DIAPHRAGM, ABDOMINAL WALL & PELVIC FLOOR Flashcards
2 sets of connective tissue
rectus sheath
tfl - 3 layers
ABDOMINOPELVIC CAVITY
Superiorly: Diaphragm Inferiorly: Pelvic Posterior abdominal wall: Psoas major Quadratus lumborum Anterolateral abdominal wall: External oblique abdominals Internal oblique abdominals Transversus abdominis Anterior: Rectus abdominis
Diaphragm: structure
• dome shape with a central tendon
• right higher than left
* direct connection to lumbar vertical column
Diaphragm: attachments etc
Attachments: L1,2 & 3; lower 6 costal cartilages & ribs superiorly = central tendon Openings: inferior vena cava (T8) oesophagus (T10) descending aorta passes behind (T12) Innervation: Phrenic nerves C3,4,5
Pelvic floor:
• Levator ani & coccygeus
• Support contents of the pelvic cavity
* if increase IAP, must maintain tone the pelvic floor
Psoas major:
posterior abdominal wall
Primarily a hip flexor
attachments:
• Anterior = from vertebral bodies / iv discs
• Posterior = from transverse processes
• Insert onto lesser trochanter of femur
• vertical orientation & close to joint axis…
• = COMPRESSION of lumbar spine
• small moment arms for flexion or extension
VERTICAL LOA
BIG PCSA - ATTACHES TO TRANSVERSE PROCESSES
Quadratus lumborum:
posterior abdominal wall Attachments: 12th rib lumbar transverse processes posterior iliac crest Moment arms: • Sagittal movements (F/E) = minimal QL • Coronal movements (LF) = large EMG activity: Active during flexion & extension activities Active during axial loading activities Innervation: thoracolumbar ventral rami
NO SIGNIFICANT MA FOR EITHER ACTION - ACTIVE DURING FLX AND EXT. THEREFORE NOT MOVER BUT INSTEAD STABALISER - LARGE MA FOR LAT. FLX COMPRESS FOR STABILITY - LARGE PSCA
Anterolateral abdominal wall:
- External oblique abdominal
- Internal oblique abdominal
- Transversus abdominis
• Movements • Increase IAP
External oblique abdominal
anterolateral abdominal wall
POSTEROSuperior attachment: external surface lower 8 ribs
ANTEROInferior attachment: linea alba via aponeurosis & anterolateral iliac crest Free posterior border
Innervation: T7-12 ventral rami
Action:
B = trunk flexion & increase IAP;
U = contralateral rotation, ipsilateral LF
GOOD MA, LARGE PCSA
INCREASES IAP
Internal oblique abdominal
anterolateral abdominal wall
Posterior attachment: TLF
Inferior attachment: anterolateral iliac crest, inguinal ligament
Superior attachment: lower 4 ribs & cartilages,
Anterior attachment:linea alba via aponeurosis
Innervation: T7 – L1 ventral rami
Action:
B = trunk flexion & increase IAP;
U = ipsilateral rotation & LF
FIBRES ABOVE ASIS GO UPWARDS AND INWARDS
- WHEN GET TO ASIS AND BELOW ARE MORE TRANSVERSE
PURE AXIAL ROTATION
TO TURN TO RIGHT=
LFT. EXTERNAL OBLIQUE
RIGHT INTERNAL OBLIQUE
AND CONTRACT MULTIFIDUS CAUSE OBLIQUES ARE FLEXORS SO NEED EXTENSION COMPONENT
Transversus abdominis
Posterior attachment: thoracolumbar fascia
Superior attachment: internal aspect of lower ribs/cartilages
Inferior attachment: iliac crest & inguinal ligament
Insertion: linea alba (& lower fibres onto pubic crest)
Innervation: T7 – L1 ventral rami
Action: increase intra-abdominal pressure
NO VERTICAL COMPONENT SO NO FLX., EXT. OR LAT FLX
Rectus abdominis
Superior attachment: xyphoid process & adjacent rib cartilages Inferior attachment: pubic crest & symphysis Innervation:T7 – 12 ventral rami
Action:
trunk flexion
Midline linea alba & 3 tendinous intersections
Rectus sheath: layering of aponeuroses of the anterolateral abdominal muscles
upper 3⁄4
anterior = aponeuroses of: external oblique abdominal 1⁄2 internal oblique abdominal
posterior = aponeuroses of: 1⁄2 internal oblique abdominal transversus abdominis
Below arcuate line: lower 1⁄4
aponeuroses all anterior posterior = transversalis fascia
FUNCTION = IMPROVES EXT. OBLIQUE MA
LOA IS REDIRECTED = ENHANCES ACTION
Thoracolumbar fascia (TLF)
3 layers: Anterior & middle layers: • attach to lumbar t.p’s • envelope Quadratus lumborum • posterior attachment for transversus abdominis & internal oblique abdominal Posterior Layer: • attaches to T/L/S sp processes • encloses erector spinae group • laterally fuses with middle layer Blends with (CROSSING OF FIBRES): • erector spinae aponeurosis • latissimus dorsi • gluteus maximus
Thoracolumbar fascia (TLF) - 2
STRONGEST AND MOST DEFINITE IN LUMBAR REGION AND BECOMES LESS IN THORACIC
- EXTERNAL OBLIQUE HAS NO INFLUENCE ON SPINAL CORD VIA TFL
FUNCTION = MUSCLE ATTACH. AND SPINAL STABILITY
ESA
FLAT TENDONS OF 2 PARS THORACIC MUSCLES
Do the muscles of the abdominopelvic cavity play a role in spinal stability?
What is “stability”?????
• not only at end of range
• control of the motion segment
Experimentally:
the force required to buckle the vertebral column or displace the vertebra
GAIN CONTROL VIA:
• Bony
• Ligamentous / intervertebral disc • Muscular (VERTICAL LOA ACROSS JOINT, WHEN CONTRACTS CREATES COMPRESSION)
• Intra-abdominal pressure (WHEN INCREASES SUPPORTS VERTICAL COLUMN)
Muscular co-contraction
Muscular co-contraction can “stiffen” the vertebral motion segment
- PM, MULTIFIUS, RECTUS AB WHEN CONTRACT = COMPRESS JOINT
Extensive muscular attachments into the thoracolumbar fascia
Extensive muscular attachments into the thoracolumbar fascia which, in turn, attach to lumbar transverse & spinous processes - possible contributions to motion segment stability
OBLIQUE FIBRES THEREFORE WHEN STRETCH, INCREASE COMPRESSION AND TRANSVERSE PROCESSES TOGETHER
- WHEN CONTRACT PULLS TFL TIGHT
Diaphragm: function
1. Respiration
contraction pulls central tendon inferiorly
increases intra-thoracic volume / decreases intra-abdominal volume
if abdominal muscles are relaxed – abdominal viscera pushed anteriorly if abdominal muscles are contracted – increase intra-abdominal pressure
- FAVOURS RESPIRATION OVER STABILITY
Diaphragm: function
2. Trunk posture:
Standing at rest:
diaphragm relaxed during expiration
Sitting / standing + repetitive fast UL movements: diaphragm active throughout expiration
78 +/- 17%
“support the argument that diaphragm contraction is related to trunk control”
“postural activity of diaphragm changed
when respiratory drive increased”
Increased intra-abdominal pressure
- INCREASES STIFFNESS OF THE LUMBAR SPINE
- creates an extension moment
Increased IAP…
• increased extensor moment & increased the force required to flex the lumbar spine
• contributes to spinal stability
** “the net effect of this extensor torque in functional tasks would be dependent on the muscles used to increase the IAP and their associated flexion torque”
