Dr Ahmed Fathalla Ibrahim CAROTID TRIANGLE BOUNDARIES Superiorly

Dr. Ahmed Fathalla Ibrahim

CAROTID TRIANGLE BOUNDARIES: • 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

CONTENTS OF CAROTID TRIANGLE CAROTID SHEATH: • A condensation of deep fascia that contains: 1. Common & internal carotid arteries: (medially) 2. Internal jugular vein: (laterally) 3. Vagus nerve: between & a little posterior to arteries & vein

CONTENTS OF CAROTID TRIANGLE • ARTERIES: 1. Termination of common carotid: at level of disc between C 3 & C 4 (level of upper border of thyroid cartilage) 2. Proximal part of external carotid 3. Proximal part of internal carotid 4. Five branches of external carotid: superior thyroid, ascending pharyngeal, lingual, facial & occipital

CONTENTS OF CAROTID TRIANGLE • VEINS: 1. Internal jugular vein 2. 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: 1. Ansa cervicalis (anterior rami of C 1, 2, 3): embedded in the anterior wall of sheath 2. Sympathetic trunk: embedded in the posterior wall of sheath

CONTENTS OF CAROTID TRIANGLE • THREE NERVES BETWEEN INTERNAL JUGULAR VEIN & INTERNAL CAROTID ARTERY: 1. Vagus (10 th cranial) nerve: descends between internal jugular vein & common carotid artery 2. Spinal part of accessory (11 th cranial) nerve: crosses internal jugular vein, passes deep to sternomastoid to reach posterior triangle 3. Hypoglossal (12 th 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: 1. Sternohyoid: medially 2. Omohyoid: laterally • Deep layer: 1. Thyrohyoid: above 2. Sternothyroid: below

MUSCULAR TRIANGLE

MUSCULAR TRIANGLE FLOOR: • • 1. 2. 3. 4. 5. 6. 7. 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 • Action: depression of hyoid bone

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 C 1, 2, 3) EXCEPT: thyrohyoid (by anterior ramus of C 1)