Pectineus

Origin, Insertion, Action, Innervation

Origin: Pectineal line (pecten) of the superior pubic ramus and the adjacent bone surface
Insertion: Pectineal line of the femur (a line running from the lesser trochanter to the linea aspera, on the posterior proximal femoral shaft)
Action:
Primary: Adduction of the hip
Flexion of the hip
Internal (medial) rotation of the hip (slight)
Innervation: Femoral nerve (L2, L3); occasionally receives a branch from the obturator nerve (variable)

Palpation Guide

Client position: Supine with the hip slightly flexed, abducted, and externally rotated (the knee may be bent and allowed to fall to the side).
Landmark sequence:

Locate the inguinal ligament — it runs from the ASIS to the pubic tubercle. The femoral triangle lies just inferior to the inguinal ligament.
Locate the adductor longus tendon — the most prominent cord in the medial groin when the client adducts against resistance. Pectineus lies lateral and slightly superior to adductor longus, directly in the floor of the femoral triangle.
Palpate just lateral to the adductor longus tendon, aiming toward the superior pubic ramus. Pectineus is the muscle in the floor of the femoral triangle, between the iliopsoas (laterally) and adductor longus (medially).

Tissue feel: Flat and broad, spanning the gap between the hip flexors and adductors. In the resting state, it blends with the surrounding muscles. When contracted (resisted adduction with slight flexion), it firms up in the floor of the femoral triangle. Tenderness at the superior pubic ramus attachment is common in groin strains.
Confirmation test: Ask the client to adduct the hip against your resistance while simultaneously flexing slightly. Pectineus should contract under your fingers in the femoral triangle floor. If the contraction is more medial and cord-like, you are on adductor longus.
Common errors:
Confusing with adductor longus — adductor longus is more superficial, medial, and has a prominent tendon at the pubic tubercle. Pectineus is deeper, more lateral, and originates from the pectineal line (superior pubic ramus), not the pubic tubercle.
Excessive pressure near the femoral neurovascular bundle — the femoral artery, vein, and nerve pass through the femoral triangle directly over pectineus. Palpate gently and check for pulse before applying pressure.

Trigger Point Referral

Common TrP locations: In the muscle belly, approximately midway between the pubic ramus and the pectineal line of the femur, in the floor of the femoral triangle.
Referral pattern: Deep groin pain, just inferior to the inguinal ligament. May extend to the anterior proximal thigh.
Clinical significance: Pectineus TrP referral produces groin pain that mimics adductor strain, hip flexor strain, or inguinal hernia. In a client with groin pain worsened by combined adduction and flexion, and no palpable inguinal hernia bulge, pectineus should be assessed — it is often overlooked in favor of the more prominent adductor longus.

Trigger point referral diagram — coming soon

Image coming soon. For visual reference, see [Pectineus at TriggerPoints.net](http://www.triggerpoints.net/muscle/pectineus).

Clinical Notes

Common conditions:

Commonly involved in conditions/groin-strain — pectineus is one of the most frequently strained muscles in acute groin injuries, particularly in athletes performing rapid hip flexion-adduction movements (kicking, cutting, skating).
Relevant to conditions/hip-osteoarthritis — as a hip flexor and adductor crossing the hip joint, pectineus shortens and guards in early-stage OA, contributing to the flexion-adduction contracture pattern.
Relevant to femoral nerve entrapment — the femoral nerve passes over pectineus in the femoral triangle. Chronic hypertonicity could theoretically contribute to nerve compression in this region, though this is uncommon.

What you'll typically find:

In acute groin strain presentations, pectineus is tender at its pubic attachment and through the muscle belly. The client reports sharp pain with combined adduction and flexion, and pain with stretch into abduction and extension.
In chronic presentations (desk workers, cyclists), pectineus shortens alongside the other hip flexors, contributing to limited hip extension and anterior pelvic tilt. It is less dramatic than iliopsoas but contributes to the overall flexor tightness pattern.
Pectineus is often involved in adductor strains but is not assessed separately — clinicians test adductor longus and assume it represents the group. Palpating lateral to adductor longus, in the femoral triangle floor, catches pectineus.

Treatment effects:

Responds well to gentle, sustained compression in the femoral triangle floor and cross-fiber techniques along the muscle belly. This is a sensitive area — work slowly and communicate.
Post-treatment stretching into hip extension, abduction, and external rotation (the combined opposite of pectineus's actions) extends the treatment effect.
In acute strain, treatment is limited to gentle lymphatic drainage and pain-free ROM in the early stages. Direct muscle work is contraindicated until the acute inflammatory phase resolves.

Cautions:

The femoral artery and vein pass directly over pectineus in the femoral triangle. Always check for a pulse before applying sustained pressure in this region. If you feel a strong pulse, you are on or near the femoral vessels — move your contact point.
The femoral nerve also passes through this region, lateral to the artery. Paresthesia in the anterior thigh during treatment indicates nerve compression — lighten pressure immediately.
Inguinal region sensitivity — this area is close to the genitalia. Clear communication about what you are doing and explicit consent are essential before working here.

Clinical pearl:

Pectineus is the "forgotten muscle" in groin pain. When adductor longus tests normal but the client still has groin pain with combined flexion-adduction, test pectineus specifically — resisted adduction from a slightly flexed and externally rotated starting position (which pre-lengthens pectineus) isolates it more effectively than standard adduction testing.

Assessment

Resisted adduction:

Client supine with the leg slightly abducted. Ask the client to adduct against your resistance at the medial knee or ankle. Pain in the groin, particularly the upper groin near the pubic ramus, implicates pectineus (and the adductor group generally).

Resisted hip flexion from adducted position:

Client supine with the hip in slight adduction. Resist hip flexion. This loads pectineus preferentially because it combines its flexion and adduction actions.

Passive hip extension + abduction + external rotation:

Stretch test: with the client supine, extend, abduct, and externally rotate the hip. Tightness or reproduction of groin pain implicates pectineus (the stretch opposes all three of its actions simultaneously).

Muscle Groups

Hip adductors (functional):

Hip flexors (functional):

Femoral nerve group (innervation):

Related Muscles

Synergists for hip adduction:

anatomy/muscles/adductor-longus — lies medial to pectineus; the most prominent adductor
anatomy/muscles/adductor-magnus — largest and most powerful adductor
anatomy/muscles/gracilis — the only adductor crossing the knee

Synergists for hip flexion:

anatomy/muscles/iliopsoas — primary hip flexor; lies lateral to pectineus in the femoral triangle
anatomy/muscles/rectus-femoris — two-joint hip flexor

Antagonists (hip abduction and extension):

anatomy/muscles/gluteus-medius — primary abductor
anatomy/muscles/gluteus-maximus — primary extensor

Key Takeaways

The "forgotten muscle" in groin pain — lies in the femoral triangle floor between iliopsoas and adductor longus, and is frequently overlooked.
Always check for the femoral pulse before sustained pressure — the femoral artery passes directly over pectineus.
Combines adduction, flexion, and internal rotation — groin pain worsened by all three actions points to pectineus.