ANA 301 Neck Flashcards
Describe the neck
●The neck is a tube providing continuity from the head to the trunk.
●It extends anteriorly from the lower border of the mandible to the upper surface of the manubrium of sternum.
●Posteriorly from the superior nuchal line on the occipital bone of the skull to the intervertebral disc between the CVII and TI vertebrae.
Describe visceral compartment of the neck
the visceral compartment is anterior and contains parts of the digestive and respiratory systems, and several endocrine glands;
Describe vertebral compartment of the neck
the vertebral compartment is posterior and contains the cervical vertebrae, spinal cord, cervical nerves, and muscles associated with the vertebral column;
Describe vascular compartments of the neck
●the two vascular compartments are lateral and contain the major blood vessels and the vagus nerve [X].
Outline of anterior triangle
The anterior triangle of the neck is outlined by the anterior border of the sternocleidomastoid muscle laterally, the inferior border of the mandible superiorly, and the midline of the neck medially.
Submandibular triangle of the anterior triangle
the submandibular triangle is outlined by the inferior border of the mandible superiorly and the anterior and posterior bellies of the digastric muscle inferiorly;
submental triangle of the anterior triangle
the submental triangle; outlined by the hyoid bone inferiorly, the anterior belly of the digastric muscle laterally, and the midline;
muscular triangle of the anterior triangle
•the muscular triangle is outlined by the hyoid bone superiorly, the superior belly of the omohyoid muscle, and the anterior border of the sternocleidomastoid muscle laterally, and the midline;
carotid triangle of the anterior triangle
the carotid triangle is outlined by the superior belly of the omohyoid muscle anteroinferiorly, the stylohyoid muscle and posterior belly of the digastric superiorly, and the anterior border of the sternocleidomastoid muscle posteriorly.
The four suprahyoid muscles are in the
submental and submandibular triangles.
Passage and general function of suprahyoid muscles
They pass in a superior direction from the hyoid bone to the skull or mandible and raise the hyoid, as occurs during swallowing.
Stylohyoid: innervation and function
Stylohyoid; innervated by the facial nerve [VII], it pulls the hyoid bone posterosuperiorly during swallowing.
Digastric: description and innervation
Digastric; has 2 bellies (anterior and posterior) connected by a tendon which attaches to the body of the hyoid bone. Innervation of the digastric muscle is from two different cranial nerves.
Anterior belly is by trigeminal nerve (CN V)
•Posterior belly is by facial nerve (CN VII)
Mylohyoid: innervation and function
Mylohyoid; It is innervated by the trigeminal nerve [CN V]. It supports and elevates the floor of the mouth and elevates the hyoid bone.
Geniohyoid: innervation and function
Geniohyoid; is innervated by a branch from the anterior ramus of C1 carried along the hypoglossal nerve [XII].
•It has two functions depending on which bone is fixed:
●fixation of the mandible elevates and pulls the hyoid bone forward;
●fixation of the hyoid bone pulls the mandible downward and inward.
Infrahyoid muscles are also known as
Strap muscles
The four infrahyoid muscles are where?
muscular triangle.
General function of the infrahyoid muscles
They attach the hyoid bone to inferior structures and depress the hyoid bone.
●They also provide a stable point of attachment for the suprahyoid muscles.
Sternohyoid: innervation and function
Sternohyoid; is innervated by the anterior rami of C1 to C3 through the ansa cervicalis.
●It depresses the hyoid bone
Omohyoid: innervation and function
Omohyoid; Lateral to the sternohyoid muscle, This muscle consists of two bellies with an intermediate tendon in both the posterior and anterior triangles of the neck.
●It is innervated by the anterior rami of C1 to C3 through the ansa cervicalis.
●The omohyoid depresses and fixes the hyoid bone
Thyrohyoid: innervation and function
Thyrohyoid; is located deep to the superior parts of the omohyoid muscle. It is innervated by fibers from the anterior ramus of C1 that travel with the hypoglossal nerve [XII].
Sternothyroid: innervation and function
•Sternothyroid; the last of the infrahyoid group of muscles. is innervated by the anterior rami of C1 to C3 through the ansa cervicalis.
●The sternohyoid muscle draws the larynx (thyroid cartilage) downward
Vessels in the anterior triangle
●Passing through the anterior triangle of the neck are the common carotid arteries and their branches, the external and internal carotid arteries.
●These vessels supply all structures of the head and neck.
What are at beginning of the carotid system?
The common carotid arteries are the beginning of the carotid system
•the right common carotid artery originates from
the brachiocephalic trunk;
the left common carotid artery begins in
the thorax as a direct branch of the arch of the aorta.
