Superficial and Deep Back Muscles

Latissimus Dorsi Origin: Insertion: Innervation: Action: Extra/How to Test:

"BROADEST MUSCLE IN THE BACK" Origin: T6-T12 spinous process thoracolumbar fascia iliac crest Insertion: Intertubercular sulcus of HUMERUS Innervation: THORACODORSAL n. (branch of the BRACHIAL PLEXUS) Action: Extends, adducts, medially rotates HUMERUS @ GLENOHUMERAL JOINT Extra/How to Test: extrinsic muscle superficial layer "swimmers muscle"

Trapezius Palsy Injury to what nerve? How can it be treated?

"DROOPY SHOULDER" -TRAPEZIUS muscle weakness/wasting -result of injury to CRANIAL NERVE XI (the nerve that innervates it) -scapula is translated laterally & rotated downward -Treated surgically w/ muscle transfers of levator scapulae and the rhomboids -->"Eden-Lange Procedure" levator scapulae is moved to the scapular spine, rhomboids are moved to the posterior inferior scapula

Intrinsic Back Muscles - Deep Layer "_________ ___ Group"

"TRANSVERSOSPINALIS MUSCLE GROUP" Semispinalis Rotatores (rotate spine) Multifidus **can't see in gross anatomy lab**

RAMI (RAMUS) Muscle innervation to: Spinal n. TRUNK emerges ___ from the _ _____. Trunk divides into __ branches that go to __ & __, respectively

*GENERAL SENSATION OF BACK* - Muscle innervation to INTRINSIC muscles of the back -General sensation of back -spinal n. trunk emerges LATERALLY from the IV FORAMEN -trunk divides into 2 branches: 1. anterior (ventral) rami - to body wall/limbs 2. posterior (dorsal) rami - go to the back

Structures inferior to suboccipital triangle __ & __ are posterior rami of spinal nerves Least occipital nerve is from:

*Suboccipital n. & Greater Occipital n. *least occipital n. is from anterior ramus

Dermatomes Innervated by: Useful in neurology for: (2) # in each level of vertebrae?

-Unilateral area of skin innverated by the sensory (GSA) fibers of a SINGLE SPINAL NERVE - Useful in neurology for finding the site of damage to the spine; identifying where a lesion has occured 8 cervical 12 thoracic 5 lumbar 5 sacral

Obliquus Capitis Superior (OCS) 1. Origin: 2. Insertion: 3. Innervation: 4. Action: **Extra/How to Test:

1. C1 transverse process 2. Occipital bone (between sup. & inf. nuchal lines) 3. Suboccipital n. (C1 spinal n. posterior ramus) 4. extension/lateral flexion of atlanto-occipital joint **Suboccipital triangle lateral border**

Obliquus Capitis Inferior (OCI) 1. Origin: 2. Insertion: 3. Innervation: 4. Action: **Extra/How to Test:

1. C2 posterior arch 2. C1 transverse process 3. Suboccipital n. (C1 spinal n. posterior ramus) 4. Ipsilateral rotation of atlanto-axial joint **Suboccipital triangle inferior border**

RCPM's "Rectus Capitis Posterior Minor" "Rectus Capitis Posterior Major" 1. Origin: 2. Insertion: 3. Innervation: 4. Action: **Extra/How to Test:

1. Minor - C1 posterior arch Major - C2 spinous process 2. Inferior Nuchal Line 3. Suboccipital n. 4. Both = extension of atlanto-occipital joint RCP MAJOR ONLY = ipsilateral rotation of atlanto-axial joint *Suboccipital triangle's medial border**

Multifidus 1. Origin: 2. Insertion: 3. Innervation: 4. Action: **Extra/How to Test:

1. Posterior sacrum Transverse processes of lumbar Thoracic & Cervical vertebrae 2. Spinous processes of vertebrae, 2-4 segments SUPERIOR TO THEIR ORIGIN 3. POSTERIOR RAMI of spinal n. 4. EXTENSION LATERAL FLEXION ROTATION **RUNS ENTIRE LENGTH OF SPINAL CORD** Transversospinalis intrinsic muscle deep layer

Intermediate Extrinsic Muscles of the Back (name 2) Describe: (...commonly designated as ____muscles, but are more likely___rather than___.)

