General plan of the neck
Introduction
Surface anatomy
Simplified plan of the neck
Musculo-vertebral block
Pharynx-larynx block
Carotid sheath
Triangles of the neck
Deep fascia of the neck
Neck dissection
In the midline of the neck , from above down, you can feel :-
1- the hyoid bone—at the level of C3;
2- the notch of the thyroid cartilage—at the level of C4;
3- the cricothyroid ligament—important in cricothyroid puncture;
4- the cricoid cartilage—terminating in the trachea at C6;
5- the rings of the trachea, over the second and third of which can be rolled the isthmus of the thyroid gland;
6- the suprasternal notch.
Introduction
According to Greek mythology, Atlas was condemned to bear the Earth and the heavens on his shoulders forever as a punishment
Because his figure often appeared in early map collections, the name Atlas has come to denote a volume of maps.
Because the 1st cervical vertebra bears the head above, it is called the atlas vertebra
Introduction
The length of the neck is variable, and a long neck is apparently necessary for success as a ballet dancer.
Introduction
Among some tribes in Burma (Myanmar) lengthening of the neck by wearing metal rings is more apparent than real, it is achieved by pushing down the ribs and clavicle.
Introduction
Laryngeal prominence
Laryngeal prominence
Supposedly this is where the forbidden fruit stuck in Adam s throat, since it is more prominent in the male
Laryngeal prominence
Adam s Apple is anatomically formed by the thyroid cartilage
Laryngeal prominence
In the male, the angle is narrow and corresponds to the angle between the index and middle fingers.
In the female, the angle is wider and corresponds to the angle between the thumb and index fingers.
Laryngeal prominence
Recall the same relationship in the subpubic angle of the male and female.
Because of these anatomical differences, the superior border of the thyroid cartilage in most males projects anteriorly producing a distinct laryngeal prominence
Laryngeal prominence
Hyoid bone
like the thyroid cartilage, the hyoid bone can be grasped by the index and thumb and can be noted that it moves during swallowing
\Hyoid bone
Consequently, following fracture of the hyoid bone the fine balance of these muscles would be disturbed, causing problems in breathing, speaking, and swallowing
Transverse process of atlas
The tip of the transverse processes of the Atlas (C1 vertebra) can be felt by deep palpation between the angle of the mandible and the tip of the mastoid process
Cricoid cartilage
The cricoid cartilage, part of the laryngeal skeleton, can be felt inferior to the laryngeal prominence
Cricoid cartilage
is located at the level of the 6th cervical vertebra where the pharynx joins the esophagus and the larynx and trachea join each other
Trachea
As you move your fingers downwards in the midline, they will sink as they pass the cricoid, this is where you can palpate the trachea just superior to the jugular notch between the medial ends of the clavicle
Jugular notch
Surface anatomy
The bony landmarks forming the superior limit of the neck are:
inferior margin of the mandible
mastoid process of the temporal bone
external occipital protuberance
Sternomastoid muscle
divides the lateral side of the neck into anterior and posterior triangles
Surface anatomy
The hard palate lies on a level with the anterior arch of the Atlas
the lower border of the mandible lies between C2 & 3 vertebrae
Plan of the neck
Musculo-vertebral block
consists of the cervical vertebrae, and the muscles that are grouped around them
This block is bound together (plastered) by a dense layer of prevertebral fascia
Pharynx-larynx block
Placed in front of the musculo-vertebral block
composed of the pharynx and larynx or, lower down (at the level of C6), the trachea and esophagus.
partially enclosed in a thin sheath of fascia called the pre-tracheal fascia
Plan of the neck
The whole is enclosed in a musculo-fascial tube composed of sternomastoid and trapezius muscle and the investing layer of the deep fascia of the neck.
Plan of the neck
Plan of the neck
Filling in the angle between the vertebral block and the larynx-pharynx block is the carotid sheath containing the internal jugular vein, the common or internal carotid arteries (depending on the level) and the vagus nerve between them posteriorly
Plan of the neck
remember that the transverse process of a cervical vertebra has an interior and a posterior tubercle and a foramen transversarium.
