Clavotrapezius muscle (cat only)

Dscn1774.jpg (75814 bytes) Dscn1775.jpg (69158 bytes) Dorsal view, left side

 Cat information:
 clavotrapezius (cat only corresponds
         to the superior portion of the trapezius)
 origin:  superior nuchal line of occipital
         bone and the mid-dorsal line of
           the neck to the spine of the axis

 insertion:  clavicle and the raphe between
         the clavotrapezius and the clavobrachialis
 nerve:  spinal accessory (XI) and ventral
  rami of cervical vertebrae 1-4
 action:  elevates and retracts (adducts)

2.gif (27789 bytes) Posterior view, left side Posterior (superficial) view of origin and insertion, left side
Superior view of superior division of the trapezius insertion, right side
Posterior (superficial) view of insertion, right side

Human information:
clavotrapezius (cat only corresponds
        to the superior division of the trapezius)
origin:  external occipital protuberance,
        medial third of superior nuchal line,
        ligamentum nuchae, and spinous process
        of C7
insertion:  lateral third of clavicle and the acromion
nerve:  spinal accessory (XI) and
        anterior rami of C3 and C4 (sensory component)
action:  elevation and upward rotation of scapula,
        when contracting with other portions of the
        trapezius it retracts (adducts) the 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 drawing of the insertion on the clavicle might help visualize this information (blue is the insertion).  The other drawings of the origin and insertion might help visualize this information (red is the origin and blue is the insertion).  These other 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