Figure Drawing - Individual Muscles - Trunk

Spinal Muscles The spinal muscles are a complicated group of muscles that pass along the back of the animal from the pelvis to the middle of the neck. Each muscle consists of numerous overlapping bundles that continuously originate and insert along the spine. They lie on either side of the upper surface of the vertebral column, separated by the upright spines. This powerful muscle group consists of four units: the longissimus, the iliocostalis, the spinalis & semispinalis, and the multifidus, all of which may be divided into regional components (cervicis, thoracis & lumborum).The longissimus, iliocostalis and spinalis comprise the...
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Figure Drawing - Individual Muscles - Trunk52 INDIVIDUAL MUSCLES > TRUNK Spinal Muscles DOG AND FELINEThe spinal muscles are a complicated group of muscles that pass along Longissimus (cervicis, thoracis & lumborum)the back of the animal from the pelvis to the middle of the neck. Each • Origin: Inner (deep) surface of the wing (ilium) of the pelvis and itsmuscle consists of numerous overlapping bundles that continuously orig- crest, and the upper bony projections (spinous processes) of theinate and insert along the spine. They lie on either side of the upper sur- lumbar vertebrae.face of the vertebral column, separated by the upright spines. This • Insertion: Sides of all the lumbar and thoracic vertebrae, the upperpowerful muscle group consists of four units: the longissimus, the ilio- ends of all the ribs, and the side of the sixth neck vertebra.costalis, the spinalis & semispinalis, and the multifidus, all of which may • Structure: This is the largest of the spinal muscles, and along with thebe divided into regional components (cervicis, thoracis & lumborum).The iliocostalis, forms a very thick, columnar muscle mass in the lumbarlongissimus, iliocostalis and spinalis comprise the erector spinae region. In the feline, the lumbar portion of the longissimus is not(sacrospinalis). The longissimus capitis (to the head) and longissimus covered by the iliocostalis, which begins from a more forward position.atlantis (to the first neck vertebra) are described with the neck muscles. Iliocostalis (thoracis & lumborum)• Action: They primarily extend the vertebral column. Their contraction • Origin: Inner surface of the wing of the pelvis and its crest, the sideswill also fix the spine into a rigid column. A muscle contracting on one of the lumbar vertebrae, and the upper ends of the ribs.side only will bend the spine toward that side. Some units also pull the • Insertion: Upper ends of the ribs, and the side of the last (seventh)ribs rearward, which assists in breathing. neck vertebra. • Structure: Outermost of the spinal muscles, the iliocostalis passesHORSE AND OX from the pelvis to the base of the neck. In the feline, this muscle Longissimus (cervicis, thoracis & lumborum) is thinner than in the dog and begins at the rear end of the rib cage,• Origin: Deep surface of the front of the pelvis from its inner to its outer not at the pelvis.expansions, and the upper bony projections of the thoracic and lumbarvertebrae and front half of the sacrum. Spinalis & Semispinalis (thoracis)• Insertion: Sides of the thoracic and lumbar vertebrae, the upper ends • Origin: Surface of the longissimus dorsi toward the rear of the rib cageof all the ribs except the first, and the sides and tops of the last four (from the level of the seventh to the eleventh thoracic vertebrae).neck vertebrae (fourth through the seventh). • Insertion: Upward projections on the tops of the sixth neck vertebra to• Structure: The longissimus is the longest and largest muscle in the body. the sixth thoracic vertebra.The thick lumbar portion is called the common mass. A depression in its • Structure: The muscle mass of the spinalis & semispinalis sits aboveupper surface, just to the front of the pelvis, gives origin to the gluteus the longissimus, toward the midline of the back. Not directly seen on themedius muscle. This depression in the ox is smaller and doesnt advance surface, it adds a muscular fullness to the back before diving under theas far forward as in the horse. At the middle of the trunk, the longissimus shoulder blade.divides into upper and lower portions, both of which insert into the last Multifidus (thoracis & lumborum)four neck vertebrae. The upper portion, the spinalis & semispinalis, • Origin ...