dorsal muscle of head and trunk Flashcards
The broad muscle posterior to the eye and on the same level as the tympanum is the temporalis. It extends from the median dorsal line of the skull, stretching ventrally, passing between the eyes and the eardrum to the posterior portion of the lower jaw, and acting as levator of the mandible and constrictor of the mouth.
Temporalis
The flat fan-shaped muscles posterior to the temporalis are the depressor mandibulae. It originates from the tough fascia in the middorsal line. It inserts into the lower jaw and serves as a jaw depressor.
Depressor mandibulae
Beneath the depressor mandibulae and best exposed by making an incision on the fascia of the depressor mandibulae along the median dorsal line, the dorsalis scapulae take origin from the dorsal surface of the suprascapula and scapula and insert into the side of the humerus to abduct the arm.
Dorsalis scapulae
This is a short muscle along the middorsal line medial to dorsalis scapulae.
Cucullaris
Broad muscles posterior to and partly covered by the depressor mandibulae are the latissimus dorsi. They extend from the lumbodorsal fascia to the side of the proximal end of the humerus and draw limbs upward and backward.
Latissimus dorsi
Lateral to the longissimus dorsi, it is separated from the external oblique by a connective tissue, the lateral or horizontal skeletogenous septum. Taking origin from the anterior portion of the ilium, it inserts into the transverse processes of the vertebral column. Itis a flexor of the back.
Iliolumbaris
A pair of narrow V-shaped muscles posterior to the longissimus dorsi is the coccygeo-sacralis. It originates from the lateral anterior half of the urostyle and inserts into the transverse processes of the sacral vertebrae.
The muscle draws the back and
urostyle closer to each other.
Coccygeo-sacralis
Coccygeo-iliacus. A pair of broad V-shaped muscles posterior to coccygeo-sacralis, the coccygeo-iliacus is found between the ilia of the pelvic girdle. It originates from the side of posterior half of the urostyle. It inserts at the ilium and helps extend the back and fixes the urostyle with respect to the pelvic girdle.
Coccygeo iliacus