Dorsolateral view, left side
Dorsolateral view, left side
Cat information:
acromiotrapezius (cat only � corresponds
to
the middle portion of the human trapezius)
origin: spinous process of the axis to a
point between the first and fourth
thoracic vertebrae
insertion: metacromion, scapular spine to
tuberosity, and superficial surface
of
spinotrapezius
nerve: spinal accessory (XI) and ventral
rami of cervicals 1-4
action: hold the vertebral border of the two
scapulae together and
retracts
(adducts) them
Posterior view, left side
Posterior
(superficial) view of origin and insertion, left side
Posterior
(superficial) view
of trapezius insertion, right sideHuman information:
acromiotrapezius (cat only � corresponds
to
the middle division of the trapezius
which is pictured above)
origin: spinous processes of
7th cervical and
1st-3rd thoracic vertebrae
insertion: superior border
of the spine of
scapula
nerve: spinal accessory (XI)
and anterior rami
of C3 and C4
action: retracts (adducts)
and helps in
elevation of scapula
This is one of the five muscles that are grouped as muscles of the scapula, or sometimes as muscles that moor the scapula. The above drawings of the origin and insertion might help visualize this information (red is the origin and blue is the insertion). Both drawings are for the entire muscle and includes the origin and insertion for all three divisions of the trapezius muscle. Notice that part of the origin is on a ligament called the ligamentum nuchae, and this portion of the origin is represented by a line between the skull and the spinous process of C7. Thanks to Laura Holder for the excellent drawing!
COPYRIGHT
2009 by William C. Johnson II
ALL RIGHTS RESERVED!
