The Journal of Bone and Joint Surgery (American). 2009;91:1-7.
doi:10.2106/JBJS.H.01426
© 2009 The Journal of Bone and Joint Surgery, Inc.
Humeral Insertion of the Supraspinatus and Infraspinatus. New Anatomical Findings Regarding the Footprint of the Rotator CuffSurgical Technique
Tomoyuki Mochizuki, MD1,
Hiroyuki Sugaya, MD2,
Mari Uomizu, MD1,
Kazuhiko Maeda, MD2,
Keisuke Matsuki, MD3,
Ichiro Sekiya, MD1,
Takeshi Muneta, MD1 and
Keiichi Akita, MD1
1 Unit of Clinical Anatomy (M.U. and K.A.) and Section of Orthopaedic Surgery
(T. Mochizuki, I.S., and T. Muneta), Graduate School, Tokyo Medical and Dental
University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. E-mail address
for T. Mochizuki:
mochizuki.orj{at}tmd.ac.jp.
E-mail address for K. Akita:
akita.fana{at}tmd.ac.jp
2 Funabashi Orthopaedic Sports Medicine Center, 1-833 Hazama, Funabashi, Chiba
274-0822, Japan
3 Department of Orthopedic Surgery, Teikyo University Chiba Medical Center,
3426-3 Anegasaki Ichihara, Chiba 299-0111, Japan
Investigation performed at the Unit of Clinical Anatomy, Graduate
School, Tokyo Medical and Dental University, Tokyo, Japan
The original scientific article in which the surgical technique was
presented was published in JBJS Vol. 90-A, pp. 962-9, May 2008
DISCLOSURE: In support of their research for or preparation of this work,
one or more of the authors received, in any one year, outside funding or
grants in excess of $10,000 from KAKENHI (19890069) Grant-in-Aid for Young
Scientists (Start-up). Neither they nor a member of their immediate families
received payments or other benefits or a commitment or agreement to provide
such benefits from a commercial entity. No commercial entity paid or directed,
or agreed to pay or direct, any benefits to any research fund, foundation,
division, center, clinical practice, or other charitable or nonprofit
organization with which the authors, or a member of their immediate families,
are affiliated or associated.
The line drawings in this article are the work of Joanne Haderer
Müller of Haderer & Müller
(biomedart{at}haderermuller.com).
BACKGROUND: It is generally believed that the supraspinatus is the
most commonly involved tendon in rotator cuff tears. Clinically, however,
atrophy of the infraspinatus muscle is frequently observed in patients with
even small to medium-size rotator cuff tears. This fact cannot be fully
explained by our current understanding of the anatomical insertions of the
supraspinatus and infraspinatus. The purpose of this study was to
reinvestigate the humeral insertions of these tendons.
METHODS: The study included 113 shoulders from sixty-four cadavers.
The humeral insertion areas of the supraspinatus and infraspinatus were
investigated in ninety-seven specimens. In sixteen specimens, all muscular
portions of the supraspinatus and infraspinatus were removed, leaving the
tendinous portions intact, in order to define the specific characteristics of
the tendinous portion of the muscles. Another twenty-six shoulders were used
to obtain precise measurements of the footprints of the supraspinatus and
infraspinatus.
RESULTS: The supraspinatus had a long tendinous portion in the
anterior half of the muscle, which always inserted into the anteriormost area
of the highest impression on the greater tuberosity and which inserted into
the superiormost area of the lesser tuberosity in 21% of the specimens. The
footprint of the supraspinatus was triangular in shape, with an average
maximum medial-to-lateral length of 6.9 mm and an average maximum
anteroposterior width of 12.6 mm. The infraspinatus had a long tendinous
portion in the superior half of the muscle, which curved anteriorly and
extended to the anterolateral area of the highest impression of the greater
tuberosity. The footprint of the infraspinatus was trapezoidal in shape, with
an average maximum medial-to-lateral length of 10.2 mm and an average maximum
anteroposterior width of 32.7 mm.
CONCLUSIONS: The footprint of the supraspinatus on the greater
tuberosity is much smaller than previously believed, and this area of the
greater tuberosity is actually occupied by a substantial amount of the
infraspinatus.
LEVEL OF EVIDENCE: The present study suggests that rotator cuff
tears that were previously thought to involve only the supraspinatus tendon
may in fact have had a substantial infraspinatus component as well.

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