L3.3 Muscles & Movements of the Back

Question 1

Where do movements in the back occur?

Answer 1

Flexion and extension: lumbar
Lateral flexion: lumbar (limited by ribs in thorax0
Rotation: thorax (limited)

Question 2

What are the muscle groups of the back and the muscles and their features?

Answer 2

Superficial (extrinsic): all attach to upper limb, trapezius (CNXI), rhoboids, lat dorsi, levator scapulae (all anterior rami)

Intermediate: serratus anterior, posterior and inferior, accessory resp muscles

Deep (intrinsic):

• Erector spinae: flexes trunk, spinalis, longissimus and iliocostalis, run medial to lateral across 5-7 spinal segments
• Transversospinalis: run lateral to medial, short stabilisers, rotatores, multifidus, form corset with transversus abdomens and thoracolumbar fascia, if injured - 30-40% wastage within days

Question 3

Where do vessels pass in relation to muscles?

Answer 3

Veins and lymphatics anteriorly, arteries and nerves through muscle

Question 4

What do posterior rami innervate?

Answer 4

Deep back muscles, facet joints and overlying skin

Question 5

What are the features of a disc prolapse?

Answer 5

Bulge, protrusion or herniation - moves posterolaterally due to posterior longitudinal ligament, saving spinal cord but endangering nerve roots

Question 6

What is the difference between spondylosis and spondylitis?

Answer 6

Spondylosis - drying out of bone and formation of osteophytes leading to stenosis of the space for IV disc

Ankylosing spondylitis: fusion of spinal segments seen in young males