Akimoto Nimura1, Hitomi Fujishiro1, Yoshiaki Wakabayashi1, Junya Imatani1, Hiroyuki Sugaya1, Keiichi Akita2. 1. Unit of Clinical Anatomy, and the Department of Orthopaedic Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo; the Department of Orthopaedic Surgery, Okayama Saiseikai General Hospital, Okayama; and the Shoulder and Elbow Service, Funabashi Orthopaedic Sports Medicine Center, Funabashi, Japan. 2. Unit of Clinical Anatomy, and the Department of Orthopaedic Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo; the Department of Orthopaedic Surgery, Okayama Saiseikai General Hospital, Okayama; and the Shoulder and Elbow Service, Funabashi Orthopaedic Sports Medicine Center, Funabashi, Japan. Electronic address: akita.fana@tmd.ac.jp.
Abstract
PURPOSE: To identify the unique anatomical characteristic of the extensor carpi radialis brevis (ECRB) origin and points of differentiation from other extensors and to clarify the specific relationship of the ECRB to the underlying structures. METHODS: We studied the origin of each extensor macroscopically for its muscular and tendinous parts; to identify the relationship between the ECRB origin and the deeper structures, we also examined the attachment of the joint capsule under the ECRB origin. RESULTS: The ECRB simply originated as a tendon without any muscle, whereas other extensors originated as a mixture of tendon and muscle. At the anterior part of the ECRB origin, the thin attachment of the joint capsule (average width, 3.3 mm) lay deep to the ECRB and was distinct. However, at the posterodistal portion, the joint capsule, annular ligament, and supinator were intermingled and originated as a single wide sheet from the humerus (average width, 10.7 mm). CONCLUSIONS: The anterior part of the ECRB origin was delicate, because the ECRB origin was purely tendinous, and the attachment of the articular capsule was thin compared with that of the posterodistal attachment. This thin attachment could be an initial factor leading to the development of lateral epicondylitis. CLINICAL RELEVANCE: The results of the current study may enhance magnetic resonance imaging understanding and may help clarify the etiology of the lateral epicondylitis.
PURPOSE: To identify the unique anatomical characteristic of the extensor carpi radialis brevis (ECRB) origin and points of differentiation from other extensors and to clarify the specific relationship of the ECRB to the underlying structures. METHODS: We studied the origin of each extensor macroscopically for its muscular and tendinous parts; to identify the relationship between the ECRB origin and the deeper structures, we also examined the attachment of the joint capsule under the ECRB origin. RESULTS: The ECRB simply originated as a tendon without any muscle, whereas other extensors originated as a mixture of tendon and muscle. At the anterior part of the ECRB origin, the thin attachment of the joint capsule (average width, 3.3 mm) lay deep to the ECRB and was distinct. However, at the posterodistal portion, the joint capsule, annular ligament, and supinator were intermingled and originated as a single wide sheet from the humerus (average width, 10.7 mm). CONCLUSIONS: The anterior part of the ECRB origin was delicate, because the ECRB origin was purely tendinous, and the attachment of the articular capsule was thin compared with that of the posterodistal attachment. This thin attachment could be an initial factor leading to the development of lateral epicondylitis. CLINICAL RELEVANCE: The results of the current study may enhance magnetic resonance imaging understanding and may help clarify the etiology of the lateral epicondylitis.
Authors: Renée Keijsers; Michel P J van den Bekerom; Koen L M Koenraadt; Ronald L A W Bleys; C Niek van Dijk; Denise Eygendaal Journal: Knee Surg Sports Traumatol Arthrosc Date: 2016-07-02 Impact factor: 4.342
Authors: Jonathan P Evans; Jeremy Metz; Rahul Anaspure; William J Thomas; Andrew King; Vicki A Goodwin; Chris D Smith Journal: J Exp Orthop Date: 2018-07-18