Saturday, December 30, 2006 

Lower back|hip|and groin pain: The role of adductor magnus

In treating lower back pain, hip pain and groin pain, all muscles that cross the hip and groin region have to be considered.  The muscles that are most responsible for the hip pain and groin pain are the large muscles that are subjected to lengthening contractions and those which cross multiple joints.  Adductor magnus muscle is a large muscle subjected to constant lengthening contractions and although it does not cross multiple joints, it helps the function of the gluteus maximus and tensor fascia lata and thus comes one of the most important muscles to be treated for hip pain and groin pain.

The name "magnus" in adductor magnus signifies that this a large muscle like the gluteus maximus.  This is thus the other huge muscle supplied by the spinal nerve roots from the lower back.  The adductor magnus has nerve root fibers from L2 to S3 nerve roots. It is supplied by two peripheral nerves, the obturator nerve and the sciatic nerve.  The obturator portion supplies the L2-L4 nerve roots and the sciatic portion supplies the L4-S3 nerve roots to the muscle. 

Adductor magnus muscle arises from the ischial tuberosity and the adjacent parts of the ischial and pubic bones.   The ischial tuberosity bone is underneath the gluteus maximus and is the bone of the pelvis upon which you sit. The muscle inserts into the inner aspect of the thigh bone stretching from the hip to just above the knee. 

There are 2 parts to this muscle.  The upper part’s function is to bring the thigh toward the midline (adduction).  It also assist in bending the hip up (flexion) and to roll the thigh inward (internal rotation) and thus helps the tensor fascia lata in its capacity to perform hip flexion and internal rotation. The lower part together with the gluteus maximus brings the thigh backward (extension) and rolls it outward (external rotation). 

Since the lower spinal nerve roots, especially the L5 and S1 roots are commonly injured or irritated from presence of degenerative arthritis of the spine, slipped disc, bulging disc etc., the lower part of adductor magnus is commonly weaker than the upper part. Those of us who have sedentary life-styles sitting and working all day long, creates a condition for shortening and tightening of the upper fibers of the adductor magnus which assist in flexion and adduction.  Simultaneously, the sitting position causes a lengthening contraction of the lower part of this muscle causing overstretching and weakening these fibers. 

Due to the tight and shortened muscles that bend the thigh upward (hip flexors) from habitual sitting, all the muscles that bring the thigh backward (hip extensors) such as gluteus maximus, adductor magnus and hamstring muscles become prone to injury.  Any motion that involves a sudden forceful contraction of these muscles, such as in a fall or a car accident will cause significant injury since these muscles as well as the nerve roots supplying these muscles are vulnerable to trauma. 

In all cases of nerve related muscular groin pain, there is excessive contraction of the hip flexor muscles in the presence of weakness of the hip extensor muscles.  Treatment of groin pain must first start with relaxing the spasm within the spine extensors and hip extensors by using massage or electrical stimulation.  The treatment of choice is motor point stimulation using eToims Twitch Relief Method. 

Reduction of spasm within the spine and hip extensor muscles will allow return of effective length for these muscles to contract efficiently.   As the spine and hip extensor muscles become stronger, the hip flexor muscles are no longer contracting unopposed and the hip pain and groin pain treatment can then be directed to the hip flexor muscles such as tensor fascia lata, rectus femoris, and the upper part of the adductor magnus muscles.   

Please also refer to the blog posted on 12/13/06 concerning the see-saw principle of muscle action.

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Tags: lower body topics
Categories: Lower Body Topics