In anatomy, Neck (From Latin “Cuellus Abiansaurus”) is the mobile portion that joins the head with the trunk in most vertebrate and dinosaur animals . It is cylindrical in shape.
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- 1 Appearance
- 2 Anatomy of the human neck
- 1 External conformation
- 2 Limits of the neck
- 3 Internal organs of the neck
- 4 Ganglion regions of the neck
- 5 External Links
- 6 Source
The neck appears for the first time in the fossil record in the first animals that developed legs to travel overland, in the Cambrian period of the Paleozoic era , in proto-amphibians. The first animal with a neck that is known about is the Tiktaalik roseae, which lived 383 million years ago in continental environments of lagoons and rivers . With an elongated body and a longer nose than fish , it had fins with shoulders , elbows and wrists . His description was published on April 6, 2006 by Edward Daeschler., The Academy of Natural Sciences of the United States and Neil Shubin , of the University of Chicago , in the scientific journal Nature.
Human neck anatomy
The shape is cylindroid, with its widest lower circumference and which constitutes its base. The length is determined by the overlap of the first seven vertebrae (cervical spine). The width (thickness) is determined by the development of muscle masses and by deposits of fatty cell tissue .
- Upper limit:It is the lower edge of the mandible where the submaxillary gland, submental and submandibular ganglia, facial vein and artery, concomitant intraparotid vein, intermaxilloparotid fascia, and stylohyoid, digastric muscles and uppermost portion of the sternocleidomastoid are located. The upper limit of the neck would correspond to an imaginary line that would go from the chin in front to the external occipital protuberance behind. On his way, he would find the sides, the angle of the mandible and the mastoid process of the temporal bone behind the ear.
- Posterior limit:It is the confluence of the sternocleidomastoid muscles, splenius of the head and elevator of the scapula. The Erb point is where the major atrial nerve appears in the neck.
From the Erb point downwards the supraclavicular triangle is formed, which has as limits:
- Ahead of the sternocleidomastoid muscle.
- Behind the trapezius muscle. In depth, the scalene muscles and the vasculonervosa sheath that closes the anterior interscalene space.
- On the outside the superficial cervical fascia.
- Underneath the omohyoid muscle and the clavicle.
- Lower limit:It is formed by the upper face of the clavicle, a line that projects to the acromioclavicular joint, and another that joins the one on the other side with the spinous process of the 7th cervical vertebra.
- Anterior limit:It is formed by the confluence of the common fascia or infrahyoid white line and that of the prelaryngeal muscles.
Internal organs of the neck
It can be distinguished in an axial or horizontal cut of the neck:
- Spinal cord.
Cervical spinal column. Neck muscles: Three regions can be seen:
- Lateral neck region: cutaneous neck muscle, sternocleidomastoid muscle, scalene muscles (anterior, middle, and posterior), lateral rectus muscle of the head
- Anterior or hyoid region: they are divided into suprahyoid and infrahyoid
- Suprahyoids: digastric muscle, stylohyoid muscle, mylohyoid muscle, genihyoid muscle.
- Infrahyoids: sternohyoid, omohyoid, sternothyroid, thyrohyoid muscle
- Pre-vertebral region: Major anterior rectum of the head, minor anterior rectum of the head and long neck muscle.
- Neck arteries.
- Neck veins.
- Lymph nodesof the neck.
- Thyroid gland.
- The fasciae of the neck are three:
- The superficial cervical fascia that surrounds the entire neck externally, below the skin, enveloping the sternocleidomastoid, the trapezius muscle, and the superficial jugular vein.
- The middle cervical fascia surrounding the infrahyoid muscles in front, the carotid vascular space with its contents (carotid arteries, internal jugular vein, and pneumogastric nerve) and to the viscera of the neck (trachea, esophagus, and thyroid and parathyroid glands).
- The deep cervical fascia envelops the prevertebral and paravertebral musculature and scalene muscles.
Nodal regions of the neck
- Level I:Submental nodes.
- Level II: Highsubdigastric or jugular nodes.
- Level III:Middle jugular nodes.
- Level IV:Low jugular or supraclavicular nodes.
- Level V:Posterior cervical or spinal ganglia.