RADT 1542 SKULL RADIOGRAPHY Wynn Harrison, Med, RT(R)(N)

What a Bad Day!!!!

Section 1: The Cranium New Words: HEMANGIOMA: tumor containing blood vessels and fibrous tissue TRAUMATIC PNEUMOCEPHALUS: injury causing gas/air in the extracranial cavity

HYDROCEPHALUS: increased cerebrospinal fluid in the ventricles PAGET’S DISEASE: overproduction of bone CRANIOTOMY: Incision into the head

SUBDURAL HEMATOMA: Blood collected beneath the dura TERATOMA: Congenital tumor containing 1+ embryonic germ layers (hair/teeth/skin may be present)

ENCEPHALITIS: Inflammation of the brain GLIOMA: Primary tumor of the brain MENINGIOMA: Slow growing benign tumor in the meninges

ACOUSTIC NEUROMA: Benign tumor involving hearing CRANIO-PHARYNGIOMA: Benign tumor above the sella turcica CONCUSSION: Impact injury

ANENCEPHALUS: Congenital absence of the brain ACEPHALUS: Absence of head MICROCEPHALIC: Small head BURR HOLES: Holes bore into skull for pressure relief

Why Dogs Bite Their Owners

POSITIONING CONCERNS Some people don’t like to have their face touched Wash your hands FIRST CLEAN BUCKY or TABLE (and have them watch you) Remember body habitus The body is attached to the head!!!!

Lines/Landmarks/Planes Median saggital Coronal

Composition Composed of 22 Bones Eight Cranial Bones Fourteen Facial Bones

Radiographic Landmarks Glabella: Triangular area between and slightly superior to the eyebrows and above the bridge of the nose Nasion: Depression at the bridge of the nose Junction of the two nasal bones and the frontal bone

Radiographic Landmarks Inner Canthus: Where the eyelids meet near the nose Outer Canthus: Lateral junction of the eyelids Acanthion: Midline point at the junction of the upper lip and the nasal septum. Point where the nose and the upper lip meet

Radiographic Landmarks Gonion: Angle of the mandible (Jaw) Mental Point: A triangular area projects forward as the chin (mentum). The center of the mentum is the mental point

Radiographic Landmarks EAR Auricle/Pinna: External portion of the ear. Large flap of ear made of cartilage TEA: Top of the ear attachment. Superior attachment of the auricle. Level of the petrous ridge on each side

Radiographic Lines Radiographic lines are important to skull positioning Certain lines are formed from anterior structures on the face and connect to the EAM EAM: External acoustic (auditory) meatus, Opening of the external ear canal

Radiographic Landmarks Eye Supraorbital Margin (SOML): Superior rim of the bony orbit of the eye Infraorbital Margin (IOML): Inferior rim of the bony orbit of the eye Midlateral Orbital Margin: (OML) Portion of the lateral rim near the outer canthus of the eye

Radiographic Lines Orbitomeatal Line (OML): Located between the outer canthus (midlateral orbital margin) and the EAM Infraorbitomeatal Line (IOML): Formed by connecting the middle of the infraorbital margin to the EAM

Radiographic Planes Interpupillary Line (IPL): A line connecting either the pupils or the outer canthi of the patient’s eyes The IPL must be exactly perpendicular to the IR in a TRUE LATERAL position

Talk about TOO MUCH RAIN~

Radiographic Landmark Inion or EOP: External occipital protuberance Rise or bump along the midline of the lower back of the head near the junction of the head and neck Extension of the IOML posteriorly approximates the location of the inion

Radiographic Landmark Vertex Top portion of the head

Sutures of the Skull Joints formed between the cranial bones are known as sutures Fibrous connective tissue hold bones tightly together Synarthrodial – Don’t permit movement

Sutures of the Skull Coronal Suture: Sagittal Suture: Lambdoidal Suture: Squamosal Suture:

Arthrology Temporomandibular Joint: Only movable joints in the cranium Formed by the mandibular fossa on each temporal bone with corresponding condyle of the mandible

Fontanels Soft spots Present at birth Unossified connective tissue Where three or more bones ajoin Six Fontanels Gradually replaced with bone Allow for skull compression during birth Most prominent are the anterior and posterior fontanels Located on the anterior and posterior ends of the sagittal suture