1. Seratus Posterior Superior (SPS) *not pictured* 2. Seratus Posterior Inferior (SPI) Seratus Posterior are thin muscles, commonly designated as superficial respiratory muscles, but are more likely PROPRIOCEPTIVE rather than motor. (Proprioception tells your body where it is in space)

Rhomboid Major 1. Origin: 2. Insertion: 3. Innervation: 4. Action: **Extra/How to Test:

1. Spinous process of T2-T5 2. MEDIAL BORDER of scapula 3. Dorsal Scapular n. (branch of the BRACHIAL PLEXUS) 4. Retract scapula Inferior rotation of glenohumeral joint Fix scapula to thoracic wall **Extrinsic muscle Superficial layer LIES BELOW RHOMBOID MINOR, BUT LARGER

Levator Scapulae 1. Origin: 2. Insertion: 3. Innervation: 4. Action: **Extra/How to Test:

1. TRANSVERSE PROCESS of C1-C4 (all other muscles are attached to the spinal processes of C7-T1) 2. Medial border of scapula Superior root of scapular spine 3. Dorsal scapular n. (C3-C4) (branch of the BRACHIAL PLEXUS) 4. ELEVATES scapula ROTATES glenoid cavity INFERIORLY

Rotatores 1. Origin: (best in ___ region) 2. Insertion: 3. Innervation: 4. Action: **Extra/How to Test:

1. Transverse processes of vertebrae (best developed in THORACIC region) 2. Lamina of vertebrae immediately (or 2 segments) SUPERIOR TO ITS ORIGIN 3. POSTERIOR RAMI of spinal n. 4. ROTATES vertebral column STABILIZES vertebrae

Iliocostalis 1. Origin: 2. Insertion: 3. Innervation: 4. Action: 5. Blood Supply: **Extra/How to Test:

1. broad tendon from posterior iliac crest, sacrum, ribs, spinous processes of lumbar & sacrum, supraspinous ligament 2. lateral to longissimus on ribs & cervical transverse processes 3. POSTERIOR RAMI of spinal n. 4. Unilaterally - LATERALLY FLEX vertebral column Bilaterally - EXTEND vertebral column & head 5. Lateral Sacral a. **most LATERAL erector spinae muscle** deep layer intrinsic muscle

Longissimus 1. Origin: 2. Insertion: 3. Innervation: 4. Action: 5. Blood Supply: **Extra/How to Test:

1. broad tendon from posterior iliac rest, sacrum, ribs, sacral & lumbar spinous processes, supraspinous ligament 2. Postero-medial aspect of ribs cervical transverse processes mastoid process 3. POSTERIOR RAMI of spinal n. 4. Unilaterally - LATERALLY FLEX vertebral column Bilaterally - EXTEND vertebral column & head **MIDDLE ERECTOR SPINAE MUSCLE** deep layer intrinsic muscle

Semispinalis 1. Origin: 2. Insertion: 3. Innervation: 4. Action: 5. Also called: **Extra/How to Test:

1. c4-T12 transverse processes 2. (into skull, runs entire length of spinal cord) Cervical & Thoracic transverse processes Space between superior & inferior nuchal lines on cranium 3. POSTERIOR RAMI of spinal n. 4. "One side engaged, Opposite side moves" -EXTENDS head, cervical, thoracic vertebrae -CONTRALATERAL ROTATION of head, cervical, thoracic vertebrae (one side engaged, opposite side moves) 5. "Semispinalis Capitis" **Roof of suboccipital triangle** intrinsic muscle deep layer transversospinalis

Splenius Capitus & Splenius Cervicus 1. Origin: 2. Insertion: 3. Innervation: 4. Action: 5. Blood Supply: **Extra/How to Test:

1. nuchal ligament C7-T3/4 spinous processes 2. CAPITUS: Mastoid process Nuchal line CERVICUS: C1-C4 transverse processes 3. POSTERIOR RAMI of spinal n. 4. Unilaterally - LATERALLY FLEX neck & ROTATE head to the side of the active muscle Bilaterally - EXTEND head & neck 5. CAPITUS: Occipital a. CERVICUS: Occipital a. & Intercostal a. **CAPITUS ABOVE CERVICUS*** Intrinsic muscle deep layer

Spinalis 1. Origin: 2. Insertion: 3. Innervation: 4. Action: 5. Blood Supply: **Extra/How to Test:

1. spinous process of lumbar & lower thoracic vertebrae, sacrum, ilium, ribs, broad tendon from posterior iliac crest 2. spinous processes of thoracic & cervical vertebrae (fibers run superiorly to spinous processes) 3. POSTERIOR RAMI of spinal n. 4. Unilaterally - LATERALLY FLEX vertebral column Bilaterally - EXTEND vertebral column & head 5. Lateral Sacral a. **Touches vertebral column/spine** Erector Spinae Deep layer Intrinsic muscle

