ANTERIOR TRIANGLE OF THE NECK II Dr. Ahmed Fathalla Ibrahim

CAROTID TRIANGLE BOUNDARIES: FLOOR: Superiorly: posterior belly of digastric Inferiorly: superior belly of omohyoid Posteriorly: sternomastoid FLOOR: Anteriorly: hyoglossus & thyrohoid muscles Posteriorly: middle & inferior constrictors of pharynx C

CAROTID TRIANGLE

CAROTID TRIANGLE

CAROTID TRIANGLE

CONTENTS OF CAROTID TRIANGLE CAROTID SHEATH: A condensation of deep fascia that contains: Common & internal carotid arteries: (medially) Internal jugular vein: (laterally) Vagus nerve: between & a little posterior to arteries & vein

CONTENTS OF CAROTID TRIANGLE ARTERIES: Termination of common carotid: at level of disc between C3 & C4 (level of upper border of thyroid cartilage) Proximal part of external carotid Proximal part of internal carotid Five branches of external carotid: superior thyroid, ascending pharyngeal, lingual, facial & occipital

CONTENTS OF CAROTID TRIANGLE VEINS: Internal jugular vein Five tributaries to internal jugular veins: common facial, lingual, superior thyroid, middle thyroid, pharyngeal veins

CONTENTS OF CAROTID TRIANGLE FIVE NERVES: TWO NERVES RELATED TO CAROTID SHEATH: Ansa cervicalis (anterior rami of C1,2,3): embedded in the anterior wall of sheath Sympathetic trunk: embedded in the posterior wall of sheath

CONTENTS OF CAROTID TRIANGLE THREE NERVES BETWEEN INTERNAL JUGULAR VEIN & INTERNAL CAROTID ARTERY: Vagus (10th cranial) nerve: descends between internal jugular vein & common carotid artery Spinal part of accessory (11th cranial) nerve: crosses internal jugular vein, passes deep to sternomastoid to reach posterior triangle Hypoglossal (12th cranial) nerve: crosses internal & external carotid arteries, passes deep to posterior belly of digastric to reach digastric triangle

CONTENTS OF CAROTID TRIANGLE DEEP CERVICAL LYMPH NODES: embedded in the anterior wall of sheath, along the internal jugular vein

MUSCULAR TRIANGLE BOUNDARIES: Anteriorly: midline of neck Superiorly: superior belly of omohyoid Inferiorly: sternomastoid M

MUSCULAR TRIANGLE CONTENTS: THE INFRAHYOID MUSCLES Superficial layer: Sternohyoid: medially Omohyoid: laterally Deep layer: Thyrohyoid: above Sternothyroid: below

MUSCULAR TRIANGLE

MUSCULAR TRIANGLE

MUSCULAR TRIANGLE FLOOR: PRETRACHEAL FASCIA STRUCTURES IN THE INFRAHYOID PART OF MEDIAN REGION OF FRONT OF NECK: Thyrohyoid membrane Thyroid cartilage Cricothyroid ligament & muscle Cricoid cartilage Cricotracheal ligament Trachea Structures in front of trachea: jugular arch, inferior thyroid vein, isthmus of thyroid gland

INFRAHYOID MUSCLES (SUPERFICIAL LAYER) Sternohyoid: Origin: back of manubrium sterni Insertion: hyoid bone Action: depression of hyoid bone Omohyoid: Superior belly: hyoid bone Inferior belly: upper border of scapula Insertion: intermediate tendon (deep to sternomastoid) attached to clavicle

INFRAHYOID MUSCLES (DEEP LAYER) Thyrohyoid: Origin: oblique line of thryroid cartilage Insertion: hyoid bone Action: depression of hyoid bone, elevation of larynx Sternothyroid: Origin: back of manubrium sterni Insertion: oblique line of thryroid cartilage Action: depression of larynx

INFRAHYOID MUSCLES NERVE SUPPLY: All muscles are supplied by ansa cervicalis (anterior rami of C1,2,3) EXCEPT: thyrohyoid (by anterior ramus of C1)