Like other regions of the body, the neck has a central bony skeletal core upon which other structures attach or are related. The bones of the neck consist of the base of the skull and the 7 cervical vertebrae.
If we take a look at the base of the skull, the major parts that are related to the upper neck are the:
|Below the base of the skull, you will find the vertebral column. The top vertebrae (7 cervical) provide support for the neck structures. You will also note that these vertebrae allow passage of an important arterial supply to the brain and brain stem, the vertebral artery.|
|The first cervical vertebra is the atlas and is considered an atypical cervical vertebra because it has no body or spinous process. It articulates with the occipital condyles of the skull above it and with the superior articular processes of the axis below it. It also articulates with the dens of the axis below. If viewed from above, you can identify the following parts of the atlas:
|The axis is the second cervical vertebra. This vertebral is also called an atypical vertebra because it has an upward projection called the dens that articulates with the inner aspect of the anterior arch of the atlas just posterior to the anterior tubercle. Some of the identifiable parts are the:
|The 3rd, 4th, 5th, and 6th cervical vertebrae are known as the typical cervical vertebrae because they all have the same characteristics and except for the foramen for the vertebral artery similar to other typical vertebrae of the spinal cord. These characteristics are:
|The 7th cervical vertebra starts to pick up characteristics of the upper thoracic vertebrae and may even produce a cervical rib, which can cause pathological problems related to the brachial plexus.
It has the same characterists as other typical cervical vertebra except that there is no foramen for the vertebral artery and it may not have a bifid spinous process. After the vertebral artery arises from the subclavian artery, it enters the transverse foramen of the 6th cervical vertebra bypassing the 7th.
The spinous process of the 7 cervical vertebra is longer than those of the other cervical vertebrae and is not buried under the ligamentum nuchae of the neck. Therefore, it is easy to see and to palpate and is called the vertebra prominens. This can serve as a surface landmark demarcating the neck (cervical) from the thoracic regions of the body.
||Superficial structures that you should know from the lateral view of the neck.
|Triangles of the Neck||Anterior Triangle||Posterior Triangle|
|Once the skin over the mandible and upper neck is removed, you can identify the submandibular triangle and its boundaries.
|The superficial (roof) structures of the submandibular region are:
|Removal of the superficial structures displays the submandibular salivary gland itself.|
|The remaining contents of the submandibular triangle are structures passing through:
|The submental triangle is located between the two anterior digastric muscles (abd). Structures found here are the submental lymph node(s) (ln) that drain the floor of the mouth. The mylohyoid muscle (mh) arise from the body of the hyoid bone and insert into the mylohyoid line of the inside of the mandible. This muscle aids in swallowing and in depressing the mandible.|
|The boundaries of the carotid triangle are:
||Boundaries of Carotid Triangle|
|Starting from the most superficial aspects of the carotid triangle, we will point out the items that are related to it.|
|Roof of carotid triangle
The first layer, under the skin and superficial fascia includes the platysma, which forms the roof of the carotid triangle. Note the location of the carotid triangle in purple.
Vein of the carotid triangle
With the roof removed, you can see the boundaries of the carotid triangle and the superficial veins related to it:
|The nerves that enter the carotid triangle and that lie superficial to the internal jugular vein, internal and external carotid arteries are:
||Nerves within the carotid triangle|
|Reflection of sternomastoid and removal of common facial vein||cca-common carotid artery
eca-external carotid artery
|Finally, we reach the deepest aspect of the carotid triangle, frequently called the floor. The muscles, at this level, are the middle and lower pharyngeal constrictors (mpc and ipc). The structures seen passing through this level are:
|The muscular triangle has the following boundaries:
|When the strap muscles are reflected, you are able to see the thyroid gland (tg) with its arteries (superior thyroid artery from the external carotid (sta) and the inferior thyroid artery from the thyrohyoid trunk from the subclavian (ita).
If the thyroid gland is reflected laterally, the structures making up the larynx and trachea are seen:
|Thyroid gland and it arterial supply||Cartilages and membranes|
|The thyroid gland is hidden under the sternohyoid and sternothyroid muscles and consists of two lobes and an isthmus. An occasional pyramidal lobe extends upward near the mid line.
The thyroid is supplied by superior (sta) and inferior (ita) thyroid arteries derived from the external carotid and thyrocervical trunk respectively. The inferior thyroid artery is closely associated with the recurrent laryngeal nerve (rln).
|Anterior View of Thyroid Gland||Deep Surface of Thyroid Gland
Four small reddish-brown pea-sized glands may be seen on the deep surface of the thyroid gland. These are the superior and inferior parathyroid glands (ptg). Also note the close relationship of the recurrent laryngeal nerves to the thyroid gland and inferior thyroid artery (rln, ita).
The cricothyroid ligament and membrane are frequently pierced in emergency situations to open the airway. You should be able to palpate this space on yourself or a friend, just to appreciate where it is. It has been known that an empty ball-point pen or a hollow stem has been used in the field to save lives, where an air passage has been closed above this region.
|You will now disarticulate the sternoclavicular joint and identify the structures located at the root of the neck. The root of the neck is bounded by the manubrium of the sternum anteriorly, the first rib laterally and the first thoracic vertebra posteriorly. All structures passing from the head through the neck to lower regions pass through this area as well as structures arising in the thoracic cavity and passing out through this region. The following description of the root of the neck starts with the most anteriorly placed structures and proceeds to the most posteriorly placed ones.|
|Most anterior structures:
|The next layer can be considered the artery-nerve layer:
|The upper lobe of the lung (1) extends into the neck region. This is clinically important for anyone entering this region surgically since the lung can be punctured if the surgeon isn't careful.|
|The posterior part of the root of the neck is made up of the anterior surface of the body of the 1st thoracic vertebra with its anterior longitudinal ligament (in gray). When observing this area, you can see the nerves:
mastoid process of temporal bone
body and angle of mandible
manubrium of sternum
1st thoracic vertebra
thoracic duct on left
|Parotid & Infratemporal Regions||Posterior Cervical Triangle|
|Copyright© 1999 by Wesley Norman, PhD, DSc|