Humerus Lateral (Recumbent) is a radiography positioning projection of the Upper Extremity. Supine, arm internally rotated, back of the hand against the side. SID 40". The centering point is located at the midpoint of the humerus in the lateral position, epicondyles perpendicular to the IR. The central ray is perpendicular to IR, vertical with the tube above the supine patient. 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.
- Verify patient identity using two identifiers.
- Remove watches, bracelets, and radiopaque items from the arm.
- Position patient supine on the table.
- Internally rotate the arm and rest the back of the hand against the side.
- Adjust the rotation until the epicondyles are perpendicular to the IR; the elbow may be partially flexed.
- Suspend respiration during the exposure.
Position & centering point
At the midpoint of the humerus in the lateral position, epicondyles perpendicular to the IR.
Central ray
Perpendicular to IR, vertical with the tube above the supine patient.
Exposure / technique
- kVp
- 75
- mAs
- DR 2.8 / CR 5.6
- SID
- 40" (102 cm)
- Notes
- Vertical CR, tube above the supine patient. 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 proximal 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 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, such as osteoporosis, in a recumbent patient.
- Proximal humeral pathology assessment in recumbent patients.