Fontanels Articulation between the frontal and both parietal bones at the anterior end of the sagittal suture is the bregma Articulation between the occipital bone and both parietal bones at the posterior end is the lambda Anterolateral (sphenoid) fontanel is the pterion Posterolateral fontanel is the asterion

Fontanels

Fontanels

Fontanels

Calvarium Skull Cap Composed of four bones Frontal bone Right Parietal bone Left Parietal bone Occipital bone

Calvarium

Calvarium

Cranial Floor Composed of four bones Ethmoid bone Sphenoid bone Right Temporal bone Left Temporal bone

Cranial Floor

Skull Morphology Mesocephalic: Average shaped head, the petrous ridges lie at a 47 degree angle with the MSP Brachycephalic: Short, broad, shallow head. Petrous ridges form a 54 degree angle with the MSP Dolichocephalic: Long, narrow, deep head. Petrous ridges form a 40 degree angle with the MSP

Occipital Bone

Occipital Bone

Sphenoid Bone Location and purpose Midline of cranial floor Anchor to hold the 8 cranial bones together Articulates with all cranial bones Forms the base of skull, small portion of each lateral wall, and posterior wall of each orbit

Sphenoid Bone Bat shaped Composition Body Central portion of the bone Paired lesser wings and greater wings Pterygoid processes Body Central portion of the bone Between the ethmoid and occipital bones Anterior surface forms posterior wall of nasal cavity Body is hollow and enclosed with air – filled sphenoid sinuses

Sphenoid Bone Body of sphenoid Sella Turcica Saddle – shaped depression Superior surface of the body Houses pituitary gland Sella turcica is localized for a radiographic exam by centering ¾ inches anterior and ¾ superior to the EAM on a lateral projection

Body of Sphenoid Dorsum Sellae: is the posterior portion of the sella turcica Posterior Clinoid Processes: Extend superiorly from the lateral margin of the dorsum sellae Optic Groove: Depression that runs horizontally across the body Optic Chiasm: Formed by crossing of the optic nerves, situated in the optic groove

Sphenoid Bone Lesser Wings of the Sphenoid Extends laterally and horizontally across the anterosuperior aspect of the body Junction at the midline is the sphenoid ridge Anterior clinoid processes extend from the posterior portion of each lesser wing

Sphenoid Bone Greater Wings of Sphenoid Posterior to the lesser wings Arise from the lateral surfaces of the body and extend outward Openings on each greater wing serve as passageways for the nerves and blood vessels supplying the orbits and face

Sphenoid Bone

Sphenoid Bone Pterygoid Processes Extensions of bone from under the sphenoid bone at the junction of the body and greater wings Articulates anteriorly with the palatine bone and vomer Comprised of two plates of bone fused together Medial plate is called the pterygoid hamulus because it has a small hook – like process

Sphenoid Bone

Sphenoid Bone

Sella Turcica Sphenoid Bone

Temporal Bones

Temporal Bones Named for the region around the temples Location Below the parietal bone Articulates with the greater wing of the sphenoid and the occipital bones Contains 4 Regions Squamous Tympanic Mastoid Petrous

Temporal Bones

Temporal Bones

Temporal Bones

Group Photo Anyone?

AP and PA projections Petrous pyramids fill the orbit if there is no angulation Petrous pyramid will lie in lower 1/3 of orbit with 15 degree angulation if AP is it caudal or cephalic?

ROUTINE PROCEDURES AP View OML and sagittal plane perpendicular to the cassette Petrous pyramids fill the orbits

AP Axial (Townes) OML = 30 degrees IOML = 37 degrees Posterior clinoids HAAS is reverse Townes view

PA Skull OML = perpendicular to cassette 0 degree angulation Petrous pyramids fill the orbits

PA Caldwell Patient PA with 12 – 15 degree caudal angulation of CR CR exits nasion Petrous pyramids in bottom 1/3 of orbit

Lateral Skull Interpupillary line perpendicular to cassette Midsagittal plane parallel to cassette (Look at patient body habitus)

Submentovertex (SMV) IOML parallel to cassette Midsagittal plane perpendicular to cassette

Positioning Errors Rotation occurs when the median Saggital plane is not parallel to the film.   

Tilt occurs when the interpupilary line is not at 90 to the film

Trauma and Pathology

Golf club

Paget’s Disease

Pituitary tumor

Film critique

Critical thinking