The biceps femoris is a fusiform muscle comprising two heads: lengthy and brief. The lengthy head originates from the Ischial tuberosity and is innervated by the Tibial department of the sciatic nerve. The fast head originates from the lateral aspect of the Linea Aspera of the femur and is innervated by means of the Peroneal Department of the sciatic nerve. Distally, the two heads of the biceps lie simply posterior to the ITB. Both heads of the biceps have complex attachments to the posterolateral aspect of the knee. Those wonderful attachments are described. In cadaveric dissections and at surgery, many of the attachments blend together distally and are tough to discover as separate structures. The Peroneal nerve lies simply distal and posterior to the biceps, curving across the fibular neck. The biceps flexes the knee and also externally rotates the leg while the knee is flexed.
Biceps Femoris Anatomy
There are various descriptions of the anatomy of the biceps and the quantity of attachment. The alternative facial additives are the contemplated arm and the anterior Aponeurotic expansion.
The maximum proximal aspect is the meditated arm. It originates just proximal to the fibular head and ascends anteriorly to insert on the posterior fringe of the ITB. The direct arm inserts onto the posterolateral fringe of the fibula simply distal to the end of the Styloid. The anterior arm has a greater complex attachment and some crucial anatomic factors. A part of the anterior arm inserts onto the lateral element of the fibular head, and the rest maintains distally simply lateral to the FCL. Simply proximal and at this fibular insertion, portions of the anterior arm ascend anteriorly, forming the lateral Aponeurotic boom that attaches to the posterior and lateral aspect of the FCL. Here, a small bursa separates the anterior arm from the distal fourth of the FCL. The anterior arm consequently bureaucracy the lateral wall of this bursa. This is an essential surgical landmark because of the reality a small horizontal incision may be made right here, 1 cm proximal to the fibular head, to go into this bursa and find out the insertion of the FCL into the fibular. The anterior arm then maintains distally over the maximum essential attachments are the direct arm, the anterior arm, and the capsular arm.
The capsular arm originates just before the fast head accomplishing the fibula. It then continues deep to the FCL to insert onto the posterolateral knee capsule and Fabella. Right here, the fibers of the capsular arm maintain distally as the Fabello-Fibular ligament.45 just distal to the capsular arm, Capsulo-osseous layer paperwork a Fascial confluence with the ITB (the biceps-Capsulo-osseous-Iliotibial tract Confluence). The direct arm of the fast head inserts onto the fibular head simply posterior and proximal to the direct arm of the lengthy head tendon. The anterior arm blends with the anterior Tibio-Fibular ligament and keeps medial or deep to the FCL. Afterwards, it inserts onto the tibia 1 cm posterior to Gerdy’s tubercle. This internet site is likewise the attachment of the mid-1/three lateral knee capsule. Forty-five it’s miles vital clinically because of the fact an avulsion fracture may be seen right here in ACL injuries, known as a Segond fracture.
Biceps Femoris Muscle
The quick head of the biceps femoris muscle joins the stomach of the long head of the biceps femoris muscle on its deep surface because it descends within the thigh. After the two heads unite, the biceps femoris muscle narrows to a tendon step by step. It then attaches to the pinnacle of the fibula. It further links to the fibular collateral ligament, and the lateral Tibial condyle. The long head of the biceps femoris muscle is innervated through the Tibial element and the short head through the way of way of the not unusual fibular (Peroneal) part of the sciatic nerve.
The ones muscle businesses produce flexion at the knee and extension on the hip once they settle. While the thigh is flexed, the hamstring muscles tissues (especially the biceps femoris) assist tilt the pelvis backward. Tight hamstrings sometimes are associated with low back pain.
Lengthy head: Tuberosity of the ischium.
Brief head: Linea Aspera at the posterior femur.
Insertion: The pinnacle of the fibula that articulates with the lateral Tibial condyle.
- Flexes knee joint.
- Laterally rotates knee joint (whilst the knee is flexed).
- Extends hip joint (lengthy head simplest).
- External rotation of the thigh (long head only).