Adductor Muscles of the Upper Leg (Thigh)
The adductor muscle group of the thigh consists of seven distinct muscles: adductor brevis, adductor longus, adductor magnus, adductor minimus, pectineus, gracilis, and obturator externus 1.
Anatomical Composition
These muscles form the medial compartment of the thigh and are primarily responsible for adduction (bringing the leg toward the midline). The evidence from recent anatomical studies provides detailed characterization:
Individual Muscle Components
- Adductor longus: Consistently innervated by the anterior branch of the obturator nerve in 100% of cases 2
- Adductor brevis: Supplied by both anterior and posterior branches of the obturator nerve in 90% of cases 2
- Adductor magnus: The largest muscle of the medial thigh compartment, innervated by the posterior branch of the obturator nerve in 100% of cases 2. Recent anatomical work reveals it can be subdivided into four distinct components: adductor minimus, superior adductor part, inferior adductor part, and hamstring part 3
- Adductor minimus: A distinct component often grouped with adductor magnus 1
- Gracilis: Innervated by the anterior branch of the obturator nerve in 100% of cases 2
- Pectineus: Part of the adductor group with variable innervation patterns 2
- Obturator externus: Shows variable innervation—posterior branch in 60%, direct branch from main trunk in 10%, and no obturator nerve innervation in 30% of cases 2
Functional Significance
The adductor muscle group is particularly important for activities requiring leg stabilization and gripping motions, such as horseback riding, where riders must keep their legs pressed to the horse's side to maintain their mount 1. These muscles also play a role in external rotation of the femur at the hip during gait, particularly during terminal stance and preswing phases 4.
Clinical Relevance
The adductor muscles attach to the pubis through complex aponeurotic connections. The external oblique aponeurosis extends to the adductor longus aponeurosis, while the gracilis aponeurosis merges with the adductor brevis aponeurosis 5. These anatomical relationships are critical for understanding athletic groin pain patterns and surgical approaches in this region 6, 5.