Vertebral column: muscles of the back Flashcards
what are the 2 divisions of the extrinsic muscles of the back
superficial and intermediate extrinsic muscles
what is the function of the superficial extrinsic muscles of the back
connect to appendicular skeleton
what is the function of the intermediate extrinsic muscles of the back
secondary/superficial respiratory muscles
what are the 5 superficial extrinsic muscles
trapezius
latissimus dorsi
rhomboid major
rhomboid minor
levator scapulae
what nerve innervates trapezius
spinal accessory nerve (CN XI)
describe the attachments of trapezius
very broad - starts at base of skull on medial 1/3 of superior nuchal line, continues down in cervical region along nuchal ligament and spinous processes of C7-T12. Fibres then converge as they travel laterally to attach to lateral clavicle, acromium of scapula and longer attachment along length of spine of scapula
what are the attachments of trapezius
medial 1/3 nuchal line, nuchal ligament, spinous processes C7-T12
–> lateral clavicle, acromium and spine of scapula
what is the function of trapezius when it acts as a whole
rotate scapula so that the glenoid cavity will point more superiorly allowing a greater degree of abduction of upper limb
what is another function of the trapezius
retract scapula (particularly the central fibres) pulling it closer to midline
what nerve innervates the latissimus dorsi
thoracodorsal nerve (C6-8) from brachial plexus
describe the attachments of latissimus dorsi
very broad - spinous processes of T7-T12, thoracolumbar fascia, iliac crest, lower 3/4 ribs
fibres then converge as they head to distal attachment - pass onto anterolateral aspect of humerus by passing medial to humerus then wrapping around in order to reach insertion point on bicipital groove of humerus
what are the attachments of latissimus dorsi
spinous processes T7-T12
thoracolumbar fascia
iliac crest
lower 3/4 ribs
edge of bicipital groove of humerus
what is the function of latissimus dorsi
powerful extensor of shoulder joint - important when e.g. climbing and pulling body weight upwards
what are the attachments of rhomboid major
spinous processes of T2-5
–> medial border scapula
(angle inferiorly from vertebrae to scapula)
what are the attachments of rhomboid minor
nuchal ligament
spinous processes C7,T1
–> medial end of spine of scapula
what is the innervation of the rhomboids
dorsal scapular nerve (C4,5)
what are the attachments of levator scapulae
posterior tubercles of transverse processes C1-4
–> medial border of scapula above spine
what is the innervation of the levator scapulae
cervical spinal nerves C3,4 and dorsal scapular nerve (C4,5)
what is the function of levator scapulae
raise scapula
what is the function of the rhomboids
retract scapula pulling them closer to midline
what is the nuchal ligament
very broad ligament connecting the base of the skull and the spinous processes of the cervical vertebrae
what are the 2 intermediate extrinsic back muscles
serratus posterior superior and inferior
what are the attachments of serratus posterior superior
nuchal ligament
spinous processes C7-T3
superior borders ribs 2-4
what is the nerve supply of serratus posterior superior
intercostal nerves 2-5
what is the function of serratus posterior superior
assists in raising the upper ribs
what are the attachments of serratus posterior inferior
spinous processes T11-L2
inferior borders of ribs 8-12 near angle of ribs
what is the nerve supply of serratus posterior inferior
anterior rami T9-T12
what is the function of serratus posterior inferior
assists in lowering lower ribs
are the serratus posterior muscles substantial
no - in many individuals are membranous and very thin
what is the function of the deep muscles of the back
maintain posture and control movements of the vertebral column
what are the divisions of the intrinsic muscles of the back
superficial
intermediate
deep
what is the nerve supply of the intrinsic muscles of the back
posterior (dorsal) rami of spinal nerves
what muscles make up the superficial intrinsic muscles
splenius muscles
what muscles make up the intermediate intrinsic muscles
erector spinae muscles
what muscles make up the deep intrinsic muscles
many small muscles
the superficial intrinsic muscles are found only in the
cervical region
the intermediate intrinsic muscles are found where
whole length of back
true/false
deep intrinsic muscles of the back individually produce large movements
false - each individual muscle will not produce large movement but together they produce more dramatic movement
what muscles make up the superficial intrinsic muscles
splenius muscles - splenius capitis and splenius cervicis
what are the attachments of splenius capitis
nuchal ligament and spinous processes C7 - T3/4
to mastoid process and lateral 1/3 of superior nuchal line
what are the attachments of splenius cervicis
nuchal ligament and spinous processes of C7-T3/4 to tubercles of transverse processes C1 to C3/4
what is the common attachment of the splenius muscles
nuchal ligament and spinous processes of C7 - T3/4
what muscles make up the intermediate intrinsic back muscles
erector spinae muscles:
- iliocostalis
- longissimus
- spinalis
how are the erector spinae muscles arranged
in 3 columns from lateral to medial: iliocostalis, longissimus, spinalis
what is the common proximal attachment of the erector spinae muscles
- posterior iliac crest
- posterior sacrum and sacroiliac ligaments
- spinous processes of sacral and lower lumbar vertebrae
- supraspinous ligament
what are the 3 parts of iliocostalis
lumborum
thoracis
cervicis
what are the attachments of iliocostalis
fibres travel up from common proximal attachment to angle of lower ribs and cervical transverse processes
what are the 3 parts of longissimus
thoracis
cervicis
capitis
what are the attachments of longissimus
common proximal attachment to
- ribs between tubercles and angles
- thoracic and cervical transverse processes
- mastoid process
what are the 3 parts of spinalis
thoracis
cervicis
capitis
what are the attachments of spinalis
common proximal attachment to upper thoracic spinous processes and cranium
describe spinalis
often poorly developed, quite small and right in beside spine
what muscles make up the deep intrinsic muscles of the back
semispinalis
multifidis
rotatores
levator costarum
interspinale
intertransversari
what parts does semispinalis have
thoracis
cervicis
capitis parts
what are the attachments of semispinalis
transverse processes C4-T12 to occipital bone and thoracic and cervical spinous processes
where is multifidis thickest
lumbar region
what are the attachments of multifidis
fibres pass superomedially to spinous processes 2-4 vertebrae above
where is rotatores best developed
thoracic region
what are the attachments of rotatores
fibres pass superomedially to junction of lamina and transverse process 1 or 2 vertebrae above
what is the function of levator costarum
assist in raising ribs
where is levator costarum found
thoracic region
where do fibres of levator costarum run
from transverse process of vertebra down to upper border of rib
where is interspinale most developed
cervical and lumbar regions
where is interspinale found
between adjacent spinous processes
where is intertransversari located
between transverse processes of adjacent vertebrae
where is intertransversari best developed
cervical and lumbar regions
