Medial Longitudinal Arch
The primary arch of the foot, running along its inner border from the heel to the first metatarsal head, critical to shock absorption and propulsion.
Full Definition
The medial longitudinal arch (MLA) is the dominant architectural structure of the foot, supported by the plantar fascia, intrinsic musculature, and the spring ligament. In orthotic documentation, the MLA is central to descriptions of foot type (pes planus, pes cavus), orthotic design (arch fill, arch height), and correction strategy. Editors should distinguish 'medial longitudinal arch' from 'lateral longitudinal arch' and 'transverse arch,' which are separate anatomical structures. Abbreviation to 'MLA' is acceptable in technical reports after first-use expansion. Incorrect arch identification in clinical notes can lead to fabrication errors.
Usage
Usage note: Spell out in full on first use; 'MLA' is acceptable thereafter in technical documents. Do not use the lay term 'arch' alone in clinical documentation without specifying which arch.
In Context
- "The orthotic shell was designed with a 4 mm arch fill to support the collapsed medial longitudinal arch." — Orthotic fabrication record
- "Clarify whether 'arch support' in the prescription refers to the medial longitudinal arch or the transverse arch before proceeding." — Editorial query to clinician