Ann Rehabil Med.  2017 Aug;41(4):589-594. 10.5535/arm.2017.41.4.589.

Anatomical Localization of Motor Points of the Abductor Hallucis Muscle: A Cadaveric Study

• Choi A
• Kwon NY
• Kim K
• Kim Y
• Oh J
• Oh HM
• Park JH

• KMID: 2389404
• DOI: http://doi.org/10.5535/arm.2017.41.4.589

Abstract

OBJECTIVE
To identify the anatomical motor points of the abductor hallucis muscle in cadavers.
METHODS
Motor nerve branches to the abductor hallucis muscles were examined in eight Korean cadaver feet. The motor point was defined as the site where the intramuscular nerve penetrates the muscle belly. The reference line connects the metatarsal base of the hallux (H) to the medial tubercle of the calcaneus (C). The x coordinate was the horizontal distance from the motor point to the point where the perpendicular line from the navicular tuberosity crossed the reference line. The y coordinate was the perpendicular distance from the motor point to the navicular tuberosity.
RESULTS
Most of the medial plantar nerves to the abductor hallucis muscles divide into multiple branches before entering the muscles. One, two, and three motor branches were observed in 37.5%, 37.5%, and 25% of the feet, respectively. The ratios of the main motor point from the H with respect to the H-C line were: main motor point, 68.79%±5.69%; second motor point, 73.45%±3.25%. The mean x coordinate value from the main motor point was 0.65±0.49 cm. The mean value of the y coordinate was 1.43±0.35 cm. All of the motor points of the abductor hallucis were consistently found inferior and posterior to the navicular tuberosity.
CONCLUSION
This study identified accurate locations of anatomical motor points of the abductor hallucis muscle by means of cadaveric dissection, which can be helpful for electrophysiological studies in order to correctly diagnose the various neuropathies associated with tibial nerve components.

Keyword

Cadaver; Tibial nerve; Abductor hallucis; Motor point; Electromyography

MeSH Terms

Cadaver*
Calcaneus
Electromyography
Foot
Hallux
Metatarsal Bones
Muscles
Tibial Nerve

Figure

• 

  Fig. 1 Motor branches of the medial plantar nerve to the abductor hallucis were dissected. (A) Multiple branches for the abductor hallucis muscle (arrow). (B) Enlarged image of multiple branches to the abductor hallucis muscle (arrow). (C) Schematic of the anatomical landmarks and nerves (H, metatarsal base of the hallux; C, medial tubercle of the calcaneus; N, navicular tuberosity; 1, posterior tibial nerve; 2, medial plantar nerve; 3, branch for the abductor hallucis).

• 

  Fig. 2 Anatomic dissection showed the medial plantar nerve branch entering the abductor hallucis muscle. The anatomical motor point was defined as the most distal point at which the motor branch entered the muscle (arrow).

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  Fig. 3 A plot of the location of the main motor points (blue dots) in the abductor halluces muscles. The x coordinate was defined as the horizontal distance from the motor point to the point where the perpendicular line from navicular tuberosity (N) crossed the reference line. The perpendicular distance from the motor point to the N point was defined as the y coordinate.

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