Bryant Triangle

Bryant Triangle is a hypothetical triangle shape that is drawn to determine the supra trochanteric shortening of the hip joint.

How do you identify Bryant’s triangle?

• The patient is in supine position.
• Identify ASIS (anterior superior iliac spine) with thumb and tip of greater trochanter with forefingers.
• Draw a perpendicular line from ASIS toward the bed, and another perpendicular from the tip of greater trochanter to the previous line.
• The Bryant’s triangle is formed by these three points (the tip of greater trochanter, the ASIS and the Junction of the two perpendicular lines drawn before).
• The triangle should be marked on both the sides and each side of the triangle is compared with its counterpart on the normal side.
• Measure the distance between the tip of greater trochanter and the junction of the 2 perpendicular lines and compare it to the normal side.
• Decreased distance indicates a supratrochanteric shortening of the hip joint.

See Also: Thomas Test of the Hip

Supratrochanteric shortening can be due to:

1. Fracture neck of femur,
2. Traumatic dislocation of hip,
3. Developmental dislocation of hip,
4. Avascular necrosis with collapse,
5. Arthritis hip: rheumatoid,
6. Infective and coxa vara.

Shortening of base (B-C) suggests upriding of greater trochanter seen in:

1. Coxa vara, coxa breva,
2. Destruction of head,
3. Nonunion fracture neck femur,
4. Old dislocations,
5. Girdlestone arthroplasty,
6. Perthes disease.

Shortening of perpendicular (A-C) only Suggests:

1. Internal rotation of femur or central migration of head,
2. Old unreduced posterior dislocation,
3. Central fracture dislocation etc.

Shortening of hypotenuse (A-B): It is always associated with shortening of either or both of other lines (Remember Pythagoras theorem).

Isolated shortenings are rare and a combination is often seen:

1. Base + perpendicular shortening (definite hypotenuse shortening): Central fracture dislocation, neck resorption, head resorption, protrusio acetabuli.
2. Base shortened but perpendicular lengthening: Non-union fracture neck femur, anterior dislocation of hip, SCFE, girdlestone arthroplasty.
3. Base shortened + lengthened perpendicular: Malunited fracture neck femur.

All lines lengthened: Coxa magna, coxa valga.

In Bilateral diseases, the Bryant’s triangle measurement has no clinical value, if ASIS cannot be palpated, lines are quite arbitrary and errors are easy to occur.

See Also: Pelvic Fractures

Other Measurements

Other lines that can be drawn to assess the supratrochanteric shortening include:

Roser Nelaton’s line:

Roser Nelaton’s line is used if both hips are affected. Roser Nelaton’s line is a line joining ASIS to ischial tuberosity. The tip of the greater trochanter should touch this line normally. If it lies above this line, supratrochanteric shortening is confirmed.

Chiene’s lines:

The lines joining the two ASIS and two greater trochanter are normally parallel to each other. This is disturbed if trochanter is shifted up.

Schoemaker’s line:

The lines joining the greater trochanter and ASIS when extended above from both sides may cross above the umbilicus in the midline normally. In supratrochanteric shortening on one side the lines may cross above the umbilicus away from the midline. In bilateral supratrochanteric shortening these lines may cross in the midline below the umbilicus.

Morris bitrochanteric line:

The distance from pubic symphysis to greater trochanter is measured. This again indicates supratrochanteric shortening.

Infratrochanteric shortening is accounted by actual measurements of individual components of femur and tibia. This can be from femoral shaft or tibia or calcaneum malunited fracture or from growth disturbance.

References

1. Wikipedia
2. Kamath BJ, Saraswati V, Bansal A, Pai V. Clinical evaluation of hip joint in sagittal plane using pelvifemoral angle. J Clin Orthop Trauma. 2013 Dec;4(4):171-3. doi: 10.1016/j.jcot.2013.09.003. Epub 2013 Oct 7. PMID: 26403877; PMCID: PMC3880947.
3. Clinical Assessment and Examination in Orthopedics, 2nd Edition Book