Muscles Flashcards
Muscles of the anterolateral wall
> External Oblique
Internal Oblique
Transversus Abdominis
+ Rectus Abdominis on anterior aspect only (associated with rectus sheath)
External Oblique
> P: Most superficial muscle of the anterolateral wall of the abdominal cavity with fibres running inferomedially
O: Outer surface of 5th - 12th ribs + costal cartilages
I : Linea alba via rectus sheath
: Pubic tubercle to ASIS (inguinal ligament)
: Ant. 2/3 of iliac crest
(free posterior border - doesn’t connect to TLF)
A: Bilaterally: flex trunk
: posterior pelvic tilt
: Ipsilaterally: Side flex trunk
: Contralaterally: Rotation of trunk on pelvis
N: Ventral Rami of T7-12
Internal Oblique
> P: Middle muscle of anterolateral wall (deep to ext. oblique but superficial to trans abs) with fibres running superomedially
O: Lower border of 10th-12th ribs + costal cartilages
: Linea alba via rectus sheath
: Pectin pubis via conjoint tendon with trans abs
I: Lateral 2/3 of inguinal ligament
: Anterior 2/3 of iliac crest
: TLF
A: Bilaterally: Flex trunk
: Posterior pelvic tilt
: Ipsilaterally: Side flexion
: Rotation
N: Ventral Rami of T7-T12
: L1 nerve supply
Transversus Abdominis
> P: Deepest muscle of anterolateral wall with horizontally running fibres
O: Internal surfaces of 7th-12th costal cartilages
: TLF
: Iliac crest
: Lateral 1/3 of inguinal ligament
I: Linea alba via rectus sheath
: Pectin pubis via conjoint tendon with int. oblique
A: Stabilising muscle for lumbar spine
: Raises intra-abdominal pressure
N: Anterior rami of T7-T12
: L1 nerve supply
Rectus abdominis
> P: Anterior aspect of abdominal wall, within rectus sheath with fibres running vertically
> O: Xiphoid process
: 5th-7th costal cartilages
> I: Pubic symphysis
: Pubic crests
> A: Bilaterally: flexes trunk
: Posterior pelvic tilt
: Ipsilateral: side flexion
: Contralateral: rotation
> N: Anterior rami of T6-T12Functions of the abdominals
> Trunk Movement > Sitting up from lying > Protect abdominal viscera > Spinal stabilisation > Abdominal pressure (for forced expiration, micturition, defecation, parturition, vomiting)
Muscles of posterior abdominal wall
> Erector Spinae: Iliocostalis
: Longissimus
: (spinalis is not in lumbar spine)
Quadratus Lumborum
Transversospinalis Muscles: Intertransversus
: Interspinalis
: Rotatores
: Multifidus
: (semispinalis - thoracic)
+ Diaphragm forming superior aspect
+ Psoas major
Iliocostalis Lumborum
> P: Most lateral erector spinae
O: TLF (to posterior sacrum + medial iliac crest)
: Spinous processes of Lumbar vertebrae and T11-T12 (+supraspinous ligaments)
I: Inferior borders of rib angles of lower 6 or 7 ribs
A: Bilaterally: Extends trunk
: Anterior pelvic tilt
: Ipsilaterally: side flexor
: rotation
Quadratus Lumborum
> P:
O: Lower border of medial 12th rib
: Transverse processes of lumbar region
I : Iliac crest + iliolumbar ligament (L5 - inner iliac crest)
A: Bilaterally: Lumbar extension
: Muscle of inspiration
: Unilaterally: Ipsilateral side flexion
Multifidus
> P: Deep muscle of posterior back, superficial to interspinalis + intertransversus + rotatores
O: Posterior Sacrum + dorsal sacro-iliac ligaments
: PSIS
: Mamillary processes of lumbar vertebrae
I: Spinous processes superiorly depending on layer (deepest = 1 above, mid = 2 or 3, superficial = 3 or 4)
A: Stabiliser
Interspinales
> P: Deep muscles of back
O/I: Muscle fibres within the interspinous ligaments
A: extend spine on segmental level
: Stabiliser
Intertransversus
> P: deepest muscles of back
O/I: Muscle fibres within the intertransverse ligament
A: Ipsilateral side flexion on segmental level
: Stability
Rotatores
> P: Deep muscles of back
O: Transverse processes
I: Spinous processes (how many levels above is determined by layer of muscle)
A: Contralateral rotation on segmental level
: stability
