WEEK 15 - C Spine

Flashcards for C-Spine Radiography Review

What does AML stand for and what landmarks define it?

Acanthiomeatal Line — from the acanthion (anterior nasal spine) to the external auditory meatus.

Why is the AML important in AP Axial C-spine positioning?

It ensures proper head tilt and avoids superimposition of the occiput over the cervical spine.

What’s a common error when positioning for the open-mouth (C1/C2) view?

Telling the patient to open their mouth wide — this often causes neck extension and occiput to superimpose the dens.

How should you instruct the patient for an open-mouth view to avoid extension?

Ask the patient to drop your jaw down rather than tilt the head back.

What is the CR angle for AP Axial Oblique C-spine projections?

20° cephalad.

What is the CR angle for PA Axial Oblique C-spine projections?

20° caudad.

Which IVF is demonstrated in an RPO C-spine position?

Left intervertebral foramina.

Which IVF is demonstrated in an LPO C-spine position?

Right intervertebral foramina.

Which IVF is demonstrated in an RAO C-spine position?

Right intervertebral foramina.

Which IVF is demonstrated in an LAO C-spine position?

Left intervertebral foramina.

Why is the patient’s head turned laterally in oblique C-spine views during lab?

To reduce superimposition of the mandible over the cervical spine.

What must you consider when planning the order of C-spine projections?

Changes in CR angle, patient positioning, and SID between projections.

What is the CR angle for an AP Axial C-spine in an erect position?

20° cephalad.

What is the CR angle for an AP Axial C-spine in a supine position?

15° cephalad.

What is the CP for the AP Axial C-Spine?

Midline at C4 — slightly inferior to the most prominent point of the thyroid cartilage.

Which vertebrae must be included in the AP Axial C-spine view?

Superior portion of C3 through T2.

What soft tissue margins must be included in the AP Axial C-spine?

From EAM (ear) to jugular notch, and both lateral soft tissue margins of the neck.

What anatomical indicator confirms correct chin extension?

Inferior mandible superimposed on the base of the skull.

What confirms correct beam to part (BTP) alignment in AP Axial C-spine?

Open intervertebral disc spaces.

What indicates no head rotation in an AP Axial C-spine view?

Mandibular angles are equidistant to the cervical spine.

What indicates no body rotation in AP Axial C-spine?

Spinous processes are midline in the vertebral bodies.

How should the chin be positioned for an AP Axial C-spine?

Chin should be extended so the AML (acanthiomeatal line) is perpendicular to the IR.

Why must the CR be parallel to the line between the mandible and base of the skull?

To be parallel with intervertebral joints, ensuring they appear open.

What is the CR for the AP C1-C2 open mouth projection?

Perpendicular.

What is the CP for the AP C1-C2 open mouth view?

Midpoint of the open mouth.

What size collimation is typically used for the Dens view?

Approximately 10x10 cm (tight collimation).

What anatomical structures must be included in the Dens projection?

From the base of the skull and upper incisors to C2, including the transverse processes of C1.

How do you know the chin is in the correct position for the Dens view?

The inferior margins of the upper teeth and base of the skull are superimposed.

What indicates no head rotation in the Dens view?

Lateral masses of C1 are equidistant from the dens, and mandibular rami are equidistant to the lateral masses.

If the space between the dens and lateral mass is wider on one side, what does this indicate?

The head is rotated toward that side.

How do you prevent the tongue from superimposing C1/C2?

Have the patient say “ahhh” during the exposure to depress the tongue.

What is the correct head position before asking the patient to open their mouth?

Align the lower edge of the upper incisors with the mastoid tip (AML perpendicular to IR).

Should the patient tilt or rotate the head for the Dens projection?

No – head should be in true AP: no tilt, no rotation.

What is the CR for a lateral C-spine?

Perpendicular.

What is the CP for a lateral C-spine projection?

Level of C4 on the coronal plane of the mastoid tip or EAM.

What structures must be included in a lateral C-spine image?

Clivus (top of ear attachment), C1–C7, top third of T1, and all soft tissues including the airway.

How do you ensure the clivus is included in the lateral C-spine image?

Extend the superior light field to include the top of the ear attachment.

What indicates proper head positioning on a lateral C-spine?

Chin elevated to prevent mandible superimposing the spine; AML parallel to the floor.

What radiographic signs confirm no tilt or rotation on a lateral C-spine?

Vertebral body margins superimposed, zygapophyseal joints superimposed, and intervertebral disc spaces open.

What is a reliable anatomical landmark for finding C7?

The prominent spinous process at the base of the neck.

Where should the marker be placed in a lateral C-spine image?

Wherever there is light spill on the bucky — usually posterior to the spine due to lordosis.

How should the patient’s shoulders be positioned?

Relaxed and in the same transverse plane, touching the bucky for stability.

What modification is made for trauma lateral C-spine?

Done supine with a horizontal beam (HB lateral).

What is the CR angle for a PA axial oblique C-spine projection (erect)?

20° caudad.

What is the CP for a PA axial oblique C-spine?

Midline at the level of C4.

What SID is used for PA axial oblique C-spine?

180 cm.

What patient positions are used for PA axial oblique C-spine?

RAO or LAO.

What anatomy is best demonstrated in a PA axial oblique C-spine projection?

Intervertebral foramina (IVF) and pedicles of the side closest to the IR.

What structures should be included in a PA axial oblique C-spine?

C1–C7, T1, and related soft tissue.

How should the patient’s body and head be positioned for obl C spine?

Rotated 45° toward the IR, with the head in the same plane as the body.

How do you position the chin for a PA axial oblique C-spine?

Slightly extended; AML parallel to the floor.

What signs indicate proper positioning on a PA axial oblique C-spine?

IVF of the side closest to the IR are open and clearly seen; no superimposition of mandible on spine.

Why is the bucky offset during PA axial oblique C-spine imaging?

To align with the angled central ray.

What is the CR angle for an AP axial oblique C-spine projection (erect)?

20° cephalad.

What is the CR angle for an AP axial oblique C-spine if the patient is supine?

15° cephalad (or 20° if the patient has severe lordosis).

What is the CP for an AP axial oblique C-spine?

Midline at the level of C4.

What patient positions are used for AP axial oblique C-spine?

RPO or LPO.

What anatomy is best demonstrated in an AP axial oblique C-spine projection?

Intervertebral foramina (IVF) and pedicles of the side farthest from the IR.

What structures should be included in an AP axial oblique C-spine?

C1–C7, T1, and related soft tissue.

How should the patient’s body and head be positioned?

Rotated 45° toward the IR, with the head in the same plane as the body.

How do you position the chin for an AP axial oblique C-spine?

Slightly extended; AML parallel to the floor.

What signs indicate proper positioning on an AP axial oblique C-spine?

Open IVF of the side raised, pedicle seen on the anterior vertebral body, and mandible not superimposed on C1–C3.

Why is the bucky offset during AP axial oblique C-spine imaging?

To align with the angled central ray.