Muscles of the Back Flashcards
Name the categories of back muscles based on location and function.
Extrinsic (superficial and intermediate) and Intrinsic (deep).
What are the functions of the extrinsic back muscles?
The superficial extrinsic muscles act on the upper limbs, while the intermediate extrinsic muscles primarily assist in respiration.
List the superficial extrinsic muscles of the back and their primary action.
Trapezius, Latissimus Dorsi, Rhomboid Major, Rhomboid Minor, Levator Scapulae - they primarily aid in movement of the upper limbs.
Name the intermediate extrinsic back muscles.
Serratus Posterior Superior and Serratus Posterior Inferior, which assist in respiratory movements.
What are the three layers of intrinsic (deep) back muscles?
Superficial (Spinotransversalis), Intermediate (Erector Spinae), and Deep (Transversospinalis).
What are the muscles of the Spinotransversalis group?
Splenius Capitis and Splenius Cervicis, which extend and rotate the head and neck.
What muscles are in the Erector Spinae group, and what is their function?
Iliocostalis, Longissimus, Spinalis - they help with extension and lateral flexion of the vertebral column.
List the muscles in the Transversospinalis group.
Semispinalis, Multifidus, Rotatores - these stabilize and extend the spine and are involved in rotation.
What distinguishes intrinsic muscles from extrinsic muscles of the back?
Intrinsic muscles are involved in maintaining posture and movement of the vertebral column, whereas extrinsic muscles are involved in movement of the upper limbs or assist with respiration.
Which intrinsic muscles are primarily responsible for extension of the head and neck?
Splenius Capitis and Splenius Cervicis from the Spinotransversalis group.
Which group of muscles runs the entire length of the vertebral column?
The Erector Spinae group: Iliocostalis, Longissimus, Spinalis
How do the transversospinalis muscles contribute to spinal stability?
By connecting adjacent vertebrae and providing rotational stability, extending the spine, and postural support.
What action do the Serratus Posterior Superior and Inferior muscles facilitate?
Serratus Posterior Superior assists in inhalation, and Serratus Posterior Inferior aids in exhalation by controlling rib movement.
Which muscle group would you target to improve overall back stability and posture?
The Erector Spinae and Transversospinalis groups, as they are integral to maintaining posture and spinal alignment.
What are the two subgroups of the extrinsic back muscles?
Superficial (Posterior Axio-appendicular) and Intermediate.
List the superficial extrinsic muscles of the back.
Trapezius, Latissimus Dorsi, Rhomboid Major, Rhomboid Minor, Levator Scapulae.
What is the primary function of the superficial extrinsic muscles?
To facilitate movements of the upper limbs.
Which nerve innervates the Trapezius?
The spinal accessory nerve (Cranial Nerve XI).
Which muscle elevates the scapula and where is it located?
Levator Scapulae, which elevates the scapula, is located on the superior part of the medial border of the scapula.
List the intermediate extrinsic muscles of the back.
Serratus Posterior Superior and Serratus Posterior Inferior.
Describe the origin, insertion, and action of the Serratus Posterior Superior.
Origin: Ligamentum Nuchae & Spinous processes of C7-T3.
Insertion: 2nd to 5th ribs.
Action: Elevates ribs during inspiration.
Describe the origin, insertion, and action of the Serratus Posterior Inferior.
Origin: Spinous processes of T11-L2.
Insertion: 9th to 12th ribs.
Action: Depresses ribs during expiration.
What is the function of the intermediate extrinsic muscles in relation to respiration?
They assist in breathing by elevating and depressing the ribs.
Which rami innervate most of the extrinsic back muscles, and what is the exception?
Most are innervated by the anterior (ventral) rami of spinal nerves. The exception is the Trapezius, which is innervated by the spinal accessory nerve.
