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Hypopharynx, Larynx, and Infrahyoid Neck

Hypopharynx, Larynx, and Infrahyoid Neck Axial 1 Diagnostic Consideration Axial 1 on the next page shows both a T2-weighted sequence (upper image) and a T1-weighted image (lower). Note that cerebrospinal fluid (CSF) around the spinal cord is bright on T2-weighted magnetic resonance imaging and dark gray on T1-weighted MRI. Usually the brightest structure on T1-weighted imaging is fat. Note that the fat is somewhat bright on…

Oral Cavity, Pharynx, and Suprahyoid Neck

Oral Cavity, Pharynx, and Suprahyoid Neck Axial 1 Normal Anatomy Note the enhancement of the mucosal surfaces of the aerodigestive tract on the lower magnetic resonance (MR) image in Axial 1 after gadolinium contrast administration. The subcutaneous adipose tissue and the adipose planes between the structures in the neck are visible on both the upper pre-contrast T1-weighted MR image and the lower post-contrast T1-weighted MR image.…

Temporal Bone (Middle Ear, Cochlea, Vestibular System)

Temporal Bone Axial 1 Normal Anatomy The temporal bone initially may seem a daunting area for magnetic resonance imaging because of the apparent structural complexity. To understand the temporal region better, trace the hearing pathway from auricle through external auditory canal, to tympanic membrane attached to small bones (ossicles; malleus, incus, and stapes) in the middle ear cavity, through stapes stirrup on oval window, then vestibule…

Mandible and Muscles of Mastication

Mandible and Muscles of Mastication Axial 1 Normal Anatomy Four paired muscles—temporalis, masseter, medial pterygoid, and lateral pterygoid—are the primary muscles of mastication, responsible for adduction and lateral motion. In the axial MR image on the next page, note the temporalis muscle superficial to the temporal lobe of the brain. These muscles are innervated by the mandibular branch (V 3 ) of the trigeminal nerve, cranial…

Orbits

Orbits Axial 1 Orbits Axial 1 Orbits Axial 2 Orbits Axial 2 Orbits Axial 3 Normal Anatomy The lenses are normally biconvex in shape. If this configuration is replaced by a thin line, the patient likely has had the lens removed because of cataracts and replaced with an artificial lens. Orbits Axial 3 Orbits Axial 4 Orbits Axial 4 Orbits Axial 5 You’re Reading a Preview…

Paranasal Sinuses

Paranasal Sinuses Axial 1 Normal Anatomy The paranasal sinuses are composed of the frontal sinuses, the ethmoid sinuses or ethmoid air cells, the maxillary sinuses or maxillary antra, and the sphenoid sinuses. The names are derived from the bones that form the walls of the sinuses. Paranasal Sinuses Axial 1 Paranasal Sinuses Axial 2 Normal Anatomy The sphenoid sinuses are at the center of the skull…

Sella turcica

Sella Turcica Coronal 1 Technical Note The upper MR image is a coronal T1-weighted pre-contrast sequence and the lower is a coronal T1-weighted post-contrast sequence. Sella Turcica Coronal 1 Sella Turcica Coronal 2 You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

Ventricles and Cerebrospinal Fluid Cisterns

Ventricles and CSF Cisterns Axial 1 Normal Anatomy The ventricular system is located deep within the brain and is filled with cerebrospinal fluid (CSF). The normal appearance of CSF on magnetic resonance images is that of water. This axial MR image shows the choroid plexus within the ventricles, where CSF is produced. CSF is also seen outside the brain and within the sulci (subarachnoid space). Pathologic…

Brainstem and Cranial Nerves

Cranial Nerve I Axial 1 Normal Anatomy The olfactory nerve, or cranial nerve (CN) I, is the first of 12 cranial nerves and provides innervation for the sense of smell. CN I can often be seen on axial magnetic resonance imaging of the brain at the level of the temporal lobes. Nerve fibers from the olfactory mucosa in the anterosuperior nasal cavity join with the olfactory…

Limbic System

Limbic System Axial 1 Limbic System Axial 1 Limbic System Axial 2 Normal Anatomy Note how the fornix (Latin, “arch” or “vault”) is more easily seen as a paired structure on the T2-weighted axial magnetic resonance image (upper radiology image), compared with the fornix as seen in the Chapter 3 images focusing on the basal ganglia and thalami. The fornix is a C -shaped bundle of…

Thalamus and Basal Ganglia

Thalamus and Basal Ganglia Axial 1 Normal Anatomy The centrum semiovale, corona radiata, and internal capsules are all continuous white matter tracts. The centrum semiovale is the white matter deep to the gray matter on the surface of the brain and has an ovular shape. On axial imaging, it is generally a term used for white matter superior to the ventricles. The corona radiata (Latin: “sunburst”)…

Brain

Brain Axial 1 Normal Anatomy Named after the French anatomist Paulin Trolard (1842–1910) and also known as the superior anastomotic vein, the vein of Trolard is the largest cortical vein at the convexity (see also Brain Coronal 15 ). The vein of Trolard anastomoses with the middle cerebral vein and the superior sagittal sinus. Note the first cranial nerves, the olfactory nerves, in the olfactory grooves…

Head and Neck

1 Introduction The head and neck area offers a unique challenge for students because of the density of small neurovascular structures; the complexity of its bony features, especially the skull; and the compactness of its anatomy. The head protects the brain, participates in communication and expresses our emotions, and houses the special senses (sight, sound, balance, smell, and taste). The neck connects the head to the…

Upper Limb

1 Introduction The upper limb is part of the appendicular skel­eton and includes the shoulder, arm, forearm, and hand. It is continuous with the lower neck and is suspended from the trunk at the shoulder. It is anatomically and clinically convenient and beneficial to divide the limb into its functional muscle compartments and to review the nerve(s) and vessels supplying these compartments. Thus, for each component…

Lower Limb

1 Introduction As with the upper limb in Chapter 7 , this chapter approaches our study of the lower limb by organizing its anatomical structures into functional compartments. Although the upper limb is organized into two functional compartments (extensor and flexor compartments), the thigh and leg each are organized into three functional compartments, with their respective muscles and neurovascular bundles. The lower limb subserves the following…

Pelvis and Perineum

1 Introduction The bowl-shaped pelvic cavity is continuous superiorly with the abdomen and bounded inferiorly by the perineum, the region between the proximal thighs. The bones of the pelvic girdle demarcate the following two regions: Greater or false pelvis: the lower portion of the abdomen that lies between the flared iliac crests. Lesser or true pelvis: demarcated by the pelvic brim, sacrum, and coccyx, and contains…

Abdomen

1 Introduction The abdomen is the region between the thorax superiorly and the pelvis inferiorly. The abdomen is composed of the following: Layers of skeletal muscle that line the abdominal walls and assist in respiration and, by increasing intraabdominal pressure, facilitate micturition (urination), defecation (bowel movement), and childbirth. The abdominal cavity is a peritoneal lined cavity that is continuous with the pelvic cavity inferiorly and contains…

Thorax

1 Introduction The thorax lies between the neck and abdomen, encasing the great vessels, heart, and lungs, and provides a conduit for structures passing between the head and neck superiorly and the abdomen, pelvis, and lower limbs inferiorly. Functionally, the thorax and its encased visceral structures are involved in the following: Protection: the thoracic cage and its muscles protect the vital structures in the thorax. Support:…