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Irreparable posterior cuff tears can cause pain and lack of shoulder function. Surgical treatment includes musculotendinous transfers of either latissimus dorsi (LD) or teres major (TM). This study aimed to give a detailed description of the morphology of these two muscles with particular regard to their suitability for use in transfers. Sixty-two shoulders in 31 cadaveric specimens (mean age 50 years) were dissected. The mean length of the TM was 13.7 cm at its superior edge while the distance from the muscle origin to the greater tuberosity (GT) was 19.2 cm. The tendon of the TM had a length of 1.5 cm, a width of 3.4 cm, and a thickness of 1.3 mm. The mean length of the LD was 26.0 cm and the distance from its origin to the GT was 32.9 cm. The mean length of the LD tendon was 5.2 cm, its width 2.9 cm, and its thickness 1.0 mm. The increased length required to achieve transfer was 47% (of the original length) for TM and 33% for LD. Both TM and LD could reach the GT with ease, according to the potential muscle excursions. Tension of the neurovascular bundle is more probable with LD because it enters the muscle relatively closer to the tendon. Problems with regard to reattachment may be more likely to occur in a transfer of the TM because of its short tendon.

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Comparative anatomical studies of the avian middle ear provide structural data from which functional models can be derived. Subsequent phylogenetic analyses may reveal the phylogenetic history of taxon and the evolution of the functional model of the middle ear. We studied serial sections of a nestling of Grus japonensis. The microscopic anatomy of the middle ear (including skeletal parts, nerves, blood vessels, tendons, and tympanic recesses) was described with the help of a polystyrene plate reconstruction. These results were compared to those from skulls of adult cranes. Structural peculiarities of the crane middle ear are: 1) the ventral and anterior closure of the middle ear cavity by a dense plate of connective tissue, which ossifies during posthatching development; 2) the S-shaped infracolumellar process of the columella, of which the distal end forms a horizontal bar, and abuts against the ventral wall of the middle ear cavity; and 3) the absence of an intracolumellar hinge between the stapes and extracolumella. The crane middle ear shows the plesiomorphic pattern of middle ear structures of neognathous birds. We propose a one-lever-arm functional model for the middle ear of the crane, similar to that of paleognathous birds.