Back 2/3: Back Musculature
What is the innervation and blood supply of latissimus dorsi?
Innervation: Thoracodorsal nerve (C6-C8), off brachial plexus Blood supply: thoracodorsal artery
What are the proximal and distal attachments of serratus posterior inferior and superior?
P: SPS: nuchal ligamnet, SP's C7-T3 SPI: Sp's T11-L2/3 D: SPS: ribs 2-5, lateral to angles SPI: ribs 9-12, lateral to angles
What are the proximal and distal attachments of rhomboid major and minor?
P: minor: nuchal ligamnet, sp's C7-T1 major: sp's T2-T5 R7OMBO1D5 D: minor: medial border of scapula at level of spine major: medial border of scapula inferior to spine
What are the proximal and distal attachments of splenius cervicis?
P: SP's T3-T6 D: TP's C1-C3
What are the proximal and distal attachments of latissimus dorsi?
P: SPs T7-T12, thoracolumbar fascia, iliac crest D: floor of intertubercular sulcus (bicipital groove)
What are the proximal and distal attachments of levator scapulae?
P: TPs C1-C4 D: superior angle/ medial border of scapula
What are the proximal and distal attachments of splenius capitis?
P: nuchal ligament and SPs C7-T4 D: mastoid process and superior nuchal line
What are the proximal and distal attachments of trapezius?
P: superior nuchal line, nuchal line, spinous processes C7-T12 D: scapular spine, acromion, lateral 1/3 of clavicle
What is the function of the greater occipital nerve, and what is the clinical relevance?
POsterior ramus of C2 is strictly sensory to the back of the head transverses semispinalis capitis : dysfunction in this muscle can lead to sensory issues on back of head
What is the attachment of iliocostalis?
Proximal: ileum, sacrum, lumbar Distal: ribs
What are the borders of the triangle of auscultation? what is heard here?
Trapezius medial, latissimus dorsi inferior, and medial border of scapula lateral used to hear posterior lung sounds at 6th intercostal space
What is the action of latissimus dorsi?
extension, medial rotation, and adduction of the upper limb (pull up muscle)
What is the function of the thoracolumbar fascia?
functions as a retinaculum preventing dorsal protrusion of muscles upon contraction, also attachment for transverse abdominis mm.
What is shown in the following image?
herniation through inferior lumbar triangle: petit's hernia
What are the attachments of rectus capitis posterior minor?
inferior nuchal line to posterior tubercle C1
What are the attachments of rectus captis posterior major
inferior nuchal line to spinous process C2
What is the innervation and blood supply of the suboccipital muscles?
innervation: suboccipital nerve (C1 posterior ramus) blood supply: vertebral and occipital arteries
What are the intersegmental muscles?
intertransversii and interspinales (true segmental) levatores costarum
What muscles are covered by thoracolumbar fascia?
intrinsic back muscles
A 35-year-old female presents with the chief complaint of upper back discomfort. Physical exam reveals that T3 - T8 vertebra are SL [side-bent left] and RR [rotated right]. what muscle is responsible?
left semispinalis
Where is multifidus found and how many vertebrae does it span?
most prominent in lumbar region spans 2-4 vertebrae
Where is semispinalis found and how many vertebrae does it span?
most prominent in thoracic region spans 4-6 vertebrae
Describe the posterior layer of thoracolumbar fascia
most superficial, covers deep back muscles; posterior to erector spinae
What is the function of the suboccipital nerve?
motor to the muscles of the SOT, NO cutaneous sensory branch
What are the contents of the suboccipital triangle
vertebral artery and suboccipital nerve (C1)
What are the attachments of longissimus?
proximal: ileum, sacrum, lumbar distal: mastoid process and transverse process
What muscles form the suboccipital triangle?
rectus capitis posterior major, obliqus capitis inferior, obliqus capitis superior
What are the actions of the rhomboids?
retract and fix scapula
Describe the anterior layer of thoracolumbar fascia
separates abdominal cavity from posterior abdominal wall; is anterior to quadratus lumborum
What is the function of the suboccipital muscles?
support of the head in the upper cervical region extension of the head on the neck, lateral flexion
Label the parts of the following
thoracolumbar fascia (anterior middle and posterior) slide 23 for reference
What are the attachments of obliquus capitis inferior?
transverse process C1 to spinous process C2
What is the unilateral and bilateral action of erector spinae?
unilateral: lateral flexion of the spine bilateral: extension of the spine *main extensors of the vertebral column*
What is the unilateral and bilateral action of transversospinales?
unilateral: rotation to the opposite side bilateral: support
What muscles are included in erector spinae?
