Healthcare and Medicine Reference
In-Depth Information
Fig. 7.18 The Deep Back Arm Line in
dissection in situ, showing the connections
from the rhomboids and scapula down to
the little finger.
unfamiliar with avian anatomy in detail, in most birds
the SFAL provides both the motive power of the wing
beat, and the control of the 'ailerons' - the outer feathers.
In a quadruped, the SFAL provides the forward motive
power for the foreleg.
The Deep Back Arm Line
The Deep Back Arm Line (DBAL) begins at the spinous
processes of the upper thoracic and 7th cervical verte-
brae, passing down and out with the rhomboid muscles
to the vertebral border of the scapula (Fig. 7.18 and DVD
ref: Shoulders and Arm Lines, 52:03-52:18). The rhom-
boids are thus part of both the Spiral Line (Ch. 6) and
the DBAL (Fig. 7.19 and DVD ref: Shoulders and Arm
Lines, 53:18-1:01:57). The fascial track splits here with a
switch at the vertebral border: the Spiral Line continues
deep to the scapula with the serratus anterior muscle
(DVD ref: Spiral Line, 16:00-20:28), while this DBAL con-
tinues around the scapula with the rotator cuff, specifi-
cally from the rhomboids to the infraspinatus, picking
up the teres minor along the way (DVD ref: Shoulders
and Arm Lines, 1:04.21-1:08:10). These two muscles tack
down to the next station on the posterior aspect of the
humerus, on the greater tubercle, contiguous with the
joint capsule.
Another branch line of the DBAL begins on the lateral
lower surface of the occiput with the rectus capitis late-
ralis, continuing down with the levator scapulae from
Stretch assessment for the Superficial
and Deep Front Arm Lines
To feel the difference between the Superficial and Deep
Front Arm Lines, lie supine near the edge of a treatment
table or hard bed, and drop the arm, with the palm up
and the shoulder abducted, off the edge. This is a stretch
for the SFAL, and will be felt in the pectoralis major or
somewhere along the SFAL track. To change the stretch
to the DFAL, turn the thumb up (medially rotating the
shoulder to do it) and then reach it out along the other
fingers, stretching the thumb away from the shoulder,
as if reaching the thumb to grasp a piece of paper out
behind you as you let the arm drop off the table. You
will feel the stretch track up the DFAL, all the way to
the pectoralis minor.
Alternately, stand behind a model holding her wrists.
Allow the model to lean forward from the ankles like
the beginning of a swan dive, with you counterbalanc-
ing the weight - assuring yourself and the model that
you can easily hold her from falling forward. She is now
both hanging from and leaning into both Front Arm
Lines. Have the model laterally rotate the humeri
(thumbs up), then take her wrists and have her lean
forward, and report to you where the stretch is. She is
likely to report feelings of stretch somewhere in the
SFAL - from the pectoralis major on out through the
hand flexors - and this can give you a good idea of
where the tissues might be shortened or challenged
(DVD ref: Shoulders and Arm Lines: 17:20-17:52).
Then have the model medially rotate her humeri
(thumbs down) and lean forward with you holding the
wrists again. This time, the challenge is likely to come
in some part of the DFAL - the pectoralis minor on out
through the biceps and thumb, giving you some indica-
tion of where to work. The qualification in these two
statements comes from the abundance of crossover
muscles that, in the variety of human arm usages, make
blanket statements unwise.
Teres minor
Fig. 7.19 The Deep Back Arm Line opens with the rhomboids,
whose superficial layers of fascia pass across to the infraspinatus.
This represents a switch, as we saw the rhomboids also
connecting under the scapula to the serratus anterior in the Spiral
Line (see Fig. 6.4, p. 133).
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