Adductor Minimus
| Adductor Minimus | |
|---|---|
| Muscle Type | |
| Origin | Ischiopubic ramus (inferior pubic ramus to ischial ramus) |
| Insertion | Linea aspera (proximal medial lip) and adductor tubercle (via shared tendon) |
| Action | Adducts thigh; assists lateral rotation and extension of thigh |
| Synergists | |
| Antagonists | Gluteus Medius, Gluteus Minimus |
| Spinal innervation | |
| Peripheral Innervation | Obturator nerve (L2–L4) and tibial division of sciatic nerve (L4–L5) – same innervation as adductor magnus |
| Vasculature | Medial femoral circumflex artery; first perforating branch of profunda femoris |
The adductor minimus is often considered the uppermost division of the adductor magnus. It is a small, triangular muscle slip located between the adductor brevis and the adductor magnus. Not always distinct, it functions to adduct and slightly laterally rotate the thigh, and is separated from the rest of adductor magnus by the first perforating branch of the deep femoral artery. Clinically, it’s usually described as part of adductor magnus, but some anatomists give it separate status.
Structure
Adductor minimus is essentially the superior part of adductor magnus, sometimes described as a separate small flat muscle. It lies in the medial compartment at the junction of the anterior and posterior components of adductor magnus.
Origin
It originates from the ischiopubic ramus (the inferior pubic ramus and adjoining part of the ischial ramus) – effectively the same area as the adductor part of adductor magnus.
Insertion
Its fibers insert on the upper part of the linea aspera (just distal to the insertion of adductor brevis) and also into the adductor tubercle via the adductor magnus tendon. Thus, it spans the gap between the main linea aspera attachment of magnus and the magnus’s hamstring part tendon, forming the adductor minimus at the superior edge of the adductor hiatus.
Action
The adductor minimus adducts the thigh. Because of its upper position, it can also contribute slightly to lateral rotation of the femur and assist in extension (as it blends with the extensor portion of magnus). Essentially, it acts as the uppermost part of adductor magnus: bringing the thigh toward the midline and stabilizing the femur.
Synergists
It works with the adductor magnus (rest of the muscle) and adductor brevis/longus to adduct the hip. Its slight lateral rotation action aligns with the posterior fibers of adductor magnus and the lateral rotators.
Antagonists
The hip abductors (gluteus medius/minimus, TFL) antagonize its adduction. Internal rotators would oppose its minor lateral rotation contribution.
Spinal Innervation
Receives innervation similar to adductor magnus: L2–L4 (obturator) and L4–L5 (tibial sciatic).
Peripheral Innervation
The obturator nerve (posterior division) and possibly the tibial division of the sciatic nerve (as part of magnus) innervate it. Usually it’s innervated by the branch of obturator nerve that goes to adductor magnus.
Vasculature
Blood comes from the medial circumflex femoral artery and the first perforating artery of the profunda femoris (which marks its inferior border).
Clinical Relevance
Often, the adductor minimus is not separately considered in clinical settings. Injuries or strains to it would be encompassed in adductor magnus injuries. It’s rarely an isolated focus.
In surgery, the separation between adductor minimus and magnus is where the first perforating artery emerges. Surgeons note that the top of the adductor hiatus region may contain this small muscle slip. Ensuring perforating vessels are protected/cauterized around this area is important.
Anatomically, variations exist: some have a distinct adductor minimus muscle belly, others just a superior division of magnus.
The presence of an adductor minimus could theoretically contribute to a tight groin or reduced abduction if very developed, but functionally, it’s part of magnus – so tightness is addressed by stretching the adductor group as a whole.
In cadaveric contexts, identifying adductor minimus helps to orient between the two parts of adductor magnus. For example, if performing a medial approach to the femur, one might reflect adductor longus and brevis to see the minimus leading into magnus.
