12- ABDOMINAL & BACK MUSCLES

Question 1

What actions are possible in the cervical spine( and its attachment to the skull)?
And what joints do these primarily occur at?

Answer 1

Flexion-extension, lateral flexion, rotation

Atlanto-occiptal joint and atlanto-axial joint

Question 2

States the muscle of the neck

Answer 2

Scalenes

Sternocleiodomastoid

Question 3

Origin: Manubrium and medial portion of the clavicle
Insertion: Mastoid process of the temporal bone, superior nuchal line
Innervation: Accessory nerve (CN XI)
Actions: (unilaterally) contralateral cervical rotation,ipsilateral flexion of the cervical spine
(bilaterally) cervical flexion, assist with forced exhalation by elevating the sternum

Answer 3

Sternocleidomastoid

Question 4

3 muscles (ant., middle and post) in the neck

Answer 4

Scalenes

Question 5

Origin, insertion, innervation and actions of scalenes

Answer 5

Origin: Cervical vertebrae (C2-C7)
Insertion: First and second ribs
Innervation: Cervical nerves (C3-C6)
Actions: Elevation of the first and second ribs. Lateral flexion of the neck. Assists with forced inhalation

Question 6

States the erector spinae muscles

Answer 6

Spinialis
longissimus
iliocostalis

Question 7

Function of the erector spinae muscles:

Answer 7

• Extension of vertebral column (bilateral)
• Maintenance of erect posture (bilateral)
• Stabilization of vertebral column during flexion (bilateral)
• Lateral bend to same side (unilateral)
• Rotation to same side (unilateral)
• opposite side contracts to stabilize eccentrically (unilateral)

Question 8

Thoracic portion of iliocostalis and longissimus

Answer 8

75% slow-twitch fibres
Line of action parallel to spine
Greatest mechanical advantage for extension

Question 9

Lumbar portion of iliocostalis and longissimus

Answer 9

Even mixed slow- and fast- twitch fibres
line of action oblique (posterior- caudal)
Function: Extension of the bertebral column
Create posterior shear forces against anterior shear forces during
flexion
NOTE: oblique line lost during flexion caused by posterior hip rotation

Question 10

• Forces affect only local areas of the spine. Therefore provide ability for corrections at specific joints.
• Span only a few vertebrae

Answer 10

Multifidus

Question 11

So small that contribution to twisting is limited

have a proprioception function

Answer 11

rotatores

Question 12

Origin: iliac crest and iliolumbar ligament
Insertion: Base of the 12th rib and transverse processes of the lumbar vertebrae
research has shown that the length of the muscle remains fairly constant when activated. Thought to help stabilize the lumbar spine

Answer 12

Quadratus lumborum

Question 13

Function of Quadratus Lumborum

Answer 13

(unilaterally) lateral flexion of the vertebral column

(bilaterally) depression of the rib cage

Question 14

Origin: Crest of the pubis
Insertion: Costal cartilages of ribs 5-7, xiphoid process
Innervation: thoracoabdominal nerves (T7-T11) and subcostal nerve (T12)
Actions: Flexion of the lumbar spine

Answer 14

Rectus abdominis

Question 15

External obliques

Answer 15

Origins: ribs 5-12
Insertion: iliac crest, pubic tubercle, linea alba
Innervation: Thoracoabdominal nerves (T7-T11) and subcostal nerve (T12)
Actions: Contralateral rotation of torso

Question 16

Internal obliques

Answer 16

Origin: Inguinal ligament, iliac crest and the lumbodorsal fascia
Insertion: Linea alba, and ribs 10-12
Actions: (unilateral) ipsilateral trunk
(Bilateral) compresses abdomen

Question 17

Action: compresses abdominal cavity

Answer 17

Transverse abdominus

Question 18

Other functions of transverse abdominus

Answer 18

Spine stability and increased intra- abdominal pressure
Recruited during ballistic movements
Belt-like action around abdomen- delayed recruitment in people with lower back pain.

Question 19

Muscles for flexion of the spine

Answer 19

Rectus abdominis, psoas major

Question 20

Muscles for extension of the spine

Answer 20

Erector spinae, gluteus maximus

Question 21

Which muscles contract for lateral flexion of the spine?

Answer 21

Splenius
sternocleidomastoid
Rhomboids
Serratus anterior
Obliques
Quadratus lumborum
Gluteus medius
Gluteus maximus

Question 22

Which muscles contract for rotation of the spine?

Answer 22

Sternocleidomastoid
Splenius
Transversospinalis
Iliocostalis and longissimus
Obliques