Cutaneous Nerves

Main sensory nerves supplying Anterior part of neck are derived from? Which are the 4 nerves?

- Derived from Anterior rami of C2-C4. 1. Greater Auricular Nerve 2. Lesser Occipital Nerve 3. Transverse Cervical Nerve 4. Supraclavicular Nerves

Pretracheal fascia's upward attachment is limited by the attachments of __________________muscles, the _______________________ at the midline and the oblique line of the ______________________laterally.

- Infrahyoid muscles (ant triangle) - Hyoid bone - thyroid

inferior attachment of investing layer

- Manubrium - Clavicle - Acromion process - Spine of scapula.

Ludwig's Angina

- commonly arises from an infected 2 nd or 3 rd mandibular molar tooth. • Bilateral involvement of sublingual, submandibular and submental spaces. • Aggressive, rapidly spreading cellulitis, without lymphadenopathy, with potential for airway obstruction. • Involvement of sublingual space leads to lifting of tongue causing airway obstruction. • The infection requires careful monitoring and rapid intervention for prevention of asphyxia and aspiration pneumonia. • has to be treated surgically by incision and drainage to relieve patient's respiratory distress

posterior (midline) attachment of investing layer

- external occipital protuberance - ligamentum nuchae. - C7 cervical spine

Superior attachment of investing layer

- external occipital protuberance - superior nuchal line - mastoid process - lower border of the mandible.

commonest spaces involved in infection of the retropharyngeal and parapharyngeal space are? where do these spaces communicate?

- sublingual (first molar) and submandibular (commonly from 2 nd or 3 rd Molar and sometimes from 1 st molar). - these 2 spaces communicate with each other at posterior border of mylohyoid.

anterior (midline) attachment of investing layer

- symphysis menti - hyoid bone - fascia of opposite side

Significance of Lines of Langer (cleavage lines)

-correspond to the natural orientation of collagen fibers in the dermis. -direction is imp for cosmetic surgery -Incisions made parallel to Langer's lines may heal better and produce less scarring than those that cut across. -incisions perpendicular to Langer's lines have a tendency to pucker and remain obvious (Keloids)

2nd most important source of infection in retropharyngeal and parapharyngeal space

-impacted third molar.

Parapharyngeal space

-postero- lateral to the pharynx -shaped like a cone or a pyramid, inverted with its base at the sphenoid bone, with its apex inferiorly pointing to the greater cornu of the hyoid bone. -occupies the space between muscles of mastication (mandible) and the muscles of deglutition (constrictors of pharynx).

Superficial Fascia of the Neck

-thin layer of subcutaneous connective tissue. -between the dermis of the skin and the deep cervical fascia. -platysma, cutaneous nerves, blood and lymphatic vessels -fat -considered by some to be a part of the Panniculus adiposus, and not true fascia

Which part of the neck do the greater occipital nerve and 3rd occipital nerve supply?

DERIVATIVES OF THE POSTERIOR RAMI - POSTERIOR PART OF THE NECK - Greater Occipital nerve (C2) medial occipital region - Third Occipital nerve (C3) upper neck

clinical significance of retropharyngeal space

It acts as a route through which infection from the mouth and throat can reach the superior mediastinum.

where does the parapharyngeal space receive infection from?

It may receive infection from teeth, submandibular gland & space, masticator space, parotid space and peritonsillar space. From this space infection can pass to retropharyngeal space and then to superior mediastinum.

Main sensory nerves supplying Posterior part of neck are derived from?

Posterior rami of C2-C5 spinal nerves. Rest part of neck directly by posterior rami.

Function of the prevertebral fascia

Provides a fixed basis on which the pharynx, esophagus, and carotid sheaths can glide during neck movements and swallowing undisturbed by movements of the prevertebral muscles.

Why is the parapharyngeal space liable to infection?

Since they intervene between the interfascial spaces and the mandible, on the one hand, and the pharynx on the other, they are liable to infection from either of these sources by extension from them. -these spaces which are most intimately related to the lymph nodes receiving the drainage from the nose, throat and jaw

Supraclavicular Nerve is formed from? What is its course? and provides sensation to?

• C3 and C4 roots. • arise from the behind the posterior border of sternocleidomastoid. • provide sensation to the skin overlying the suprascapular fossa and upper thoracic region and sternoclavicular joint. • divide into three branches- Medial, Intermediate and lateral. • Supply lower medial and lateral parts of neck.

The pretracheal fascia blends inferiorly with _______________________________________, and laterally with ________________________________.

the adventitia of the arch of the aorta (inf) carotid sheath (lat)

Neck pain (cervicalgia)

• Acute, subacute or chronic • Complaint: dermatomal neck and/or shoulder pain, numbness in arm and hand. Sometimes muscle weakness and diminished or absent reflexes. • Causes: degenerative disc, neck strain, poor posture, osteoarthritis, cervical spondylosis, neck injuries such as whip lash, herniated disc, pinched nerve • prevalence of neck pain is the 4 th leading cause of global disability* • Management: Treatment of cause (correct posture...), pain medication and rest

Boundaries of retropharyngeal space

• Anteriorly - Posterior wall of pharynx • Posteriorly - Prevertebral fascia • Superiorly - Base of skull • Inferiorly - Communicates with superior mediastinum

Commonest source of infection of the retropharyngeal and parapharyngeal space

The first permanent tooth to erupt in human beings is first molar (maxillary and mandibular)

_____________________________ is the most superior process which can be readily palpated.

The spinous process of C7 (vertebra prominens)

when does the infection of retropharyngeal/parapharyngeal space become life threatening?

infection can reach lateral pharyngeal space and from there to retropharyngeal space which communicates with superior mediastinum of thorax. Once that is involved, it becomes a potentially life threatening situation.

Retropharyngeal space:

interfascial space between pretracheal (anteriorly), prevertebral (posteriorly), and carotid sheaths (laterally) base of the skull to diaphragm.

Pretracheal fascia surrounds

larynx, pharynx, trachea, esophagus, and thyroid gland

Where do the nerves of the cervical plexus emerge from? What is this point called and what is it used for?

middle of the posterior border of the sternocleidomastoid (SCM) -utilised when performing a cervical plexus nerve block.

Parapharyngeal extends forward into the _________________ region, so that together with the retropharyngeal they actually form a ring about the pharynx.

sublingual

Extension of prevertebral fascia

• Extends from the base of the skull downwards to the level of T3 vertebra. • Prolonged laterally towards the axilla as the axillary sheath.

contents of carotid sheath

• Internal jugular vein. • Common or internal carotid arteries. • Vagus nerve • between the artery and vein posteriorly.

Platysma - attachment, nerve supply

• Lies in the superficial fascia. • Extends from the pectoral region. • Attached to facial skin and mandible. • Nerve supply: facial nerve (CN VII).

Where is the sympathetic trunk located?

• The sympathetic trunk is located behind the carotid sheath but anterior to the prevertebral fascia

Greater Auricular nerve is formed from? and provides sensation to?

• formed by fibres from C2 and C3 roots. • provides sensation to the: - external ear (both sides), - skin over the parotid gland - angle of mandible.

Transverse cervical Nerve is formed from? and provides sensation to?

• is also formed by fibres from C2 and C3. • curves around the posterior aspect of the sternocleidomastoid, and supplies sensation to: - the anterior and lateral neck. - Upper middle neck, anteriorly.

Lesser Occipital Nerve is formed from? and provides sensation to?

• is derived solely from the C2 root. • supplies cutaneous sensation to the: - posterosuperior scalp (lateral occipital region) - posterior part (medial surface) of auricle - upper middle neck posteriorly.