Questions and Answers
What is the primary role of extrinsic back muscles?
Which muscle receives motor fibers from the spinal accessory nerve (CN XI)?
Which group of muscles is described as being responsible for producing posture and spinal movements?
Which of the following muscles is classified as an intermediate extrinsic back muscle?
Signup and view all the answers
What is the primary function of the serratus posterior muscles?
Signup and view all the answers
Which nerve innervates the serratus posterior superior muscle?
Signup and view all the answers
Where are the intrinsic back muscles primarily located?
Signup and view all the answers
What muscle connects the axial skeleton to the superior appendicular skeleton?
Signup and view all the answers
What is the primary function of the intrinsic back muscles?
Signup and view all the answers
Which layer of intrinsic back muscles covers the deep neck muscles?
Signup and view all the answers
What is the role of the thoracolumbar fascia?
Signup and view all the answers
Which muscle group is considered the chief extensor of the vertebral column?
Signup and view all the answers
How are the erector spinae muscles organized?
Signup and view all the answers
Which structure does the deep fascia of the intrinsic back muscles attach to laterally?
Signup and view all the answers
What does the term 'splenion' refer to in the context of intrinsic back muscles?
Signup and view all the answers
What type of innervation do intrinsic back muscles receive?
Signup and view all the answers
Study Notes
Overview of Back Muscles
- Body weight distribution is anterior to the vertebral column, necessitating strong back muscles for support and movement.
- Back muscles are categorized into two main groups: extrinsic and intrinsic.
Extrinsic Back Muscles
- Comprises superficial and intermediate muscles responsible for limb and respiratory movements.
- Superficial extrinsic muscles include:
- Trapezius: Receives motor fibers from the spinal accessory nerve (CN XI).
- Latissimus Dorsi: Attaches to the humerus, facilitating arm movements.
- Levator Scapulae: Elevates the scapulae.
- Rhomboids: Retracts the scapulae.
- Intermediate muscles, mainly serratus posterior (superior and inferior), act as proprioceptors rather than motors, innervated by intercostal nerves:
- Serratus posterior superior: Located deep to rhomboids and innervated by the first four intercostal nerves.
- Serratus posterior inferior: Located deep to latissimus dorsi and innervated by the last four intercostal nerves.
Intrinsic Back Muscles
- These muscles maintain posture and control vertebral column movements, innervated by the posterior rami of spinal nerves.
- Enclosed by deep fascia that connects to the nuchal ligament, spinous processes, and various vertebral landmarks.
- The thoracolumbar fascia provides structural support to the lumbar intrinsic back muscles.
Muscle Layers
-
Superficial Layer:
-
Splenius Muscles: Thick and flat, covering deeper neck muscles. Includes:
- Splenius Cervicis: Extends to cervical vertebrae.
- Splenius Capitis: Extends to the cranium.
-
Splenius Muscles: Thick and flat, covering deeper neck muscles. Includes:
-
Intermediate Layer:
-
Erector Spinae Muscles: Chief extensors of the vertebral column, positioned in a groove alongside the spine.
- Iliocostalis: Lateral column of the erector spinae.
- Longissimus: Intermediate column.
- Spinalis: Medial column.
-
Erector Spinae Muscles: Chief extensors of the vertebral column, positioned in a groove alongside the spine.
Function and Structure
- Superficial muscles are primarily involved in limb movement, while intrinsic muscles focus on spine stability and movement.
- Proper function of these muscles is essential for maintaining posture and enabling complex movements of the upper body.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz focuses on the back muscles discussed from pages 117 to 129. Learn about the major groups of muscles, including extrinsic and intrinsic back muscles, their functions, and their importance in supporting the vertebral column. Test your knowledge on the anatomical details and mechanics of these essential muscles.