Head, Neck, and Neuroanatomy (THIEME Atlas of Anatomy) (eBook)

A Head and neck regions

Right anterior view.

B Head and neck regions

Right posterior view.

D Regions of the neck (cervical regions)

a Right lateral view, b left posterior oblique view.

These neck muscles are easily visible and palpable making them suitable as landmarks for a topographical classification of the neck.

E Palpable bony landmarks at the head and neck

a Frontal view; b Dorsal view.

1. Investing layer: envelops the entire neck, and splits to enclose the sternocleidomastoid and trapezius muscles.

2. Pretracheal layer: the muscular portion encloses the infrahyoid muscles, while the visceral portion surrounds the thyroid gland, larynx, trachea, pharynx, and esophagus.

3. Prevertebral layer: surrounds the cervical vertebral column, and the muscles associated with it.

4. Carotid sheath: encloses the common carotid artery, internal jugular vein, and vagus nerve.

5. Visceral fascia: encloses the larynx, trachea, pharynx, esophagus and thyroid.

C Superficial and inferior boundaries of the neck

Left lateral view. The following palpable structures define the superior and inferior boundaries of the neck:

• Superior boundaries: inferior border of the mandible, tip of the mastoid process, and external occipital protuberance

• Inferior boundaries: suprasternal notch, clavicle, acromion, and spinous process of the C7 vertebra.

D Relationships of the deep fascia in the neck. Transverse section at the level of the C5 vertebra

The full extent of the cervical fascia is best appreciated in a transverse section of the neck:

• The muscle fascia splits into three layers:

– Superficial lamina (orange),

– Pretracheal lamina (green), and

– Prevertebral lamina (violet).

• There is also a neurovascular fascia, called the carotid sheath (light blue), and

• a visceral fascia (dark blue).

E Fascial relationships in the neck

a Anterior view. The cutaneous muscle of the neck, the platysma, is highly variable in its development and is subcutaneous in location, overlying the superficial cervical fascia. In the dissection shown, the platysma has been removed at the level of the inferior mandibular border on each side. The cervical fasciae form a fibrous sheet that encloses the muscles, neurovascular structures, and cervical viscera (see B for further details). These fasciae subdivide the neck into spaces, some of which are open superiorly and inferiorly for the passage of neurovascular structures. The investing layer of the deep cervical fascia has been removed at left center in this dissection. Just deep to the investing layer is the muscular portion of the pretreacheal layer, part of which has been removed to display the visceral portion of the pretracheal layer. The neurovascular structures are surrounded by a condensation of the cervical fascia called the carotid sheath. The deepest layer of the deep cervical fascia, called the prevertebral layer, is visible posteriorly on the left side. These fascia-bounded connective-tissue spaces in the neck are important clinically because they provide routes for the spread of inflammatory processes, although the inflammation may (at least initially) remain confined to the affected compartment

b Left lateral view. This midsagittal section shows that the deepest layer of the deep cervical fascia, the prevertebral layer, directly overlies the vertebral column in the median plane and is split into two parts. With tuberculous osteomyelitis of the cervical spine, for example, a gravitation abscess may develop in the “danger space” along the prevertebral fascia (retropharyngeal abscess). This fascia encloses muscles laterally and posteriorly (see D). The carotid sheath is located farther laterally and does not appear in the midsagittal section.

A Cleavage or tension lines

Anterior oblique view.

Skin and its subcutaneous tissue are under tension explaining why a small, round needle hole can result in a small longish slit in...