Thoracic and Lumbar Regions of the Vertebral Column

This set of flashcards covers important concepts regarding the thoracic and lumbar regions of the vertebral column, highlighting anatomical features, functions, and clinical relevance.

What are the five regions of the vertebral column?

Cervical (7), Thoracic (12), Lumbar (5), Sacral (5 fused), Coccyx (typically 3–5 fused). These regions provide bony protection for the spinal cord and also balance mobility vs. stability by area.

Why is it clinically useful to know the number of vertebrae in each region?

It helps with accurate documentation, localization of symptoms (e.g., dermatomes/nerve roots), understanding motion patterns, and recognizing region-specific pathologies (e.g., lumbar disc issues vs thoracic rib-related restrictions).

Which spinal regions are lordotic and which are kyphotic?

Cervical and lumbar regions are lordotic (convex anteriorly). Thoracic and sacral regions are kyphotic (concave anteriorly). These curves improve shock absorption and balance the head/trunk over the pelvis.

Define lordosis and kyphosis in pathological terms.

Lordosis is excessive anterior curvature (usually in lumbar); kyphosis is excessive posterior curvature (usually in thoracic).

What does describing the vertebral column as triaxial mean?

It can move about three axes (frontal, sagittal, vertical), allowing motion in flexion/extension, lateral bending, and rotation.

Match each trunk/neck motion with its plane and axis.

Flexion/extension occur in the sagittal plane about a frontal axis. Lateral bending (lateral flexion) occurs in the frontal plane about a sagittal axis. Rotation occurs in the horizontal (transverse) plane about a vertical axis.

How does facet orientation affect motion in the cervical spine?

Cervical facets are oriented primarily in the frontal plane with a unique slope (lateral portion more anterior than medial). This orientation permits motion in all three planes—flexion/extension, lateral bending, and rotation.

How does facet orientation and ribs affect thoracic spine motion?

Thoracic facets are oriented more in the frontal plane, but trunk motion is limited by the rib cage. Rotation is available, but overall thoracic mobility is constrained by costovertebral/costotransverse mechanics and the sternum.

How does facet orientation affect lumbar spine motion?

Lumbar facets are oriented more in the sagittal plane, favoring flexion/extension and limiting rotation. Lateral bending occurs but is relatively limited compared to flexion/extension.

Why is lumbar rotation limited clinically significant?

Excessive twisting can load discs and ligaments, leading to low back pain.

Where do ribs articulate with the vertebral column?

Posteriorly, ribs articulate with vertebral bodies and transverse processes. Anteriorly, they articulate with the sternum via costal cartilage at costosternal and costochondral joints.

What motions occur at the ribs and why are they important?

Ribs elevate and depress during breathing and may show slight flaring of individual ribs. Rib mobility influences thoracic expansion, posture, and thoracic spine mechanics.

What is notable about movement of the sternum?

There is minimal movement between the manubrium and body, and between the body and xiphoid process, but the sternum participates in respiratory mechanics via rib and cartilage motion.

In general, how do cervical, thoracic, and lumbar vertebrae differ functionally?

Cervical vertebrae prioritize mobility; thoracic vertebrae balance stability with rib articulations; lumbar vertebrae prioritize weight-bearing and sagittal-plane motion with larger bodies and more sagittal facet orientation.

What is the intervertebral foramen and why is it clinically significant?

It is the opening between adjacent vertebrae where spinal nerve roots exit. Narrowing (e.g., from disc height loss, osteophytes, or spondylosis) can contribute to radicular symptoms.

What is a facet joint (zygapophyseal joint)?

A synovial joint formed by the superior articular process of the vertebra below and the inferior articular process of the vertebra above. Facet joints guide/limit motion and can be a pain source when irritated or arthritic.

What are costovertebral facet joints?

Joints between the head of a rib and the vertebral body. These joints may involve one rib and two adjacent vertebral bodies (common pattern in the thoracic region).

What is the costotransverse joint?

The joint between the tubercle of the rib and the costal facet on the anterior tip of the transverse process of a thoracic vertebra.

Why are costovertebral/costotransverse joints clinically relevant?

They contribute to thoracic motion and breathing mechanics. Restrictions can limit thoracic rotation, rib elevation/depression, and may be associated with thoracic pain or respiratory limitations.

Why include the pelvis in a thoracic/lumbar region chapter?

