Muscles of the lower back and abdominal wall

Question 1

What are the main 3 spinal diseases that result in abnormal curvatures of the spine?
And what direction do they each curve in?

Answer 1

• Scoliosis; abnormal lateral curvature of the spine.
• Kyphosis; excessive posterior thoracic curvature.
• Lordosis; excessive anterior lumbar curvature.

Question 2

There are 3 different layers that different Back muscles reside in, each layer is associated with different movements of the back.

What layers are there and what movements are they associated with?

Answer 2

• Deep layer; Associated with movements of the vertebral column.
• Intermediate layer; Associated with movements of the thoracic cage.
• Superficial layer; Associated with movements of the shoulder.

Question 3

The deep layer of back muscles are further dived again into what 3 sub-layers?

Answer 3

• Superficial.
• Intermediate
• Deep.

Question 4

What deep back muscles reside in the deep-superficial layer?

And what movements are they responsible for?

Answer 4

The pair of muscles are known as: Spinotraversales.

• Splenius capitis.
• Splenius cervicis.

They’re both responsible for movements of the head and neck.

Question 5

What deep back muscles reside in the deep-intermediate layer?

And what movements are they responsible for?

Answer 5

These are bilateral muscles that lye either side of the spine. They’re ordered from most medial –> Lateral.

As a group they’re known as the erector spinae muscles, aka intrinsic back muscles.

• Spinalis
• Longissimus
• Iliocostalis

These muscles work unilaterally, to laterally flex the vertebral column, and bilaterally they extend the vertebral column and the head.

Question 6

What innervates the Erector spinae muscles, aka intrinsic back muscles.

Answer 6

Innervated by posterior rami of spinal nerves.

Question 7

What deep back muscles reside in the deep-deep layer?

And what movements are they responsible for?

Answer 7

They’re known as the Transversospinales muscles.

• Semispinalis; Bi-lateral, more lateral
• Multifidus; Bi-lateral, more medial,
• Rotatores; smaller muscles

Movements:
Semispinalis; Extends and rotates the head contralaterally.

Multifidus and rotatores: stabilise the vertebral column.

Question 8

What innervates the Transversospinales muscles?

Answer 8

Innervated by posterior rami of spinal nerves.

Question 9

What are the minor deep intrinsic muscles?

Answer 9

• Intertransversarii
• Interspinales
• Levatores costarum, attaches to C7 - T11 vertebrae, and the ribs.

Question 10

What back muscles make up the Superficial layer?

Answer 10

• Trapezius.
• Levator scapulae.
• Latissimus dorsi.
• Rhomboid minor.
• Rhomboid major.

Question 11

What back muscles make up the intermediate layer?

Answer 11

• Serratus posterior superior.

- Serratus posterior inferior.

Question 12

What is the name of the facia that is throughout most of the posterior thoracic and abdomen?

Answer 12

Thoracolumbar facia

Question 13

How many layers does the Thoracolumbar facia have?

Answer 13

3

Question 14

What is the role of the Thoracolumbar facia?

Answer 14

• Stabilising and mobility of the region.

- Stabilise the pelvis

Question 15

What muscles are present between the middle and posterior layer of the Thoracolumbar facia?

Answer 15

The deep muscles of the back.

Question 16

What muscle is between the middle and anterior layer of the Thoracolumbar facia?

Answer 16

Quadratus lumborum

Question 17

What are the movements of the vertebral column?

Answer 17

• Flexion.
• Extension.
• Lateral flexion.
• Rotation.

Question 18

What limits the ROM of the vertebral column?

Answer 18

• The thickness, elasticity and compressibility of the intervertebral discs.
• The shape, orientation and articular capsules of the facet joints.
• The resistance of the back muscles and ligaments. e.g. Ligamenta flava.

Question 19

Starting superiorly, what are the layers of the abdomen?

Answer 19

• Skin.
• Subcutaneous tissue/ superficial facia. Made of two layers the fatty layer and membranous layer.
• Muscular layer.
• Fascia transversalis.
• Parietal peritoneum.

Question 20

What are the 3 paired (Bi-lateral) flat muscles of the anterior and lateral abdominal wall?

Answer 20

• External oblique: most superficial
• Internal oblique
• Transverse abdominis: Deepest

Question 21

What is the 1 paired(Bi-lateral) strap muscle of the anterior abdominal wall?

Answer 21

Rectus abdominis.

Question 22

What innervates the muscles of the anterior and lateral abdominal wall?

Answer 22

• Thoracoabdominal nerves (T7-T11).
• Subcostal nerve (T12).
• The lower parts of internal oblique and transverse abdominis muscles are also innervated by the branches of the lumbar plexus.

Question 23

What is the function of the External oblique muscle?

Answer 23

• Contralateral rotation of the torso.

Question 24

What is the function of the internal oblique?

Answer 24

• Bi-lateral contraction, compresses the abdomen.

- Unilateral contraction rotates the torso ipsilaterally.

Question 25

What is the function of the Transverse abdominis?

Answer 25

• Compression of abdominal contents.

Question 26

What is the function of the Rectus abdominis?

Answer 26

• Assist the flat muscles in compression of the abdominal viscera.
• Stabilises the pelvis during locomotion.

Question 27

What is the small muscle below rectus abdominis?

Answer 27

• Pirimedalis (idk the spelling)

Question 28

What is the function of Pirimedalis

Answer 28

• It facilitates in tensing the linea alba.

Question 29

Reminder

Answer 29

LEARN THE DERMATOMES!!

Question 30

What is Sciatica?

Answer 30

Compression/ irritation of the sciatic nerve.

Question 31

What can cause Sciatica?

Answer 31

• Injury, disc herniation, spinal stenosis and spondylolisthesis.

Question 32

What are the primary curvatures of the spine?

Answer 32

These curve anteriorly:

• Thoracic
• Sacrococcygeal

Question 33

What are the secondary curvatures of the spine?

Answer 33

These curve posteriorly:

• Cervical
• Lumbar