Head and Neck Anatomy Jake Pickering MS IV Suprahyoid Neck • Skull Base to Hyoid Bone (the different spaces) – Parapharyngeal Space – Pharyngeal Mucosal Space – Masticator Space – Parotid Space – Carotid Space – Retropharyngeal Space – Perivertebral Space – Posterior Cervical Space Suprahyoid Spaces Suprahyoid Spaces Suprahyoid Spaces Lateral Neck CT of Suprahyoid Spaces CT of Suprahyoid Spaces CT of Suprahyoid Spaces CT of Suprahyoid Spaces Parapharyngeal Space • Internal structures – Fat – Minor salivary glands – Internal maxillary artery – Ascending pharyngeal artery – Pterygoid venous plexus Parapharyngeal Space Parapharyngeal space Parapharyngeal Space Parapharyngeal Space • Clinical implications – Direct extension from neoplasm • From pharyngeal mucosal space (see neoplasm differential for pharyngeal mucosal space) • From masticator space (see neoplasm differential) • From parotid space (see neoplasm differential) – Direct extension from abscess • Tonsillar abscess • Acute Parotiditis – Primary lesion • Lipoma • Venolymphatic malformation Pharyngeal Mucosal Space • Internal structures – Minor salivary glands – Torus tubarius: Cartilaginous end of eustachian tube – Muscles • Superior, middle and inferior constrictor muscles • Salpingopharyngeus muscle • Levator palatini muscle – Lymphatic ring (Waldeyer ring) • Nasopharynx: Adenoids • Oropharynx: Palantine tonsil • Oropharynx: Lingual tonsil Pharyngeal Mucosal Space Torus tubarius Adenoids Pharyngeal mucosal space Lingual tonsil Pharyngeal muscoal space Palantine tonsil Axial T1 MR Nasopharyngeal mucosal space Oropharyngeal mucosal space Hypopharyngeal mucosal space Pharyngeal Mucosal Space • Clinical Implications – Differential diagnosis of lesion in Nasopharyngeal space • • • • • • • • • • Adenoid inflammation Tornwaldt cyst Retention cyst Nasopharyngeal carcinoma Non-Hodgkin lymphoma Benign mixed tumor (uncommon) Post-radiation mucositis (uncommon) Minor salivary gland malignancy (rare) Rhabdomyosarcoma (rare) Extraosseous chordoma (rare) Pharyngeal Mucosal Space • Clinical implications – Differential diagnosis of lesion in oropharynx space • • • • • • • • • • Squamous cell carcinoma Non-hodgkin lymphoma Retention cyst Palantine tonsil abscess Tonsillar inflammation Thryoglossal duct cyst (uncommon) Post-radiation mucositis (uncommon) Vallecular cyst (uncommon) Minor salivary gland malignancy (uncommon) Rhabdomyosarcoma (rare) Masticator Space • Internal contents – Muscles of Mastication • • • • Masseter Temporalis Medial pterygoid Lateral pterygoid – Mandibular division, trigeminal nerve (V3) • • • • Masticator nerve branch Mylohyoid nerve branch Lingual nerve Inferior alveolar nerve branch – Ramus and posterior body of mandible – Pterygoid venous plexus Masticator Space Masseter muscle Temporalis muscle Lateral pterygoid muscle Medial pterygoid muscle Masticator Space Axial T1 MR Masticator Space • Clinical Implications – Trismus – Differential diagnosis of masticator space lesion • • • • • • • • • • • • • Abscess Benign masticator muscle hypertrophy Metastasis Sarcoma Osteosarcoma Chondrosarcoma (uncommon) Perineural tumor CNV3 (uncommon) Schwannoma (uncommon) Odontogenic keratocyst (uncommon) Osteoradionecrosis (uncommon) Pigmented villonodular synovitis (rare) Synovial chondromatosis (rare) Dentigerous cyst (rare) Parotid Space • Internal structures – Parotid Gland – Facial Nerve (CN7) – External carotid artery – Retromandibular vein – Intraparotid lymph nodes – Parotid Duct – Accessory parotid glands (20% of population) Parotid space (green) Parotid Space External carotid artery Retromandibular vein Parotid gland Parotid space Axial T1 MR Parotid Space • Clinical Implications • • • • • Parotid Tumors benign mixed tumor (75%) Warthin tumor (5%) Adenoid cystic carcinoma (5%) Mucoepidermoid carcinoma (5%) Other (10%) – Other masses in parotid space • • • • • • • • • • Salivary gland malignancies (uncommon) Non-Hodgkin lymphoma (uncommon) Schwannoma (uncommon) Infantile hemangioma (uncommon) Lipoma (uncommon) Oncocytoma (rare) Venous malformation (rare) Lymphatic malformation (rare) 1st Branchial cleft cyst (rare) Rhabdomyosarcoma (rare) Carotid Space • Internal structures – Suprahyoid • • • • Internal carotid artery Internal jugular vein Cranial nerves 9-12 Sympathetic plexus Carotid Space Carotid Space External carotid artery (not in carotid space) Internal carotid artery Internal jugular vein Carotid space Carotid Space • Clinical implications – Differential diagnosis of carotid space lesion • • • • • • • • • • • • • Reactive lymph nodes Atherosclerosis of carotid artery Thrombosis of jugular vein Squamous cell carcinoma Dissection of carotid artery Paraganglioma of carotid body Schwannoma Neurofibroma (uncommon) Hodgkin and Non-Hodgkin lymphoma (uncommon) Meningioma (rare) Pseudoaneurysm of carotid artery (rare) Metastases (rare) Acute Idiopathic carotidynia (rare) – CN 9-12 neuropathy • Vagus Nerve injury- vocal cord paralysis Retropharyngeal Space • Internal Structures – Suprahyoid • Fat • Lymph nodes (none below hyoid) – Lateral group (nodes of Rouviere) – Medial group Retropharyngeal space Retropharyngeal space Retropharyngeal Space • Clinical Implications – Differential diagnosis of focal lesion • • • • • • • • • • Reactive adenopathy Suppurative adenopathy Squamous cell carcinoma Metastatic node Non-Hodgkin lymphoma Tortuous carotid artery Multinodular goiter (uncommon) Lipoma (uncommon) Schwannoma (rare) Ectopic parathryoid adenoma (rare) Retropharyngeal Space • Clinical Implications – Differential diagnosis of diffuse space lesion • • • • • • • Abscess Effusion Longus colli tendonitis (uncommon) Venous malformation (uncommon) Lymphatic malformation (uncommon) Multinodular goiter (uncommon) Lipoma (rare) Perivertebral Space • Internal structures – Prevertrebral muscles-longus colli and capitis – Scalene muscles – Phrenic nerve – Vertebral artery and vein – Vertebral body – Paraspinal muscles – Brachial plexus Perivertebral Space Perivertebral space Prevertebral portion of the perivertebral space Paraspinal portion of the perivertebral space Perivertebral Space Perivertebral Space • Clinical implications – Differential diagnosis of perivertebral space lesion • • • • • • • • • • • Vertebral body metastasis Infection Schwannoma of brachial plexus Longus colli tendinitis Chordoma (uncommon) Venous malformation (uncommon) Lipoma (uncommon) Non-Hodgkin lymphoma (uncommon) Lymphatic malformation (rare) Fibromatosis (rare) Hemangiopericytoma (rare Posterior Cervical Space • Internal structures – Fat is primary occupant – Accessory nerve (CNII) – Spinal accessory lymph node chain – Pre-axillary brachial plexus – Dorsal scapular nerve Posterior Cervical Space Posterior Cervical Space Posterior cervical space Posterior Cervical Space • Clinical implications – Differential diagnosis of cervical space lesion • • • • • • • • • • • • • • • • Reactive lymph nodes Squamous cell carcinoma Non-hodgkin lymphoma Suppurative lymph node Thyroid carcinoma Abscess (uncommon) Metastases (uncommon) Sarcoidosis (uncommon) Tuberculosis (uncommon) Lipoma (uncommon) Venous Malformation (uncommon) Schwannoma (rare) Liposarcoma (rare) Sinus histiocystois 3rd Branchial cleft cyst Giant lymph node hyperplasia References • Harnsberger HR, Osborn AG, Ross JS. Diagnostic and Surgical Imaging Anatomy: Brain, Head and Neck, Spine. 1st edition. Salt Lake City: Amirsys, 2006. • Harnsberger HR, Koch BL, Phillips CD. EXPERTddx: Head and Neck. 1st edition. Salt Lake City: Amirsys, 2009. • Neck CT. Retrieved Sept 11 2012. http://headneckbrainspine.com
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