Neck

Key takeaways

Neck belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Neck to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Neck from memory before moving on to harder problems.

Reference excerpt

The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Additionally, the neck is highly flexible, allowing the head to turn and move in all directions. Anatomically, the human neck is divided into four compartments: vertebral, visceral, and two vascular compartments. Within these compartments, the neck houses the cervical vertebrae, the cervical portion of the spinal cord, upper parts of the respiratory and digestive tracts, endocrine glands, nerves, arteries⁣⁣ and veins. The muscles of the neck, which are separate from the compartments, form the boundaries of the neck triangles. In anatomy, the neck is also referred to as the cervix or collum. However, when the term cervix is used alone, it often refers to the uterine cervix, the neck of the ⁣⁣uterus⁣⁣. Therefore, the adjective cervical can refer either to the neck (as in cervical vertebrae or cervical lymph nodes) or to the uterine cervix (as in cervical cap or cervical cancer).

Structure

Compartments The neck structures are distributed within four compartments:

Vertebral compartment contains the cervical vertebrae with cartilaginous discs between each vertebral body. The alignment of the vertebrae defines the shape of the human neck. As the vertebrae bound the spinal canal, the cervical portion of the spinal cord is also found within the neck. Visceral compartment accommodates the trachea, larynx, pharynx, thyroid, and parathyroid glands. Vascular compartment is paired and consists of the two carotid sheaths found on each side of the trachea. Each carotid sheath contains the vagus nerve, common carotid artery and internal jugular vein. Besides the listed structures, the neck contains cervical lymph nodes which surround the blood vessels.

Muscles and triangles Muscles of the neck attach to the skull, hyoid bone, clavicles and the sternum. They bound the two major neck triangles; anterior and posterior. Anterior triangle is defined by the anterior border of the sternocleidomastoid muscle, inferior edge of the mandible and the midline of the neck. It contains the stylohyoid, digastric, mylohyoid, geniohyoid, omohyoid, sternohyoid, thyrohyoid and sternothyroid muscles. These muscles are grouped as the suprahyoid and infrahyoid muscles depending on if they are located superiorly or inferiorly to the hyoid bone. The suprahyoid muscles (stylohyoid, digastric, mylohyoid, geniohyoid) elevate the hyoid bone, while the infrahyoid muscles (omohyoid, sternohyoid, thyrohyoid, sternothyroid) depress it. Acting synchronously, both groups facilitate speech and swallowing. Posterior triangle is bordered by the posterior border of the sternocleidomastoid muscle, anterior border of the trapezius muscle and the superior edge of the middle third of the clavicle. This triangle contains the sternocleidomastoid, trapezius, splenius capitis, levator scapulae, omohyoid, anterior, middle and posterior scalene muscles.

Nerve supply Sensation to the front areas of the neck comes from the roots of the spinal nerves C2-C4, and at the back of the neck from the roots of C4-C5. In addition to nerves coming from and within the human spine, the accessory nerve and vagus nerve travel down the neck.

Blood supply and major vessels The major blood vessels traveling through the neck provide the primary conduit for supplying oxygenated blood to and draining venous blood from the head. The main arteries supplying oxygenated blood to the head and neck are the external carotid arteries, the internal carotid arteries, the vertebral arteries and the thyrocervical trunks. The carotid and vertebral arteries mostly supply the head, whilst the many small blood vessels of the thyrocervical trunk vascularise the structures of the neck. The subclavian artery gives rise to the vertebral arteries and thyrocervical trunks, which provide blood to the cerebrum, the cerebellum, posterior neck, upper limbs and the superior and anterior chest wall. The thyrocervical trunk mainly vascularizes anterior neck structures, the thyroid gland, and regional muscles. The external carotid arteries (ECA) rise from the common carotid artery, as one of two main branches, which stem from the aortic arch on the left side and from the brachiocephalic trunk on the right side. The carotid bifurcation occurs at the level of the thyroid cartilage in the larynx. The external carotid artery is the only division of the common carotid that gives branches to the neck region and supplies the superficial structures of the head and face. The external carotid artery has eight branches: the superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, maxillary and superficial temporal arteries, the last two being the terminal branches of the external carotid.

The internal carotid artery is the second branch of the common carotid artery, supplying blood blood primarily to the anterior part of the brain, the eye and its appendages, and branches to the forehead and nose. It begins at the bifurcation of the common carotid artery (typically at the upper border of the thyroid cartilage, around cervical vertebrae C3–C4 level) and ascends to the base of the skull. The internal carotid artery’s course can be divided into four regions: I. Cervical Portion (Pars cervicalis); Course: Extends from the common carotid bifurcation up to the entrance of the carotid canal in the petrous portion of the temporal bone.

Relations: Lies within the carotid sheath along with the internal jugular vein and the vagus nerve. The cervical portion gives off no branches. II.Petrous Portion (Pars petrosa); Course: Enters the carotid canal in the temporal bone, ascending slightly before curving anteriorly and medially. It exits the canal near the foramen lacerum to enter the cranial cavity.

Branches: Caroticotympanic branch: A small vessel entering the tympanic cavity.

Pterygoid canal branch (Vidian artery): An occasional small branch passing through the pterygoid canal. III. Cavernous Portion (Pars cavernosa);

Course: Passes forward within the cavernous sinus along the side of the sphenoid bone body, forming a distinct S-shaped curve (often referred to as the carotid siphon). Branches: Cavernous branches: Tiny twigs supplying the trigeminal ganglion and the walls of the sinus.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Neck

Start with the simplest possible case. Write down what Neck claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Neck before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Neck ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Neck

In research: Neck appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Neck in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Neck is common in secondary-school and first-year university syllabi. It links to neighbouring topics Human head and neck, so understanding it makes those chapters shorter.
In everyday life: Look for Neck outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Neck in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Neck means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Neck out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Neck in simple terms?

The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body.

Why does Neck matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Neck?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Neck.