DEPARTMENT OF RADIOLOGY Head and Neck Anatomy Gerald R. Aben, MD, FACR Associate Professor Radiology College of Osteopathic Medicine In the section we'll be spending sometime evaluating imaging objectives related to the head and neck anatomy 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY The frontal skull x-ray provide us the opportunity of evaluating a number of bony and air-containing structures. Note the bony structures of the bones of the skull including the frontal bone superimposed upon parietal bone and occipital bone. Note the zygomatic bone as indicated on the patient's right side. Note air-containing structures including the frontal sinuses, the ethmoid sinuses and the maxillary sinuses. The superior orbital fissure is well defined on the left side as is lesser wing of the sphenoid. The crista gala noted as a vertical structure centrally. The nasal bone has a vertical structure just below the crista galla. Also note the optic foramina seen both on the left and right side with a marker on the left side. We can identify the nasal turbinates, the maxilla, the teeth and the mandible on this individual as well. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY The Townes view is optimized for evaluation of the occipital bone. on the Townes view, we identify the sagittal suture the Petrous bones, internal auditory canals, lamboid suture. The foramen magnum is the oval structure in the midline and seen many times through the foramen magnum the dens of C2. We also identify the mandibular condyles and portions of the zygoma, seen just lateral to the mandibular condyles on this view. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY Lateral skull evaluation allows evaluation of the structures that are not clearly seen on the frontal study. We can again identify the lamboid suture, but also identify the coronal suture on this projection. The external auditory meatus is noted as an area of decreased density or lucency superimposing the Petrous bones. Mastoid air cells are noted just posterior to the external auditory meatus. We are also able to identify the external occipital protuberance. The posterior margin of the foramen magnum can be evaluated in many individuals. We can identify the mandibular condyle and its relationship to its articular surfaces. We also identify portions of the mandible, maxilla and teeth. Air-containing spaces including the sphenoid and maxillary sinuses are noted in the void representing the orbits and portions of the orbital walls also are identified on this examination. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY The Waters evaluation is optimized for evaluation of the maxillary sinuses. The maxillary sinuses and the floor the orbit are well defined on this exam. We also identify the zygomatic arch, the superior margins of the orbit and frontal sinus and the maxillary sinuses. Other structures clearly defined include the dens of the odontoid and the atlantal axial joints as indicated on the labeled images. Also note superposition of the mandible on the lower portion of the image 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY The skull base view is somewhat different than the Waters view. this view is optimized for evaluation of foramen at the base of the middle cranial fossa. In a well-positioned base view you should be able to identify foramen rotundum as well as foramen ovale. Other structures that can be demonstrated include the mandible, the mastoid air cells, the mastoid process, the foramen magnum, the dens of C2, maxillary sinuses and the orbits. Note the high density material superimposing the teeth representing dental restorations. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY Evaluation of facial structure requires specialized imaging focused on the anterior portion of the skull. In this case we are able to identify the frontal sinus as well as the maxillary and sphenoid sinuses. Note the intimate relationship of the sphenoid sinus to the sella turcica, indicated by white lines. Also note clear definition of the angle of the mandible, the mandibular condyle, the body of the mandible and the teeth. The mastoid air cells are seen posterior to the Petrous ridge. We also note the anterior maxillary spine in relationship to the anterior portions of the maxilla. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY A detailed frontal image of the facial bones more clearly defines the nasal septum as well as the maxillary sinuses and frontal sinus. Ethmoid air cells are also noted paralleling the nasal septum. Also noted on this particular examination are portions of the body of the mandible. The mandibular condyles are not well seen although they are present. We also note the dens of the odontoid sitting just above the incisors of the maxilla on this particular projection. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY As previously reviewed when evaluating back and thorax the relationship of C1 to the base of the skull is clearly defined on the spot images. We are able to identify the atlantoaxial joint as well as the joint between the base of skull and C1. Intervertebral foramina unco-vertebral joints and facet joints also noted as in the neck and thorax sections. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY MRI of the head and neck allows exquisite evaluation of soft tissue detail. On these images through the orbits we are able to identify the various ocular muscles including the superior and lateral recti and superior oblique and medial rectus. Other structures including the optic nerve are demonstrated. The lacrimal gland can be seen on the lower right image just beneath the words. We also identify the nasal cavity as outlined by the bracket on the lower image. Maxillary sinus is represented by an area of low signal representing air within the maxillary sinus. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY Additional imaging with a slightly different technique on this examination demonstrates the muscles as low signal. Also noted on this examination, the ethmoid air cells, the superior and inferior conchae of the nasal turbinates as well as the ocular muscles. Can you identify the ocular muscles on this exam as described on the earlier study? 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY Axial imaging through the orbits demonstrate the relationship of the ethmoid air cells to the lateral margins of the orbits. Again demonstrated structures including muscles as well as the optic nerve. Optic nerve noted as the low signal structure extending posterior from the globes. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY MR angiography and CT angiography allow evaluation of the vascular supply to the neck and the head with limited invasion. Here on a MR angiogram we're able to identify the common carotid and vertebral arteries, the internal and external carotid arteries as well as the origins of the great vessels from the arch of the aorta 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY By doing slight rotation or slight tilting of the neck we are able to look at different structures and get more detailed evaluation of these vessels. Depending upon presentation we are able to identify each vessel separately and provide good anatomic delineation. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY A somewhat wider field as presented in this image allows us to demonstrate the origin of the innominate or brachiocephalic artery, the left carotid artery and left subclavian from the arch of the aorta. The origins of the right and left vertebral arteries as well as the course of the carotid arteries can be defined and seen more clearly on this particular set of images. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY I have included on this presentation a standard angiogram with contrast injected into the common carotid artery. In this case we are able to identify areas of significant narrowing by atherosclerotic or arterioclerotic plaque in the region of the common carotid artery, in the region of the carotid bulb as well as at the origins of both the internal and external carotid arteries. Note that various portions of these vessels can be followed and a portion of the intracranial circulation is also included on this evaluation. 11/19/2018 DEPARTMENT OF RADIOLOGY

DEPARTMENT OF RADIOLOGY Finally intracranial venous structures including all the sinuses superior sagittal, sigmoid, straight, transverse and the confluence can be clearly seen on this noncontrast evaluation. Various branching structures venous structures can also be correlated evaluated using both MRI as in this presentation as well as by CT techniques. 11/19/2018 DEPARTMENT OF RADIOLOGY