The muscles of the fore and hind limbs in Dasypus sexcinctus / by John Charles Galton.

  • Galton, John Charles.
Date:
[1868]
Catalogue details

Licence: Public Domain Mark

Credit: The muscles of the fore and hind limbs in Dasypus sexcinctus / by John Charles Galton. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    inserted immediately beneath the inner tuberosity of the humerus, and above the terminal portion of the latissimus dorsi, and is also fused at origin with the tendon of the single (coracoid) head of the biceps. In Hystrix the coraco-bracMalis has no com- munication whatever with the biceps, which is single-headed in this rodent. It is repre- sented by the middle and long varieties of Wood. At about the level of the middle of the tendon of the latissimus dorsi, the muscle is pierced by a nerve (“ perforans Casserii ”?) which bores through the fleshy portion on the inner side of the median tendon of the muscle, passes behind this latter, and emerges at its outer side, through the muscular substance, to run across to the posterior part of the biceps. Erom immediately below the lower edge of the tendon of the latissimus dorsi the muscle takes insertion into the humerus, its inserted part being prolonged as far as the inner condyle, just above the origin of the epitrochleo-anconeus. That portion of this muscle which is cut off by the nerve at its emergence, and which is inserted immediately helow the tendon of the latis- simus dorsi, may be regarded, I think, as the representative of the middle or ordinary variety, the rest of the muscle, from this point downwards, representing the long variety. Professor Polleston has pointed out to me this muscle in the Tenrec (Centetes ecau- datus). It was represented by both short and long varieties, and was, moreover, quite distinct from the biceps for its whole length. Meckel, I find, describes only the long variety of the coraco-brachialis as present in the “ Tatu.” * Cuvier, too, represents this variety alone in his figures of the myology of Dasypus sexcinctus.^ Biceps.—A single-headed muscle, arising by a strong flat tendon from the superior- edge of the glenoid cavity of the humerus, immediately- external to the root of the coracoid process of the scapula, being completely covered by the terminal portion of the supraspinatus. It then passes through a deep groove, excavated in the anterior face of the humerus, between the two tuberosities, which is converted into a complete foramen by the bridging over of its channel by a strong broad ligament stretched between the tuberosity piers on either side. Soon after its emergence from the above groove, the biceps gradually loses its ten- dinous character, gradually, too, swells out laterally, and at the middle of the arm attains its greatest size, becoming somewhat ampulliform in shape. Prom this point it, by degrees, diminishes, and receives, immediately below the same, on its inner side and posterior aspect, those fibres of the coraco-brachialis which are not continued to the supracondyloid ridge. At a short distance from its termination, it divides into two tendons, or rather its very short single tendon splits into two branches, the outer of which is inserted into the palmar aspect of the neck of the radius, and the inner into the fossa scooped out of the radial edge of the ulna, and overhung by the coronoid pro- In Martes ahietum, among Carnivora, according to the same authority, “ The coraco-brachialis has an accessory muscle inserted next between the suhscajmlaris and teres major. According to Meckel, however, this muscle is entirely wanting in the Kangaroo ; hut in the Opossum it is very short, and is attached to the iipper sixth of the humerus.—Op. cit. p. 515. 1 Op. cit. p. 514. ' Op. cit. pi. 260.