Anterior Triangle of the Neck and Root of the Neck Flashcards
Anterior Cervical Triangle
Wraps around to lateral side of neck, contains platysma m.
Boundaries: midline of the neck (anterior), anterior border of SCM (posterior), inferior border of mandible (superior), jugular notch of manubrium (inferior/apex), subcutaneous tissue with platysma m. (roof), pharynx/larynx/thyroid gland (floor)
Contents: muscles, veins, arteries, nerves, cervical viscera
Veins of the Neck
Retromandibular v.
- Formed by superficial temporal v. & maxillary v.
- Divides into anterior & posterior divisions:
o Anterior division + facial v. = common facial v. (drains into interval jugular v.)
o Posterior division + posterior auricular v.= external jugular vein
Clinical Correlation: central line catheterization can go into the subclavian vein or internal jugular vein
Suprahyoid mm.
Action: elevate hyoid bone
Postion: superior to hypoid bone
Include: stylohoid m., digastric m., mylohyoid m., geniohyoid m.
Infrahyoid mm.
Action: depresses hyoid bone
Postion: inferior to hyoid bone
Include: omohyoid m., sternohyoid m., thyrohyoid m., sternothyroid m.
Stylohyoid m.
O: styloid process
I: hyoid bone
Inn: facial n. (CN VII)
Action: Pulls hyoid bone upward in posterosuperior direction
Elevation of hyoid
Diagastric m.
O: Ant. Belly: digastric fossa (lower inside of mandible)
Post. Belly: mastoid notch (medial side of mastoid process of temporal bone)
I: hyoid bone
Inn: Ant. Belly: N. to mylohyoid
Post. Belly: Facial n. (CN VII)
Action: Mandible flexed- raises hyoid
Hyoid bone fixed- opens mouth by lowering mandible
Mylohyoid m.
O: mylohyoid line
I: hyoid bone
Inn: N. to mylohoid (off inferior alveolar n. from mandibular division of trigeminal n. V3)
Action: supports and elevates floor of mouth; elevates hyoid
Geniohyoid m.
O: inferior mental spine of mandible
I: hyoid bone
Inn: N. to geniohyoid; Branch from anterior ramus of C1 via hypoglossal n. (CN XII)
Action: Mandible fixed- elevates and pulls hyoid forward
Hyoid fixed- pulls mandible downward and inward
Sternohyoid m.
O: SC joint & manubrium of sternum
I: hyoid bone
Inn: Anterior rami of C1-C3 via ansa cervicalis
Action: Depresses hyoid bone after swallowing
Omohyoid m.
O: scapula
I: hyoid bone
Inn: Anterior rami of C1-C3 via ansa cervicalis
Action: Depresses and fixes hyoid bone
Thyrohyoid m.
O: throid cartilage
I: hyoid bone
Inn: Fibers from anterior ramus of C1 carried via hypoglossal n. (CN XII)
N. to thyrohyoid m.
Action: Depresses hyoid bone and raises larynx
Sternothyroid m.
O: manubrium of sternum
I: thyroid cartilage
Inn: Anteior rami of C1-C3 via ansa cervicalis
Action: Draws larynx downward
Muscular Triangle
Contents:
- Muscle: omohyoid m., sternohyoid m., sternothyroid m., thyrohyoid m.
- Viscera: thyroid gland, parathyroid glands, trachea, esophagus, esophagus, common carotid a., internal jugular v.
Submental
Contents:
- Mylohyoid m., submental lymph nodes, some small veins
Submandibular (Digastric) Triangle
Contents:
- Submandibular gland
- Submandibular lymph nodes
- Marginal mandibular branch of facial n. (CN VII)- supplies mm. of facial expression
- Hypoglossal n. (CN XII)
- Mylohyoid n. (of CN V3)- supplies mylohyoid m. & anterior belly of digastric m.
- Facial a. & v.
Carotid Triangle
Contents:
- Nerves: Acessory (CN XI), Vagus (CN X), Hypoglossal (CN XII), Ansa cervicalis (C1-C3), Larygeal nn. (CN X branches)
- Arteries: common, internal & external carotid aa., 6 branches of ext. carotid a. (3 ant. & 3 post.)
- Veins: all branches have accompanying vv. Draining into IJV
Carotid Sheath
Contents:
- Carotid artery- common carotid artery, internal carotid artery (carotid sinus)
- Internal jugular vein
- Vagus nerve (CN X)
3 Anterior External Carotid Artery Branches
Superior thyroid a.
Lingul a.
Facial a.
3 Posterior External Carotid Artery Branches
Ascending pharyngeal a.
Occipital a.
Posterior auricular a.
External carotid a. terminates as:
Superficial temporal a. and maxillary a.
Ansa Cervacalis
Nerve loop formed from anterior rami of cervical n. C1-C3
-Innervates infrahyoid mm.
-Superior root- mainly of C1 fibers from anterior rami
-Inferior root- anterior rami of C2 & C3
Neurovasculature
- Superior thyroid artery runs with external larygeal nerve
- Superior larygeal artery runs with internal larygeal nerve
Both external and interal laryngeal nn. are branches of the superior laryngeal n. (branch of vagus n. CN X) - Superior thyroid artery gives rise to the superior larygeal a.
Root of the Neck
Junction between thorax and neck
Includes phrenic n., right vagus n., left vagus n., right recurrent laryngeal n., left recurrent laryngeal n.
Roots of Neck Vascular
Vertebral artery is deep and sizable
- Thyrocervical trunk gives rise to suprascapular a., transverse cervical a., and
- Second portion: costocervical trunk
- Transverse cervical bifurcates into superficial and deep
Vertebral Vessels
Vertebral v. - drains into brahiocephalic v.
Vertebral a. post. to vertebral a. & deep in the neck
-Arises from subclavian a. prior to thyrocervical trunk
-Enters transverse foramen of C6
Root of the Neck Lymphatics
Right lymphatic duct
Thoracic duct
Prevertebral mm.
Lie directly posterior to retropharyngeal space
- Longus colli & capitis mm.
- Rectus capitis anterior m.
- Anterior scalene m.
Cervical Viscera
From anterior to posterior:
1. Thyroid & parathyroid glands
2. Larynx & trachea (inferior)
3. Pharynx & esophagus
Thyroid ima artery is present in about 10% of thyroid glands
Pyramidal lobe is present in about 50% of thyroid glands
Horizontal Zones of the Neck
Zone I= thoracic inlet to cricoid cartilage (treated as upper thoracic injury)
Zone II= cricoid cartilage to angle of mandible
Zone III= angle of mandible to base of skull (approach as head trauma)
