06/08/2025
🔹 Posterior Neck and Back Muscles
The posterior muscles of the neck are primarily concerned with head movements, like extension.
The back muscles stabilize and move the vertebral column, and are grouped according to the lengths and direction of the fascicles.
🌀 Splenius Muscles
Originate at the midline and run laterally and superiorly to their insertions.
From the sides and the back of the neck:
Splenius capitis inserts onto the head region.
Splenius cervicis extends onto the cervical region.
These muscles can extend the head, laterally flex it, and rotate it.
💪 Erector Spinae Group
Forms the majority of the muscle mass of the back.
Primary extensor of the vertebral column.
Controls flexion, lateral flexion, and rotation of the vertebral column.
Maintains the lumbar curve.
Comprises:
Iliocostalis group (laterally placed)
Longissimus group (intermediately placed)
Spinalis group (medially placed)
📍 Iliocostalis Group
Iliocostalis cervicis – cervical region
Iliocostalis thoracis – thoracic region
Iliocostalis lumborum – lumbar region
📍 Longissimus Group
Longissimus capitis – head region
Longissimus cervicis – cervical region
Longissimus thoracis – thoracic region
📍 Spinalis Group
Spinalis capitis – head region
Spinalis cervicis – cervical region
Spinalis thoracis – thoracic region
🔗 Transversospinales Muscles
Run from the transverse processes to the spinous processes of the vertebrae.
Similar to erector spinae muscles.
Semispinalis muscles include:
Semispinalis capitis
Semispinalis cervicis
Semispinalis thoracis
🧱 Multifidus
Located in the lumbar region.
Helps extend and laterally flex the vertebral column.
🔧 Segmental Muscle Group
Important in the stabilization of the vertebral column.
Includes:
Interspinales muscles
Intertransversarii muscles
These muscles bring together the spinous and transverse processes of each consecutive vertebra.
🌬️ Scalene Muscles
Work together to flex, laterally flex, and rotate the head.
Contribute to deep inhalation.
Include:
Anterior scalene muscle – anterior to the middle scalene
Middle scalene muscle – the longest, intermediate between anterior and posterior scalenes
Posterior scalene muscle – the smallest, posterior to the middle scalene
