Questions and Answers
What is the primary innervation for the splenius capitus muscle?
Which of the following muscles is primarily responsible for lateral flexion of the neck?
Which part of the erector spinae muscle group is most lateral?
What is the common origin for the muscles of the erector spinae?
Signup and view all the answers
Which action is associated with the splenius cervicis muscle?
Signup and view all the answers
Which intercostal muscles run inferoanteriorly from superior rib to inferior rib?
Signup and view all the answers
What is the primary neurovascular arrangement found in the costal groove?
Signup and view all the answers
Which muscle is continuous with the internal oblique abdominal muscle anteriorly?
Signup and view all the answers
Which intercostal muscle is located deepest and spans 2-3 levels?
Signup and view all the answers
What is the main muscle innervated by segmental anterior primary rami (APR)?
Signup and view all the answers
Which muscle is continuous inferiorly with the transverse abdominus muscle?
Signup and view all the answers
What is the function of the innermost intercostals in relation to the internal intercostals?
Signup and view all the answers
Which of the following structures provides arterial supply to intercostal spaces 3-7?
Signup and view all the answers
What is the primary action of the Semispinalis muscle?
Signup and view all the answers
Which muscle spans the greatest number of vertebral segments?
Signup and view all the answers
What is the innervation of the Multifidus muscle?
Signup and view all the answers
Which muscle is specifically responsible for stabilizing the spine through proprioception?
Signup and view all the answers
What is the likely function of the Interspinales muscle?
Signup and view all the answers
Which structure serves as the origin for the Semispinalis muscles?
Signup and view all the answers
What anatomical regions are primarily acted upon by the Multifidus muscle?
Signup and view all the answers
Which of the following muscles has the shortest span of vertebral segments?
Signup and view all the answers
What is the primary action of the levator costarum muscles?
Signup and view all the answers
Which muscles are primarily involved in stabilizing the spinal column?
Signup and view all the answers
What actions do the deep layer muscles of the back primarily facilitate?
Signup and view all the answers
Which muscle primarily assists with raising the ribs during inspiration?
Signup and view all the answers
What is the role of the intertransverserii muscles?
Signup and view all the answers
What characterizes the thoracolumbar fascia?
Signup and view all the answers
Which of the following is NOT a function of back muscles?
Signup and view all the answers
What anatomical structure connects the deep fascia to the thoracolumbar fascia?
Signup and view all the answers
What is the primary function of the thoracolumbar fascia?
Signup and view all the answers
Which component of the thoracolumbar fascia envelopes the intrinsic muscles of the back?
Signup and view all the answers
What nerves innervate the serratus posterior superior and inferior muscles?
Signup and view all the answers
Which of the following correctly describes the innervation of most connective tissue structures in the back?
Signup and view all the answers
The outer portions of the intervertebral discs are innervated by which nerves?
Signup and view all the answers
Study Notes
Intercostal Muscles
- External intercostals extend from the tubercles of ribs to the costochondral junctions, running inferoanteriorly from a superior rib to an inferior rib.
- Internal intercostals occur deep to the external intercostals at a 90° angle, spanning ribs and costal cartilages to the sternum.
- Innermost intercostals are separated from internal intercostals by the intercostal neurovascular bundle and span the internal surfaces of adjacent ribs.
- Subcostalis muscles span 2-3 levels and originate near the angles of the lower ribs, positioned deep to the innermost intercostals.
- Transverse thoracis is continuous inferiorly with the transverse abdominis muscle.
- Levator costarum is generally categorized with intrinsic back muscles.
Neurovascular Supply to Intercostals
- Neurovascular structures run in the costal groove between internal and innermost intercostal layers, arranged from superior to inferior as vein, artery, nerve (VAN).
- Innervation is provided by segmental anterior primary rami (APRs).
- Arterial supply varies by intercostal space:
- Spaces 1-2 receive blood from the superior/supreme intercostal arteries (from axillary artery).
- Spaces 3-7 are supplied by intercostal arteries.
- Below rib 8, blood supply is via the musculophrenic artery (off the internal thoracic artery).
- Venus drainage is achieved through intercostal veins.
Intrinsic Back Muscles
Superficial Intrinsics
-
Splenius Capitis
- Originates at the ligamentum nuchae and spinous processes of C7-T4.
- Inserts at the mastoid process and the lateral third of the superior nuchal line.
- Functions include lateral flexion, ipsilateral rotation, and extension (bilaterally).
-
Splenius Cervicis
- Originates at ligamentum nuchae and spinous processes of T3-T6.
- Inserts at the posterior tubercles of transverse processes of C1-C4.
- Similar functions as splenius capitis.
Intermediate Intrinsics: Erector Spinae
-
A common aponeurotic origin from the thoracolumbar fascia attaches at the iliac crest, sacrum, and lumbar processes.
-
Iliocostalis
- Divided into lumborum, thoracis, and cervicis sections.
-
Longissimus
- Divided into thoracis, cervicis, and capitis sections.
-
Spinalis
- Divided into thoracis and cervicis, with the added semispinalis spanning 4-6 vertebral segments.
-
Multifidus and Rotatores
- Multifidus spans 2-4 vertebral segments.
- Rotatores span 1-2 vertebral segments.
Minor Deep Layer
- Interspinales: Located between the spinous processes of adjacent segments.
- Intertransversarii: Positioned between the transverse processes of adjacent vertebrae, aiding in lateral flexion.
- Levator Costarum: Elevates the rib between the tubercle and angle during respiration and lateral flexion.
Thoracolumbar Fascia
- Composed of superficial and deep layers.
- The superficial layer contains subcutaneous tissue, possibly with adipose tissue.
- The deep layer blends with gluteal fascia and contains multiple laminae enveloping intrinsic back muscles, stabilizing the lumbar spine during muscle contraction.
Innervation to the Back
- Extrinsic Muscles: Innervated by branches of the brachial plexus; serratus muscles innervated by ventral rami (T2-5, T9-12).
- Intrinsic Muscles: Innervated by segmental posterior primary rami (PPRs), with the lateral portion of intertransversarii receiving APRs.
- Most connective tissues are also innervated by segmental PPRs, including outer portions of intervertebral discs via sinuvertebral nerves.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers the anatomy of intercostal muscles, including their origins, insertions, and functions. Additionally, it addresses the neurovascular supply relevant to these muscles, detailing the arrangement of veins, arteries, and nerves. Perfect for anatomy students seeking to solidify their understanding of thoracic muscle structure.
