What’s Carrying Angle of Elbow? Its Anatomy

• The carrying angle is formed between the arm and the forearm when the arm is in an anatomical position.
• It is also known as the cubital angle or the angle of inclination of the forearm.
• The carrying angle is more pronounced in females than in males due to differences in bone structure and hormonal influences.
• The carrying angle is essential in the arm’s mechanics and helps distribute weight while carrying objects.
• Deviations from the normal carrying angle can lead to medical conditions such as cubital tunnel syndrome and tennis elbow.

Have you ever observed that when you fully extend your hand, the hand does not remain straight? That is, the forearm does not align in a straight line with the arm. It is because of the formation of the carrying angle of the elbow, and this article is all about it.

If you have never observed it, try this: stand straight in front of the mirror, expose your arm and forearm or wear sleeveless clothes so you can see your hands. Now stand straight with both the palms facing forward and try to observe the elbow joint. The angle at the elbow joint will be apparent.

What’s the carrying angle of elbow joint?

The carrying angle is defined as the acute angle made by the median axis of the arm with the fully extended and supinated forearm. An extended forearm is never in a straight line with the arm and makes the angle at the elbow joint. This angle is about 10 – 15 degrees short of full extension, known as the carrying angle.

It is a standard elbow anatomical phenomenon, but it disappears when we fully flex/bend our elbow. Angle also disappears when we pronate (make forearm facing backwards) our forearm. This may also change or be altered if there is any pathological change in the elbow or due to injury to the structure of the elbow like Intercondylar fracture humerus, or supracondylar fracture humerus.

Anatomy behind carrying angle of the elbow

If we look at the anatomy of the elbow joint, we will find that the transverse axis of the joint is directed medially and downward. Let us try to understand it with figures, and we will explore the factors responsible for it.

1. The transverse axis of the elbow is directed medially and downwards.
2. The medial flange of the trochlea is 6 mm deeper than the lateral flange. The trochlea is an articular surface on the humerus bone where the ulna (forearm bone) articulates to form the elbow joint.
3. Superior articular surface The superior articular surface of the conoid process of the ulna is placed obliquely to the long axis of the bone.

Normal carrying angle of elbow

Carrying angle is a normal phenomenon in our elbow; it has a significant role when lifting heavy weights with our hands. It gives leverage and helps it initiate elbow flexion while holding the heavy object in our hand. It also helps to clear the hip when we are walking or running. So, what causes the formation of a carrying angle in the elbow?

As you can see in the table, the normal carry angle of the elbow ranges between 5 to 15 angles. However, the carrying angle is always greater in females than in males. It may be due to hormonal influences or increased joint laxity in females. The increased growth of the medial lip on the trochlea compared to the lateral lip in females, along with the increased vagal tilt of distal humeral articulation with the longitudinal axis of the humerus, also contributes to the increased carrying angle¹.

Fracture around the elbow joint affects the normal carrying angle, leading to elbow varus and valgus deformity. If the angle increases after fracture, we call it valgus elbow deformity. In another situation, if the normal carrying angle of the elbow reduces from a 5-degree angle, then it is termed elbow varus deformity. Varus elbow is also termed a gunstock deformity elbow as it resembles a gun.

How to check carrying angle of elbow at home

Measuring the carrying angle of your elbow at home is easy. Simply stand in front of a mirror and keep your elbow straight while your forearm faces forward. Ask someone to draw a straight line using a marker and ruler along your arm and forearm, using the guide in this figure for reference.

Then, using a protractor (which can be found in most school instrument boxes), measure the angle that’s formed at the point where the two lines meet.

Sunit. S. Ekka

Dr Sunit Sanjay Ekka is a physiotherapist in practice for the last 15 years. He has done his BPT from one of the premium Central Government physiotherapy colleges, ie, SVNIRTAR. The patient is his best teacher and whatever he gets to learn he loves to share it on his Youtube channel and blog.