Back and Posterior Neck Flashcards
What are the 7 extrinsic muscles of the back?
Trapezius, Latissmus dorsi, rhomboid major, rhomboid minor, levator sacpulae, serratus posterior superior, serratus posterior inferior
What are the 7 intrinsic muscles of the back?
erector spinae (spinalis, longissmus, ilocostalis), splenius capitis, splenius cervicis, semispinalis capitis, semispinalis cervicis, multifidus, rotatores, intertransversarii
What are the 4 muscles that make up the suboccipital triangle?
rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis superior, obliquus capitis inferior
What are the 3 muscles that form the posterior neck?
anterior scalene, middle scalene, posterior scalene
What nerve innervates all of the 4 suboccipital muscles?
suboccipital nerve = cervical nerve 1 (C1)
What is the action of the rectus capitis posterior major?
extends and rotates head to same side
What is the action of the rectus capitis posterior minor?
extends head
What is the action of the obliquus capitis superior?
extends and bends head laterally
What is the action of the obliquus capitis inferior?
rotates atlas to turn face to same side
What is the origin of the suboccipital nerve?
posterior rami of C1 spinal nerve
What is a “ramus” in nervous system anatomy?
branch or division of a nerve
Where does the suboccipital nerve distribute into?
muscles of the suboccipital triangle
What is the origin of the greater occipital nerve?
posterior ramus of C2 spinal nerve
Where does the greater occipital nerve distribute into?
skin over the neck of occipital bone; innervates semispinalis capitis
Where is the vertebral artery found?
within the suboccipital triangle
What are the 4 cervical ligaments?
alar | apical | cruciate/cruciform (superior band, transverse band, inferior band) | tectorial membrane
What is the alar ligament and its function?
attaches dens bilaterally inserting on the base of skull
located behind superior longitudinal band
(Fx): prevents excessive rotation at the joints
What is the apical ligament and its function?
connects dense to anterior margin of foramen magnum
(Fx): stability
What is the cruciate ligament?
holds dens in articulation
forms = atlanto-axial joint
What are the 3 parts of the trapezius muscle?
ascending fibers, transverse fibers, descending fibers
What is the proximal attachment (origin) of the trapezius muscle? (4 attachments)
external occipital protuberance –> medial third of nucal line –> nuchal ligament –> spinous processes of C7 to T12 vertebrae
What is the distal attachment (insertion) of the trapezius m.? (3 attachments)
- lateral third of clavicle
- spine of scapula
- acromion process
What is the innervation and blood supply of the trapezius m.?
innervation = spinal accessory nerve, C3 and C4
blood supply = thryocervical trunk + superficial branch of transverse cervical artery
What is the action of the trapezius m.?
- descending fibers = elevates scapula
- ascending fibers = depresses scapula
- transverse fibers = retracts scapula
- descending + ascending fibers together = superiorly rotate glenoid cavity (upward rotation of scapula)
What is the proximal attachment (origin) of the latissmus dorsi?
- spinous process of inferior 6 thoracic vertebrae
- inferior 3-4 ribs
- thoracolumbar fascia
- iliac crest
What is the distal attachment (insertion) of the latissmus dorsi m.?
floor of intertubercular sulcus of humerus
What innervates the latissmus dorsi?
thoracodorsal nerve
nerve roots; C6, C7, and C8
What is the action of the latissmus dorsi?
extends, adducts, & medially rotates humerus
(ie: swimming or rock climbing)
What is the proximal attachment (origin) of the rhomboid minor?
- nuchal ligament
- spinous process of C7 to T1 vertebrae
What is the proximal attachment (insertion) of the rhomboid major?
spinous process of T2 through T5
What is the distal attachment (insertion) of the rhomboid minor?
smooth triangular area at the medial border of the scapular spine
What is the distal attachment (insertion) of the rhomboid major?
along medial border of scapula from scapular spine to the inferior angle
What innervates both rhomboid minor and major?
dorsal scapular nerve (C4 and C5)
What is the action of the rhomboid minor and major?
- retract scapula
- inferiorly (downward) rotate glenoid cavity
- fix scapula to thoracic wall
What is the proximal attachment of the anterior scalene?
transverse processes of C3 to C6 vertebrae
What is the proximal attachment of the medius and posterior scalenes?
posterior tubercles of the trransverse processes of C5 to C7 vertebrae
What is the distal attachment of the anterior scalene?
