Thoracic Anatomy

Question 1

What do ribs 2-10 articulate with?

Answer 1

Articulates with 2 vertebral bodies (costal facets composed of a demi-facets from the superior and inferior vertebrae) and the disc

Articulates with the transverse process (costotransverse joint),

Question 2

What do ribs 11 and 12 articulate with?

Answer 2

At T11 and T12

• one facet articulates with one rib
• do not have a costotransverse articulation

**These joints are more important for respiration more than anything else (not so much for spine movement)

Question 3

Describe the typical thoracic vertebral body:

Answer 3

It seems rounder than the c-spine body

Has superior and inferior demi-facets that combine to articulate with the heads of the ribs

Question 4

What size is the thoracic central canal compared to the central canal in the C-spine

Answer 4

relatively smaller

Question 5

Describe the spinous processes in the Thoracic spine:

Answer 5

project downwards, especially T1

Very prominent

Significantly limit extension

provide outriggers for muscles

Question 6

Are spinous processes lined up with the spinal levels?

Answer 6

not completely lined up with spinal level
will line up with transverse process of segment below (but Dr. Mincer says in lab we won’t worry about this fact much; we would still just slide off of it for UPAs)

Question 7

Describe the transverse processes:

Answer 7

Project posterolateral

Have transverse costal facets that articulate with a tubercle on the neck of the rib

Provide outriggers for muscle

Question 8

What is the orientation of the facets

Answer 8

nearly vertical

Question 9

Why is mobility so limited in the thoracic versus the cervical and lumbar region? What mostly limits motion?

Answer 9

Ribs limit thoracic movement

Spinous processes also significantly limit extension

Question 10

What are the least restricted to the most restricted motions in the T-spine and what’s normal range of motion?

Answer 10

Have slightly flexion > rotation > LF > Ext (but all combined give us roughly between 25-40* of motion)

Question 11

Describe the costotransverse joint:

Answer 11

Neck of rib (tubercle) articulates with transverse process (costal facets) to form costotransverse joint. (just ribs 2-10)

Question 12

what type of joints are the costotransverse joints?

Answer 12

synovial

Question 13

What are costotransverse joints stabilized by?

Answer 13

stabilized by

• costotransverse ligaments
• capsular ligaments

Question 14

Describe how increased kyphosis changes the effect of gravity and the amount of compression at the vertebral body:

Answer 14

kyphotic posture moves center of gravity forwards, which increases compression forces on the anterior vertebral body and increases the lever arm for extensor muscles to work against
Example: ideal posture in an 180 lb person = 170 lbs of compression on mid-thoracic bodies
moderate kyphosis in same person = 324 lbs (triples)

Question 15

Why is kyphosis clinically significant?

Answer 15

kyphosis is the most common typical thoracic abnormality

It can be a simple postural problem (like forward head) - very, very common

Question 16

Describe Scheuermann’s Disease

Answer 16

mostly ages 10-12
also known as juvenile kyphosis

very significant anterior wedging of the vertebral bodies (I think without fracture)

dramatic kyphosis

Question 17

How does osteoporosis cause kyphosis?

Answer 17

Often compression fractures and microfractures (anterior vertebral body) cause anterior wedging

when vertebral body/bodies begin to wedge, it moves center of gravity forwards, which increases compression anteriorly and creates longer lever arm for extensor muscles to work against (which also increases compressive load). A vicious cycle.

Question 18

What is scoliosis and what happens to an individual thoracic vertebrae in scoliosis?

Answer 18

scoliosis = abnormal lateral curvature of the spine (but it is not purely lateral)

right thoracic curve causes rotation to the right (also causes rib hump)
Curve is named by the convex side
Ribs follow direction of rotation which is opposite of LF creating rib hump on convex side.

Question 19

What are some causes for scoliosis?

Answer 19

Most of what we talk about is idiopathic scoliosis (80-90% of all scoliosis)
Occurs mainly in adolescent females
Usually a “C” curve with apex at T9-10 (Dr. Mincer verbal, but ppt and neumann said T7-9)

Scoliosis can also be caused by muscle imbalance

Question 20

How do we name two scoliotic curves?

Answer 20

If there are two curves, one is considered primary, the other secondary

Question 21

What is the best way to detect a rib hump,

Answer 21

A rib hump is traditionally detected by observing from behind as the pt bends forward as far as possible with their shirt off. You are analyzing the symmetric rise of the two sides when pt bends over. This is known as Adam’s Forward Bend Test and has traditionally been performed in schools.

Question 22

On which side does the rib hump appear?

Answer 22

(e.g. in a right thoracic scoliosis, the rib hump will appear on the right side.

Question 23

Why does the rib hump happen in scoliosis?

Answer 23

Rib hump happens because of the rotation

Question 24

Describe the muscle force requirements of the right lumbar extensors when carrying loads in the right hand?

Answer 24

think about lever arm and how much compressive force is being generated. The closer the load is the less the lever arm the less the compressive force.

Right handed carry would increase the lumbar extensor loads, but more in the contralateral side than the ipsilateral side.

Question 25

Describe the muscle force requirements of the right lumbar extensors when carrying loads in the left hand

Answer 25

The muscle force is larger than on the left (ipsilateral)

a lot more muscle force is needed compared to the load being carried, because of the increased lever arm.