Thoracic Spine Muscle Flashcards
Thoracic Spine Musculature :
Latissimus Dorsi (Layer 1):
O: sp of last six thoracic vertebrae, last 3-4 ribs, through thoracolumbar fascia in lumbar and sacral regions, posterior ⅓ of external lip of iliac crest, a slip from the inferior angle of the scapula.
I: intertubercular groove of the humerus
A: unilaterally: medially rotates, adducts, the extends the shoulder, lateral flexion of the trunk, , assists in tilting pelvis,
A: bilaterally: hyperextending the spine, flexing the spine
N: Thoracodorsal Nerve (C6, C7, C8)
Muscle Testing: Lattisimus Dorsi:
Patient: prone
Fixation: examiner places one hand for counterpressure on the pelvis
Test: adduction of the arm with extension in the medially rotated position
Pressure: against the forearm in the direction of abduction and slight flexion of the arm.
Thoracic Spine Musculature :
Rhomboid Minor (Layer 2):
O: ligamentum nuchae, spinous processes of C7 and T1.
I: medial border at root of spine of the scapula
A: adduct and elevate the scapula, rotation
N: Dorsal Scapula, C4, C5
Thoracic Spine Musculature (Layer 2):
Rhomboid Major:
O: spinous processes of T2-T5 thoracic vertebrae
I: by fibrous attachment to the medial border of the scapula between the spine and the inferior angle
A: adduct and elevate the scapula, rotation
N: Dorsal Scapula, C4, C5
Serratus Posterior, Superior:
O: spinous processes of C7-T3
I: ribs 2-5 on the superior external border
A: expands the chest, elevates the ribs
N: ventral rami of upper thoracic nerves
Serratus Posterior, Inferior:
O: SP spines of T11, T12, L1, L2, L3
I: lower four ribs (9-12)
A: draws ribs backwards and downwards
N: T9, T10, T11, T12 (ventral rami of the lower thoracic nerve)
*considered an accessory muscle of expiration
Erector Spinae - Iliocostalis Thoracis-Layer5:
O: upper borders of the angles of ribs 7-12
I: angle of ribs 1-6, transverse process of C7
A: bilateral - extension flexion of thoracic spine, draws ribs down
A: unilateral - lateral flexion of thoracic spine
N: spinal nerve (dorsal rami)
Muscle Testing: Back Extensors:
Patient: prone, hands clasped behind head
Fixation: examiner stabilizes legs firmly on table
Test: trunk extension to full range
Pressure: gravity
Erector Spinae - Iliocostalis Lumborum-Layer 5:
O: sacrum, SPs of T11, T12 & upper lumbar, iliac crest, supraspinous ligament
I: angle of ribs 7-12
A: extension of spine, eccentric stabilization during trunk flexion
N: spinal nerve (dorsal rami)
**has three parts: cervicis, thoracis, lumborum
Muscle Testing: Back Extensors:
Patient: prone, hands clasped behind head
Fixation: examiner stabilizes legs firmly on table
Test: trunk extension to full range
Pressure: gravity
Erector Spinae - Longissimus Thoracis -Layer 5:
O: transverse processes of L1-L5 and thoracolumbar fascia
I: transverse processes of T1-T12 and angles of ribs 4-12
A: bilateral - extension of the thoracic spine, draws ribs down
A: unilateral - lateral flexion of the thoracic spine
N: spinal nerve (dorsal rami)
Muscle Testing: Back Extensors:
Patient: prone, hands clasped behind head
Fixation: examiner stabilizes legs firmly on table
Test: trunk extension to full range
Pressure: gravity
Erector Spinae - Spinalis Thoracis-Layer 5:
O: tendons from spinous processes of T11-L2
I: spinous processes of T1-T4 to T8 (variable)
A: extension of the thoracic spine
N: spinal nerve (dorsal rami)
Muscle Testing: Back Extensors:
Patient: prone, hands clasped behind head
Fixation: examiner stabilizes legs firmly on table
Test: trunk extension to full range
Pressure: gravity
Deepest Layer - Transversospinalis - Layer 6:
Semispinalis Thoracis:
O: transverse processes of lower 6-10 thoracic vertebrae
I: spinous processes of C6-T4
A: bilateral - extension of the thoracic spine
A: unilateral - contralateral rotation of the thoracic spine
N: spinal nerve (dorsal rami)
Muscle Testing: Posterolateral Neck Extensors: Semispinalis Capitis & Cervicis/ Splenius Capitis & Cervicis/ Cervical Erector Spinae
