Achilles Tendon Essay

The hamstrings contract eccentrically acting as the synergist and help the flexion of the hip to occur. The Rectus femoris of the quadriceps contract eccentrically to help flex the hip, they are co-contracting with the hamstrings. The hip flexors may contract rapidly to stabalise the body on the way down if there is a loss of balance (Wynsberghe et al., 1995). The adductor longus, adductor brevis and adductor Magnus contract isometrically to prevent adduction and abduction. The Sartorius muscle contracts eccentrically to cause flexion and abduction at the knee. The sartoris originates from the anterior superior iliac spine and inserts onto the tibia. The adductor and abductor muscles at the hip joint contract to prevent movement that may cause injury (Tortora and Derrickson, 2009).

As explained by Opar (3) the hamstring consists of three muscles, biceps femoris (BF), semitendinosus (ST) semimembranosus (SM), this composes a muscle group crossing the hip and knee joint that acts synergistically in extending the hip and flexing the knee.

Descriptive terms are used to name skeletal muscles. Some names give the location in the body. The temporalis muscle is attached to the temporal bone in the skull. The brachialis muscle is attached to the humerus bone, but brachial refers to the main artery in the arm. Some muscles are named for their origins and insertions, like the genioglossus muscle, for example, originates at the chin (geneion) and inserts in the tongue (glossus). Some muscles are named for the arrangement of the fascicle groups. For example the rectus abdominus is the straight muscle that is in the adbominus.

These muscles begin at the ischial tuberosity, which is at the bottom of the pelvis. The muscles meet at the knee joint and end at the lower leg, where they are joined together through connective tissue that attach the tendons to the bones like double-sided tape. The hamstring muscle groups work to help extend the leg back and provide motion at the knee. Due to the crossing

The vastus lateralis muscle is situated in side of the thigh.This Muscle is the biggest of the quadriceps group which also includes the rectus femoris, the vastus intermedius, and the

The biceps femoris is one of the three muscles including the semitendinosus, and the semimembranosus, that make up the group of muscles called the hamstrings. The hamstrings are located on the posterior side of the leg. The biceps femoris originates on the ischial tuberosity and inserts on the head of the fibula. The movement of the biceps femoris is responsible for the flexion of the knee and the external rotation of the lower leg. Flexion of the knee happens when the back of the foot is raised toward the back of the leg.

Two other muscles have origin above the knee. The gastrocnemius muscle is a rather large muscle that has two heads of origin above the knee. The medial head originates just above the posterior medial condyle of the femur. The lateral head has its origin on the posterior lateral surface of the lateral condyle of the femur. These two heads come together to form a large muscle that

Supraspinatus tendonitis typically occurs when there is an impingement of the supraspinatus muscle of the shoulder joint between the acromion as it passes by the acromion and humerus head. In response, the supraspinatus tendon and the contiguous peritendinous soft tissues become inflamed. The supraspinatus is a muscle located in the supraspinatus fossa of the scapula located in the shoulder and is largely affected by supraspinatus tendonitis. The supraspinatus allows for the abduction of the shoulder and its insertion is the greater tuberosity of the humerus. Tendonitis is the inflammation of a tendon and commonly occurs in the elbows, knees, and shoulders. Therefore, supraspinatus tendonitis is the inflammation of the supraspinatus. This condition is a very common inflammatory problem because it can be caused by the abduction of the arm, which is involved in many sports and activities.

The quadriceps are comprised of four muscles: vastus lateralis, vastus medialis, vastus intermedialis, and rectus femoris. These muscles attach proximally at differing locations along the shaft of the femur and on the hip bone (rectus femoris only). They span the length of the femur and converge on the quadriceps tendon on the superior aspect of the patella and continue to the tibial tuberosity via the patellar tendon. The quadriceps are responsible for extending the knee, assisting in proper tracking of the patella, and preventing posterior translation of the tibia on the femur (Moore

Then the hip eccentrically extends by the gluteus maximus and hamstrings. The muscles in the left leg are able to relax as momentum is transferred to slow down the kicking leg and bring the planted leg off the ground. The right knee is carried through extension by momentum and gradually slowed through eccentric contraction of the hamstrings. In the left knee the quadriceps and hamstrings relax to help provide energy for the kicking leg. The right ankle remain plantar flexed by momentum, but gradually relax through eccentric contraction of the gastrocnemius and soleus. The left ankle plantar flex from concentric contraction of the gastrocnemius and

The quads include the rectus femoris, and the vastus lateralis, intermedius, and medialis. This muscle group shares a common tendon at insertion. The patellar tendon inserts at the tibial tuberosity, and within this tendon lies the patella. The patella is anterior to the femur-tibia articulation, and this sesmoid bone increases the leverage of the quads by acting as a pulley. The major contributor to the stability of the knee joint is the strength of the quads. The only muscle that assists in extension is the tensor fascia lata.

The plantaris muscle is a vestigial structure, absent in 7-20% of population. Gastrocnemius and soleus muscles are commonly involved in trauma to the calf. Partial or complete tears at the myotendinous junction of the plantaris muscle can have a similar clinical presentation. Initially termed as the tennis leg, injury to the plantaris muscle was usually associated with torn anterior cruciate ligament or partial tears of the gastrocnemius or popliteus muscle.

For example, to extend the knee, a group of four muscles called the quadriceps femoris in the anterior compartment of the thigh are activated (and would be called the agonists of knee extension). However, to flex the knee joint, an opposite or antagonistic set of muscles called the hamstrings is activated.

The Achilles tendon is the largest tendon in the body, but also happens to be the most frequently torn tendon (Reiman et al., 2014). It originates from the soleus muscle extending over to the two heads of the gastrocnemius and is inserted into the calcaneus. (Benjamin, Suzuki, & Toumi,2009, p.5). Occasionally it has been noted that in 2.9 – 5.5% of people, there is a third head of the gastrocnemius. (Benjamin, Suzuki, & Toumi, 2009, p.7). It is also the strongest and thickest tendon in the body. As the tendon reaches the calcaneus, it allows for elongation (which is the amount of extension that the tendon is able to undergo when it’s under stress). Furthermore, the elongation allows for a release of energy during movement.

The plantaris is so small some people usually confuses it as a nerve. Many people do not have this muscle. The plantaris descends medially, condensing into a tendon that runs down the leg, between the gastrocnemius and soleus. Because it crosses at the knee it goes all the way to the ankle it allows one to point their toes downward. There are four muscles in the deep part of the posterior leg. One muscle, the popliteus, deal with the knee joint. The remaining three muscles (tibialis posterior, flexor hallucis longus and flexor digitorum longus) deals with the ankle and foot.