Muscles Flashcards
Insertion of anterior scalene
Anterior scalene tubercle of 1st rib
Innervation of anterior/middle/posterior scalene muscles
Direct branches of cervical and brachial plexus (C3-C6)
Action of scalene muscles
With ribs mobile: Raise upper ribs (inspiration)
With ribs fixed:
-bilateral: flex neck
-unilateral: ipsilateral lateral flexion of cervical spine
Origin of middle scalene
Posterior tubercles of transverse process C3-C7
Insertion of middle scalene
1st rib (posterior to groove for subclavian artery)
Origin of posterior scalene
posterior tubercles of transverse processes C5-C7
Insertion of posterior scalene
Outer surface of 2nd rib
Origin/Insertion of external intercostal muscles
Lower margin of rib (superior) to upper margin of next inferior rib
(fibers run obliquely forward and downward from costal tubercles to chondroosseus junction)
Origin/insertion of internal intercostal muscles
- Lower margin of superior rib to upper margin of inferior rib
- Fibers run obliquely forward and upward from costal angle to sternum
Action of external intercostal muscle
- Raise ribs (inspiration)
- Stabilize intercostal space
- Support chest wall
Action of internal intercostal muscle
- Lower ribs (expiration)
- Stabilize intercostal space
- Support chest wall
Origin of innermost intercostal muscles
Lower margin of upper rib to upper margin of next lower rib
fibers run obliquely forward and upward from costal angle to sternum
Innervation of intercostal muscles (external, internal, innermost internal)
1st to 11th intercostal nerves
T1-T11
Origin/Insertion/Innervation/Action of subcostal muscle
O/I-Lower margin of lower rib to inner surface of 2-3 ribs below
Innerv - adjacent intercostal nerves
Action - lower ribs (expiration
Origin of transversus thoracis muscle
Sternum and xiphoid process (inner surface)
Insertion of transversus thoracis
2nd-6th ribs (costal cartilages and inner surface)
Innervation of transverus thoracis muscle
2nd-6th intercostal nerves
Action of transversus thoracis
Weakly Lower ribs (expiration)
Origin of diaphragm
- 7th -12th ribs (inner surface)
- L1 to L3 vertebral bodies, IV disks
- posterior surface xiphoid process
- anterior longitudinal ligament (as right and left crura)
Insertion of diaphragm
Central tendon of diaphragm
Innervation of diaphragm
Phrenic nerve (C3,C4,C5) - most motor and sensory
*Subcostal and lower intercostal nerves supply sensory innervation to periphery
Origin of anterior scalene
Anterior tubercles of transverse process of C3-C6
Origin of rectus abdominis
Lateral head - From pubic crest to pubic tubercle
Medial head - anterior region of pubic symphysis
Insertion of rectus abdominis
- Costal cartilages of ribs 5-7
- Xiphoid process
Innervation of rectus abdominis
Intercostal nerves (T5-T12)
Action of rectus abdominis
- Flex trunk
- Compress abdomen
- Stabilize pelvis
Origin of external oblique
5th-12th ribs (outer surface)
insertion of external oblique
- Linea alba
- pubic tubercle
- Iliac crest
Innervation of external oblique
Intercostal nerves T7-T12
Action of external oblique
Unilateral: -ipsilateral lateral flexion of trunk -contralateral rotation of trunk Bilateral: -flex trunk, compress abdomen, stabilize pelvis
Origin of internal oblique
- Thoracolumbar fascia (deep)
- Iliac crest
- Anterior superior iliac spine
- Iliopsoas fascia
Insertion of internal oblique
- Linea alba,
- 10th -12th ribs (lower borders)
Innervation of internal oblique
- Intercostal nerves (T1-T11)
- Iliohypogastric nerve
- Ilioinguinal nerve
Action of internal oblique
Unilateral: -Ipsilateral lateral flexion of trunk -Ipsilateral rotation of trunk Bilateral: -Flex trunk, compress abdomen, stabilize pelvis
Origin of transversus abdominis
- Thoracolumbar fascia (deep)
- Iliopsoas fascia
- Anterior Superior Iliac Spine
- Iliac crest
- 7th-12th costal cartilages
Insertion of transversus abdominis
- Linea alba
- Pubic crest
Innervation of transversus abdominis
- Intercostal nerves (T7-T12)
- Iliohypogastric nerve (of lumbar plexus)
- Ilioinguinal nerve
Action of transversus abdominis
Unilateral: ipsilateral rotation of trunk
Bilateral: compresses abdomen
Origin of psoas major
Superficial: -T12-L4 vertebral bodies -Associated IV discs Deep: L1-L5 (transverse processes)
Insertion of psoas major
- Femur (lesser trochanter)
- Joint insertion as illiopsoas muscle
Innervation of psoas major
Direct branches from lumbar plexus
Muscles of the pelvic diaphragm
Levator ani, coccygeus
Origin of coccygeus
Sacrum (inferior end)
Insertion of coccygeus
Ischial Spine
Innervation of coccygeus
Direct branches of sacral plexus (S4-S5)
Action of coccygeus
Supports pelvic viscera; flexes coccyx
Pelvic Wall muscles
Piriformis, Obturator internus
Origin of piriformis
Sacrum (Pelvic surface)
Insertion of piriformis
Femur (apex of greater trochanter)
Innervation of piriformis
Direct branches of sacral plexus (S1-S2)
Action of piriformis
Hip joint: external rotation, stabilization, abduction of flexed hip
Origin of obturator internus
Obturator membrane and bony boundaries of obturator foramen
Insertion of obturator internus
Femur (Medial surface of greater trochanter)