Muscles of the Back Quiz

Superficial Muscles of the Back

• Trapezius and Latissimus Dorsi are superficial muscles of the back.
• These muscles move the upper limb and are considered extrinsic muscles of the back.

Intermediate Muscles of the Back

• Serratus Posterior Superior and Serratus Posterior Inferior are intermediate muscles of the back.
• Serratus Posterior Inferior braces the ribs and pulls them down, helping with respiration.
• Serratus Posterior Superior elevates the ribs and braces them.

Deep Muscles of the Back

• Deep muscles of the back, also known as intrinsic muscles, are responsible for extending the vertebral column.
• These muscles contract concentrically to extend the back and eccentrically to lower it.
• These muscles also contribute to lateral flexion and rotation of the back.

Erector Spinae

• The erector spinae muscle group consists of multiple deep muscles of the back, grouped together, running along the vertebral column from the sacrum and coccyx to the cervical vertebrae.
• The erector spinae's main function is extension of the vertebral column and maintenance of spinal posture.

Erector Spinae Subgroups

• The erector spinae muscle group is further divided into three subgroups: Spinalis, Longissimus, and Iliocostalis.
• Spinalis muscles run between the spinous processes of vertebrae, helping with extension.
  • Origin: Spinous processes of thoracic and upper lumbar vertebrae.
  • Insertion: Spinous processes of upper thoracic and cervical vertebrae.
• Longissimus muscles run between the transverse processes of vertebrae.
  • Origin: Ribs, transverse processes of lumbar and thoracic vertebrae, upper sacrum.
  • Insertion: Transverse processes of upper thoracic and lower cervical vertebrae.
  • Function: Extending and laterally bending the spine. Largest muscle of the group.
• Iliocostalis muscles originate at the iliac crest and sacrum and run up to the ribs.
  • Origin: Iliac crest, ribs, lumbar vertebrae.
  • Insertion: Ribs and transverse processes of vertebrae.
  • Function: Extending and laterally flexing the spine. Most lateral muscle of the group.

Regional Subdivisions of Erector Spinae

• Each subgroup of erector spinae is further divided into regional groups based on their location:
  • Lumborum for muscles in the lumbar region
  • Thoracis for muscles in the thoracic region
  • Cervicis for muscles in the neck region
  • Capitis for muscles that extend to the head.

Splenius Muscles

• Splenius Capitis and Splenius Cervicis are muscles in the neck that contribute to extension and rotation of the neck and head.
• Splenius Capitis attaches to the mastoid process of the temporal bone.
• Splenius Cervicis runs between cervical vertebrae.

Transverse Spinal Muscles

• The transverse spinal muscles are a deeper layer of muscles in the back.
• These muscles run between the processes of adjacent vertebrae.
• They play a role in back pain and spasms.

Actions of the Erector Spinae Muscles

• Extension of the spine (straightening the back)
• Lateral flexion of the spine (bending the spine sideways)
• Maintenance of posture: crucial for upright posture and balance
• Stabilization of the spine during movement: helping to prevent excessive spinal movement during activities like lifting.

Innervation

• The erector spinae muscles are innervated by the dorsal rami of spinal nerves, specifically the posterior rami of the spinal nerves, supplying each segment of the vertebrae.
• This innervation pattern contributes to the localized control of the movements of individual vertebral segments.

Relationships & Attachments

• The erector spinae muscles are located bilaterally on either side of the spinal column.
• They are situated posterior to the spinal column and deep to the back muscles (trapezius, latissimus dorsi, rhomboids).
• Their attachments span the length of the vertebral column, from the lower back to the neck, forming a broad, continuous muscle mass.

Clinical Significance

• Muscle strain and spasm: Overuse, poor posture, or trauma can lead to muscle strain and spasm.
• Pain: Pain can result from conditions like spinal stenosis, herniated discs, or arthritis.
• Postural abnormalities: Weakness or tightness in the erector spinae can contribute.
• Treatment for muscle pain often involves rest, physical therapy, and pain relief medications.
• Exercise and stretching: Strengthening the erector spinae muscles is often part of rehabilitation programs.

Additional Considerations

• The erector spinae muscles work in conjunction with other back muscles to maintain posture and facilitate movement.
• Proper posture and core strength are essential to prevent muscle strain.
• Any issues with the erector spinae or surrounding muscles should be addressed by a healthcare professional.