Human Anatomy - Neck PDF

PART II NECK OLSZTYN 2019 16 Lab. session 2 1. Arteries of the neck 1.1. Common carotid artery 1.2. External carotid artery 1.3. Internal carotid artery 1.4. Subclavian artery 6. Veins of the neck 2.1. Internal jugular vein 2.2. External jugular vein 2.3. Anterior jugular vein 7. Lymphatic drainage...

PART II NECK OLSZTYN 2019 16 Lab. session 2 1. Arteries of the neck 1.1. Common carotid artery 1.2. External carotid artery 1.3. Internal carotid artery 1.4. Subclavian artery 6. Veins of the neck 2.1. Internal jugular vein 2.2. External jugular vein 2.3. Anterior jugular vein 7. Lymphatic drainage of the neck 3.1. Groups of the superficial nodes 3.2. Groups of the deep nodes 8. Nerves of the neck 4.1. Ventral branches of upper cervical spinal nerves 4.2. Dorsal branches of upper cervical spinal nerves 4.3. Cranial nerves 4.4. The autonomic nervous system of the neck NECK 17 1. Arteries of the neck Arteries of the neck consists of the four following arteries (Fig. 2-1): 1.1. Common carotid artery Common Carotid Artery - CCA (arteria carotis communis) is a main artery of the neck. Origin of the vessel: The left side - arises from the aortic arch The right side - arises from the brachiocephalic trunk (the first branch of the aortic arch) End of the vessel: It ends at the bifurcation of the common carotid artery, where the carotid sinus or carotid bulb (sinus caroticus) is located. It is sensitive to the pressure changes in the blood (baroreceptor). The carotid body (glomus caroticum) is a neurovascular structure located on the posterior wall of the bifurcation of the common carotid artery. It is sensitive to chemical changes in the blood (chemoreceptor). Both structures above are innervated by the CN IX nerve. Relations: anterolaterally: infrahyoid and sternocleidomastoid muscles posteriorly: prevertebral fascia and muscles medially: trachea, oesophagus, larynx, and pharynx. Branches: The common carotid artery has no branches. In the carotid triangle, the CCA is divided into two branches: external carotid artery ( ECA ) and internal carotid artery ( ICA ). ECA and ICA are separated by: styloglossus stylopharyngeus CN IX pharyngeal branches of CN X. NECK 18 1.2. External carotid artery External Carotid Artery - ECA (arteria carotis externa) is a anteromedial branch of the common carotid artery. Origin of the vessel: Bifurcation of the common carotid artery. End of the vessel: It divides into two terminal branches. Relations: At the level of the upper border of thyroid cartilage, the ECA passes through the parotid gland and terminates behind the neck of the mandible by dividing into the maxillary and superficial temporal arteries. In the carotid triangle: Under the investing layer of the deep cervical fascia Medially to ICA, hypoglossal nerve, cervical ansa (ansa cervicalis) and internal jugular vein laterally to the pharynx deep to the posterior belly of the digastric muscle. Within parotid gland: Lateral to ICA Medial to the CN VII and retromandibular vein. NECK 19 Fig.6-5. Localisation of the arteries, veins, and main nerves of the neck Branches: The external carotid artery gives off eight branches that can be categorised into two groups: a. From the anterior aspect Superior thyroid artery (arteria thyroidea superior) descends with the external laryngeal nerve, under the superior belly of the omohyoid muscle, from the carotid triangle to the muscular triangle to the upper pole of the thyroid gland. NECK 20 Branches: Superior laryngeal artery with the superior laryngeal nerve (branch of CN X ) pierces the thyrohyoid membrane to supply the larynx and proceeds to give off small branches that supply the pharynx. cricothyroid artery - supplies the middle part of the larynx. branches for the thyroid gland branches for the infrahyoid muscles. Lingual artery Relations: * above the superior thyroid artery at the level of the hyoid bone * it forms a distinct loop which is related to the hypoglossal nerve (its crossed superficially) * passes beneath the hypoglossal muscle to enter the tongue. Branches: dorsal branches for the tongue and the tonsil of the soft palate sublingual artery for sublingual gland and floor of the mouth deep lingual artery for the body and the tip of the tongue suprahyoid artery Facial artery Relations on the neck: * It arises just above the