Neck Ant/Post Triangles Anatomy PDF

Functional Human Anatomy Neck – Ant/Post Triangles D R. D O N AL M U R R AY PH D C O N T R IBU T IO N S BY: D R. E LLE N C O S T E LLO, PT, P H D Session Objectives Differentiate between the 4 layers Describe the of fascia in the neck. attachments/actions/innervation...

Functional Human Anatomy Neck – Ant/Post Triangles D R. D O N AL M U R R AY PH D C O N T R IBU T IO N S BY: D R. E LLE N C O S T E LLO, PT, P H D Session Objectives Differentiate between the 4 layers Describe the of fascia in the neck. attachments/actions/innervation of muscles identified in this Describe relationships of region structures in the neck (e.g.superficial/deep/ant Explain the structure and /post/med/lateral) functions of the Cervical Plexus ID the borders of the ant and post Identify the Ansa Cervicalis triangles of the neck. Describe and identify the Identify the structures in the branches off of the External ant/post triangles of the neck. Carotid A. platysma  Hyoid bone External jugular vein Cervical Fascia Investing Pretracheal Prevertebral Carotid Sheath  SCM Red: investing fascia Blue: pretracheal fascia Carotid Brown: carotid sheath sheath Orange: prevertebral fascia Scalene muscles Deep cervical ms. Investing Layer of Fascia Surrounds: Trapezius Sternocleidomastoid Acts as a roof to anterior triangle of neck Trapezius & SCM Pretracheal Fascia Strap muscles Surrounds:  thyroid gland trachea  infrahyoid (aka strap) muscles  trachea  esophagus (located deep to the trachea) Thyroid gland Prevertebral Fascia (aka Fascial Carpet/Floor) Surrounds:  Prevertebral muscles Prevertebral fascia Scalene  longus colli, longus capitus muscles  Scaleni Musculature  Anterior Scalene  Middle Scalene  Posterior Scalene  Levator scapulae  Phrenic nerve  Deep muscles of the back Forms the floor of the posterior triangle  Phrenic n. Upper trunk brachial plexus Carotid Sheath surrounds: Common carotid & int carotid artery Internal jugular vein Vagus nerve (CN X) Sometimes ansa cervicalis  At times ansa cervicalis may lie superficial to carotid sheath Strap muscles Anterior Triangle Borders Roof- investing fascia & platysma Superior- inferior border of the mandible Anterior- median line of the neck Posterior- anterior border of SCM Floor-prevertebral fascia Contents of Anterior Triangle Muscular triangle- infrahyoid muscles, thyroid & parathyroid glands Carotid triangle- common carotid a., internal jugular v., portions of last 3 cranial nerves Digastric triangle- submandibular gland, facial artery, internal carotid a., internal jugular v., CN IX, CN X Strap (infrahyoid) ms: Sternohyoid Sternothyroid Thyrohyoid Omohyoid Omohyoid m. Sternohyoid m Thyrohyoid m. Sternothyroid m. Posterior Triangle Borders Roof- fascia & platysma Anterior- posterior border of SCM Posterior- anterior border of trapezius muscle Inferior- superficial aspect middle 1/3 of clavicle Floor- prevertebral fascia Contents of Posterior Triangle Transverse cervical a. CN XI Upper trunk of brachial plexus Subclavian a. Dorsal scapular n. Long thoracic n. N. to subclavius Long thoracic n Suprascapular a. & n. Upper trunk brachial plexus Cervical Plexus Formed by branches of ventral rami C1-4 Supplies:  Nuchal (neck) muscles  diaphragm muscle  infrahyoid (strap) musculature  skin of head/neck/chest Superficial branches (sensory only):  lesser occipital n. - C2  great auricular n. - C2,3  transverse cervical n. - C2,3  supraclavicular n. - C3,4  c1 c2 c3 Ansa c4 cervicalis to strap muscles c5 Cervical Plexus Deep branches include:  Motor to prevertebral ms. (longus colli & longus capitus): ventral rami C1-4  Motor to levator scapula