Trunk Muscles O/I

Question 1

External oblique

Answer 1

Origin: Outer borders lower 8 ribs

Insertion: outer lip anterior 2/3 iliac crest forming large aponeurosis join that from other side at linea alba.

Question 2

Internal oblique

Answer 2

Origin: lateral 2/3 inguinal ligament, anterior 2/3 iliac crest and thoracolumbar fascia.

Insertion: inferior border lower 4 ribs, forms aponeurosis which joins its fellow at linea alba. Portion from inguinal ligament joins with transverse abdominals forming conjoint tendon attaching to pubic crest.

Question 3

Transversus abdominis

Answer 3

Origin: lateral 1/3 inguinal ligament, anterior 2/3 inner lip iliac crest, thoracolumbar fascia, inner surface lower 6 ribs and their costal cartilages.

Insertion: forms aponeurosis attaching to its fellow at linea alba. Portion from inguinal ligament forms conjoint tendon with internal oblique.

Question 4

Rectus abdominis

Answer 4

Origin: front of symphysis pubis and pubic crest

Insertion: xiphoid process, costal cartilages of 5th, 6th, 7th ribs.

Question 5

Psoas minor

Answer 5

Origin: from 12th thoracic and 1st lumbar vertebral bodies and IVD

Insertion: inserts into iliopubic eminence. Forms thin tendon. Anterior primary ramus L1

Question 6

Quadratus lumborum

Answer 6

Origin: iliolumbar ligament and adjacent part of iliac crest

Insertion: medial half of 12th rib, lateral part TP of L5-L1

Question 7

Psoas major

Answer 7

Origin: with iliacus into lesser trochanter of femur

Insertion: anterior rami of L1, 2, 3 (4)

Question 8

Iliacus

Answer 8

Origin: upper and posterior 2/3 of iliac fossa, ala of sacrum and anterior sacroiliac ligament

Insertion: into lesser trochanter of femur with psoas major

Question 9

(Intermediate) Erector Spinae

Origin only

Answer 9

Origin: spinous processes and supraspinous ligament T11-L5, posterior sacral crests, sacrotuberous ligament and posterior part of iliac crest.

Question 10

(Erector spinae) 
Insertions of iliocostalis:
- Lumborum 
- Thoracis 
- Cervicis

Answer 10

Insertions;

• lumborum: attaches to lower 6 ribs
• thoracis: lower 6 to upper 6 ribs
• cervicis: upper 6 ribs to TP C4-7

Question 11

(Erector spinae)
Insertions of longissimus:
- thoracis
- cervicis
- capitis

Answer 11

Insertions:

• thoracis: TP of lumbar vertebrae to TP all thoracic vertebra and adjacent part lower 10 ribs
• cervicis: TP T1-6 to those of C2-6
• capitis: TP T1-5 and articular process C4-7 to mastoid process.

Question 12

(Erector spinae)
Insertions of spinalis
- cervicis & capitis
- thoracis

Answer 12

Cervicis and capitis: blend with adjacent muscles

Thoracis: SP T11-12 to those of T1-6

Question 13

(Deep)

Semispinalis

Answer 13

Thorax (O): TP T6-10 to (I) SP C6-T2
Cervicis (O): TP T1-6 to (I) SP C2-6
Capitis (O) TP T1-5 and articular processes C4-7 to (I) nuchial lines on skull.

Question 14

(Deep)

Multifidus

Answer 14

Origin: posterior sacrum, mammillary processes lumbar vertebrae, TP thoracic vertebrae, articular processes lower 5 cervical vertebrae

Insertion: all SP L5-C1

Question 15

(Deep)

Rotatores

Answer 15

Origin: TP in lamina

Insertion: to vertebra above