Articulation

A way to describe movement of a muscle based on it's joint. Ex: Bicep performs flexion at the ELBOW (joint)

Rhomboid Minor 1. Origin: 2. Insertion: 3. Innervation: 4. Action: **Extra/How to Test:

ABOVE RHOMBOID MAJOR, BUT SMALLER 1. Nuchal ligament Spinous processes of C7 & T1 2. MEDIAL END of scapula 3. Dorsal Scapular n. (branch of the BRACHIAL PLEXUS) 4. Retract scapula Inferior rotation of glenohumeral joint Fix scapula to thoracic wall **Extrinsic muscle Superficial layer LIES BETWEEN LEVATOR SCAPULAE & RHOMBOID MAJOR

Deep Muscles of Posterior Neck ("SUBOCCIPITAL MUSCLES) Name 4: Innervation:

ALL BENEATH SEMISPINALIS CAPITIS: (RCPM) Rectus Capitis Posterior MINOR (RCPM) Rectus Capitis Posterior MAJOR (OCI) Obliquus Capitis Inferior (OCS) Oblique Capitis Superior INNERVATION: Suboccipital nerve (C1 spinal n. posterior ramus)

Atlanto-Occipital Joint Extension involves contraction of: (3) Lateral flexion involves contraction of: (3)

Atlanto-Occipital Joint Extension involves contraction of: -RCP Major -RCP Minor -OCS Lateral flexion involves contraction of: -OCS -Splenius Capitis -Longissimus Capitis

Lumbar Triangle: Borders: Roof: Contents:

Borders: -Latissimus Dorsi -External Abdominal Oblique -Iliac Crest Roof: skin Contents: Internal Abdominal Oblique

Triangle of Auscultation Borders: Roof: Contents:

Borders: -Latissimus Dorsi -Trapezius (inferior border) -Medial margin of Scapula (Rhomboid Major) Roof: skin Contents: Serratus Posterior Superior (SPS)

Vertebral Artery Branch from __ artery Travels through: Does NOT travel through: What does it supply? Clinical (arteriosclerosis) example:

Branch from SUBCLAVIAN a. Travels through TRANSVERSE FORAMEN of C1-C6 *Does not go through C7* (C7 DOES HAVE foramina, but vertebral arteries just don't run through them) -->Passes medially along posterior arch of C1-->Passes superiorly through FORAMEN MAGNUM to SUPPLY THE BRAIN *When blood flow is reduced (e.g. arteriosclerosis), prolonged turning of head may reduce blood flow to brain - causes light-headedness, dizziness, etc

Palpable Structures of the Back

C7 (vertebra prominens) Scapular spine Medial border Inferior angle Iliac crest POSTERIOR SUPERIOR ILIAC SPINE Acromion greater tuberosity 6th thru 12th ribs Anterior superior iliac spine Sacrum Greater trochanter Ischial tuberosity

SUBOCCIPITAL TRIANGLE Boundaries: (3) Which deep posterior neck muscle is NOT included? Suboccipital Triangle contains: Which nerve? Which artery? "Roof" of triangle: "Floor" of triangle:

Demarcated (bound) by 3 muscles: 1. Rectus Capitis Posterior Major 2. Obliquus Capitis Inferior 3. Obliquus Capitis Superior (RCP Minor is not included) Contains: -Suboccipital n. (C1) -Vertebral a. "Roof" = Semispinalis Capitis muscle "Floor" = Posterior atlanto-occipital membrane & posterior arch of C1

What 3 Muscles does the Dorsal Scapular Nerve (C5) Innervate? Emerges between: Innervates:

Emerges between anterior & middle neck muscles ("scalenes") Innervates rhomboid major & rhomboid minor Innervates levator scapulae via separate branch

Atlanto-Axial Joint Head ROTATION to LEFT involves: -contraction of ..... -contraction of....

