Exam III: Neck I Flashcards
Neck Boundaries
Superior boundaries: investing fascia: trapezius muscle, sternocleidomastoid (attaches along mandible); border the mandible, to base of skull; mastoid process to back of the skull; follows of attachments of sternocleidomastoid and trapezius
Inferior boundaries: goes down clavicle and back along the spine of scapula; find the superior thoracic aperture- space bound by first thoracic vertebrae and first rib; all arteries, lymphatics, veins, and nerves follow it; muscles that cross the structure; transition area
Laryngeal structures: hyoid bone connected by the ligaments to rest of structures; hyoid anchors everything; use muscles in swallowing
Deep Fascia
- Investing Fascia - completely surrounds the neck; arises from skull and mandible and extends inferiorly to the sternum, clavicles, manubrium…
- Infrahyoid fascia - begins at hyoid bone, forms an investing fascia for the infrahyoid muscles; superficial and deep layers; continuous across the midline
- Pretracheal - a continuous fascial tube that surrounds the viscera in the neck:
a. Pre-tracheal proper – attaches to the hyoid bone above and fibrous pericardium below
b. Buccopharyngeal – attaches to base of the skull, covering the buccinator and pharyngeal constrictors, fuses with pre-tracheal, fuses with adventitia of esophagus - Prevertebral fascia - attaches to base of skull and vertebrae and encloses the deep muscles, has specializations: alar fascia, axillary sheath and Sibson’s fascia
- Carotid Sheath: is a column of fascia that surrounds the common and internal carotid artery, internal jugular vein, and the vagus nerve as these structures pass through the neck
Superficial Cervical Fascia
subcutaneous CT; superficial fatty layer and deeper fibrous layer; contains superficial nerves, vessels, lymph nodes and the platysma muscle
Cervical Subcutaneous Tissue and Platysma
Platysma: very thin muscle; extends over the mandible and all the way down the pectoral major muscle; changes the tension of the skin on your neck
Does not attach to bone, only attaches to superficial tissue
Action: moves bottom lip down, tighten fascia in neck
Innervation: facial nerve (CN 7)
Extension of muscle on face
Muscles in the superficial fascia; most attachments and insertions are in the fascia
Platysma Paralysis
Paralysis of the platysma: will be unable to move the lower lip and corners of the mouth down
With age the platysma loosens
Face Lift: is a surgical procedure which involves removing the localized fat deposits under the chin. It also tightens the platysma muscle further defining the neckline. Fat deep to the platysma muscle may also require removal as well as weakening of some of the deeper muscles (anterior belly of the digastric muscle). The procedure is performed through a small incision under the chin. This procedure significantly improves the neck and jawline.
Attachments of the Investing Fascia
Completely surrounds the neck attaching anteriorly to the ligamentum nuchae and spinous process of C7. It splits as it passes forward to enclose the trapezius and then reunites into a single layer as it forms the roof of the posterior triangle, splits again as it surrounds the sternocleidomastoid and reunites again to join on the other side
Anteriorly: surrounds the infrahyoid muscles
Superiorly: attaches to mandible, mastoid, trapezius; external occipital protuberance and superior nuchal line
Laterally: mastoid process, and zygomatic arch
Inferiorly: manubrium of the sternum, clavicle, spine of scapula and blend across midline, acromion
Specializations of the Pre-Vertebral Fascia
Axillary sheath: follows all big arteries, nerves, veins; is a fibrous sheath that encloses the first portion of the axillary artery, together with the axillary vein and the brachial plexus. It is an extension of the prevertebral fascia of the deep cervical fascia
Sibson’s fascia: sits on top of first rib (apex of lung pokes above the first rib) and protects things under; sits deep to subclavian artery to cover gray mass underneath it (apex of lung); protects the lung/a little extra protection
Specializations of the Infrahyoid and Pre-Tracheal Fascia
Two Slings:
1. Posterior digastric belly
