The Back Flashcards
What structures make up the pectoral girdle?
The clavicle, scapula and humerus
What ligaments are associated with the pectorial girdle?
Acromioclavicular
- coacoacromial
- glenohumeral
- scapulothoracic joint
- anterior sternal clavicular joint/ ligament
What is another name for Hypaxial muscle and what do they do?
-Extrinsic Muscles
-Move limbs.
Innervated by CN XI or brachial plexus branches
Intrinsic Muscles are innervated by what and are associated with muscles where?
- Support upright posture, and vertebral column movements
- proprioception
- Innervated by dorsal rami spinal nerves
What are the most superficial layers of back muscles?
Trapezius, and latissimus dorsi
What are muscles are deep to the trapezius and the latissimus dorsi?
- levator scapulae
- rhomboid major
- rhomboid minor
Explain what a axioappencidular muscle is…
Posterior muscle attaching the scapula and humerus to the axial skeleton. and/or scapula to the humerus.
What nerve innervates the scapula and the rhomboids?
CN IV
Describe the trapezius. (origin, insertion, actions, innervation)
- Origin: ext. occipital protuberance, nuchal ligament, C7-T12 spinous process.
- Insertion: ant. lateral 3rd clavicle. acromion, scapular spine.
- Action: elevation, depression, retraction of scapula. Superior rotation of glenoid fossa
- Innervation: motor: CN XI. sernory: Ventral rami C3/C4
Latissimus dorsi (actions, origin, insertion, innervation)
-Origin: Iliac crest, inferior 3 ribs, inferior thoracic vertebra 6, thoracolumbar fascia.
-Insertion: Intertubercular sulcus of humerus
-ACtion: extend, adduct, medial rotation.
Innervation: thoracodorsal nerve
What muscle compose the deep posterior axioappendicular muscles, that are still superficial/hypaxial
- Levator Scapula
- Rhomboid Major
- Rhomboid Minor
- these are supplied by thoracodorsal artery/veins and nerve
Rhomboid Major…
- origin:T2-T5 spinous process
- insertion: medial border of scapula from spine to inferior angle.
- action: retract, elevate, rotate scapula down. Fix to thoracic wall also.
- innervation: dorsal scapular nerve. Motor: C3/C4
Rhomboid Minor…
- origin: nuchal ligament, c7 and t1 spinous process
- insertion: medial end of scapular spine
- action: retract, elevate, rotate down scapula.
- innervation: dorsal scapular nerve, Motor: c3/c4
Levator Scapula
- origin: posterior tubercle of transverse process of c1-c4
- insertion: medial scapular border, superior scapular spine
- action: elevate scapula, inferior rotation of glenoid fossa.
- innervation: dorsal scapular nerve, ventral rami of cervical spine nerves
What muscles compose the Extrinsic back Muscles?
- Serratus posterior superior
- serratus posterior inferior
- compose the third layer of muscles. Provide the postural and rotation of the vertebral column
Serratus Posterior Superior
- origin: nuchal ligament, c7-t3 spinous process
- insertion: superior border of ribs 2-4
- action: elevate the ribs
- innervation: t2-t5 intercostal nerves (ventral rami)
Serratus Posterior Inferior
- origin: t11-l2 spinous process
- insertion: inferior border of ribs 8-12
- action: depression of the ribs
- innervation: intercostal nerve and subcostal nerve
What is the deepest group of major epaxial muscles, and the components from deepest to superficial?
- Transversospinalis group
- -rotatores
- -multifidus
- -semispinalis
What is the more superficial layer of epaxial back muscles, labeled deepest to superficial?
- Erector spina group
- -Spinalis
- -Longissimus
- -Iliocostalis
Of the Hypaxial muscle group, list muscles from deepest to superficial.
-serratus posterior
-latissimus dorsi
-trapezius (roughly)
have some amount of overlap
The splenius back muscle.
Composed of the splenius cervicis and splenius capitis
Splenius Cervicis
- origin: nuchal ligament and t1-t6 spinous process
- insertion: transverse tubercles of c1-c4
- action: extend head and neck or rotate head
- innervation: dorsal rami
Splenius Capitis
- origin: nuchal ligament and t1-t6 spinous process
- insertion: lateral aspect of mastoid process, superior nuchal line
- action: extend,flex head neck. rotation when one is activated
- innervation: dorsal rami
Muscles of the erector spinae group
- iliocostalis
- longissimus
- spinalis
- -innervated: dorsal rami of spinal nerves.
- -extension/ or lateral flexion
Iliocostalis muscle
- most lateral muscle
- origin:iliac crest, post sacrum, sacroiliac ligament, sacral and inferior lumbar spinous process, supraspinous ligament.
- insertion: lumbar section (rib 6-12) thoracic (rib 1-6) cervicis (ribs 1-6, post tubercle of c4-c6)
Longissimus Cervicis muscle
- origin: transverse process of cervical vertebra
- insertion: transverse process of cervical vertebra
Longissimus Thoracis Muscle
- origin: iliac crest, post sacrum, sacroiliac ligament, sacral and inferior lumbar spinous process, supraspinous ligament.
- insertion: ribs and adjacent transverse process of thoracic vertebra
Longissimus Capitis muscle
- origin: transverse process of cervical vertebra
- insertion: mastiod process
Spinalis Thoracis muscle
- origin: the spinous process
- insertion: spinous process superior to origin
Spinalis Cervicis and Capitis muscle
difficult to differentiate and capitis may be missing in some cases
Intrinsic back muscles (transversospinalis group)
- innervated: dorsal rami or spinal nerves.
- the deep layer consisting of: semispinalis, rotatores, and mutltifidus
Semispinalis Cervicis muscle
- cervical to spinous process of 2nd vertebra.
- action: extend head and rotate contralaterally
- innervation: dorsal rami of spinal nerve
Semispinalis Capitis muscle
- origin: connects superficial to cervicis
- insertion: transverse process t1-t6 to nuchal line.
- action: extend head, thoracic, and cervical region. contralateral rotation.
Semispinalis Thoracis muscle
- origin: transverse process of t1-t12
- insertion: spinous process t1-t12
action: extend head, thoracic, and cervical region. contralateral rotation.
Multifidus
- cover lamina and span the vertebral segments from sacrum to c2.
- origin: transverse process
- insertion: spinous process
- action: stabilize vertebra during localized movements of vertebral column
Rotatores Brevis muscle
- origin: transverse process
- insertion: base of spinous process superior to the origin vertebra
- action:extend head, thoracic, and cervical region. contralateral rotation.
Rotatores Longus muscle:
- origin:transverse process of on vertebra
- insertion: base of spinous process of 2nd vertebra suprior. spans two IV disks.
- action: extend head, thoracic, and cervical region. contralateral rotation.
