Muscles of the Back (Maria) Flashcards
What is the organization of back muscles according to innervation?
Which one is intrinsic? which one is extrinsic?
- Hypaxial mucles:
- extrinsic back musles
- innervated by cranial nerves and ventral rami of spinal nerves.
- superficial muscles.
- Epaxial muscles:
- intrinsic back muscles
- innervated by dorsal rami of spinal nerves.
- What constitute the superficial group?
- To what muscle group do they belong?
- Superficial muscles: muscles realted to and involved in movements of appendicular elements of skeleton
* Clavicle, scapula, humerus - They belong to the hypaxial muscle group.
- What constitute the intermediate muscle group?
- To what muscle group to they belong?
- intermediate group: muscles attached to costal elements and with possible respiratory functions.
- they belong to the hypaxial muscle.
1.Name the group of muscles that constitute the epaxial musles?
- spinotransversales group
- erector spinae group
- transversospinales group
- segmental group
- suboccipital group
What muscles are part of the superficial group of the hypaxial muscles?

Superficial group:
- Trapezius
- Latissims dorsi
- levator scapulae
- rhomboid minor
- rhomboid major
State the following for the Trapezius:
- Origin
- Insertion
- Function
- Innervation
Trapezius:
- Origin:
- Superior nuchal line
- ligamentum nuchae
- external occiipal protuberance
- thoracic vertebral spines.
- Insertion: lateral 1/3 clavicle + acromion and spinae of scapula
- Funtion:
- Upper fibers: elevation of shoulder girdle (as in shrug and during arm elevation)
- Middle fibers: retraction of scapula
- Lower fibers: depression of scapula + participation in cranial rotation of glenoid during arm abduction
- Innervation:
- Motor: Accessory n. (CN XI)
- (Motion sensor) Proprioception: C3-C4 ventral rami
State the following for the Latissimus Dorsi:
- Origin
- Insertion
- Function
- Innervation
- Origin: Iliac Crest + spinous process of T6-sacrum
- Insertion: Floor of intertubercular sulcus of humerus.
- Function:
- Extension
- adduction
- medial rotation of humerus
- Innervation: Middle subscapular nerve ( C6-C8)
State the following about Levator Scapulae:
- Origin
- Insertion
- Function
- Innervation
- Origin: Transverse processes of C1-C4
- Insertion: Upper portion of vertebral border of scapula
- Function: Upward and anterior movement of superior angle of scapula –> as in reaching forward or extending arm.
- Innervation: Dorsal scapular nerve (C4-C5)
State the following about the Rhomboid minor:
- Origin
- Insertion
- Functions
- Innervations
- Origin: Lower part of ligamentum nuchae + C7-T1 spines
- Insertion: Vertebral border of scapula at root of spine
- Function:
- Retraction (adduction)
- elevation
- caudal rotation of glenoid fossa of scapula
- Innervation: Dorsal scapular nerve (C4-C5)
State the following about the Rhomboid Major:
- Origin
- Insertion
- Function
- Innervation
- Origin: T2-T5 spines
- Insertion: Vertebral border of scapula between spine and inferior angle.
- Function:
- Retraction (adduction)
- elevation
- caudal rotation of glenoid fossa of scapula
- Innervation: Dorsal Scapular nerve (C4-C5)
Which mucles are part of the intermediate group of the Hypaxial Mucles?

- Serratus posterior inferior.
- Serratus posterior superior.
State the following about the Serratus Posterior Superior:
- Origin
- Insertion
- Function
- Innervation
- Origin:
- Lower part of ligamentum nuchae
- C7-T3
- subraspinous
- Insertion: Upper border of ribs 2-5 just lateral to their angles
- Function: elevate rib 2-5
- Innervation: ventral rami of spinal nn.
State the following about the Serratus posterior inferior:
- Origin
- Insertion
- Function
- Innervation
- Origin:
- T11-L3 spines
- supraspinous ligament
- Insertion: lower border of ribs 9-12 lateral to their ribs angles.
- Functions:
- Depression of ribs 9-12
- possible prevention of elevation of lower ribs during contraction of diaphragm
- Innervation: Dorsal rami of spinal nn.
- Where is this located?
- To what is this attached to?

- The Thoracolumbar fascia is the separartion between the hypaxial and epaxial muscles in the thoracic region.
What does the posterior layer of the Thoracolumbar fascia covers?
Erector Spinae

What does the anterior layer of the Thoracolumbar fascia covers?
Quadratus lumborum

- Which muscles are part of the Spinotransversales group?
- To which group of muscles do they belong?
- Are the intrinsic or extrinsic?
- Splenius capitis and Splenius cervisis
- They belong to the epaxial muscle group
- They are intrinsic muscles of the back
State the following about Splenius capitis:
- Origin
- Insertion
- Functions
- Innervation
- Origin:
- Ligamentum nuchae
- C7-T4 spines
- Insertion:
- Mastoid process
- skull bellow superior nuchal line
- Functions:
- Bilateral activation: Extension of head and neck. Extend the head to one side when activated.
- Unilateral activation: Rotation of head toward ipsilateral side
- Innervation: Dorsal Rami spinal nn.
State the following about the Splenius Cervicis:
- Origin
- Insertion
- Functions
- Innervation
- Origin: T3-T6
- Insertion: Transverse processes of C1-C3
- Function:
- Bilateral activation: Extension of head and neck. Extend the head to one side when activated.
- Unilateral activation: Rotation of head toward ipsilateral side
- Innervation: Dorsal rami spinal nn.
- Which muscles are part of the Erector spinae group?
- To what muscle groups do they belong?
- Are they intrinsic or extrinsic?

State the following about Spinalis:
- Origin
- Insertion
- Function
- Innervation
- Origin: Vertebral spines
- Insertion: vertebral spines
- Function:
- Bilateral activation: Extension of vertebral column and head. Rate head to active side and the spine.
- Unilateral activation: Lateral flexion of vertebral column + rotation of head to ipsilateral side. Rotate the spine
- Innervation:
- Dorsal Rami of spinal nerves
State the following about the Longissimus:
- Origin
- Insertion
- Function
- Innervation
- Origin: Aponeurotically from sacrum. More cranial fibers originate from transverse processes of pre-sacral vertebrae
- Insertion: transverse and costal elements of vertebrae near their junctions. Most cranial fibers insert onto mastoid process, and are called longissimus capitis.
- Function:
- Bilateral activation: Extension of vertebral column and head. Rate head to active side and the spine.
- Unilateral activation: Lateral flexion of vertebral column + rotation of head to ipsilateral side. Rotate the spine
- Innervation: Dorsal rami of spinal nerves
State the following for the Iliocostalis muscle:
- Origin
- Insertion
- Function
- Innervation
- Origin: Aponeurotically from sacrum and iliac crest. More cranial fibers originate near costal angles
- Insertion: ribs near their angles. Mores cranial fibers insert onto posterior tubercles of cervical vertebrae.
- Functions:
- Bilateral activation: Extension of vertebral column and head. Rate head to active side and the spine.
- Unilateral activation: Lateral flexion of vertebral column + rotation of head to ipsilateral side. Rotate the spine
- Innervation: Dorsal rami of spinal nerve.
- What muscles are part of the Transversospinales muscle group?
- To what group do they belong?
- Are they intrinsic or extrinsic muscles?

- Semispinalis capitis, semispinalis, rotatores, multifidus
- They belong to the epaxial muscles
- They are intrinsic muscles.