Course of the CCA’s
They both ascend through the neck, lateral to the tracheal and oesophagus not giving any branch in the neck.
•Near the superior edge of the thyroid cartilage each common carotid artery divides into its two terminal branches-the external and internal carotid arteries
Carotid sinus
At the bifurcation, the common carotid artery and the beginning of the internal carotid artery are dilated.
•This dilation is the carotid sinus and contains receptors that monitor changes in blood pressure and are innervated by a branch of the glossopharyngeal nerve [IX].
Carotid sinus
Another accumulation of receptors in the area of the bifurcation is responsible for detecting changes in blood chemistry, primarily oxygen content.
•This is the carotid body and is innervated by branches from both the glossopharyngeal [IX] and vagus [X] nerves.
Describe the course of the internal carotid artery
After its origin, the internal carotid artery ascends toward the base of the skull.
•It gives off no branches in the neck and enters the cranial cavity through the carotid canal in the petrous part of the temporal bone.
The internal carotid arteries supply
the cerebral hemispheres, the eyes and the contents of the orbits, and the forehead
branches of the external carotid artery
superior thyroid
ascending pharyngeal
lingual
facial
occipital
posterior auricular
superficial temporal
maxillary arteries.
Superior thyroid artery supplies
Thyrohyoid muscle, internal structures of the larynx, sternocleidomastoid and cricothyroid muscles, thyroid gland
Ascending pharyngeal artery supplies
Pharyngeal constrictors and stylopharyngeus muscle, palate, tonsil, pharyngotympanic tube, meninges in posterior cranial fossa
Lingual artery supplies
Muscles of the tongue, palatine tonsil, soft palate, epiglottis, floor of mouth, sublingual gland
Facial artery supplies
All structures in the face from the inferior border of the mandible anterior to the masseter muscle to the medial corner of the eye, the soft palate, palatine tonsil, pharyngotympanic tube, submandibular gland
Occipital artery supplies
Sternocleidomastoid muscle, meninges in posterior cranial fossa, mastoid cells, deep muscles of the back, posterior scalp
Posterior auricular artery supplies
Parotid gland and nearby muscles, external ear and scalp posterior to ear, middle and inner ear structures
Superficial temporal artery supplies
Parotid gland and duct, masseter muscle, lateral face, anterior part of external ear, temporalis muscle, parietal and temporal fossae
Maxillary artery supplies
External acoustic meatus, lateral and medial surface of tympanic membrane, temporomandibular joint, dura mater on lateral wall of skull and inner table of cranial bones, trigeminal ganglion and dura in vicinity, mylohyoid muscle, mandibular teeth, skin on chin, temporalis muscle, outer table of bones of skull in temporal fossa, structures in infratemporal fossa, maxillary sinus, upper teeth and gingivae, infra-orbital skin, palate, roof of pharynx, nasal cavity
Describe the venous system drainage of the neck
Collecting blood from the skull, brain, superficial face, and parts of the neck, the internal jugular vein begins as a dilated continuation of the sigmoid sinus, which is a dural venous sinus.
The paired internal jugular veins join with the subclavian veins posterior to the sternal end of the clavicle to form the right and left brachiocephalic veins.
Tributaries to each internal jugular vein include the inferior petrosal sinus, and the facial, lingual, pharyngeal, occipital, superior thyroid, and middle thyroid veins.
The cranial nerves of the neck
The cranial nerves in these categories include: the facial [VII], glossopharyngeal [IX], vagus [X], accessory [XI], and hypoglossal [XII].
The peripheral nerves of the neck
The peripheral nerves in these categories include the transverse cervical nerve from the cervical plexus and the upper and lower roots of the ansa cervicalis.
Facial nerve [VII]
the posterior belly of the digastric;
stylohyoid.
Glossopharyngeal nerve [IX]
stylopharyngeus muscle, sends a branch to the carotid sinus, and supplies sensory branches to the pharynx.
Vagus nerve [X]
Gives a motor branch to the pharynx, a branch to the carotid body, the superior laryngeal nerve (which divides into external and internal laryngeal branches), and possibly a cardiac branch.
Accessory nerve [XI]
No branches in the anterior triangle but innervates the trapezius
Hypoglossal nerve [XII]
No branches in the anterior triangle but innervates the tongue
Transverse cervical nerve
provides cutaneous innervation to this area
Ansa cervicalis
innervates the inferior belly of the omohyoid, and the lower parts of the sternohyoid and sternothyroid muscles.
