Agriculture Reference
In-Depth Information
Figure 6.14 Superfi cial muscles of the neck.
The Muscles of the Neck, Trunk, and Abdomen
T HE M USCLES OF THE T RUNK
The muscles of the trunk are divided in two categories:
epaxial and hypaxial. The epaxial muscles attach to the
dorsal aspect of the thoracic and lumbar vertebrae and are
responsible for (their primary function is) the extension of
the vertebral column. The hypaxial muscles attach to the
ventral aspect of the same vertebrae and do the fl exion of
the vertebral column (which is their primary function). At
the same time, all muscles of the trunk can perform lateral
movements and limited rotations of the vertebrae in their
long axis. The muscles of the trunk also include the pec-
toral (chest) muscles.
T HE M USCLES OF THE N ECK
The muscles of the neck are located dorsal and ventral to
the vertebral cervical column. They originate and insert on
the cervical vertebrae, the skull, the sternum, the ribs, the
thoracic limb, and the thoracic vertebrae. They contract
either on one side of the body, or symmetrically, to produce
all kinds of movements. The ventral muscles of the neck
protect the esophagus, the trachea, and major vessels and
nerves. The superfi cial cervical muscles are illustrated in
Figure 6.14 .
From the functional standpoint, the muscles of the neck
are holding the weight of the head, and making dorsal,
lateral, and ventral movements of varying degrees of the
neck and head.
T HE A BDOMINAL M USCLES
The abdominal muscles are divided in two categories:
dorsal and ventral. The dorsal abdominal muscles cover
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