Distal Biceps Tendinopathy, A Blanket Term
Distal biceps tendinopathy is somewhat of a blanket term that refers to an individual having an overuse injury to the biceps tendon at the elbow. Distal
biceps tendinosis and distal biceps tendonitis are other common terms used to describe pathology to the distal biceps tendon. The word ‘distal’ preceding the other anatomical terms indicates that the biceps tendon referred to is the tendon at the elbow. The reason ‘distal’ is necessary is that there are also biceps tendons proximally at the shoulder joint, these tendons can also develop tendinopathy and therefore simply writing biceps tendinopathy doesn’t indicate if it is the tendon in the shoulder, or elbow. For this short blog when referring to the biceps tendon, unless otherwise stated it is the elbow tendon we are referring to.
Muscle Anatomy Of The Biceps Brachii Muscle
There are three main muscles in the body that can act as strong elbow flexors, the biceps brachii, brachioradialis and brachiaalis. With regard to suffering with distal biceps tendinopathy, of the three it is the biceps brachii that is the muscle involved and will be discussed here. The biceps brachii muscle consists of two heads, with the name effectively taken from Latin where ‘bi’ means two and ‘ceps’ means head. For which there is a short head and a long head, the short head of biceps originates at the coracoid process at the front of the shoulder blade and the long head has its origin from the supragleniod tubercle which is at the top of the “socket” of the shoulder joint also part of the shoulder blade. The two heads of biceps meet and join in the front of the upper arm. From here the biceps brachii muscle travels down the front of the upper arm attaching via yet another tendon this one the distal biceps tendon to the radial tuberosity at the forearm, with the insertion just below the elbow joint.
In some people the distal biceps tendon like the proximal biceps tendons have two distinct parts, with each part being a continuation of the proximal short and long heads of the muscle originating from the shoulder blade attachments. In other individuals the short and long heads of biceps brachii blend into one common tendon.
Function Of The Biceps Brachii Muscle
At the elbow the muscular actions of the biceps brachii are to assist in bending the elbow, anatomically referred to as elbow flexion (functionally this is the action of moving the hand up towards the face). Biceps brachii also assists in turning the hand over, palm face up as if to take your change when paying for something in a shop. Anatomically this action is known as forearm supination important for manipulation objects, opening jars, turning door handles…
As well as the actions the biceps muscle exerts at the elbow, your biceps brachii can also act on the shoulder joint. At the shoulder it plays a role in both assisting movement and stability. The long head of biceps tendon that lies within the shoulder joint is considered important for stability of the joint. The long head tendon assists in depression of the “ball” in the socket, depressing the ball in the socket means it has a powerful role in reducing shoulder impingement. The actions of the biceps brachii muscle at the shoulder will not be discussed any further here since for the purpose of this brief blog we are only concerned with biceps function and tendinopathy at the elbow.
Potential Causes Of A Distal Biceps Tendinopathy
When the biceps muscle contracts tension is passed through the biceps tendon. Should such tension be excessive, which could manifest as too much force in a single load, or repeated loads of lower force yet beyond that which the biceps can repetitively withstand and “recover” from tendon reaction may occur. Reaction may present as tendon tearing, inflammation, or degeneration. When such changes occur then the individual may experience pain, the pain associated with a distal biceps tendon load reaction is typically a local pain. Where any pain will typically be isolated to the tendon and the individual suffering with regularly be able to pinpoint the exact area, they feel pain. Any pain experienced is frequently aggravated via lifting objects, as well as actions necessitating twisting activities of the forearm, utilizing the tendons’ role in supination movements.
Distal Biceps Tendon Vulnerability And Injury
Predisposition of the distal biceps tendon to injury may be the result of relatively poor vascular supply to the tendon. Most tendons have a what is known as an avascular zone, an area/section of the tendon where blood supply is limited. Poor blood supply can impact a tendons ability to absorb load and recover and repair ready to take more load.
Mechanical impingement, compression to the tendon is another potential predisposition for the development of distal biceps tendon injury/degeneration. Compression to the biceps tendon may occur when the forearm is pronated (position of the palm being face down towards the floor), in a pronated position available space for the distal biceps tendon can be reduced. This is due to the reduction of space between the two long forearm bones, the radius and the ulna, leaving less room for the biceps tendon. The space reduction when work is being done may lead to potential compression of a loaded biceps tendon leading to a tendon reaction.
