Mechanical humeral axis
Mechanical humeral axis
- Acronym: mHA
Definition
The mechanical humeral axis is a landmark used to assess angular deformations of the humerus and provide information for their correction.
In the frontal plane, the mechanical humeral axis is determined from a craniocaudal radiograph or a multiplanar reconstruction of the humerus.
In the frontal plane, the mechanical humeral axis is the line joining :
- the center of the head of humerus, determined by the center of the oval that best defines it
- the middle of the distal humeral joint orientation line.
In the sagittal plane, the mechanical humeral axis is determined from a mediolateral radiograph or multiplanar reconstruction of the humerus. The circles that best highlight the medial and lateral parts of the condyle of humerus should be concentric and not intersect.
The mechanical humeral axis in the sagittal plane is the line joining :
- the center of the head of humerus, determined by the center of the oval that best defines it
- The center of the circle that best defines the condyle of humerus.
References
Wood et al. (2014). Determination of the Mechanical Axis and Joint Orientation Lines in the Canine Humerus: A Radiographic Cadaveric Study. Veterinary Surgery, 43(4), 414–417. doi:10.1111/j.1532-950x.2014.12134.x
Fox J, Tomlinson JL. Principles of Angular Limb Deformity Correction. In: Tobias KM, Johnston SA, editors. Veterinary Surgery Small Animal. St Louis (MI): Elsevier Saunders; 2012. p.657-668.