lingual artery and arches over the submandibular gland. * It turns around the inferior border of the mandible and takes a course across the face to the medial angle of the eye. * It is located deep to the stylohyoid and posterior belly of the digastric muscles. * It comes into contact with the submandibular gland and weaves in and out beneath the inferior border of the mandible before crossing on to the face 4 cm in the front of the mandibular angle. Branches on the neck: ascending palatine artery tonsillar artery submental artery to the suprahyoid muscles NECK 21 b. From the posterior aspect Ascending pharyngeal artery It is the smallest branch of the ECA. Relations: * Emerges between the ECA and the ICA and then ascends on the lateral wall of the pharynx to the base of the skull. Branches: pharyngeal to the pharynx and the palate meningeal to the dura mater inferior tympanic to the middle ear Occipital artery Relations: * It arises at the same level as the facial artery. * It runs backwards across carotid sheath where the CN XII hooks around it. Branches: branches for muscles (neck and suboccipital) mastoid branch auricular branch occipital branch. Posterior auricular artery Relations: * It passes along the upper border of the posterior belly of the digastric. * It passes through the apical part of the parotid gland to the lateral aspect of the scalp. Branches: auricular branch posterior tympanic artery - to the middle ear branches to the muscles stylomastoid artery occipital branch c. The terminal branches of the ECA: superficial temporal artery NECK 22 maxillary artery are described in relation to the face (see lab. 5) 1.3. Internal carotid artery Internal Carotid Artery (arteria carotis interna) - ICA is the posterolateral branch of the common carotid artery. Relations on the neck: * In the carotid triangle - lateral to the ECA. * Laterally, the artery is crossed by the stylohyoid, posterior belly of the digastric and the XII nerve. * It leaves the neck passing through the carotid canal. Within the neck, the ICA has no branches. PATHWAY: Common Carotid ------> Internal Carotid ------> Into the Foramen Lacerum ------> medially to Carotid canal ------> then Anteriorly through Cavernous Sinus ------> Then superiorly again 1.4. Internal carotid artery Internal Carotid Artery (arteria carotis interna) ICA supplies the greater part of the brain and the contents of the orbit. Origin It arises from the bifurcation of the common carotid artery (CCA) at the level of the upper border of the thyroid cartilage (CV 6). End It terminates intracranially in the middle cranial fossa, medially to the anterior clinoid process of the sphenoid bone. NECK 23 Course of the ICA The vessel ascends to the base of the skull being first located posterolaterally to the external carotid artery then medially to that artery. ICA leaves the neck by passing through the carotid canal of the petrosus part of the temporal bone. It passes upward and then forward by the cavernous sinus piercing the roof of the sinus and then turning backwards onto itself before dividing into the anterior and middle cerebral arteries. Relations within the neck It lies within the carotid sheath with: internal jugular vein - laterally vagus nerve - behind. In the carotid triangle ICA lies: laterally and posteriorly to the ECA posteriorly and medially to the sternocleidomastoid muscle anteriorly to the prevertebral fascia and the sympathetic trunk. ICA is crossed laterally by: the stylohyoid muscle the posterior belly of the digastric muscle hypoglossal nerve. In the parapharyngeal space, the ICA lies posteriorly and medially to the ECA and separated from it by: the stylopharyngeus muscle the styloglossus muscle glossopharyngeal nerve pharyngeal branches of the vagus nerve. 