Iliocostalis, Longissimus, and spinalis
What are the attachments of semispinalis capitis?
Tp's C7-T6 to occipital bone
What is the action of intertransversarii and interspinales?
support
What are the three layers of throacolumbar fascia and where will they terminate?
Anterior, middle, and posterior terminate at attachment of transversus abdominus muscle
Describe rotation of vertebrae
Direction of the body is used for direction Dysfunction will rotate vertebrae to left if it is on right and right if it is on left
What is the innervation and blood supply to the levator scapulae and rhomboids?
Innervation: dorsal scapular nerve (think these are dorsal to scapula) Blood supply: deep cervical artery think ROM cut deep into the rhomboids and levator scapulae
What is the innervation and blood supply to serratus posterior inferior and superior?
Innervation: segmental anterior rami (intercostal nerves) blood supply: intercostal arteries
What superficial back muscle will attach to thoracolumbar fascia?
Latissimus dorsi
What borders the inferior lumbar triangle and what is the clinical significance?
Latissimus dorsi medial, external oblique lateral, and iliac crest inferior site of weakening that can lead to hernia (Petit's hernia)
A 52-year-old male presents with the chief complaint of lower back pain. Physical exam reveals that his L1 vertebra is rotated on L2; SL [side-bent left] and RL [rotated left]. what muscle is responsible?
Right rotatores
What are the actions of serratus posterior inferior and superior?
SPS: elevate ribs SPI: depress ribs accessory respiratory muscles; mainly proprioceptive
What muscles form transversospinales?
Semispinalis, multifidus, and rotatores transverse process to spinous process
What are the attachments of thoracolumbar fascia?
Superior: continuous with deep fascia of neck Inferior: lower border of Rib 12 and iliac crest Medial: spinous and transverse processes Lateral: angles of ribs and lateral abdominal wall muscles
What do the intrinsic back muscles act on?
act on vertebral column and skull most body weight is anterior to the vertebral column - back muscles must counteract to provide bipedal posture
Where is rotatores and how many vertebrae does it span?
all throughout vertebral column spans 1-2 vertebrae
What is a dermatome?
an area of skin supplied by a single spinal cord level (sensory) note: cutaneous nerves do not follow these patterns
Describe the middle layer of the thoracolumbar fascia
anterior to erector spinae, attaches to transverse processes
Where is the suboccipital region found?
associated with posterior aspects of C1 (atlas) and C2 (axis) deep to semispinalis capitis
What are the attachments of obliquus capitis superior?
between superior and inferior nuchal lines to transverse process C1
What is the action of levatores costarum?
elevates ribs (TP to ribs at thoracic region) *accessory respiratory muscles*
What is the action of levator scapulae?
elevates scapula
What is the action of trapezius?
elevation and depression of scapula, retraction of scapula, abduction of upper limb above 90 degrees
What are the bony attachments of the scapula?
not many bony attachments, most articulation is muscle so that it has increased mobility scapulothoracic or sternum (which attaches at sternoclavicular)
What is the blood supply to spinotransversales?
occipital and segmental arteries (come out at every level and supply body wall
What are the attachments of spinalis?
p: ileum, sacrum, lumbar d: spinous processes
What is a suboccipital release?
place pressure on back of skull in order to release semispinalis capitis muscle and relieve tension on greater occipital nerve (posterior rami C2)
What are the intrinsic back muscles innervated by? What covers these muscles
posterior rami of spinal nerves covered by throacolumbar fascia
Label the suboccipital muscles
slide 36 for reference
What is the innervation of trapezius?
spinal accessory nerve (CN XI): motor (think SAN TRAP) C2, 3, 4: proprioception
What are the unilateral and bilateral axions of spinotransversales?
splenius capitis and cervicis unilateral: rotation to ipsilateral side, lateral flexion bilateral action: extension of head and neck
What muscles compose spinotransversales?
splenius capitis and splenius cervicis
What is the blood supply to trapezius?
superficial branch of transverse cervical artery think SUP TRAP queen (ladies have cervix)
What are the extrinsic back muscles and what do they work on and what are they innervated by?
superficial: trapezius, latissimus dorsi, levator scapulae, and rhomboids intermediate: serratus posterios superior and inferior act on shoulder and upper limb innervated by anterior rami