the internal and external carotid arteries. This happens at the level of vertebra C-III and C-IV, roughly at the superior border of the thyroid cartilage.

The internal jugular vein, common carotid artery, and vagus nerve are all found within this compartment.

A triangle in the neck, bounded by: the mandible, the anterior belly of the digastric muscle, and the midline of the neck. It contains important structures like the submental lymph nodes and the submental artery.

A triangle in the neck, bounded by: the posterior belly of the digastric muscle, the stylohyoid muscle, and the superior belly of the omohyoid muscle. It contains structures such as the submandibular gland and the facial artery.

A muscle with two bellies joined by a tendon that attaches to the hyoid bone. It helps open the mouth and elevate the hyoid bone.

The anterior belly arises from the digastric fossa on the mandible, the posterior belly arises from the mastoid notch. The two bellies are connected by an intermediate tendon that attaches to the body of the hyoid bone.

The posterior belly is innervated by the facial nerve (CN VII), and the anterior belly is innervated by the mandibular division (V3) of the trigeminal nerve (CN V).

This muscle originates from the base of the styloid process and inserts into the hyoid bone. Its function is to pull the hyoid bone postero-superiorly during swallowing.

This muscle forms the floor of the mouth and helps to elevate the hyoid bone. It originates from the mylohyoid line on the mandible and inserts into the hyoid bone.

This muscle lies deeper than the mylohyoid muscle and elevates the hyoid bone. It is not typically considered a muscle of the anterior triangle, but it is a suprahyoid muscle.

The suprahyoid muscles are important for swallowing and speech. They work together to elevate the hyoid bone, which is essential for moving food from the mouth to the esophagus.

The suprahyoid muscles are a group of four muscles that run from the hyoid bone to the skull or mandible. They are important for swallowing and speech.