2. Omohyoid
Sling: loops of fascia that changes orientation and direction; in this case it goes down the posterior digastric belly anteriorly then goes forward along the omohyoid
Pre-Tracheal Space
Between the investing layer of the cervical fascia (covering the posterior surface of the infrahyoid muscles) and the pretracheal fascia (covering the anterior surface of trachea and the thyroid gland), which passes between the neck and the anterior part of the superior mediastinum; infections can spread inferiorly to the mediastinum
Fascial Space Deep to Pre-Vertebral Layer
Infections deep to the prevertebral layer (yellow) can extend laterally, protruding along the posterior border of the SCM
Between Buccopharyngeal Fascia and Alar Fascia
Can spread inferiorly to lower cervical levels (this space extends superiorly to the base of the skull)
Between Alar/Buccopharyngeal Fascia and Pre-Verterbal Layer
Posterior layer of pre-vertebral fascia = buccopharyngeal
Alar fascia blends in and joins the buccopharyngeal fascia
“Retropharyngeal Abscess”
Extend inferiorly to the diaphragm
Air from a ruptured airway/esophagus can result in pneumomediastinum via this fascial space
Retropharyngeal Abscess
Refers to an infection between the cervical vertebrae and the pharyngeal wall
Most common in children under 6 and immunocompromised adults
Reach the retropharyngeal space via the oral cavity (dental abscess), nasopharynx (tonsillitis, peritonsillar abscess)
Signs and symptoms include: fever, sore throat, dysphagia, odynophagia, neck, and back pain
Complications include airway obstruction, sepsis, mediastinitis, pneumonia, empyema, jugular vein thrombosis, and carotid artery erosion
Masticatory Space
Oral cavity space
Paired suprahyoid cervical spaces on each side of the face
Each space is enveloped by the superficial layer of the deep cervical fascia containing muscles of mastication, ramus and body of mandible, inferior alveolar nerve, inferior alveolar vein and artery, mandibular division of the trigeminal nerve (V3) which enters the masticator space via the foramen ovale
Common for dental infections to spread
Spread of Infections: Spaces A-D
Space A: pericardium/ thorax; only up to thyroid bone (neck to thyroid)
Space B: vertebral compartment/pre-vertebral fascia can bulge to sternocleidomastoid; between SCM and trapezius in neck; not up and down, only bulges outwards
Space C: between buccopharyngeal and alar: all the way to base of skull to middle of the neck
Space D: is most important; goes up to base of skull, down to posterior mediastinum and down to diaphragm- easy space for infections to spread through; can affect many things during an infection like the heart
Sternocleidomastoid
SCM
Superior: mastoid process
Inferior: clavicle
Origin: upper part of anterior surface of manubrium of sternum
Insertion: lateral one half of superior nuchal line
Innervation: accessory nerve XI and branches from anterior rami of C2 to C3 (C4)
Action: individually will tilt head toward shoulder on same side rotating head to turn face to opposite side; acting together, draw head forward; right SCM turns head to left and vice versa
Trapezius
Origin: superior nuchal line; external occipital protuberance; ligamentum nuchae; spinous processes of vertebrae C7 to T12
Insertion: lateral one third of clavicle; acromion; spine of scapula
Innervation: motor- accessory nerve 11; proprioception C3 and C4
Action: assists in rotating the scapula during abduction of humerus above horizontal; upper fibers elevate, middle fibers adduct, lower fibers depress scapula
Suprahyoid: Stylohyoid
Action: pulls hyoid bone upward in a posterosuperior direction
Innervation: facial nerve/ CN VII
Infrahyoid
Infrahyoid: strap muscles inferior to hyoid including omohyoid, sternohyoid, thyrohyoid, and sternothyroid (TOSS)
Needed for stabilize hyoid and larynx and reposition after swallowing
Innervations: cervical plexus (anterior rami between C1-4)
Suprahyoid: Posterior Digastric
Action: pulls hyoid bone upward and back
Innervation: facial nerve 7/ CN VII
Suprahyoid: Anterior Digastric
Action: opens mouth by lowering mandible; raises hyoid bone
Innervation: mylohyoid nerve from inferior alveolar branch of mandibular nerve