10- Muscles of Neck and Vertebral Column: Head and Trunk Movements

Question 1

Iliocostalis

Answer 1

Most lateral muscle group of erector spinae muscles; extend from pelvis to neck.

Extend vertebral column, maintain erect posture.

Question 2

Longissiumus

Answer 2

Intermediate tripartite muscle group of erector spine; extend by many muscle slips from lumbar region to skull; pass between transverse processes of the vertebrae.

Thoracis and cervicis act together to extend vertebral column and acting on one side.

Question 3

Spinalis

Answer 3

Medial muscle column of erector spinae.

Extends vertebral column.

Question 4

Semispinalis

Answer 4

Composite muscle, forms part of deep layer of intrinsic back muscles. From thoracic region to head.

Extends vertebral column and head rotates them to opposite side.

Question 5

Quadraturs Lumborum

Answer 5

Fleshy muscle forming part of posterior abdominal wall.

Flexes vertebral column laterally when acting separately; when pair acts jointly, lumbar spin is extended and 12th rib is fixed; maintains upright posture; assists in force inspiration.

Question 6

External Intercostals

Answer 6

11 pairs lie between ribs; fibers run obliquely, down and forward, from each rib to rib below; in lower intercostal spaces, fibers are continuous with external oblique muscle.

First ribs fixed by scalene muscles, pull ribs toward one another to elect rib cage.

Question 7

Internal Intercostals

Answer 7

11 pairs lie between ribs; fibers run deep to and at right angles to those external intercostals.; lower internal intercostal muscles are continuous with fibers of internal oblique muscle of abdominal wall.

12th rib fix by quadrates lumborum, aid in forced expiration; antagonistic to external intercostals.

Question 8

Diaphragm

Answer 8

Broad muscle pierced by the aorta, inferior vena cava, and esophagus, forms floor of thoracic cavity.; dome shaped in relaxed state; fibers converge from margins of thoracic cage toward a boomerang-shaped central tendon.

Prime mover of inspiration; flattens on contraction, increasing vertical dimensions of thorax; when strongly contracted, dramatically increases intra-abdominal pressure.