1.5. Subclavian artery Subclavian artery (arteria subclavia) is unique in that it has different relations on both sides of the body. Origin: The right side arises from the brachiocephalic artery The left side arises from the arch of the aorta NECK 24 Relations: The right artery: * Medially to the scalenus anterior * It lies behind the jugular vein * Laterally to the oesophagus and trachea * The right recurrent laryngeal nerve and the ansa subclavia hook around it. the left artery: * behind the left common carotid artery, the left vagus, and left phrenic nerves * laterally to the oesophagus, trachea, and left recurrent laryngeal nerve * the thoracic duct and phrenic nerve cross anterior to it, the left recurrent laryngeal nerve does not hook around it. Branches: vertebral artery (arteria vertebralis) supplies the brain and spinal cord internal thoracic artery (arteria thoracica interna) supplies the thorax thyrocervical trunk (truncus thyrocervicalis) Branches: inferior thyroid artery (arteria thyroidea inferior) branch for thyroid gland (ramus thyroideus) ascending cervical artery (arteria cervicalis ascendens) inferior laryngeal artery (arteria laryngea inferior) transverse cervical artery (arteria transversa colli) suprascapular artery (arteria suprascapularis) costocervical trunk (truncus costocervicalis) Branches: deep cervical artery (arteria cervicalis profunda) highest intercostal artery (arteria intercostalis suprema) NECK 25 2. Veins of the neck The neck encloses three main veins. 2.1. Internal jugular vein Internal jugular vein (vena jugularis externa) is the main vein of the neck. Arises as the continuation of the sigmoid venous sinus, ascends through the neck and behind the medial end of clavicle, where it is joined by the subclavian vein to form the brachiocephalic vein. Tributaries: sigmoid sinus (sinus sigmoideus) occipital sinus (sinus occipitalis) inferior petrosal sinus (sinus petrosus inferior) occipital vein (vena occipitalis) facial vein (vena facialis) pharyngeal plexus (plexus pharyngeus) lingual vein (vena lingualis) superior and inferior thyroid veins (vena thyroidea superior et inferior) thoracic duct (ductus thoracicus) on the left side right lymphatic duct (ductus lymphaticus dexter) on the right side. 2.2. External jugular vein External jugular vein (vena jugularis externa ) is a superficial vein formed behind the angle of the mandible by the union of the posterior branch of the retromandibular vein and the posterior auricular vein. It may enter either the internal jugular, brachiocephalic, or subclavian veins. Tributaries: posterior auricular vein (vena auricularis posterior) occipital vein (vena occipitalis) suprascapular vein (vena suprascapular) transverse cervical vein (vena transversa colli) NECK 26 2.3. Anterior jugular vein Anterior jugular vein (vena jugularis anterior) begins below the hyoid bone to enter the external jugular or subclavian veins. The jugular arch unites the two anterior jugular veins. There are two veins which are branches of brachiocephalic veins: the vertebral vein and the deep cervical vein. Internal jugular and subclavian veins catheterisations are procedures which allow to use central venous line for clinical needs like checking central venous pressure or parenteral nutrition 3. Lymphatic drainage of the neck Lymphatic drainage of the neck comprises the two following groups: 3.1. Groups of the superficial nodes a. Superficial cervical lymph nodes (nodi lymphatici cervicales superficiales) receive vessels from around the lower part of the ear, the floor of the external acoustic meatus, and the region of the angle of mandible. They are located in the lateral cervical triangle and along CN XI. Superficial cervical nodes get lymph from occipital nodes. Efferent lymphatic vessels go to the deep cervical nodes and mainly to supraclavicular nodes. b. submandibular lymph nodes (nodi lymphatici submandibulares) receive vessels from the oral cavity - efferent vessels go to the deep cervical nodes. c. submental lymph nodes (nodi lymphatici submentales) receive lymph from the anterior part of mandible, the lower lip, and the tip of tongue. Efferent lymphatic vessels pass to the deep cervical nodes or to the submandibular nodes. d. infrahyoid lymph nodes (nodi lymphatici infrahyoid) e. pretracheal lymph nodes (nodi lymphatici pretracheales) f. paratracheal lymph nodes (nodi lymphatici paratracheales) g. retropharyngeal lymph nodes (nodi lymphatici retropharyngei) NECK 27 All efferent vessels from (d) to (g) drain into the deep cervical nodes (nodi lymphatici cervicales profundi). 3.2. Groups of the deep nodes The deep cervical chain lies along the carotid sheath, deep to the sternocleidomastoid muscle. From the deep cervical nodes, lymph is collected into the jugular trunk. The left jugular trunk drains into the thoracic duct and the right jugular trunk drains into the right lymphatic duct. NECK