Lecture 1: Neck: Superficial Triangles and Cervical Viscera Flashcards
What triangles is the Platysma m. part of and what is it innervated by?
- Forms part of roof of the anterior and posterior triangles
- Innervated by: Cervical branch of the Facial n (VII)
What forms the borders, roof, and floor of the Posterior (lateral) triangle of the neck?
- Middle 1/3 of clavicle
- Trapezius
- SCM
- Roof = platysma and investing fascia
- Floor = prevertebral fascia
What is the action and innervation of the SCM?
Action:
Unilateral contraction = flexes and rotates the head
Bilateral = flex the head
Innervation:
Spinal accessory nerve (XI)
Conjunction of which veins form the EJV and where does this vein drain?
- Conjunction of: posterior auricular and retromandibular veins
- Drains into: subclavian vein
The spinal accessory nerve (XI) receives contributions from; innervating what muscles?
C2-3 for SCM
C3-4 for Trapezius
Where is Erb’s Point and what is found here?
- Posterior edge of the mid-point of the SCM
- C5-6 nerve roots of brachial plexus
- The 4 superficial cervical nerves
- Spinal accessory (XI) is located about 1cm above Erb’s point
Penetrating injuries to Erb’s point may lead to?
- Erb’s palsy (“waiters tips”)
- XI palsy
- Anesthesia of the skin of the neck or upper chest/shoulders
What is a Hangman’s fracture?
The fracture affects the vertebra called the axis, the second cervical vertebra (C2), with or without subluxation (slippage) of C2 on the third cervical vertebra (C3).
What important vein and nerve are found anterior to the anterior scalene muscle; what is the relationship of these vessels to one another?
- Subclavian vein
- Phrenic nerve
* The subclavian v. is immediately deep to the clavicle and just deep to the subclavian v. is the phrenic n. sitting on top of the anterior scalene muscle - the nerve is pressed between the vein and muscle
What is found posterior to the anterior scalene muscle in the interscalene triangle?
- Subclavian artery
- Brachial plexus (C5-T1)
What is the principle anatomical structure and nerve involved in Muscular Torticollis and what is the most frequent cause?
- Most frequently caused by birth trauma
- Benign fibrous tumor may accompany this condition and is known as “Fibromatosis Colli”
- A hematoma may occur and entrap branch of spinal accessory nerve (CN XI) denervating part of the SCM
What makes up the borders of the Carotid Triangle?
- Posterior Digastric
- Superior Omohyoid
- SCM
What important vascular and nervous structures are found within the Carotid Triangle?
- Branches of carotid system
- IJV + Tributaries
- Ansa Cervicalis
- CN IX, X, and XII
What makes up the borders of the Submandibular Triangle?
- Inferior edge of the mandible
- Anterior and Posterior Digastric M.
- Hyoid bone forms apex of the triangle
What are the 5 suprahyoid muscles?
1) Digastrics (Anterior and Posterior)
2) Stylohyoid
3) Mylohyoid
4) Geniohyoid
5) Hyoglossus
Innervation of the Anterior Digastric, Posterior Digastric, Stylohyoid, Mylohyoid, Geniohyoid, and Hypoglossus ms.?
Anterior = Mylohyoid n.
Posterior = VII
Stylohyoid = VII
Mylohyoid = Mylohyoid n. (V3)
Geniohyoid = C1
Hypoglossus = XII
The submandibular gland occupies most of which triangle?
Posterior portion of the Submandibular Triangle
The Submandibular Salivary Gland is drained by; describe the course of the structure that drains it and where it finally empties.
- Drained by the submandibular duct (Wharton’s duct)
- This duct courses antero-medially along the lateral surface of the hypoglossus then the genioglossus
- Submandibular duct empties into the floor of the mouth at the apex of the sublingual caruncle adjacent to the lingual frenulum
Describe the PARASYMPATHETIC innervation of the Submandibular and Sublingual Salivary Glands, including both the pre and post-ganglionic fibers routes.
- Preganglionic fibers from the superior salivatory nucleus exit the brainstem w/ the facial nerve, travel thru chorda tympania, and join w/ the lingual nerve before terminating in the submandibular ganglion
- Postganglionic fibers from submandibular ganglion distribute as numerous short branches to the parenchyma of the gland
Where do the postganglionic SYMPATHETIC fibers innervating the Submandibular Sailvary Gland originate and how to they reach the gland?
- Originate in the superior cervical ganglion
- Reach the gland by coursing in the external carotid and facial plexuses in the adventitia of the respective arteries
What are the contents of the Submandibular Triangle?
1) Submandibular ganglion
2) Lingual nerve
3) Hypoglossal (XII) nerve
4) Glossopharyngeal (IX) nerve
5) Lingual artery and vein
What cervical levels is zone 1 for penetrating neck trauma and what structures are at risk for injury?
- C5-C6
- Root of neck, Lower Parasagittal Region,
- Proximal Common Carotid, Vertebral and Subclavian arteries, Trachea, Esophagus, Thoracic Duct, Thymus Brachial Plexus, Superior mediastinum
What cervical levels is zone 2 for penetrating neck trauma and what structures are at risk for injury?
- C3-C4
- Carotid and Submandibular Triangles, Middle and Upper Parasagittal Regions
- Internal/External Carotid Arteries, Jugular Veins, Pharynx, Larynx, Esophagus, Recurrent Laryngeal n, Spinal Cord, Trachea, Thyroid, and Parathyroids
What cervical levels is zone 3 for penetrating neck trauma and what structures are at risk for injury?
- C1-C2
- Carotid and Submandibular Triangles, Retromandibular Region, Upper Parasagittal Region
- Distal Extracranial Carotid and Vertebral arteries + Uppermost segment of the Jugular Veins
What is the relationship of the recurrent laryngeal nerve to the thyroid gland; what does it innervate?
- Located medial to the lobes between the trachea and esophagus
- Innervates ALL the muscles of the larynx, except the cricothyroid
Describe the blood supply to the thyroid gland; where do these 3 arteries arise from?
- Superior thyroid artery arises from the common or external carotids
- Inferior thyroid artery arises from the thyrocervical trunk
- Lowest thyroid artery may arise from the brachiocephalic, aorta, or left common carotid
What 3 veins drain the thyroid gland and where do they drain into?
- Superior and middle thyroid veins drain into IJV
- Inferior thyroid vein drains into the brachiocephalic vein.
What are the structures involved in thoracic outlet syndrome (TOS): neurogenic, venous and arterial. What are the symptoms?
- Space between clavicle and first rib containing: brachial plexus, subclavian A and V.
Neurogenic: numbness of limb, pain, weakness
Vascular: weak pulse, blood clots, and pallor/coldness
Causes: poor posture and repetitive use
What is the anatomical structure/relationship to the trachea of the thyroid gland?
- 2 lobes adjacent to the trachea
- Usually connected by an isthmus, which overlies tracheal rings 2-4
What is a Thyroid Ima Artery and the clinical consequences of the presence of a thyroid ima artery?
- 10% of people have small unpaired thyroid ima artery branch of the brachiocephalic a.
- Other sources may be: arch of the aorta, right common carotid, subclavian, or internal thoracic as.
- Presence of this artery must be considered before tracheotomy (as a potential source of bleeding!)
What is the clinical significance of a subclavian venous puncture and what is the route?
- Often the point of entry to the venous system for central line placement, such as pulmonary artery catheter
- Needle punctures skin inferior to thumn (center of clavicle) and advances medially toward the tip of the index finger until entering right venous angle, posterior to the sternoclavicular joint
