Flounder muscle

Soleus muscle - m. soleus

It is the main flexor of the foot and also helps in supination of the foot.

Origin: head and back surface of Fibula, Tibia, Arcus tendineus m. solei

Attachment: Tuber calcanei

Innervation: spinal nerves L4-S2 - sacral plexus - n. tibialis

Palpation:

• The trigger zone is localized 2-3 cm distal to the end of the muscle belly of the gastrocnemius muscle and slightly medial to the midline.
• The trigger zone is formed on the lateral surface of the calf more proximally than in p.(a) (a rarer variant).
• The trigger zone is located slightly more proximal and lateral than in p.(a) (an even rarer variant)

The trigger points of the soleus muscle can be located by planar palpation, and the distal trigger points also by pincer palpation. The patient is either kneeling on a chair or lying on his side. The knee should be flexed so that the soleus muscle relaxes. In the first and third cases, the trigger points can be examined with the patient lying on his side with his back to the examiner; the affected leg lies on the table. The pain from these trigger points is localized deep under the aponeurosis of the Achilles tendon. The areas of compaction are palpated by pincer palpation: the muscle is held between the thumb and fingers and then rolled between them. These areas of compaction can easily be missed by inept palpation. The examiner should insert the fingers distal to the gastrocnemius muscle and posterior to the underlying tibia and fibula, elevate the muscle, and examine its posterior surface by rolling the muscle fibers under the fingers, with the thumb held in place. Alternatively, palpation is performed with the thumb and the fingers held in place. The medial and lateral aspects of the muscle may require separate examination.

In the second case, trigger zones usually exist together with more distal trigger zones of the soleus muscle. It is important to examine the area of localization of trigger zones by planar palpation against the underlying bone, while the knee should be flexed at 90° so that the soleus muscle is relaxed. This reduces the likelihood that trigger zones of the more superficial gastrocnemius muscle will be mistaken for trigger zones in the soleus muscle. Only trigger zones of the gastrocnemius muscle increase its sensitivity to palpation when the angle of knee flexion changes towards extension. When examining in a kneeling position with slight extension of the foot, the examiner can obtain additional stretching of the soleus muscle, which increases the sensitivity of its trigger zones.

Referred pain: trigger zones cause pain:

• along the back surface and plantar part of the heel, as well as in the distal part of the Achilles tendon;
• diffuse pain in the upper half of the calf;
• deep pain in the ipsilateral sacroiliac joint in an area with a diameter of about 2.5 cm, less often - less intense pain at the site of its localization and above the back and plantar surface of the heel.