and ant, middle, post scaleni  Motor to infrahyoid muscles via ansa cervicalis – ventral rami C1-3  Motor & sensory to diaphragm via the phrenic n. - C3-5 ventral rami  Sensory to SCM & trapezius- ventral rami C2,3 (pain & proprioception) Phrenic nerve Ansa Cervicalis Portion of cervical plexus that supplies the infrahyoid muscles c1 (strap ms.) C1-3 ventral rami c2 Consists of two loops (aka roots) Innervates: sternohyoid, c3 sternothyroid, omohyoid, thyrohyoid c4 Innervation thyrohyoid: C1 ventral ramus however rides along with the c5 hypoglossal nerve c1 c2 c3 c4 c5 Infrahyoid Muscles (aka strap muscles) Anchor hyoid bone to sternum, clavicle & scapula Action-depress hyoid bone & floor of mouth; elevate or depress larynx Innervated by ansa cervicalis {thyrohyoid specifically C1 via CN XII} Sternocleidomastoid Muscle Sternal head: manubrium, & Clavicular head: upper medial 1/3 clavicle To lateral surface mastoid process & lateral 1/2 superior nuchal line AXN: bilateral  flex head against resistance  neck flexion Sternocleidomastoid cont AXN: bilateral  extension at the A-O ` joint (posterior fibers only)  accessory muscle of respiration AXN: unilateral  ipsilateral sidebend with contralateral rotation of the face Innervation: CN XI (motor); C3 & C4 ventral rami (sensory) Scaleni Musculature Anterior, middle, posterior Proximally: from  anterior tubercles of transverse processes CV 3-CV6 (anterior scalene)  posterior tubercles of transverse processes CV5- CV7(middle/posterior scalenes) To 1st rib (ant/middle) and 2nd rib (post) AXN  Ipsilateral sidebending of cervical vertebra  Reverse action: elevate first and second rib during inspiration Innervation: cervical ventral rami (C3-C8) Levator Scapulae Proximally: posterior tubercles transverse processes of CV1-4 Distally: to medial border of scapula at & above the spine AXN- elevates scapula; downward rotation of scapula with pec minor ms. Innervation: C3-4 ventral rami; C5 ventral rami from dorsal scapular n.  Posterior scalene m. Middle Scalene m. Anterior scalene m Suprahyoid muscles Digastric ms.  Anterior and posterior bellies  depress mandible; elevates hyoid during swallowing  Innervation (CN V/anterior belly, CN VII/posterior belly) Stylohyoid ms. (superior to post belly digastric)  draws hyoid posteriorly & elevates it (CN VII/seven) Mylohyoid ms.  elevates hyoid and floor of mouth (CN V3 = mandibular br. of trigeminal n.)  Suprahyoid Muscles continued Geniohyoid ms. depress mandible; elevates hyoid superiorly Innervation: (C1 via CN XII) Submandibular gland CN XII & CN X  Lesser occiptal n. CN XII & CN X Superior root of Ansa cervicalis CN XII & CN X Inferior root of Ansa cervicalis Sternohyoid Sternothyroid Trapezius External Carotid Artery Branches Superior thyroid a. Ascending pharyngeal a. Lingual a. Facial a. Occipital a. Posterior auricular a. Superficial temporal a. Maxillary (gives rise to meningeal a.) Take note of the major branches off of the external carotid a: Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Superficial temporal Maxillary. Ext carotid a  Hyoid bone External jugular vein Let’s REcaP CAN YOU? CAN YOU? Differentiate between the 4 Describe the layers of fascia in the neck. attachments/actions/innervation of muscles identified in this region Describe relationships of structures in the neck (e.g. Explain the structure and superficial/deep/ant/post/me functions of the Cervical Plexus d/lateral) Identify the Ansa Cervicalis State the borders of the ant and post triangle of the Describe and identify the neck. branches off of the External Carotid A. Identify the structures in the ant/post triangles of the neck