Ligamentum Teres
Ligament of the Head of the Femur, Capitis femoris ligament
Tubular, synovial-lined ligament that spans the transverse acetabular ligament to the fovea of the femoral head1.
Vascular Function
The Ligamentum Teres functions to sheath and guide the acetabular artery (a branch of the obturator artery)to supply the femoral head1,2.
This is especially important when providing blood flow to neonates, but the blood supply from the acetabular artery decreases with age1. By adulthood the acetabular artery supplies little to no bloodflow since the majority of the bloodflow to the head and neck of the femur is through the medial and lateral circumflex arteries1.
There are speculations that the ligamentum teres may have a mechanical function to stabilize the fetal hip
Mechanoreceptive functions
Since the Ligamentum Teres has high number of mechanoreceptors and is taut in weightbearing
Stabilization Functions
Dutton termed the Ligamentum Teres the “ACL of the hip” since it functions as a stabilizer against hip subluxation3. The Ligamentum Teres is most effective at preventing subluxation in a internal rotation + extension or an ER + flexion position3.
Mechanics
According to Atlas of Anatomy by Gilroy2, the ligamentum teres has “no mechanical function”2. Neumann1 disagrees and states that the ligamentum teres “undoubtedly provides some functional stability to the hip,”1 but its exact role is unknown. There are many positions that tension the ligamentum teres such as:
Weightbearing
The ligamentum teres is attached to the transverse acetabular ligament which causes it to be taut in weightbearing3
Flexion + Abduction
In the flexed and abducted position, the ligamentum teres is theorized to act as a sling and support the inferior aspect of the femoral head when in a squat-like position1.
Sensory Function
The ligamentum teres contains mechanoreceptors and may offer an indirect function to stability through improved proprioception1.
Dysfunction
Ligamentum teres stress or injury can be a source of intra-articular hip pain1.
- Ligamentum teres injuries often present with deep posterior hip pain aggravated by hip flexion
Tear
Ligamentum Teres tears often result in hip microinstability