Ongoing shoulder tip pain when bringing the arm across the chest or when elevating the arm above the head can be caused by injury to Acromioclavicular Joint (AC Joint).
The AC joint is located at the frontal tip of the shoulder and connects the collar bone (known as the clavicle) to the acromion bone which is the highest bony part of the shoulder blade. The muscles and ligaments that connect and stabilise the AC joint included the Acromioclvicular ligaments which cross the joint and the coracoclavicular ligaments which connect from the end of the clavicle bone to a separate bone that is located below the clavicle known as the coracoids process. Additionally the attaching upper trapezius muscle which is situated on the back of the shoulder has a backward pull on the clavicle while the deltoid muscle which is situated in the front of the shoulder has a forward pull on both the acromion bone and clavicle bone.
How is the AC joint injured?
It is commonly caused by a fall on the shoulder which pushes the acromion inwards against the adjoining clavicle bone
Falling on the elbow or outstretched hand
A heavy shoulder-to-shoulder tackle
Repetitive overhead activity such as swimming, painting.
Grades of AC joint injury
- There are 6 grades of AC joint. The most severe grades, 4-6 require surgical intervention. A grade 3 injury can be treated both surgically and without surgery starting with immobilisation in a sling for 4-6 weeks. Type 1 sprain which involves a sprain to acromioclavicular ligaments and type 2 which involves spraining of the coracoclavicular ligaments and a tear to the acromioclavicular ligaments can be rehabilitated through physical therapy.
Signs and symptoms
Pain into the shoulder when moving the arm across the chest
Pain is located at the tip of the shoulder and is painful when compressed
Shoulder tip pain when lifting the arm overhead
Lifting the arm upwards in a sideways fashion from your hip to the ceiling causes shoulder pain
Pain into the back of the shoulder (upper trapezius)
Management and treatment
An X-ray is used to confirm the extent of injury following trauma to the shoulder. The shoulder is initially immobilised in a sling with cold therapy to reduce inflammation. Range of motion exercises in a painfree range are started initially with basic isometric strengthening exercises instructed by your physical therapist. Joint mobilisations are later introduced to encourage further painfree movement. Strengthening of deltoid and trapezius are increased with scapula stabilisation and neuromuscular control exercises added as full pain free movement is achieved.
Tomás Ryan is a registered physical therapist (MIAPT) with The Irish Association of Physical Therapy and is based in Clonmel & Thurles.
Contact him on: 0504 26672 or email firstname.lastname@example.org