Yudu - sportEX medicine - 1999-2010

ADDUCTOR INJURY

Iliolumbar ligament

Iliolumbar ligament - lumbosacral band

Figure 1: Main nerves, veins and arteries of the groin

One observer aptly expressed the anatomy of the groin as ‘enig- matic and confusing" (9) (Figure 1).

It is not possible to fully review every tissue and structure in this region but the anatomy relevant to adductor muscle injury is reviewed.

Joints Structurally the pelvis consists of two bony arches connecting posteriorly at the sacroiliac joint and anteriorly at the pubic sym- physis. The pubic symphysis acts as a tie beam preventing lateral separation and vertical displacement of the hemipelvises.

The anterior ligament is a weak band across the front of the body of the pubis and is reinforced by the fibres of rectus abdominus, transversus abdominus, internal obliques and the adductor longus muscle. Small amounts of movement at the sacroiliac joints are amplified by the bony lever arms of the pubic rami resulting in increased movement in the vertical plane at the pubic symphysis. The bones of the symphysis have a relatively poor blood supply from a periosteal plexus (10) but are richly innervated.

The lumbar spine must be considered as a source of groin pain. Lumbar spine disorders may cause pain which radiates into the groin and down the leg. Pain from the spine may arise from con- ditions such as a prolapsed disc, spinal stenosis, facet joint changes, spondylolisthesis and many more (16). The sacroiliac joints (SIJ) and the hip joints must also be examined in a patient presenting with groin symptoms as both of these joints may be a source of the patient’s groin pain.

Ligaments The iliolumbar ligament can refer pain into the groin and adduc- tor region (11). The iliolumbar ligament extends from the trans- verse process of the fifth lumbar vertebrae to the posterior part of the iliac crest (Figure 2). It links together the sacrum and fifth lumbar vertebrae preventing L5 moving forward in respect to S1 (6). This ligament is thought to be a frequent source of groin pain

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Figure 2: Anatomy of the pelvis

(11) and is worth considering in sports which involve rotation of the spine such as racket sports and golf.

Adductor muscles There are five muscles which are collectively known as the adduc- tors of the hip (Figure 3): ■ adductor magnus ■ adductor longus ■ adductor brevis ■ gracilis ■ pectineus

These muscles must be considered as a site of pathology in groin injury. The adductors are located on the medial side of the thigh arising from the pubic bone and inserting into the femur and are supplied by the obturator and femoral nerve (10). The adductor muscles are antagonists of the hip abductors – gluteus medius and minimus and tensor fascia lata.

Adductor magnus Adductor magnus is the largest and most powerful adductor mus- cle with an extensive origin from the pubic rami as well as an ori- gin from the ischial tuberosity and has a peculiar arrangement of muscle fibres. The most medial fibres arise from the ramus of the pubis and insert most proximally on the femur. The lateral fibres arise from the triangular roughened area on the ischial tuberosity and the ramus of the ischium and insert most distally on the linea aspera. A third set of fibres, the inferior fibres lie between the medial and lateral groups of fibres and have a distinct muscle belly – often called the third adductor (13). The muscle is sup- plied by the obturator nerve except the posterior part which is supplied by the sciatic nerve (32).

Adductor longus Adductor longus is the most anterior of the adductor muscles. Adductor longus has a small, flat, narrow, tendinous origin from the anterior aspect of the pubic bone (10). Originating on the pubis it blends with adductor magnus to insert into the linea aspera (14).