Lecture 16 - Muscles of the vertebral column and torso Flashcards
Posterior back muscles …
Muscles that support the back, and help with back movement
Functions of the vertebral column
Posture - helps to keep balance and upright standing
Support head, neck, trunk
Protect spinal cord and spinal nerves
Trunk movement (flexion, extension, lateral flexion, rotation)
The vertebral column has curvatures …
Alternation of kyphosis (primary) and lordosis (secondary)
Initially started as one kyphosis
Developed for upright position
Provide flexibility and shock absorbance (for movement especially with heavy loads)
Curvature of vertebral column
cervical = secondary Thoracic = primary lumbar = secondary sacral = primary
Curvature cervical
Secondary
Curvature thoracic
Primary
Curvature lumbar
Secondary
Curvature sacral
Primary
Intrinsic back muscles (3 layers)
Superficial (spinotransversales) • Intermediate (erector spinae) • Deep (e.g., transversospinalis)
Number of layers of intrinsic back muscles
3
Spinotransversales general trend
Superficial intrinsic back muscle
runs from spinous process to transverse process
erector spinae general trend
Intermediate intrinsic back muscle
more or less the length of the spine on the left and right
transversospinalis general trend
Deep intrinsic back muscle
runs from transverse processes to spinous processes
Spinotransversales muscles
superficial
muscles = splenius capitis (head) and splenius cervicis (cervical/neck)
splenius capitis = inserts to mastoid process of the temporal bone and originates from the lower half of the nuchal ligament and the spinous processes of the 7th cervical vertebra and the superior 3 thoracic vertebrae
splenius cervicis = origin is the spinous processes of T3-T6 and insertion are the transverse processes of C1-C3
Spinotransversales function
Bilaterally contract, extend next
Individually, rotate head
Lateral flexion
Erector spinae muscles
Pelvis to neck
liocostalis (lateral) - best seen in the lumbar region
Longissimus (intermediate)
Spinalis (medial) - thin muscles, best seen in the thoracic region
Erector spinae functions
Bilaterally (contracting), extends back
Maintain posture
Individually, lateral flexion
Back strain
Common injury from overly strong contraction (too sudden)
The muscles are stretched and may have microscopic tearing
Erector spinae muscles commonly affected
Transversospinales muscles
Rotatores (short, entire length of vertebral column) Multifidus Semispinalis (long)
Transversospinales muscle fibre orientation
They run upward, medially and obliquely from transverse processes to spinous processes
Rotatores features
From the Transversospinales muscle group
Present throughout the entire length of the vertebral column
Extends from 1-2 vertebrae
Best seen in the thoracic area
Rotatores functions
Stabilize vertebral column & maintain posture
Bilaterally, extend back
Ipsilaterally (same side of the body) , lateral flexion
Assist in rotation
(individually these muscles are small but when they work together they can create a big movement)
Multifidus features
From the Transversospinales muscle group
Spans the entire length of the vertebral column
Extends from 2-4 vertebrae
Best seen in the lumbar area
Multifidus functions
Bilaterally, extend back
Stabilize vertebral column & maintain posture
Ipsilaterally, laterally flex
Semispinalis features
From the Transversospinales muscle group
Runs for about half of the vertebral column
Best seen at the back of the neck
Semispinalis functions
Bilaterally extend back, posture
Individually rotate vertebral column
**run obliquely so can help with … **
Intercostal muscles
ribcage muscles (3 layers of muscle - external, internal and innermost )
external intercostals
Fibers run medially and inferiorly
For inspiration
Internal intercostals
Fibers run laterally and inferiorly
For expiration
Supply structures of intercostals
Veins, arteries, nerves (VAN) are found between the internal and innermost intercostals
Innermost intercostals
Fibers run laterally and inferiorly
For expiration
Diaphragm
Important muscle for breathing
Important structures in the diaphragm
Inferior vena cava Central tendon Esophagus (embedded in diaphragm muscle, contraction helps to prevent reflux into the esophagus) Aorta (abdominal aorta) Phrenic nerve
Features of the diaphragm
Separates thoracic and abdominal cavities
Important muscle for inspiration
Has a central tendon
Has multiple openings for esophagus, inferior vena cava, and abdominal aorta
Inspiration =
contraction of diaphragm and relaxation of abdominal muscles
Expiration =
Relaxation of diaphragm and contraction of abdominal muscles
Anterolateral wall muscles
(multiple layers)
External oblique
Internal oblique
Transversus abdominis
External oblique
Anterolateral wall
The muscle fibers are running inferiorly and medially
Internal oblique
Anterolateral wall
The muscle fibers are running superiorly and medially
Movement of oblique muscles in the anterolateral wall
The oblique muscles help with trunk rotation and lateral flexion
Transversus abdominis
Increase abdominal cavity pressure
The muscle fibers are running transversely
Rectus abdominis
Vertical muscle for trunk flexion
