Humerus Lateral (Upright) is a radiography positioning projection of the Upper Extremity. Upright, arm internally rotated, epicondyles perpendicular to the IR. SID 40". The centering point is located at the midpoint of the humerus in the lateral position. Shoulder against the IR. The central ray is perpendicular to IR. Image-quality criteria include entire humerus visible in true lateral position, greater tubercle superimposed over the humeral head. A sample technique is 75 kVp with DR 2.8 or CR 5.6 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Humeral head, neck, and shaft in lateral projection.
- Greater tubercle superimposed over the humeral head.
- Lesser tubercle in profile medially.
- Shoulder joint, slightly distorted by beam divergence.
- Distal humerus with the epicondyles superimposed.
- Proximal radius and ulna.
Patient preparation
- CONTRAINDICATED if a fracture or dislocation is suspected: do not rotate the arm. Bontrager points to the horizontal beam lateral for the mid-to-distal humerus and the transthoracic lateral for the proximal humerus. Merrill's also shows an upright mediolateral, with the patient facing the IR, for a broken humerus.
- Verify patient identity using two identifiers.
- Remove watches, bracelets, and radiopaque items from the arm.
- Position patient upright with the entire humerus against the IR.
- Partially flex the elbow and internally rotate the arm until the epicondyles are perpendicular to the IR.
- Keep the shoulder against the IR for support.
- Suspend respiration during the exposure.
Position & centering point
At the midpoint of the humerus in the lateral position. Shoulder against the IR.
Central ray
Perpendicular to IR.
Exposure / technique
- kVp
- 75
- mAs
- DR 2.8 / CR 5.6
- SID
- 40" (102 cm)
- Notes
- Merrill's prefers upright, standing or seated, whenever possible; Bontrager lists erect or supine. Bontrager lists a grid unless the humerus is under 10 cm thick, with 70 ± 5 kV analog and 80 ± 5 kV digital. Sample technique: DR 2.8 / CR 5.6 mAs at 75 kVp, 40 in SID, for a 12 cm part, from the Bucky/grid row of Merrill's chart. Adjust for your equipment.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- Entire humerus visible in true lateral position.
- Greater tubercle superimposed over the humeral head.
- Lesser tubercle in profile medially.
- Elbow and shoulder joints visible, slightly distorted by beam divergence.
- Distal humerus and elbow included.
- Collimation: to the soft tissue borders with the shoulder and elbow joints included (Bontrager); 2 inches above the shoulder and below the elbow, 1 inch on the sides (Merrill's).
Common errors
- 1 Insufficient internal rotation leaves the humerus off true lateral.
- 2 Epicondyles not superimposed: the humerus is not in a true lateral.
- 3 Shoulder or elbow joint cut off: set the IR so both are equidistant from its ends.
Clinical indications
- Non-traumatic humeral pathology in the lateral plane.