1st rib
What is the distal attachment of the medius scalene?
- superior surface of 1st rib
- posterior to groove for subclavian artery
What is the distal attachment of the posterior scalene?
external border of 2nd rib
What innervates the anterior scalene?
cervical spinal nerves C4 to C6
What innervates the medius scalene?
anterior rami of cervical spinal nerves
What innervates the posterior scalene?
anterior rami of cervical spinal nerves C7 and C8
What is the action of the anterior and medius scalenes?
- laterally flexes neck
- elevates 1st rib in forced inspiration
What is the action of the posterior scalene?
- laterally flexes neck
- elevates 2nd rib in forced inspiration
What is the proximal attachment (origin) of the sternocleidomastoid m.? (2x)
- lateral surface of mastoid process of temporal bone
- lateral half of superior nuchal line
What is the distal attachment (insertion) of the sternocleidomastoid m.?
SCM splits into 2:
- one attaches to the medial third superior surface of clavicle (clavicular head)
- one attaches to the anterior surface of manubrium of sternum (sternal head)
What innervates the sternocleidomastoid?
- spinal accessory nerve
- C3 and C4
What are the actions of the sternocleidomastoid m.?
- unilateral contraction: lateral flexion of neck with rotation
- bilateral contraction: [1] extends neck at atlanto-occipital joints (tilt head backward) ; [2] flexion of cervical vertebra (chin to manubrium) ; [3] extends superior cervical vertebra while flexing inferior cervical vertebra = chin thrust forward
What innervates the serratus posterior superior?
2nd to 5th intercostal nerves
What is the action of the serratus posterior superior?
elevates ribs
What innervates the serratus posterior inferior?
- 9th to 11th intercostal nerves
- T12 (subcostal) nerve
What is the action of the serratus posterior inferior?
depresses ribs
Where is the levator scapulae located?
superior medial border of scapula to root of scapular spine –> transverse processes of C1-C4 vertebra
What innervates the levator scapulae?
- dorsal scapular nerves (C5)
- cervical nerves C3 and C4
What is the action of the levator scapulae?
- elevates scapula
- inferiorly (downwards) rotation of glenoid cavity
Where is the splenius cervicis located?
attached to C1 (atlas) vertebra and spinous process of thoracic vertebra
Where is the splenius capitis located?
attached to lateral third of superior nuchal line and spinous process of C7 vertebra
What innervates the splenius capitis and cervicis?
posterior rami of spinal nerves
What is the action of splenius capitis and cervicis?
- independently: laterally flexes neck, rotates head to side of active muscles
- together: extends head and neck
What is the location of semispinalis capitis and semispinalis cervicis?
semispinalis cervicis is under the semispinalis capitis layer and is inferior to the rectus capitis major
semispinalis capitis has an attachment to the occipital bone
What innervates the semispinalis capitis and cervicis?
posterior rami of spinal nerves
What is the action of the semispinalis capitis and cervicis?
extends head, cervical and thoracic regions of vertebral column; rotates them contralaterally
What makes up the erector spinae? Where are they located?
Along the spine from medial to lateral order:
[1] spinalis (capitis, cervicis, thoracis)
[2] longissmus (capitis, cervicis, thoracis)
[3] iliocostalis (cervicis, thoracis, lumborum)
What innervates the erector spinae?
posterior rami of the spinal nerves
What action does the erector spinae perform?
unilaterally: laterally flex vertebral column
bilaterally: extend vertebral column and head
—when flexing back - controls movement via eccentric contraction
Where are the rotatores located?
attaches between the transverse vertebral processes to lamina of vertebra
brevis = short = touches 2 vertebras
longus = long = touches/extends 3 vertebras
What innervates the rotatores?
posterior rami of spinal nerves
What action do the rotatores perform?
proprioception; stabilize vertebral column during movements
Where are the multifidus located?
broad and long muscle
between the transverse and spinous processes of vertebra and spans from C2 to iliac crest/sacrum
What innervates the multifidus?
posterior rami of spinal nerves
What action does the multifidus perform?
unilateral contraction rotates to opposite side; stabilizes vertebral column
Where are the intertransversarii m. located?
between vertebral transverse processes and notches
What innervates the intertransversarii m.?
posterior AND anterior rami spinal nerves
What action do the intertransversarii m. perform?
aids in lateral flexion of vertebral column; stabilizes vertebral column