ANATOMY AND BIOMECHANICS REMEMBER

The majority of muscles with pelvic attachments are to secondary epiphysial centres: the adductors to the pubic tubercle, the abdominals to the iliac crest, hamstrings to the ischial tuberosity and iliopsoas to the lesser trochanter. This is clinically relevant in a young athlete, for example a footballer. A sliding tackle or a kick, may apply a sudden lengthening force, which may be enough to avulse both the epiphysis and attached tendon (6).

where possible palpate to assist in the differential diagnosis. These muscles are listed in box 1.

Bursa

Bursae are small fluid filled sacs which may be found between and around tendons. The function of a bursa is to reduce friction and distribute stress (15). There are thought to be around 13 bursae surrounding the hip. Iliopsoas is the largest in humans and is the most common to become inflamed and cause groin pain (16).

Fascia The interior and exterior surfaces of the groin are lined with regional sheets of fascia. Many of these sheets are interconnect- ed with the lumbar spine above or with the lower limbs below (6). Fascia consists of sheets of dense connective tissue that forms sheaths for individual muscles and partitions between muscles and has the potential to link together and influence the activities of different regions of the body. Fascia lining the pelvis is continu- ous with the perineal fascia below, obturator fascia laterally and behind with iliac fascia. This pelvic fascia extends into the leg and is pierced by the ventral rami of the lumbar and sacral nerves (6).

Muscles of the lower limb such as piriformis and obturator inter- nus must split the internal lining of fascia to attach to bone and adductors must split exterior fascia at the pubic rami (6).

Superficial fascia lies just beneath the skin and deep fascia over- lies the muscles. Fascia is flexible if kept moving but if it is allowed to become immobile or if it becomes thickened or scarred it eventually restricts our movement like gloves that fit so tight- ly that you cannot bend your fingers (17).

Nerves There are several nerves (Figure 4) to be considered in an athlete with chronic groin pain and these are listed below: ■ obturator nerve ■ femoral nerve ■ lateral femoral cutaneous nerve ■ ilioinguinal nerve ■ genitofemoral nerve

This section will focus on the anatomy of the obturator nerve as this nerve is implicated in recurrent adductor strains.

ANATOMY OF THE OBTURATOR NERVE The obturator nerve is formed from the roots of L2 within the psoas muscle (18). It emerges from the medial border of the psoas muscle and enters the pelvis anterior to the sacroiliac joint. The obturator nerve runs over the pelvic brim, descends anteriorly and

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The course of the obturator nerve places it at risk from compres- sion at several sites in the pelvis and obturator canal. The obtu- rator nerve may occasionally be traumatised by complications of gynaecological and orthopaedic surgery.

In females the nerve is only separated from the ovaries by a layer of peritoneum (18). Nerve entrapment and compression have been reported by pelvic fractures, pelvic haematomas and intra-pelvic tumours (18). A neuropathy of the obturator nerve will cause pain in the region of the adductor muscles and weakness of the adduc- tor muscles.

Note: All references can be found at the end of Part 3 on p20.

“Return to Fitness 2005” A One-Day Sports Medicine Symposium

Sunday 20 Nov 2005 Thistle Hotel, Glasgow

PRESENTATION TOPICS TO INCLUDE:

■ Anterior Knee Pain ■ Lower Limb Pain in Runners ■ Chronic Ankle Problems ■ Proprioception and its Rehabilitation ■ Adolescent Injuries ■ Hip Problem and their Rehabilitation

SPEAKERS TO INCLUDE: ■ Certified Athletic Trainers (USA) ■ Principal & Senior Lecturers (UK & USA) ■ Clinical Physical Therapists (UK & USA)

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inferiorly and passes through a fibro-osseous tunnel. The roof of the tunnel is formed by the obturator sulcus of the pubic bone and the floor is formed by the internal and external obturator muscles and their fascias (18).

The nerve divides within this tunnel into two main branches and passes through the obturator foramen to enter the thigh. The anterior branch of the obturator nerve supplies adductor brevis, adductor longus, gracilis and obturator internus.

The sensory division of the anterior branch supplies the articular capsule of the knee joint, the cruciate ligaments and the synovial membrane of the knee (29). The posterior branch supplies pectineus, external obturator and adductor magnus (18).