Back Muscle Anatomy Part 1
Lacey The back is a complex structure that supports every core in the body. It also takes the most beating when you’re doing certain activities — or not doing anything at all, like sedentary work. Non the less, it should be an important subject to make sure it is well taken care of and strong. If not, it can leave you in a heap of back pain or worse. The best way to help people understand the importance is by educating them. The muscles of your back can be divided into three groups – superficial, intermediate, and deep:
- Superficial – associated with movements of the shoulder.
- Intermediate – associated with movements of the thoracic cage.
- Deep – associated with movements of the vertebral column.
Lets Get Technical With Our Back Muscles
The deep muscles develop embryologically in the back and are described as intrinsic muscles. The superficial and intermediate muscles do not develop in the back and are classified as extrinsic muscles. The anatomy of the superficial back muscles is extremely interesting in the form and function – their attachments, innervations, and functions.
Trapezius
The trapezius is a wide, flat, and triangular muscle on the back. It is the most superficial of all the back muscles and usually causes the most painful issues.
- Attachments: Originates from the skull, ligamentum nuchae and the spinous processes of C7-T12. The fibres attach to the clavicle, acromion and the scapula spine.
- Innervation: Motor innervation is from the accessory nerve. It also receives proprioceptor fibres from C3 and C4 spinal nerves.
- Actions: The upper fibres of the trapezius elevates the scapula and rotates it during abduction of the arm. The middle fibres retract the scapula and the lower fibres pull the scapula inferiorly.
Latissimus Dorsi
The latissimus dorsi originates from the lower part of the back, where it covers a wide area.
- Attachments: Has a broad origin – arising from the spinous processes of T6-T12, thoracolumbar fascia, iliac crest, and the inferior three ribs. The fibres converge into a tendon that attaches to the intertubercular sulcus of the humerus.
- Innervation: Thoracodorsal nerve.
- Actions: Extends, adducts and medially rotates the upper limb.
Rhomboids
There are two rhomboid muscles – major and minor. The rhomboid minor is situated superiorly to the major.
Major
- Attachments: Originates from the spinous processes of T2-T5 vertebrae. Attaches to the medial border of the scapula, between the scapula spine and inferior angle.
- Innervation: Dorsal scapular nerve.
- Actions: Retracts and rotates the scapula.
Minor
- Attachments: Originates from the spinous processes of C7-T1 vertebrae. Attaches to the medial border of the scapula, at the level of the spine of scapula.
- Innervation: Dorsal scapular nerve.
- Actions: Retracts and rotates the scapula.
Feel enlighted or confused? Either way, we can help explain or take care of these pain points for you. Check out the video with some sample exercises to relieve back pain.