Clinical Anatomy The Shoulder Part 1: Normal Anatomy
My name is Gavin Jennings. I am a Surgeon specialising in shoulder problems. This is the second part of a presentation discussing the clinically relevant anatomy of the shoulder girdle.
This part will discuss the patho-anatomy of the shoulder, firstly of the AC joint.
The acromivlavicular joint may become degenerate and painful over time or acutely unstable as a result of trauma to its ligaments. Trauma of increasing severity progressively damages then disrupts the acromioclavicular ligaments followed by the strong coracoclavicular ligaments. Stabilisation surgery may be needed in those patients where the coracoclavicular ligaments have been disrupted. (For more detail look out for the video on Clavicle and AC injuries)
At the other end of the clavicle, the sternoclavicular joint may also become destabilised as a result of trauma. This can represent a clinical emergency if the clavicle displaces posteriorly putting pressure on the underlying mediastinal structures. This may present with difficultly breathing or swallowing or symptoms related to arterial or venous compression. In the emergency situation a towel clip can be used to apply traction to the clavicle to effect reduction.
Moving on to the soft tissues now, considering patho-anatomy of the biceps tendon
The long head of biceps pass through the inter tubercular groove close to the edge of the insertions of both subscapularis and supraspinatus and attaches to the superior labrum.
It is unusual for the long head to be pathological in isolation. More commonly it is associated with additional pathology of the adjacent structures, such as impingement, subscapularis and supraspinatus tears and SLAP lesions.
The labrum can be damaged inferiorly (a Bankart lesion) which may result in recurrent GH instability) or superiorly in the case of a SLAP lesion.
A Bankart lesion is the separation of the labrum from the glenoid rim
and is detected on an MRI scan following the injection of dye into the shoulder (an MR Arthrogram)
This shows an example of an anterior Bankart lesion viewing from behind in a right shoulder.
SLAP is an acronym for superior labrum anterior to posterior. ie the superior labrum is damaged from front to back. Type 1 is a frayed labrum, Type 2 is detached and is the commonest type. Type 3 is detached with a bucket handle section and Type 4 extends into the long head of biceps tendon.
Again these are visualised on an MR Arthrogram.
The rotator cuff can become inflamed or tendinopathic, often as a result of impingement or can tear either because of chronic degeneration or acutely due to trauma.
Rotator cuff tears can be seen both on ultrasound and plain MRI scans. MRI scans , however, give more information on the nature and likely reparability of the tear.
Thanks for listening to the section on patho-anatomy of the shoulder. The next part will cover some of the surgical approaches to the shoulder.
Please contact me if you would like any further information.