Root Of Neck Anatomy PDF

Root of Neck *The root of the neck is the junctional area between the thorax and neck. *It is located on the cervical side of the superior thoracic aperture, through which pass all structures going from the thorax to the head or upper limb and vice versa. SUPERIOR THORACIC APERTURE ***is formed late...

Root of Neck *The root of the neck is the junctional area between the thorax and neck. *It is located on the cervical side of the superior thoracic aperture, through which pass all structures going from the thorax to the head or upper limb and vice versa. SUPERIOR THORACIC APERTURE ***is formed laterally by -the 1st pair of ribs and their costal cartilages, anteriorly by the -manubrium of the sternum, posteriorly by the -T1 vertebra. ARTERIES IN ROOT OF NECK 1. The brachiocephalic trunk is covered anteriorly by the right sternohyoid and sternothyroid muscles. It is the largest branch of the arch of the aorta It divides into right common carotid and right subclavian arteries posterior to the sternoclavicular (SC) joint. The subclavian arteries supply the upper limbs; they also send branches to the neck and brain. The right subclavian artery arises from the brachiocephalic trunk. The left subclavian artery arises from the arch of the aorta, about 1 cm distal to the left common carotid artery. SUBCLAVIAN ARTERY Three parts of each subclavian artery are described relative to the anterior scalene muscle: 1. the first part is medial to the muscle 2. the second part is posterior to it 3. the third part is lateral to it The branches of the subclavian arteries Vertebral artery, internal thoracic artery, and thyrocervical trunk Costocervical trunk second part Dorsal scapular artery third part of the subclavian artery. First part As the subclavian arteries cross the outer margin of the first ribs, their name changes; they become the axillary arteries. The first part: *Vertebral artery *Internal thoracic artery *Thyrocervical trunk 1.The cervical part of the vertebral artery arises from the first part of the subclavian artery and ascends in the pyramidal space formed between the scalene and longus muscles (colli and capitis). The artery passes deeply to course through the foramina transversaria of vertebrae C1– C6. 2.The suboccipital part of the vertebral artery courses in a groove on the posterior arch of the atlas before it enters the cranial cavity through the foramen magnum. 3.The cranial part of the vertebral artery supplies branches to the medulla and spinal cord, parts of the cerebellum, and the dura of the posterior cranial fossa. Internal thoracic artery ***runs inferomedially and enters the thoracic cage deep into the clavicle and the first rib. ***Internal mammary artery breast and thorax supplies Terminating at the level of the sixth rib, it divides into two terminal branches: 1.superior epigastric artery 2.musculophrenic artery The left mammary artery can be used for coronary bypass grafting! INTERNAL THORACIC ARTERY Superior epigastric artery  Blood supply for the anterior abdominal wall. Musculophrenic artery  It courses from the 6th to the last intercostal space, on the anterior aspect of the thoracic cage.  blood supply to the muscles of the thoracic wall, pericardium and anterior abdominal wall important alternate blood supply if the aorta becomes occluded! Thyrocervical trunk 1. Inferior thyroid artery 2. Suprascapular artery 3. Transverse cervical artery Inferior thyroid artery  The inferior thyroid artery is considered the principal blood supplier of the thyroid gland.  The ITA gives rise to the *ascending cervical artery *inferior laryngeal artery *pharyngeal, tracheal, and esophageal branches. Also, the ITA supplies the four parathyroid glands. The anatomical importance of the ITA is that it courses medially and posteriorly to the carotid sheath. Inferior thyroid artery *Ascending cervical artery (60%) arises from the thyrocervical trunk (30%) arises from the subclavian artery Suprascapular artery *It passes over the superior transverse scapular ligament, unlike the suprascapular nerve. Transverse cervical artery *** splits into two branches, a superficial one and a deep one (dorsal scapular artery) Dorsal scapular artery  Levator scapulae  Rhomboideus major,minor Costocervical trunk  superior(supreme) intercostal and deep cervical arteries Superior(supreme) intercostal arteries provide blood flow to the first and second posterior intercostal arteries Deep cervical artery  supply for the last cervical and first thoracic vertebrae, posterior neck muscles and a segment of the spinal cord VEINS IN THE ROOT OF NECK  Two large veins terminating in the root of the neck are the External jugular vein, draining blood received mostly from the scalp and face, and the variable anterior jugular vein (AJV), usually the smallest of the jugular veins  The anterior jugular vein descends either in the subcutaneous tissue or deep to the investing layer of deep cervical fascia between the anterior median line and the anterior border of the SCM.  Superior to the manubrium, the right and left AJVs commonly unite across the midline to form the jugular venous arch in the suprasternal space  The subclavian vein, the continuation of the axillary vein, begins at the lateral border of the 1st rib and ends when it unites with the IJV  The IJV ends posterior to the medial end of the clavicle by uniting with the subclavian vein to form the brachiocephalic vein. This union is commonly referred to as the venous angle and is the site where the thoracic duct (left side) and the right lymphatic trunk (right side) drain lymph collected throughout the body into the venous circulation Nerves in the root of neck 1) vagus nerves 2) phrenic nerves 3) sympathetic trunks VAGUS NERVE  After its exit from the jugular foramen, each vagus nerve passes inferiorly in the neck within the posterior part of the carotid sheath in the angle between the IJV and common carotid artery The right vagus nerve passes anterior to the first part of the subclavian artery and posterior to the brachiocephalic vein and SC joint to enter the thorax The left vagus nerve descends between the left common carotid and left subclavian arteries and posterior to the SC joint to enter the thorax *The recurrent laryngeal nerves arise from the vagus nerves in the inferior part of the neck. The nerves of the two sides have essentially the same distribution; however, they loop around different structures and at different levels on the two sides. *The right recurrent laryngeal nerve loops inferior to the right subclavian artery at approximately the T1–T2 vertebral level. *The left recurrent laryngeal nerve loops inferior to the arch of the aorta at approximately the T4–T5 vertebral level. *After looping, the recurrent laryngeal nerves ascend superiorly to the posteromedial aspect of the thyroid gland, where they ascend in the tracheo-esophageal groove, supplying both trachea and esophagus and all the intrinsic muscles of the larynx except the cricothyroid m. PHRENIC NERVES *mainly from the C4 nerve with contributions from C3 and C5. *The phrenic nerves descend anterior to the anterior scalene muscles under cover of the IJVs and the SCMs. *They pass under the prevertebral layer of deep cervical fascia, between the subclavian arteries and veins, and proceed to the thorax to supply the diaphragm *Sensory and motor innervation for the diaphragm Sympathetic Trunks *The cervical portion of the sympathetic trunks lie anterolateral to the vertebral column, extending superiorly to the level of the C1 vertebra or cranial base. *The cervical portion of the trunks includes three cervical sympathetic ganglia: superior, middle, and inferior *In approximately 80% of people, the inferior cervical ganglion fuses with the first thoracic ganglion to form the large cervicothoracic ganglion (stellate ganglion). This star-shaped (L. stella, a star) ganglion lies anterior to the transverse process of the C7 vertebra, just superior to the neck of the 1st rib on each side and posterior to the origin of the vertebral artery