Anatomy of the Cat

by Jacob Reighard; H. S. Jennings

3. Levator scapulæ ventralis ([p. 120], and [Fig. 72], c′, c″). Observe its origin.

4. Rectus capitis anterior minor ([p. 143], and [Fig. 72], b). To see this, cut through on one side the longus capitis and one head of the levator scapulæ ventralis, and remove the proximal portions, as in [Fig. 72].

5. Obliquus capitis superior ([p. 136], and [Fig. 72], e).

6. Rectus capitis lateralis ([p. 143], and [Fig. 72], d).

VII. Muscles of the Back ([p. 123]).

Remove what remains of the dorsal portion of the latissimus dorsi, serratus posterior superior, and serratus posterior inferior. See that the skin is removed completely to the dorsal middle line, or even for a little distance over onto the other side. There is thus exposed the lumbodorsal fascia ([p. 126]), covering the muscles of the back.

Cut the superficial layer of the lumbodorsal fascia (that from which the latissimus dorsi and obliquus externus abdominis have origin) by an incision parallel to the dorsal median line, and remove it. The muscles of the back are thus exposed ([Fig. 69]). Observe in the lumbar region the longissimus dorsi (f, f′, f″); in the thoracic region the longissimus dorsi, the spinalis dorsi (g), and the iliocostal (h); in the cervical region the splenius ([Fig. 73], b).

1. The longissimus dorsi ([p. 126], and [Fig. 69], f, f′, f″). Notice in the lumbar region the strong deep layer of the lumbodorsal fascia, by which this muscle is covered, and from the under side of which many of the fibres of the muscle take origin. Cut this fascia by an incision parallel to the dorsal median line and about two centimeters from it, from the level of the crest of the ilium as far craniad as the fascia can be cut without cutting into the muscle-fibres (usually to about the level of the last rib). Reflect the medial division of the fascia to the middle line. Reflect the lateral division of the fascia until it passes into the muscle and cannot be farther reflected.

Observe then in the lumbar region the medial ([Fig. 70], a) and lateral ([Fig. 70], b) divisions of the longissimus dorsi, and the portion (b′) of the lateral division taking origin from the lumbodorsal fascia (c). Dissect apart some of the muscle-fibres of the longissimus and observe their origin and insertion.

Trace the longissimus dorsi into the thoracic and cervical regions ([Fig. 69], f′, f″) noting the separation off from it on the dorsal side of the spinalis dorsi ([Fig. 69], g); on the ventral side of the iliocostal ([Fig. 69], h).