The pelvis forms the base for the lumbar spine and strongly influences posture, lumbar lordosis, load transfer, and lumbopelvic rhythm during functional movement.

What are the main parts of an intervertebral disc?

The disc includes an outer annulus fibrosus and an inner nucleus pulposus, which absorb shock and distribute loads.

What is the clinical relevance of a herniated disc?

A disrupted or herniated disc can irritate/compress nerve roots in the intervertebral foramen, leading to radicular pain, sensory changes, and potential motor deficits depending on the level involved.

What are the two main joint types between adjacent vertebrae?

Intervertebral joints (cartilaginous, allowing slight movement) and facet joints (synovial, which guide motion).

Why are vertebral ligaments important clinically?

They provide passive stability, limit excessive motion, and contribute to proprioception. Ligament thickening and reduced disc height can narrow foramina and contribute to nerve root irritation in degenerative conditions.

How is weight-bearing primarily transmitted in the spine?

Primarily through the vertebral bodies and discs. Facet joints share load especially in extension and help guide/limit movement.

What are the three parts of the erector spinae group and their general locations?

Iliocostalis (lateral; attaches to ribs), Longissimus (middle), Spinalis (medial; closest to spinous processes). Together they run broadly from sacrum toward occiput with regional attachments.

General actions of the erector spinae group?

Bilaterally: trunk/neck extension and postural support. Unilaterally: ipsilateral lateral bending (sidebending) with contribution to stabilization.

Name the three main transversospinalis muscles and describe their relative depth.

Semispinalis (most superficial of the group; the only one that attaches to the occiput), Multifidus (deep to semispinalis), Rotatores (shortest and deepest).

What is the common line of pull and attachment pattern for transversospinalis muscles?

They have an oblique line of pull, typically attaching from a transverse process below to a spinous process above, spanning varying numbers of vertebrae (multifidus spans ~2–4; rotatores often span 1).

What are the primary actions of the transversospinalis group?

Unilateral contraction produces rotation to the opposite side; bilateral contraction produces extension. Multifidi and rotatores are especially important for segmental stabilization.

Why is multifidus clinically important?

Multifidus contributes to spinal segmental stability; inhibition/atrophy is commonly associated with low back pain, and retraining can be part of stabilization programs.

What is the likely functional role of the interspinales muscles?

Small, deep muscles between adjacent spinous processes that assist with fine extension control and segmental stabilization, especially in cervical and lumbar regions.

What is the likely functional role of the intertransversarii muscles?

Small muscles between adjacent transverse processes that assist with fine lateral bending control and segmental stabilization.

How does line of pull determine muscle action?

Muscles pull from origin toward insertion. The direction relative to joint axes determines whether the muscle produces flexion/extension, lateral bending, or rotation, and whether it stabilizes by compressing or controlling shear forces.

What is the primary function of the rectus abdominis?

Trunk flexion, posterior pelvic tilt contribution, and abdominal compression. It helps control trunk position and assists in breathing (forced expiration) by increasing intra-abdominal pressure.

Clinical relevance of rectus abdominis weakness?

May reduce trunk control during functional tasks (sit-to-stand, bed mobility), increase reliance on hip flexors/back extensors, and contribute to altered lumbopelvic mechanics.

What are the main actions of the external oblique?

Bilaterally: trunk flexion and abdominal compression. Unilaterally: trunk rotation to the opposite side and ipsilateral lateral bending (depending on stabilization demands).

What are the main actions of the internal oblique?

Bilaterally: trunk flexion and abdominal compression. Unilaterally: trunk rotation to the same side and ipsilateral lateral bending (depending on stabilization demands).

Why is the transverse abdominis often emphasized in rehab?

It functions as a deep abdominal stabilizer that increases intra-abdominal pressure and supports lumbopelvic stability. It is commonly trained in stabilization programs for low back pain and movement control.

How do the obliques work together to produce trunk flexion with rotation?

Rotation typically involves a contralateral pairing: one side’s external oblique works with the opposite side’s internal oblique, while also contributing to flexion and stabilization depending on task demands.

What are the key actions of quadratus lumborum (QL)?

Unilateral: ipsilateral lateral bending of the trunk and pelvic hiking. Bilateral: assists with trunk extension and stabilization of the lumbar spine.

Clinical relevance of QL tightness or overactivity?

May contribute to asymmetrical posture, lateral trunk shift, low back discomfort, and compensatory movement patterns during gait or lifting.