The muscles that surround the vertebrae can now be inserted
Musculo-vertebral block
Between the anterior and posterior tubercles of a cervical vertebra there is a deep groove which is occupied by a spinal nerve
Cervical nerves
Running vertically through the foramina transversaria is the vertebral artery
the spinal nerve passes behind the vertebral artery as it emerges from the vertebral canal
Cervical nerves
The anterior primary rami of spinal nerves from C5 to T1 form the roots of the brachial plexus
Cervical nerves
From the cross section, it can be appreciated that the roots are located between scalenus anterior and medius since these muscles arise respectively from interior and posterior tubercles and since the spinal nerves are between the tubercles
Relations of the superior surface of the 1st rib
Axillary sheath
The structures passing behind scalenus anterior are deep to the prevertebral fascia
Toward their destination to the upper limb they take a prolongation of the prevertebral fascia down with them in the form of a tube which surrounds them, this tube-like prolongation is called the axillary sheath
Respiratory-digestive block
In front of the musculo-vertebral block is the respiratory-digestive block, with the trachea in front and the esophagus behind together enclosed in the thin pre-tracheal fascia
Respiratory-digestive block
(pharynx-larynx block)
Pharynx-larynx block
On the left, the left recurrent laryngeal nerve occupies the groove between the trachea and esophagus
on the left side of the esophagus is found the thoracic duct
Carotid sheath
The final block is the carotid sheath and its contents
The tough fibrous tissue of the carotid sheath is very much thinner over the vein so as to allow for its expansion during increased blood flow (compare to the situation of the pulmonary veins and the pulmonary ligament; the femoral vein and the femoral canal)
Carotid sheath
Is attached to the base of the skull at the margins of the carotid foramen
Is continued downwards along the vessels to the arch of the aorta
Triangles of the neck
The neck is divided into two large triangles by sternomastoid muscle
the anterior triangle
the posterior triangle
Triangles of the neck
Deep fascia of the neck
The fascia of the neck demonstrable as membrane comprise the
investing layer
prevertebral fascia
pre-tracheal fascia
carotid sheath
Deep fascia of the neck
The investing layer surrounds the neck like a collar and splits around sternomastoid and trapezius nuscles.
The investing layer
The attachment of the investing layer on the skull extends along the superior nuchal line to the tip of the mastoid process
The investing layer
anteriorly it is attached to the lower border of the mandible
The investing layer
The lower attachment is to the pectoral girdle: to the spine of the scapula, clavicle and the sternum
The investing layer
Is attached to both clavicle and jugular notch by two layers into which it splits a short distance above them
The investing layer
Of its two layers that are attached to the middle third of the clavicle between sternomastoid and trapezius, the deeper layer splits around the inferior belly of the omo-hyoid forming a fascial sling which binds the muscle down to the clavicle.
The investing layer
The two layers, above the clavicle, represent the two layers of the clavi-pectoral fascia that encloses the subclavius muscle below the clavicle
The investing layer
Prevertebral fascia
This is a tough membrane in front of the prevertebral muscles. It extends from the base of the skull in front of longus capitis downwards to the lower limits of longus colli (body of T. 3 vertebra).
it becomes prolonged towards the axilla as the axillary sheath
Prevertebral fascia
The name ‘prevertebral’ is misleading because the prevertebral fascia surrounds the vertebral column and its musculature. It not only passes in front of the vertebrae.
Prevertebral fascia
The function of the prevertebral fascia is to provide a fixed basis on which the pharynx, esophagus, and carotid sheaths can glide during neck movements and swallowing undisturbed by any movements of the prevertebral muscles.
Prevertebral fascia
Retropharyngeal space
In front of the prevertebral fascia is a space that extends from the base of the skull to the diaphragm, the retropharyngeal space
Retro-pharyngeal abscess
Pre-tracheal fascia