Guillaume Bacle1,2, Jean-Marc Gregoire3, Frédéric Patat3,4, Philippe Clavert5, Gonzague de Pinieux6, Jacky Laulan7, Walid Lakhal7,3, Luc Favard7,3. 1. Department of Orthopaedic Surgery, Hôpital Universitaire Trousseau, Tours, France. bacle.guillaume@wanadoo.fr. 2. Unité Mixte de Recherche Imagerie et Cerveau, Inserm U930, Université François-Rabelais, Tours, France. bacle.guillaume@wanadoo.fr. 3. Unité Mixte de Recherche Imagerie et Cerveau, Inserm U930, Université François-Rabelais, Tours, France. 4. Inserm CIC-IT 1415, Tours, France. 5. Faculty of Medicine, Institut of Normal Anatomy, FMTS, Strasbourg, France. 6. Department of Pathology, Hôpital Universitaire Trousseau, Tours, France. 7. Department of Orthopaedic Surgery, Hôpital Universitaire Trousseau, Tours, France.
Abstract
PURPOSE: Despite their functional importance, the infraspinatus (ISP) and teres minor (TM) muscles have been little investigated. This study aimed to describe the macroscopic morphology, innervation, and inter-relations of the ISP and TM muscles. METHODS: Forty fresh cadaver dissections and histologic analysis were performed. Three groups of specimens were distinguished according to the rotator cuff tendon status: (1) intact rotator cuff; (2) supraspinatus tendon tears with intact ISP tendon; and (3) both supraspinatus and ISP tendons torn. Muscle fiber organization and muscle and tendon length were recorded. ISP and TM innervation and fiber structure were studied. RESULTS: ISP muscles were composed of three groups of fiber organized in two planes: two superficial groups, with mean pennation angles of, respectively, 27° ± 4° and 23° ± 3° with respect to the axis of the central tendon of the underlying group. TMs were thick fusiform muscles showing a parallel organization; 26 specimens (67 %) had aponeuroses isolating the TM, with a mean length of 5.2 ± 2.7 cm. Rotator cuff lesions were associated with relatively greater ISP tendon than muscle length. Innervation of the ISP muscle comprised 2-4 main branches from the suprascapular nerve and that of the TM 1 branch from the axillary nerve. CONCLUSION: ISP muscle body morphology derives from three groups of fibers in two planes. The TM has a parallel organization. Several nerve branches innervate the ISP muscle, whereas only one supplies the TM. The limits between the two muscles bodies consist of an aponeurotic fascia in two-thirds of cases.
PURPOSE: Despite their functional importance, the infraspinatus (ISP) and teres minor (TM) muscles have been little investigated. This study aimed to describe the macroscopic morphology, innervation, and inter-relations of the ISP and TM muscles. METHODS: Forty fresh cadaver dissections and histologic analysis were performed. Three groups of specimens were distinguished according to the rotator cuff tendon status: (1) intact rotator cuff; (2) supraspinatus tendon tears with intact ISP tendon; and (3) both supraspinatus and ISP tendons torn. Muscle fiber organization and muscle and tendon length were recorded. ISP and TM innervation and fiber structure were studied. RESULTS: ISP muscles were composed of three groups of fiber organized in two planes: two superficial groups, with mean pennation angles of, respectively, 27° ± 4° and 23° ± 3° with respect to the axis of the central tendon of the underlying group. TMs were thick fusiform muscles showing a parallel organization; 26 specimens (67 %) had aponeuroses isolating the TM, with a mean length of 5.2 ± 2.7 cm. Rotator cuff lesions were associated with relatively greater ISP tendon than muscle length. Innervation of the ISP muscle comprised 2-4 main branches from the suprascapular nerve and that of the TM 1 branch from the axillary nerve. CONCLUSION: ISP muscle body morphology derives from three groups of fibers in two planes. The TM has a parallel organization. Several nerve branches innervate the ISP muscle, whereas only one supplies the TM. The limits between the two muscles bodies consist of an aponeurotic fascia in two-thirds of cases.
Entities:
Keywords:
Anatomy; Infraspinatus; Morphology; Rotator cuff; Teres minor
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