Lab 2 - Back and Thorax


Fig1. Back Muscles Fig2. Gross Back

When are the vertebral spines most prominent - trunk extension or trunk flexion? Answer

Palpate the borders of the scapula. This bone extends between ribs 2-7 and you should be able to feel the vertebral (medial) border, axillary (lateral) border, inferior angle, spine and acromion

Fig3. Back Levels

The pleural cavity which contains the lungs extends to the level of T12 posteriorly, just above the 11th and 12th ribs.

Fig4. Pleura

What is/are the risks of a fractured 11th or 12th rib or blow to the back, on the left side, at this level? Answer

Fig5a. Pneumothorax

What position would the scapula take if the serratus anterior muscle was weak or inactive during shoulder flexion? Answer

Fig5. Winged Scapula

Map the borders of the latissimus dorsi and trapezius muscles. Rotate your shoulder through flexion, elevation, depression, retraction and extension and determine when these muscles contract. The border of these two muscles and the medial border of the scapula form a "triangle of auscultation" .

Fig6. Triangle of Auscultation

What is the clinical significance of this triangle? Answer

Note the massive bulging of muscle on either side of the vertebral column from the iliac crest to the level of T12. This is the erector spinae muscle.

Put your hands on your hips. You are resting them on the iliac crests. A horizontal line drawn through L4,5 (supracristal line) will intersect the top of the iliac crests. Follow the crest posteriorly toward the gluteal cleft and note the right and left dimple in the skin. This coincides with the posterior superior iliac spine of the ilium and marks the middle of the sacroiliac joint.

Fig7. Herniated Disc

Why is the supracristal line (level of L4,5) an important clinical landmark? Answer

Fig8. Spinal Tap


TFig1. Bony Thorax

Just above and posterior to the jugular notch you can feel the ________. Answer

The jugular notch is clinical landmark for which structures? Answer

The manubrium lies anterior to the arch of the aorta.
The sternal angle is another important landmark. It locates the costal cartilage of rib 2, the trachea divides into the right and left primary bronchi at this level and it represents the upper border of the heart.
The body of the sternum is anterior to the heart and vertebral bodies T5-T8.
Palpate the xiphisternal joint.

What is the clinical significance of the xiphisternal joint? Answer

TFig2. Sternal Angle

Locate the depression just above the clavicle in the midline. This is the location of the apex of the lung.

TFig3. Heart and Lungs

Anteriorly on the thorax mark the following locations: a) 5th intercostal space about 9cm left of the midline; b) lower border of the costal cartilage of right 6th rib, just right of the midline; c) superior border of costal cartilage of right 3rd rib, just right of the midline; d) inferior border of costal cartilage of left 2nd rib just left of midline. These four points determine the location and size of the heart.

TFig4. Heart Position TFig5. Heart Sounds

Locate the outline of the superficial muscles: pectoralis major, serratus anterior and confirm their action while performing a push-up (push yourself up from a chair or palpate these muscles on a partner while he/she is doing a push-up

TFig6. Inspiration Muscles TFig7. Pectoral Muscles