Deep Cervical Fascia

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CONTENT

INTRODUCTION

•       Fascia means fibrous connective tissue which binds together various structures of the body

•       Deep cervical fascia  is deep fascia forms a collar around the neck

•       Lies deep to platysma muscle in the interval between  muscles, vessels & organs of the cervical region

•       Gives various extensions or laminae around various structures of the neck

                                           

LAYERS OF DEEP CERVICAL FASCIA

1. Investing Layer of deep Cervical Fascia
2. Pretracheal layer
3. Prevertebral layer
4. Carotid Sheath
5. Buccopharyngeal fascia
6. Temporal fascia
7. Pharyngobasilar fascia

INVESTING LAYER OF DEEP CERVICAL FASCIA

ATTACHMENTS

·         Superiorly : External occipital protuberance, mastoid process, external acoustic meatus, base of the mandible

·         Inferiorly   : Spine of scapula, acromion process, clavicle, manubrium sterni

·         Anteriorly  : Symphisis menti , Hyoid bone & continuous with the fascia of the fascia of the opposite side

·         Posteriorly : 7^th cervical vertebra, ligamentum nuchae

                           

                                          

FEATURES OF INVESTING LAYER OF DEEP CERVICAL FASCIA

1.    It split to enclose

•       Muscles : Trapezius and Sternomastoid

•       Salivary Gland : Parotid and Submandibular

•        Spaces  : Superasternal and Supraclavicular

2.   It also form pulleys to bind the tendons of the diagastric and omohyoid muscles

PRETRACHEAL  FASCIA

ATTACHMENTS

·         Superiorly : Hyoid bone in median plane , Oblique line of thyroid cartilage , cricoid cartilage more laterally

·         Inferiorly   : Below the thyroid cartilage it encloses  the inferior thyroid veins , passed behind the branchocephalic vein

·         On Either Side  : It fuses with the front of the carotid sheath deep to the sternomastoid

FEATURES OF PRETRACHEAL  FASCIA

1.       The posterior layer of the thyroid capsule ( Pretracheal Fascia )  is thick . On eitherside it forms a suspendory ligament for the thyroid gland : Ligament of Berry. They support the thyroid gland , and donot let it  sink into mediastinum .

2.   Fascia provide a slippery surface for free movement of trachea during swallowing

PREVERTEBRAL FASCIA

ATTACHMENTS

·         Superiorly : Base of the skull

·         Inferiorly   : Anterior longitudinal ligament and to the body of the 3^rd and 4^th thoracic vertebra

·         Anteriorly  : Separted form pharynx by the retropharengeal space containing loose areolar tissue

·         Laterally : Deep to trapezius

FEATURES OF PRETRACHEAL  FASCIA

1. Cervical and branchial plexuses lie behind the prevertibral fascia. Four cutaneous branches of cervical fascia pierces this fascia

2. As the trunk of branchial plexux and subclavian artery, pass lateral through interval between the scalenus anterior and the scalenus medius , they carry with them a coverinf of prevertebral fascia known as axiallary sheath
3. It provides a fixed base for movement of pharynx the oesophagus and the carotid sheath during movement of the neck and during swallowing

CAROTID SHEATH

•      It is condensation of fibroareolar tissue around the main vessels of the neck ( common and internal carotid arteries , and internal juglar vein) and the vagus nerve

•      It is a fascial sheath situated deep to sternocleidomastoid muscle on each of the front of the neck

CONTENTS

1. Internal jugular vein laterally,
2. Common carotid artery ( in the lower part)
3. Internal carotid artery ( in the upper part) medially
4. Vagus nerve in between  them in a posterior plane

RELATIONS

·         Superiorly : Ansa cervicalis

·         Posteriorly  : Sympathetic trunk

BUCCOPHARANGEAL FASCIA

•       Parallel to the carotid sheath and along its medial aspect the prevertebral fascia  gives off a thin lamina, the buccopharyngeal fascia, which closely invests the constrictor muscles of the pharynx and is continued forward from the constrictor pharyngis superior onto the buccinator.

•       It is attached to the prevertebral layer by loose connective tissue only, and thus an easily distended space, the retropharyngeal space, is found between them.

TEMPORAL FASCIA

•      The temporal fascia covers the Temporalis muscle.

•      It is a strong, fibrous investment, covered, laterally, by the Auricularis anterior  and superior, by the galea aponeurotica, and by part of the Orbicularis oculi.

•      The superficial temporal vessels and the auriculotemporal nerve cross it from below upward.

ATTACHMENTS

·         Superiorly :  it is a single layer, attached to the entire extent of the superior temporal line

·         Inferiorly    :  it is fixed to the zygomatic arch, it consists of two layers, one of which is inserted into the lateral, and the other into the medial border of the arch.

PHARANGEOBASILAR FASCIA

•      Also known as pharyngeal aponeurosis 

•      It is situated between the mucous and muscular layers.

•      It is thick above where the muscular fibers are wanting, and is firmly connected to the basilar portion of the occipital and the petrous portions of the temporal bones.

•      As it descends it diminishes in thickness, and is gradually lost.

•      It is strengthened posteriorly by a strong fibrous band, which is attached above to the pharyngeal spine on the under surface of the basilar portion of the occipital bone, and passes downward, forming a median raphé, which gives attachment to the Constrictores pharyngis.

CLINICAL ANATOMY OF DEEP FASCIA

I. INVESTING LAYER OF DEEP CERVICAL FASCIA

    Because of the presence of thick tough parotido-masseeric fascia which covers the parotid gland swellings of the parotid gland (mumps, parotitis) are very painful

II. PRETRACHEAL FASCIA

1. The fascia forms the outer false capsule of thyroid gland, posterior part of which is thin & not well defined. Hence thyroid swellings grows posteriorly & may compress the oesophagus causing dysphagia
2. Thyroid gland moves with degluttition as the posterior aspect of the gland is attatched to the cricoid cartilage by a thickening of pretracheal fascia known as ligament of berry or suspensory ligament of thyroid gland
3. During thyroid surgeries the ligament of berry has to be cut to mobilise the thyroid gland
4. Enlargemrnt of thyroid gland leads to embarresment of the heart as the lower extension of pretrachea; fascia is pericardium which leads to a traction on the fascia due the thyroid swelling
5. Continuity of pretracheal fascia with the mediastinum leads to spread of infection to mediasinum from the neck & vise versa
6. Pretraceal fascia provides a free slippery base for the movement of the trachea during swallowing

PREVERTEBRAL FASCIA

1. Due the extension of prevertebral fascia as axillary fascia infections of verebrae- caries spine (tuberculosis of vertebrae) may lead to spread of pus to the axilla, the pus may also poin as an absess in the region of the posterior triangle
2. Prevertebral fascia forms the posterior wall of retropharyngeal space
3. Retropharyngeal absess causes dysphagiavery painful

REFERENCE

1. HUMAN ANATOMY ( Head and Neck Volume )  :  B D Chaurasia
2. HUMAN ANATOMY ( Head and Neck Volume )  :  Cunningham