Patient: prone, elbows bent, hands overhead
Fixation: none
Test: posterolateral neck extension, with face turned toward the side being tested
Pressure: against the posterolateral aspect of the head in an anterolateral direction
Deepest Layer - Transversospinalis- Layer 6:
Multifidus Thoracis:
O: transverse processes of T1-T12
I: spinous processes 3-4 segments above origin
A: bilateral - extension of the thoracic spine
A: unilateral - contralateral rotation of thoracic spine
N: spinal nerve (dorsal rami)
Deepest Layer - Transversospinalis- Layer 6:
Multifidus Lumborum:
O: mammillary processes of L1-5
I: SP’s 3-4 segments above origin
A: bilateral - extension of vertebral column
A: unilateral - contralateral rotation of vertebral bodies
N: spinal nerve (dorsal rami)
Deepest Layer - Transversospinalis- Layer 6:
Rotatores Thoracis:
O: transverse processes of T1-12
I: base of spinous processes of segments above origin
A: bilateral - extension of thoracic spine
A: unilateral - contralateral rotation of thoracic spine
N: spinal nerve (dorsal rami)
Deepest Layer - Transversospinalis- Layer 6:
Rotatores Lumborum:
O: Transverse Processes of L1-L5 (if present)
I: SP’s (base ) & lamina 1 (brevis) or 2 (longus) segments above origin
A: unilateral - contralateral rotation
A: bilateral - extension, stabilize vertebrae
N: spinal nerve (dorsal rami)
Interspinalis:
O: spinous processes of vertebrae below
I: spinous processes of vertebrae above
A: extension of thoracic spine
N: dorsal rami of spinal nerves
Intertransversarii:
O: transverse process of vertebrae below
I: transverse process of vertebra above
A: lateral flexion of the thoracic spine
N: dorsal rami of spinal nerves
Levator Costarum:
O: transverse processes of C7-T11
I: ribs 1-12
A: elevation of ribs (inspiration)
N: dorsal rami of spinal nerves
Quadratus Lumborum:
O: Iliolumbar ligament, internal lip of the iliac crest
I: inferior border of 12th rib and transverse processes of L1-L4
A: unilateral - lateral flexion of trunk, depression of 12th rib
A: bilateral - extension of lumbosacral spine (increases lumbar lordosis)
N: lumbar plexus (T12-L3)
Muscle Testing: Quadratus Lumborum:
Patient: prone
Fixation: muscles that hold the femur firmly in the acetabulum
Test: lateral elevation of the pelvis, extremity is placed in slight extension and abduction
Pressure/resistance: traction on the extremity opposing the line of fibres of the QL
Diaphragm:
O: Sternal Part: two slips from dorsum of xiphoid process
O: Costal Part: inner surface of lower six costal cartilages and the lower six ribs on either side
O: Lumbar Part: bodies of upper lumbar vertebrae, medial and lateral arcuate ligaments (crus) span from vertebrae to transverse processes to the 12th rib
I: into the central tendon (aponeurosis)
A: separates the thoracic and abdominal cavities, contracts during inspiration (the dome descends), relaxes during expiration (the dome ascends).
N: Phrenic (C3,4,5)
Subclavius:
O: 1st rib (junction of the costal cartilage)
I: middle 1/3 of clavicle (inferior surface)
A: assists in stabilization of clavicle and depresses the clavicle
N: nerve to subclavius
Intercostals:
External Intercostals:
O: lower border of ribs (fingers go in)
I: upper border of ribs below
A: elevates ribs in inspiration, supports intercostal spaces in inspiration and expiration
N: intercostal nerves
**Fibres travel inferior and medially
Intercostals:
Internal Intercostals:
O: inner surfaces of ribs and costal cartilages
I: upper borders of adjacent ribs below(fingers go out)
A: prevents pushing out or drawing in of intercostal spaces in inspiration and expiration, lowers ribs in forced expiration
N: intercostal nerves
**Fibres travel inferior and laterally
Intercostals:
Innermost Intercostals:
O: lower border of ribs
I: upper border of rib below origin
A: elevates ribs
N: intercostal nerves
**Fibres follow the same direction as internal intercostal muscles
