Extrinsic Back Muscles Flashcards
superficial muscles insertion
pectoral girdle or arm
superficial muscles innervation
cranial nerve, spinal nerve via plexus
intermediate muscles innervation
spinal nerve, anterior ramus
deep muscles insertion
vertebra, skull, proximal rib
deep muscles innervation
spinal nerve, posterior ramus
which level of muscles is anterior ramus?
intermediate
which level of muscles is posterior ramus?
deep
5 types of superficial extrinsic back muscles
- trapezius
- latissimus dorsi
- levator scapulae
- rhomboid major
- rhomboid minor
ascending and descending fibers of trapezius causes what action
upward rotation of the scapula
trapezius origin
- superior nuchal line
- external occipital protuberance
- nuchal ligament
- SP lower cervical, upper thoracic
trapezius insertion
- lateral 1/3 of clavicle
- acromion process
- spine of scapula
trapezius action
- descending fibers = elevation
- middle fibers = retraction
- ascending fibers = depression
- ascending and descending fibers together = upward rotation of the scapula
- extension of head and neck
trapezius innervation
motor = accessory nerve (11)
sensory = anterior rami of mid cervical
trapezius blood supply
superficial branch of transverse cervical artery
what is a high area for injury by physicans?
between the sternocleidomastoid and trapezius where the accessory nerve is superficial and vulnerable
levator scapulae origin
TP upper cervical
levator scapulae insertion
superior angle of scapula
levator scapulae action
elevation and downward rotation of scapula
**lateral flexion of the neck = when contraction of the muscle when the shoulder is fixed
levator scapulae innervation
motor = dorsal scapular nerve
sensory = anterior rami mid cervical
levator scapulae blood supply
-dorsal scapular artery (deep branch of transverse cervical artery)
rhomboid major origin
- nuchal ligament
- supraspinatous ligament
- SP upper thoracic
rhomboid major insertion
medial border of scapula inferior to spine
rhomboid major action
retraction and downward rotation of scapula
rhomboid major innervation
dorsal scapular nerve (C5)
rhomboid major blood supply
dorsal scapular artery (deep branch of transverse cervical artery)
rhomboid minor origin
- nuchal ligament
- supraspinatous ligament
- SP lower cervical, upper thoracic
rhomboid minor insertion
medial border of the root of spine of scapula
rhomboid minor innervation
dorsal scapular nerve (C5)
rhomboid minor blood supply
dorsal scapular artery (deep branch of transverse cervical artery)
latissimus dorsi origin
- SP lower thoracic
- ribs 9-12
- thoracolumbar fascia
- iliac crest
latissimus dorsi insertion
floor of intertubercular sulcus on anterior humerus
rhomboid major action
-fixes scapula to thoracic
wall
-retracts and rotates scapula to depress glenoid cavity
rhomboid minor action
-fixes scapula to thoracic
wall
-retracts and rotates scapula to depress glenoid cavity
latissimus dorsi action
- extends humerus
- adducts humerus
- medially rotates humerus
latissimus dorsi innervation
motor = thoracodorsal nerve (posterior cord C6-C8)
latissimus dorsi blood supply
thoracodorsal artery
2 intermediate extrinsic back muscles
- serratus posterior superior
- serratus posterior inferior
serratus posterior superior origin
- nuchal ligament
- SP lower cervical, upper thoracic
serratus posterior superior insertion
dital angle ribs 2-5
serratus posterior superior action
elevates ribs 2-5
serratus posterior superior innervation
anterior rami T2-T5 (intercostal nerves)
serratus posterior superior blood supply
posterior intercostal arteries
serratus posterior inferior origin
SP lower thoracic, upper lumbar
serratus posterior inferior insertion
distal angle ribs 9-12
serratus posterior inferior action
depresses ribs 9-12
serratus posterior inferior innervation
intercostal nerves - anterior rami T9-T11
subcostal nerves - anterior rami T12
serratus posterior inferior blood supply
posterior intercostal arteries
If the cross section image of the back has a scapula, what is the most superficial muscle?
trapezius
If the cross section image of the back DOES NOT have a scapula, what is the most superficial muscle?
latissimus dorsi
From the lower thoracic to the lumbar levels, the posterior cutaneous branch originates from the _____ branches of the posterior rami and enters the superficial fascia lateral to the thoracolumbar fascia.
lateral
map out the dorsal branch of the posterior intercostal artery
descending aorta»_space; course along thoracic wall in the intercostal spaces»_space; posterior intercostals give rise to the deep branch
what does the dorsal branch of the posterior intercostal artery course with?
posterior ramus
what is the venous drainage for the extrinsic back muscles
- intercostal veins
- azygos vein
- superior vena cava
- inferior vena cava
triangle of auscultation
- medial wall = inferior margin of trapezius
- lateral wall = medial border of scapula
- inferior wall = superior margin of latissimus dorsi
- floor = 6th and 7th rib, external intercostal within 6th intercostal space
which muscle is most likely involved in elevating, depressing, and retracting the scapula?
trapezius
what nerve is injured if movements involving adduction, medial rotation, and extension of the arm are weak?
thoracodorsal
severed transverse cervical artery would affect which muscle most?
trapezius
severed posterolateral aspect of neck causes inability to elevate tip of shoulder on the injured side, what nerve is injured?
accessory