Head rotation to the LEFT involves: -Contraction of RIGHT (contralateral/opposite side) sternocleidomastoid & semispinalis capitis -Contraction of LEFT (ipsilateral/same side) obliquus capitis inferior, rectus capitis posterior major, rectus capitis posterior minor, longissimus capitis, splenius capitis

ERECTOR SPINAE GROUP

Ileocostalis Longisimus Spinalis

Back Sprain Tissue involved: Results from: Ex:

Only LIGAMENTOUS TISSUE (ligament to bone) is involved Results from STRONG CONTRACTIONS related to vertebral movement (ex: excessive rotation/extension)

Intrinsic Muscles of Back associated with: act on: controls: innervated by:

Only associated with axial skeleton act on vertebral column controls movement & maintains posture innervated by POSTERIOR RAMI of spinal nerves

Trapezius Origin: Insertion: Innervation: Action:

Origin: Superior nuchal line/ligament C7-T12 Spinous Process Insertion: Acromion & Spine of Clavicle Innervation: Spinal accessory nerve (CN XI) Action: Superior ROTATION of shoulder (GLENOHUMERAL JOINT) Descending - ELEVATES scapula Middle - RETRACTS scapula Ascending - DEPRESES scapula

Cutaneous Branches of Posterior Rami

Provides cutaneous sensory innervation (GSA) to the back

TRANSVERSOSPINALES GROUP

SEMISPINALIS MULTIFIDUS ROTATORES

Intrinsic Back Muscles - Superficial & Intermediate Layers Superficial Layer (2) Intermediate Layer (3) "____ ____ Group"

SUPERFICIAL LAYER: - Splenius Capitis -Splenius Cervicus INTERMEDIATE LAYER: "ERECTOR SPINAE GROUP" -Iliocostalis -Longissimus -Spinalis

INNERVATION OF THE BACK: Spinal Accessory Nerve (Cranial Nerve XI) (travels from __ through __ & __ to __) Cutaneous Branches of Posterior Rami Provides __ __ ___ (__) to __.

Spinal Accessory Nerve (Cranial Nerve XI) -Travels from cranium through the neck & back to trapezius Cutaneous Branches of Posterior Rami -Provides cutaneous sensory innervation (GSA) to the back

Back Strain Results from: ___ ___ muscles often involved. ___ ___ may be response to ___.

Stretching/tearing of muscle fibers Common sports injury Results from OVERLY STRONG MUSCLE CONTRACTION Erector Spinae muscles often involved Muscle Spasms may be a response to inflammation

Extrinsic Muscles of Back Layers: Innervation (+ exception)

Superficial & Intermediate layers Innervated by ANTERIOR RAMI of spinal nerves (1 exception: CN XI)

Cutaneous Nerves

Supplies an area of the skin that is related to a PERIPHERAL NERVE Overlapping between cutaneous nerves & dermatomes **A cutaneous nerve is generally BROADER & WIDER than an area supplied by only a single spinal (dermatome) nerve

Insertion

The attachment site that DOES move during contraction

Origin

The attachment site that DOESN'T move during contraction

Innervation

The distribution or supply of nerves to a muscle

Axio-appendicular musculature (another name for___) Insertion: Innervation (+ exception):

The superficial extrinsic muscles of the back All muscles insert on the upper limb Innervated by ANTERIOR RAMI of spinal nerves (except Trapezius, CN XI)

Superficial Muscles of Posterior Cervical Region

Trapezius Splenius capitis Semispinalis capitis

Superficial Extrinsic Muscles of the Back (name 5)

Trapezius Latissimus Dorsi Levator Scapulae Rhomboid Minor Rhomboid Major

Superficial Layer Connects___ with ___. Controls:

connects axial skeleton with the superior appendicular skeleton controls UPPER LIMB

axial skeleton

cranium vertebral column ribs manubrium sternum

Thoracolumbar Fascia

fascial layer that separates extrinsic & intrinsic muscles in the back

Serratus Posterior Inferior (SPI) Lies: Origin: Insertion: Innervation: Action: Blood Supply: Extra/How to Test:

lies deep to latissimus dorsi Origin: spinous processes of T11-L2 Insertion: Ribs 8-12 Innervation: T9-T12 ANTERIOR RAMI of spinal nerves Action: DEPRESSES ribs 8-12 Blood Supply: Intercostal a. Extra/How to Test: extrinsic muscle intermediate layer

Serratus Posterior Superior (SPS) Lies: Origin: Insertion: Innervation: Action: Blood Supply: Extra/How to Test:

lies deep to the rhomboids Origin: Nuchal ligament Spinous process of C7-T3 Insertion: Ribs 2-4 Innervation: T2-T5 ANTERIOR RAMI of spinal nerves Action: ELEVATES Ribs 2-4 Blood Supply: Intercostal a.

Intermediate Layer Associated with: Controls:

only associated with axial skeleton controls respiratory/proprioceptive movements

appendicular skeleton

upper limb (clavicles, scapulae, heri, radii, ulnae, carpals, metacarpals, phalanges) lower limb (pelvis, femora, tibiae, fibulae, tarsals, metatarsals, phalanges)