Exam 2 Ch.13.1-13.2

Question 1

The epaxial muscles are found along the dorsal surface. What should their basic function/action be?

Answer 1

Extend vertebral column

Question 2

Which group of epaxial muscles rotate the vertebral column? What anatomical feature assists with this action.

Answer 2

Middle layer: oriented obliquely or @ an angle
• Semispinalis
• Multifidus
• Rotatores

Question 3

Which group(s) of epaxial muscles attach at the base of the skull? What function to they perform?

Answer 3

Longissimus dorsi
Extend vertebral column & head

Question 4

Are epaxial muscles synergists or antagonists? Explain why.

Answer 4

Synergists

Question 5

The hypaxial muscles are found along the ventral surface. What should their basic function/action be? What muscles will be antagonistic?

Answer 5

Flex vertebral column, compress the abdominal wall, increase intra-abdominal pressure
Antagonists: epaxial muscles

Question 6

Where is the ventral ramus located with respect to the hypaxial muscles?

Answer 6

Anterior division of spinal nerve

Question 7

Explain the standard pattern of the lateral hypaxial muscles and why the cervical region does not follow this pattern?

Answer 7

Standard pattern: ventral to the transverse process of the vertebrae (3 layer pattern) innervation: ventral ramus
Cervical region: scalene muscles do not follow this, innervation: cervical plexus

Question 8

Which muscles elevate ribs 1 and 2, thereby assisting the other ribs in elevation during deep inhalation?

Answer 8

Anterior & posterior scalene

Question 9

List all the muscles that will compress the abdomen and increase intra-abdominal pressure.

Answer 9

External/internal oblique
Transverse abdominus

Question 10

List all the muscles will run along the mid-ventral surface from caudal to cranial and are equivalent to rectus abdominus.

Answer 10

Rectus series: tongue, supra/infrahyoid,
Suprahyoid: genioglossus, geniohyoid
Infrahyoid: Omohyoid, sternohyoid, sternothroid, thyrohyoid

Question 11

What are the equivalents in the thorax and perineum for the following muscles?
• Transversus abdominis • Internal oblique
• External oblique

Answer 11

Thorax:
Transversus abdominus= transversus thoracis
External oblique= external intercostal
Internal oblique: internal intercostal
Perineum:
Transversus abdominus: deep transverse perineal
External oblique=external anal sphincter
Internal oblique= urethral sphincter

Question 12

Are the rectus abdominus muscles segmental? What features tell you if they are or are not? What embryonic tissue are they derived from.

Answer 12

Yes, derived from mesoderm. Bc it is paired muscle that runs on either side of the linea alba