GROSS ANATOMY Lecture Syllabus 2008 Unit #3: Head and Neck ANAT 6010 - Gross Anatomy Department of Neurobiology and Anatomy University of Utah School of Medicine David A. Morton, Ph.D. 1 Unit #3- Neck and Head G15- Neck Overview G16-17A: Triangles of the Neck Posterior Triangle Anterior Triangle Visceral Triangle G17B- Brain and Base of the Skull G18- Cranial Nerves and Autonomics- A Systemic Overview G19- Orbit G20A- Superfi cial Face and Infratemporal Fossa G20B- Pterygopalatine Fossa, Nasal Cavity, and Paranasal Sinuses G21A- Oral Cavity, Tongue and Teeth G21B- Pharynx G22- Larynx G23- Ear 2 G15: Neck Overview At the end of this lecture, students should be able to master the following: 1)Fascia a) Describe the location and anatomical structures associated with the following fascial layers (1) Superfi cial cervical fascia- same as subcutaneous layer of skin; contains the platysma m. Platysma m.: innervated by the cervical branch of CN VII (2) Deep cervical fascia Investing fascia- envelopes sternocleidomastoid and trapezius muscles; occipital bone, mastoid process, zygomatic arch inferiorly to the scapular spine, acromion, clavicle and manubrium Pretracheal fascia-the muscular portion encloses the infrahyoid muscles, while the visceral portion sur- rounds the thyroid gland, larynx, trachea, pharynx and esophagus Prevertebral fascia- surrounds the cervical vertebral column, and envelopes deep neck muscles including prevertebral, scalenes, and deep back muscles Carotid sheath- formed by the investing, pretracheal and prevertebral fascial layers; surrounds internal jugular vein, common carotid artery, and vagus nerve b) Describe the location of the retropharyngeal space and its relation to the deep cervical fascial layers 3 4 2) Cervical Plexus Draw and label the cervical plexus including all spinal levels (C1-4): Sensory nerve branches Lesser occipital (C2) Great auricular (C2-C3) Transverse cervical (C2-C3) Supraclavicular (C3-C4) Motor nerve branches Ansa cervicalis (C1 superior root) (C2-C3 inferior root) Nerve to geniohyoid and thyrohyoid mm. (C1) Nerve to superior belly of omohyoid m. (C1) Nerve to sternothyroid and sternohyoid mm. (C1-C3) Nerve to inferior belly of omohyoid m. (C2-C3) Phrenic (C3-C5) 5 6 3) Vessels of the Head and Neck a) Common Carotid Artery i) Internal carotid artery- courses through neck in carotid sheath without any branching, then travels through the carotid canal to enter to skull Carotid sinus - baroreceptor; CN IX visceral sensory Carotid body - chemoreceptor; CN IX and X visceral sensory; located at bifurcation ii) External carotid artery Describe the origin, course, and destination of the following branches of the external carotid artery: Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superfi cial temporal b) The IJV and EJV are the primary venous channels for the head and neck i) Internal jugular vein- located in carotid sheath Anterior jugular vein ii) External jugular vein - formed posterior to the angle of the mandible as the posterior auricular vein and retromandibular vein Retromandibular vein is formed by the superfi cial temporal and maxillary veins Anterior division - joins the facial vein to form the common facial vein, which joins the IJV Posterior division - joins the posterior auricular vein to form the external jugular vein 7 8 4) Muscles of the Neck Superfi cial Neck Muscles - Platysma m. - Trapezius m. - Sternocleidomastoic m. Unilateral: Tilts the head to the same side; rotates the head to the opposite side Bilateral: Extends the head; assists in respiration when the head is fi xed Innervated by CN XI Ventral Strap Muscles Suprahyoid muscles - Digastric, geniohyoid, mylohyoid, stylohyoid Infrahyoid muscles - Sternohyoid, sternothyroid, thyrohyoid, omohyoid Prevertebral Muscles: stretch between the cervical spine and skull acting on both Longus captis m. Longus colli m. Lateral, Deep Neck Muscles Scalenes: lateral, deep neck muscles; attach between the cervical spine and upper two ribs and assist in res- piration. the anterior and middle scalene are separated by the interscalene space; a topgraphicallly important interval traversed by the brachial plexus and subclavian artery Posterior scalene Middle scalene Axillary sheath Brachial plexus Subclavian artery - courses posterior to the anterior scalene m. Anterior scalene Subclavian vein - courses across the anterior scalene m. 9 10