SURGICAL ANATOMY
Remember: the shoulder is enveloped by the Deltoid and the Rotator Cuff. Surgical
exposure of the gleno-humeral joint is obtained by either splitting natural intervals
between these structures or by releasing and reattaching these structures.
Keep in mind that the anatomy of the deltoid and the rotator, in the blue part of the
photo is shown the surgical acess between the deltoid and the pectoralis major
muscle, you want to enter between the two,
AXCESS TO THE GLENO-HUMERAL JOINT:
1. ANTERIOR PASSAGE:
The blue plate indicates the anterior surgical access, in the
picture is shown the anterior margin of the deltoid, where you see
the pectoralis major muscle disappearing under the deltoid
muscle. Once you identify the 2 muscles you try to pull them
apart one from the other. You can then identify the TENDON of the
SUBSCAPULARIS MUSCLE, but be careful because exactly in this
position there is the CEPHALIC VEIN (and also the basillic, but he
didn’t stress on it), that runs immediately in your brain, you MUST
AVOID CUTTING IT (if possible), otherwise the patient dies
(oopsie). Also you need to cut the joint’s fibrous capsule in order to access to the
glenohumeral joint.
This access is the least disruptive, it just separates muscles and structures, only skin is
cut, deeper inside you can see the TENDON OF THE SUBSCAPULARIS MUSCLE (a
deep muscle).
the conjoint tendon is cut for
deep dissection.
CONJOINT TENDON
conjoint tendon on the
coracoid process, used by
biceps’ short head and
coracobrachialis
2. LATERAL PASSAGE:
In this case the surgical dissection does NOT follow anatomical plains, but THE
DELTOID IS CUT (WATCH OUT FOR THE AXILLARY NERVE, stay distal). When you cut
muscles, you try to cut them following the direction of the fibres, so that less fibres are
hurt. The joint is reached THROUGH the muscle, once you cut it, immediately below
the deltoid, there is the SUB-ACROMIAL BURSA, that allows the deltoid to slide on
the bony plates when contracting. What you can see under the bursa are: the
TENDON of the SUPRASPINATUS, which passes through the hole below the
acromioclavicular joint and above the glenohumeral joint) and the
ACROMIOCLAVICULAR joint.
3. POSTERIOR SURGICAL AGGRESSION
The posterior approach passes below the lower margin of the infraspinatus, firstly you
identify by palpation (before cutting) the direction of the SPINE OF THE SCAPULA, you
cut the same direction as muscular fibres, and below the deltoid (posteriorly) you can
see the TENDON of the INFRASPINATUS and a little piece of the teres minor. Then you
want to pass between the 2 muscles by
separating them (above supraspinatus,
down deltoid and teres minor). What
appears underneath is the POSTERIOR
ASPECT OF THE JOINT CAPSULE.
What you should keep in mind when cutting
is:
1. location of both SUPRASCAPULAR
ARTERY and NERVE, they are
immediately deep to the
infraspinatus.
2. Location of the AXILLARY NERVE, immediately the teres minor.
3. An artery near the humerus.
TO SUM UP:
TERES minor + DELTOID pull
DOWN.
SUPRASPINATUS pull UP.
Once all this is done and the
structures are separated you can cut
the posterior part of the capsule
(while keeping in mind what to do).
This allows to open the capsule to see
the
HEAD OF THE HUMERUS.
