First Ray

Original Editor - Matthew Chin

Top Contributors - Matthew Chin and Abbey Wright  

Introduction[edit | edit source]

The first ray is the segment of the foot composed of the first metatarsal and first cuneiform bones.[1] The location of this joint is important as it intersects the transverse and medial longitudinal arches.[2] This segment serves as a critical element in the structural integrity of the foot.[1]

Anatomy[edit | edit source]

The first metatarsal is the shortest, strongest, and most important weight-bearing point in the forefoot.[2] In standing, this bone carries 40% of body weight.[2]

The stability of the first metatarsal-cuneiform joint is supported by the tendinous attachments onto the first ray from the tibialis posterior, tibialis anterior, and peroneus longus muscles.[2] Additionally, the two sesamoid bones encased in the tendons beneath the head of the first metatarsal function to elevate the first ray.[1]

Function[edit | edit source]

The first ray serves numerous purposes, including[2]:

  • resisting ground reaction forces
  • maintaining medial longitudinal arch integrity during mid-stance supination
  • allowing first metatarsal head to plantarflex at heel lift
  • providing medial stability for propulsive phase.

Pathomechanics[edit | edit source]

Hypomobile First Ray[edit | edit source]

Hypomobility into dorsiflexion of the first ray may cause higher plantar pressure beneath the first ray, which may increase the risk of ulceration of the fat pad under the first metatarsal head in individuals with insensitivity associated with diabetes.[1]

Hypermobile First Ray[edit | edit source]

Hypermobility at the first ray causes a collapse of the structural framework of the medial longitudinal arch, decreasing the ability of the foot to become a rigid lever required for propulsion. Excessive mobility in the first ray has been implicated in foot pathologies such as hallux valgus, metatarsus varus, and plantar fasciitis.[2][3]

Clinical relevance[edit | edit source]

Assessing the first ray can be challenging and although has been shown to be associated with other conditions of the foot there is little standardisation of how to assess the first ray. [3][4]

The typical method of assessing the first ray would be: observation, palpation, stress testing and radiography. [3]

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 Glasoe WM, Yack HJ, Saltzman CL. Anatomy and biomechanics of the first ray. Physical therapy. 1999 Sep 1;79(9):854-9.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 D'Amico, J., Understanding the First Ray. Orthotics & Biomechanics. 2016, Sept. 109-120
  3. 3.0 3.1 3.2 Glasoe WM, Michaud TC. Measurement of dorsal first ray mobility: a topical historical review and commentary. Foot & Ankle International. 2019 May;40(5):603-10.
  4. Glasoe WM. An Operational Definition of First Ray Hypermobility. Foot & Ankle Specialist. 2022 Jun 3:19386400221093864.