SUPERFICIAL MUSCLES OF THE BACK
Dissection Instructions
SKIN INCISIONS
1. Refer to Figure 1.07.2. Use a scalpel to make a vertical skin incision in the
midline fiom the external occipital protuberance (X)
to the tip of the coccyx The skin is approximately
6-mm-thick in this region.
3. Make an incision from S to the midaxillary line (T).
This incision should pas approximately 3 cm inferior
to the iliac crest.
4. At the level of the inferior angle of the scapula, make
a transverse skin incision from the midline (U) to the
midaxillary line To facilitate skinning, make a par-
allel transverse incision above and below this one.
5. Make a transverse dcin incision from R to B, superior
to the scapula and superior to the acromion. Extend
this incision to point F, approximately halfway down
the arm.
6. At point F, make an incision around the anterior and
posterior surfaces of the arm, meeting on the medial
s'de (G). If the upper limb has been disected previ-
cusly, this incision has already been made.
7. Make a skin incision that begins at G on the medial
surface of the arm and extends superiorly to the axilla.
Extend this incision in feriorly along the lateral surface
of the trunk, through V to T.
3. Make a transverse skin incision from the external
occipital protuberance (X) laterally to the base of the
rmstoid proces (M).
9. Make an incision along the lateral surface of the neck
and superior border of the trapezius muscle (M to B).
10. Remove the skin from medial to lateral. Detach the
skin and place it in the tisue container.
SUPERHCIAI. FASCIA
1. In the superficial fascia, locate the occipital artery
and the greater occipital nerve (Fig. 1.08). First, find
the occipital arteryand then look on its medial side for
the greater occipital nerve. The greater occipital nerve
is the dorsal primary ramus of spinal nerve C2. The
greater occipital nerve pierces the trapezius muscle
approximately 3 cm inferolateral to the external
occipital protuberance. The deep fascia in this area
is very dense and tough. Therefore, it may be difficult
to find the greater occipital nerve, even though it is
large. [G I17; N 171; R 212; C 414]
2. Read a description of the dorsal primary ramus of a
qainal nerve. The posterior cutaneous branches of
the dorsal primary rami pierce the trapezius muscle or
latissimus dorsi muscle to enter the superficial fascia
(Fig. 1.08). To save time, make no deliberate efiort to
display posterior cutaneous branches of the dorsal pri-
mary rami. Ii 20; N 187; R Z04]
3. Reflect the superficial fascia of the back from medial
In lateral. Detach the superficial fascia by cutting it
along the skin incision lines and place it in the tissue
container
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4. In the neck, reflect the superficial fascia only as fir lat-
aally as the superior border of the muscle.
Domntrut lb: deepfnria along tbenipniorbordcr aftb:
tmpeziiu made. The aocaory nerve is superficial at
this location and it is in danger of cut.
After you dissect . . .
Review the branching pattern of a typical spinal nerve and
understand that cutaneous branches of the dorsal primary rami
innervate the skin of the back. Study a dermatome chart and
become familiar with the concept of segmental innervation. [G
B1; N 151; C404]
SUPERFICIAL MUSCLES OF Tl-I E
BAC K
Before you dissect . . .
The slperficial muscles of the bad: are also called the poste-
n'or thoraooappendicular muscles because they attach to the
axial skeleton and the upper limb. There are five superficial
muscles of d1e back: trapezius, latissimus dorsi, rhomboid
major, rhomboid minor, and levator scapulae.
The order of dissection will be as follows: the superficial sur-
filce of the trapezius muscle will be cleaned. The trapezius mus-
de will be examined and reflected. The latksimus dorsi muscle
will be studied and reflected. The rhomboid major muscle,
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