Musculoskeletal System Anatomy of the Neck HSC1008 PDF

Musculoskeletal System Anatomy of the Neck HSC1008 Dr Karthik Harve & Dr Frank Voon  Thyroid gland Internal carotid artery Trachea Common carotid artery Esopha...

Musculoskeletal System Anatomy of the Neck HSC1008 Dr Karthik Harve & Dr Frank Voon  Thyroid gland Internal carotid artery Trachea Common carotid artery Esophagus Internal jugular vein Carotid sheath Vagus nerve The thyroid gland develops from the tongue (foramen cecum) Tongue Foramen cecum The thyroid and four parathyroid glands are endocrine glands in the neck. The four parathyroid glands adhere to the posterior surface of the thyroid gland. The thyroid parathyroid gland is located in the neck, anterior to the trachea, and posterior to the infrahyoid muscles. Its right and left lobes are on either side of the cricoid cartilage. The isthmus connects both lobes, in front of the 1st and 2nd tracheal rings of cartilage. The thyroid gland is related posteromedially to the larynx, trachea, pharynx, oesophagus and recurrent laryngeal nerves. The thyroid gland is related posterolaterally to the carotid sheath. The carotid sheath encloses the common carotid artery, internal jugular vein and vagus nerve. The recurrent laryngeal nerves travel up the neck in the tracheo-esophageal groove, and behind the thyroid gland to innervate the larynx. The thyroid gland is supplied by the superior and inferior thyroid arteries. The superior thyroid arteries are branches of the external carotid arteries. The inferior thyroid arteries arise from the subclavian arteries. The four thyroid arteries anastomose with each other in the thyroid gland. Venous drainage of the thyroid gland is by the superior, middle and inferior thyroid veins. The middle and superior thyroid veins drain into the internal jugular vein. The inferior thyroid veins drain into the left brachiocephalic vein. The right inferior thyroid vein may also drain into the right brachiocephalic vein.  External jugular vein Subclavian vein During respiration (inspiration and expiration), air reaches the alveoli by flowing through the nasal and oral cavities, nasopharynx, oropharynx and laryngopharynx, past the epiglottis and into the larynx and trachea.  nasopharynx adenoid tonsils The posterior one-third of the tongue, lingual palatine tonsils tonsils and palatine tonsils are in the lingual tonsils oropharynx The adenoid tonsils oropharynx posterior one-third of the tongue are in the nasopharynx. The vagus and glossopharyngeal nerves supply the muscles of the pharynx. The hypoglossal nerve supplies the muscles of the tongue. The accessory nerve supplies trapezius and sternocleidomastoid. The lingual nerve supplies general sensation (like touch, pain and temperature) and special sensation (taste) to the anterior two-thirds of the tongue The following muscles elevate the hyoid bone except mylohyoid hyoglossus digastric sternohyoid  Cervical plexus The cervical plexus is a network (plexus) of the anterior rami of the first four cervical spinal nerves (C1-C4) that provides sensory and motor innervation. This slide shows motor fibers to some muscles in the neck. Infrahyoid muscles C1 - C4 Cervical plexus C5 - T1 Brachial plexus L1 - L5 Lumbar plexus S1 - S5 Sacral plexus Scalenus anterior and scalenus medius insert onto the first rib. Scalenus posterior inserts onto the second rib. The scalenes elevate the first and second ribs, laterally flex the neck, and act as accessory muscles of respiration. They do not act on the head nor rotate the head nor depress the clavicle