Why is the diaphragm relevant in a spine chapter?

The diaphragm is the primary muscle of inspiration and interacts with trunk stability. Breathing mechanics influence rib/thoracic mobility and intra-abdominal pressure, which contributes to lumbopelvic stability.

How can breathing mechanics influence posture and spinal function?

Restricted rib motion or poor diaphragmatic breathing can promote accessory muscle overuse (e.g., upper traps/scalenes), reduce thoracic expansion, and affect trunk stabilization strategies.

Define torticollis and describe its classic head position.

Torticollis presents with the head laterally flexed to one side and rotated to the opposite side due to muscular imbalance.

Define radiculopathy.

Radiculopathy is mechanical compression or irritation of a nerve root, often causing pain, sensory changes, and possible weakness in a dermatomal/myotomal pattern.

Define sciatica and the typical pain distribution.

Sciatica is pain that descends along the path of the sciatic nerve, often described as traveling down the posterior thigh and leg.

What is a herniated (disrupted) disc and why does it matter?

A herniated disc involves disruption of the disc structures that can contribute to nerve root compression and radicular symptoms, often influenced by loading, posture, and movement patterns.

Differentiate lordosis, kyphosis, scoliosis, and flat back.

Lordosis: increased anterior convexity (often lumbar). Kyphosis: increased posterior convexity (often thoracic). Scoliosis: lateral curvature of the spine (often with rotation). Flat back: decreased normal curvature, reducing shock absorption and altering mechanics.

Define ankylosing spondylitis.

A chronic inflammatory condition that can lead to fusion of vertebral column joints, reducing mobility and altering posture.

Define spondylolysis and spondylolisthesis.

Spondylolysis is a defect in the lamina/pars region of a vertebra. Spondylolisthesis is anterior slippage of one vertebra on the vertebra below.

Describe compression fractures and common risk factors.

Compression fractures involve collapse of the vertebral body, commonly due to trauma or osteoporosis. They can cause pain, postural change, and functional limitations.

Why are fractures with dislocation high risk?

They can compress the spinal cord or avulse nerve roots, potentially causing loss of motor and sensory function.

What is cervical strain (whiplash)?

A strain of muscles and ligaments supporting the cervical spine, commonly associated with rapid acceleration-deceleration injury mechanisms (e.g., rear-end collisions).

Interspinales Muscles

O:Spinous process of vertebra below
I:Spinous process vertebra above

A:Neck and trunk extension
N:Spinal nerves

Intertransversarii Muscles

O: Transverse process of vertebra below
I: Transverse process of vertebra above
A: Neck and trunk lateral flexion to same side
N: Spinal nerves

Rectus Abdominis Muscle

O: Pubic crest and symphysis
I: Xiphoid process and costal cartilages of ribs 5-7
A: Trunk flexion and abdominal compression and accessory breathing muscle
N: 7th through 12th thoracic nerves

External Oblique Muscle

O: Lower eight ribs (5-12)
I: Iliac crest, pubic tubercle, and linea alba
A: Bilaterally: trunk flexion; compression of abdomen Unilaterally: trunk lateral flexion and rotation to opposite side. When pelvis stabilized: depresses ribs. Accessory muscle of respiration
N: 8th through 12th intercostal, iliohypogastric, and ilioinguinal nerves

Internal Oblique Muscle

O: Thoracolumbar fascia, iliac crest, and inguinal ligament
I: Lower three ribs and linea alba
A: Bilaterally: trunk flexion and compression; unilaterally: trunk lateral flexion and rotation to the same side
N: 8th through 12th intercostal, iliohypogastric, and ilioinguinal nerves

Transverse Abdominis Muscle

O: Thoracolumbar fascia, iliac crest, and lower six ribs
I: Linea alba and pubis
A: Compresses abdomen and provides stability to pelvis and lumbar spine
N: 7th through 12th thoracic, iliohypogastric, and ilioinguinal nerves

Quadratus Lumborum Muscle

O: iliac crest
I: Twelfth rib; transverse processes of all five (5) lumbar vertebrae
A: Trunk lateral flexion to same side. Pelvic elevation on same side
N: 12th thoracic and 1st lumbar nerves

Diaphragm Muscle

O: Xiphoid process, ribs, lumbar vertebrae

I:Central tendon

A: Inspiration
N: Phrenic nerve (C3, C4, C5)