Michael J. Morrison, M.D. is a Board-Certified Orthopaedic Surgeon in the Marietta,Georgia area who performs total joint replacementsurgery and advanced arthroscopic surgery. Michael J. Morrison received an Engineering Degree from Case Western Reserve University and his Medical Degree from Ohio State University. State-of-the-art procedures include arthroscopic rotator cuffrepair, anterior total hip replacement, muscle sparing total knee replacement, and arthroscopic hip surgery.
Dr Morrison also does general orthopedics and spine . He uses conservative as well as surgical treatment modalities.
Disclaimer: The following information is for educational purposes only. It is not and should not be construed as medical advice. One needs to talk to his/her doctor regarding specific medical recommendations concerning their medical condition.
Shoulder Anatomy & General
The Amazing Shoulder
There are 3 bones that comprise the shoulder joint- the humerus, scapula, and clavicle. The head of the humerus is a round ball that sits in the shallow "dished out" area of the scapula called the glenoid.
The Rotator Cuff:
The head of the humerus sits in the shallow dish of the glenoid. What holds it in place? The answer is the rotator cuff, a complex of 4 tendons that insert into and wrap around the head of the humerus.This complex of tendons not only helps stabilize the shoulder joint but it initiates shoulder motion. For the purposes of simplification, only the top tendon of the rotator cuff, the supraspinatous, is shown in the adjacent picture.The deltoid muscle sits over the entire shoulder joint, and helps provide significant strength for overhead motion.
Additional Stability: Capsule, Ligaments, Labrum
The rotator cuff provides dynamic stability to the shoulder joint. Just under the tendons where they wrap around the humeral head is a tough fibrous capsule and reinforced fibrous bands, capsular ligaments. These insert into the rim of the glenoid and provide static stability. One additional important structure is the labrum, a raised lip of fibrous tissue around the rim of the glenoid, just under the capsule where it inserts on the glenoid rim. This structure provides an additional raised lip to the glenoid, in effect deepening it and so providing additional static stability to the joint. Please see the sections on Instability and Labrum Tear for pictures of these structures.
The shoulder mounts on the upper body mainly through muscles and tendons attached to the scapula, and this helps provide the amazing flexibility that the shoulder exhibits. The only bony link to the main skeleton is through the clavicle which articulates with the scapula through the acromioclavicular("AC") joint! The clavicle acts as a strut to hold the shoulder away from the chest; this is the structure that is stressed when a football player "stiff-arms" an opponent. Please see the section on Acromioclavicular Joint for pictures and discussion of the problem related to these structures
Commonly Encountered Shoulder Conditions
The following links give a description of the evaluation, diagnosis, and treatment of commonly encountered shoulder conditions: