Understanding the Fascial planes of head and Neck Fascia • A sheet of connective tissue covering or binding together body structures • Types – Superficial Fascia – Deep Fascia Superficial Fascia • Muscles of facial expression • Continuous with superficial Cervical fascia http://media-2.web.britannica.com/eb-media/56/118356-004-EE793D60.jpg Deep Fascia• Geography of Deep Fasica • Deep fascia of head and Neck Deep Fascia of Jaws • Muscles of Mastication – Temporal Fascia – Masseteric fascia – Parotidomasseteric fascia – Pterygoid fascia Continuous with Deep Fascia of Neck Fascia of Neck • Cervical Fascia- 2 components – Superficial Cervical Fascia • Envelops Platysma muscle • Continuous with superficial fascia of face – Deep Cervical Fascia • Superiorly-attached to inferior border of Mandible • Lower in the neck has 3 divisions – Anterior Layer – Middle Layer – Posterior Layer Deep Cervical Fascia • Anterior layer – Investing fascia • Parotideomasseteric • Temporal • Middle layer – Sternohyoid-omohyoid – Sternothyroid-thyrohyoid – Visceral Division • Buccopharyngeal • Pretracheal • Retropharyngeal • Posterior layer – Alar Division – Prevertebral Division Anterior Layer (superficial or investing layer) • Encircles the neck, splits around SCM and Trapezius-attaches posteriorly to the spinous processes of the cervical vertebrae Anterior Layer (superficial or investing layer) • Forms superficial border of the submandibular space and splits to form the capsule of the gland • Attaches to the inferior border of mandible – Anteriorly-blends with the periosteum of facial bones and is under the muscles of facial expressions • Covers the anterior/posterior belly of digastricus muscle, submandibular salivary gland • Stylomandibular ligament – dense band of the investing fascia – (extends from styloid process to angle of the mandible) Anterior Layer (superficial or investing layer) • Superficially it splits at the inferior border of the mandible to become continous with – Parotidomasseteric fascia – • Covers superficial part of the masseter and splits around the parotid gland – Pterygoid fascia • Encloses the – hyoid bone – Suprahyoid muscles Superficial or Investing layer(contd…) • Inferiorly-Attaches to the shoulder girdle and sternum • At the superior edge of the sternum it splits to form the Suprasternal space (Space of Burns.) Middle Layer • Surrounds infrahyoid (strap) muscles: Sternohyoid, Sternothyroid, Omohyoid, Thyrohyoid • Runs between hyoid bone and clavicle • Thickens to form a pulley through which the intermediate tendon of the digastric muscle passes, suspending the hyoid bone Middle Layer-Visceral Division – Below hyoid-surrounds trachea, esophagus and thyroid gland – Above the hyoid it wraps around the lateral and posterior sides of the pharynx lying on the superficial side of the pharyngeal constrictor muscles.(Called Buccopharyngeal fascia in this region) – Deep spaces of the neck (lateral pharyngeal, retropharyngeal and pretracheal spaces) all lie on the superficial side of the visceral division. Carotid Sheath• Base of the skull to the root of the neck – Common and Internal Carotid artery – Internal Jugular vein – Vagus nerve Posterior Layer • From skull base(occipital bone) to diaphragm • 2 divisions – Alar – Prevertebral • Envelops – Thyroid and cricoid cartilages – Pharyngeal tubercle of occipital bone – Attaches to the pterygomandibular raphe, pharyngeal aponeurosis • Inferiorly – Continues into thorax blends with pericardium Posterior Division • 2 layers – Alar – Prevertebral • Extends from base of skull to diaphragm Posterior Layer-Alar Fascia • Alar fascia – –Ribbon of fascia and it attaches to the carotid sheath and visceral fascia(middle layer) – Extends from skull to seventh cervical vertebra Posterior Division- Prevertebral Fascia • Prevertebral Fascia surrounds the vertebrae and postural muscles of neck and back • Lies just anterior to the periosteum of the vertebrae and is susceptible to infections of it (tuberculosis osteomyelitis) • Usually not invaded by oral and maxillofacial infections.
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